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Sample records for polyvalent element-containing glasses

  1. Polyvalent immunogen

    DOEpatents

    Haynes, Barton F.; Korber, Bette T.; De Lorimier, Robert M.; Liao, Hua-Xin

    2007-02-06

    The present invention relates, generally, to a polyvalent immunogen and, more particularly, to a method of inducing neutralizing antibodies against HIV and to a polyvalent immunogen suitable for use in such a method.

  2. Polyvalent immunogen

    DOEpatents

    Haynes, Barton F.; Korber, Bette T.; De Lorimier, Robert M.

    2007-03-27

    The present invention relates, generally, to a polyvalent immunogen and, more particularly, to a method of inducing neutralizing antibodies against HIV and to a polyvalent immunogen suitable for use in such a method.

  3. Recent Advances in Engineering Polyvalent Biological Interactions

    PubMed Central

    2015-01-01

    Polyvalent interactions, where multiple ligands and receptors interact simultaneously, are ubiquitous in nature. Synthetic polyvalent molecules, therefore, have the ability to affect biological processes ranging from protein–ligand binding to cellular signaling. In this review, we discuss recent advances in polyvalent scaffold design and applications. First, we will describe recent developments in the engineering of polyvalent scaffolds based on biomolecules and novel materials. Then, we will illustrate how polyvalent molecules are finding applications as toxin and pathogen inhibitors, targeting molecules, immune response modulators, and cellular effectors. PMID:25426695

  4. Polyvalent carbocyanine molecular beacons for molecular recognitions.

    PubMed

    Ye, Yunpeng; Bloch, Sharon; Achilefu, Samuel

    2004-06-30

    Polyvalent carboxylate-terminating near-infrared (NIR) carbocyanine molecular beacons were prepared by homologation of reactive carboxyl groups of the beacon with imino diacetic acid. Their conjugation with unprotected d-(+)-glucosamine gave dendritic arrays of the carbohydrate on an inner NIR chromophore core. In vivo evaluation of the dendritic glucosamine constructs shows enhanced uptake in proliferating tumor cells relative to surrounding normal tissue. The structural framework of these polyvalent beacons permits the amplification by synergistic effects of a variety of bioactive motifs or chemical sensors in molecular recognition interactions without dramatic change of their desirable NIR spectral properties.

  5. Polyvalent Catalysts Operating on Polyvalent Substrates: A Model for Surface-Controlled Reactivity.

    PubMed

    McKay, Craig S; Finn, M G

    2016-10-01

    Unusually fast rates of nucleophilic catalysis of hydrazone ligation were observed when polyvalent anthranilic acid catalysts operating on polyvalent aldehyde substrates were used with PAMAM dendrimers as the common platform. When presented in this way, the catalyst has a strong accelerating effect at concentrations 40-400 times lower than those required for similar monovalent catalysts and displays unique kinetic parameters. We attribute these properties to polyvalent engagement between the dendrimer surface groups, and a potential "rolling" effect leading to fast interparticle kinetic turnover. The phenomenon is sensitive to the density of functional groups on each dendrimer, and insensitive to factors that promote or inhibit nonspecific particle aggregation. These findings constitute a rare experimental example of an underappreciated phenomenon in biological and chemical systems that are organized on interacting surfaces.

  6. Squalamine: a polyvalent drug of the future?

    PubMed

    Brunel, Jean Michel; Salmi, Chanaz; Loncle, Celine; Vidal, Nicolas; Letourneux, Yves

    2005-06-01

    The purpose of this mini-review is to summarize and highlight the different advances in our understanding of the antimicrobial and antiangiogenic activity of squalamine, a cationic steroid isolated in 1993 from the dogfish shark Squalus Acanthias. Indeed, squalamine has shown to be useful for the treatment of important diseases such as cancers (lung, ovarian, brain and others), age-related macular degeneration (AMD) and the control of body weight in man. All these results led to a question: could we consider squalamine as a polyvalent drug of the future? PMID:15975047

  7. Mixed polyvalent-monovalent metal coating for carbon-graphite fibers

    NASA Technical Reports Server (NTRS)

    Harper-Tervet, J.; Tervet, F. W.; Humphrey, M. F. (Inventor)

    1982-01-01

    An improved coating of gasification catalyst for carbon-graphite fibers is provided comprising a mixture of a polyvalent metal such as calcium and a monovalent metal such as lithium. The addition of lithium provides a lighter coating and a more flexible coating when applied to a coating of a carboxyl containing resin such as polyacrylic acid since it reduces the crosslink density. Furthermore, the presence of lithium provides a glass-like substance during combustion which holds the fiber together resulting in slow, even combustion with much reduced evolution of conductive fragments. The coated fibers are utilized as fiber reinforcement for composites.

  8. Rapid polyvalent screening for largescale environmental Spiroplasma surveys

    PubMed Central

    French, Frank E.; Whitcomb, Robert F.; Williamson, David L.; Regassa, Laura B.

    2009-01-01

    Surface serology is an important determinant in Spiroplasma systematics. Reciprocal antigen/antibody reactions between spiroplasmas and individual antisera delineate the 38 described groups and species. However, reciprocal serology is impractical for large-scale studies. This report describes a successful, streamlined polyvalent screening approach used to examine isolates from an environmental survey. PMID:24031412

  9. Design and Testing of Prototypic Elements Containing Monolithic Fuel

    SciTech Connect

    N.E. Woolstenhulme; M.K. Meyer; D.M. Wachs

    2011-10-01

    The US fuel development team has performed numerous irradiation tests on small to medium sized specimens containing low enriched uranium fuel designs. The team is now focused on qualification and demonstration of the uranium-molybdenum Base Monolithic Design and has entered the next generation of testing with the design and irradiation of prototypic elements which contain this fuel. The designs of fuel elements containing monolithic fuel, such as AFIP-7 (which is currently under irradiation) and RERTR-FE (which is currently under fabrication), are appropriate progressions relative to the technology life cycle. The culmination of this testing program will occur with the design, fabrication, and irradiation of demonstration products to include the base fuel demonstration and design demonstration experiments. Future plans show that design, fabrication, and testing activities will apply the rigor needed for a demonstration campaign.

  10. Isolation of Polyvalent Bacteriophages by Sequential Multiple-Host Approaches

    PubMed Central

    Yu, Pingfeng; Li, Mengyan; Dai, Zhaoyi; Alvarez, Pedro J. J.

    2015-01-01

    Many studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of the Podoviridae family and PEf1 of the Siphoviridae family) were characterized in terms of adsorption rate (3.54 × 10−10 to 8.53 × 10−10 ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putida F1 or Escherichia coli K-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed for Pseudomonas aeruginosa relative to uninfected controls. The corresponding lethality for Pseudomonas syringae was ∼50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications. PMID:26590277

  11. Isolation of Polyvalent Bacteriophages by Sequential Multiple-Host Approaches.

    PubMed

    Yu, Pingfeng; Mathieu, Jacques; Li, Mengyan; Dai, Zhaoyi; Alvarez, Pedro J J

    2015-11-20

    Many studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of the Podoviridae family and PEf1 of the Siphoviridae family) were characterized in terms of adsorption rate (3.54 × 10(-10) to 8.53 × 10(-10) ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putida F1 or Escherichia coli K-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed for Pseudomonas aeruginosa relative to uninfected controls. The corresponding lethality for Pseudomonas syringae was ∼ 50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications.

  12. Polyvalent Recognition of Biopolymers:The Design of Potent Inhibitors of Anthrax Toxin

    NASA Astrophysics Data System (ADS)

    Kane, Ravi

    2007-03-01

    Polyvalency -- the simultaneous binding of multiple ligands on one entity to multiple receptors on another -- is a phenomenon that is ubiquitous in nature. We are using a biomimetic approach, inspired by polyvalency, to design potent inhibitors of anthrax toxin. Since the major symptoms and death from anthrax are due primarily to the action of anthrax toxin, the toxin is a prime target for therapeutic intervention. We describe the design of potent polyvalent anthrax toxin inhibitors, and will discuss the role of pattern matching in polyvalent recognition. Pattern-matched polyvalent inhibitors can neutralize anthrax toxin in vivo, and may enable the successful treatment of anthrax during the later stages of the disease, when antibiotic treatment is ineffective.

  13. Measurement of monovalent and polyvalent carbohydrate-lectin binding by back-scattering interferometry.

    PubMed

    Kussrow, Amanda; Kaltgrad, Eiton; Wolfenden, Mark L; Cloninger, Mary J; Finn, M G; Bornhop, Darryl J

    2009-06-15

    Carbohydrate-protein binding is important to many areas of biochemistry. Here, backscattering interferometry (BSI) has been shown to be a convenient and sensitive method for obtaining quantitative information about the strengths and selectivities of such interactions. The surfaces of glass microfluidic channels were covalently modified with extravidin, to which biotinylated lectins were subsequently attached by incubation and washing. The binding of unmodified carbohydrates to the resulting avidin-immobilized lectins was monitored by BSI. Dose-response curves that were generated within several minutes and were highly reproducible in multiple wash/measure cycles provided adsorption coefficients that showed mannose to bind to concanavalin A (conA) with 3.7 times greater affinity than glucose consistent with literature values. Galactose was observed to bind selectively and with similar affinity to the lectin BS-1. The avidities of polyvalent sugar-coated virus particles for immobilized conA were much higher than monovalent glycans, with increases of 60-200 fold per glycan when arrayed on the exterior surface of cowpea mosaic virus or bacteriophage Qbeta. Sugar-functionalized PAMAM dendrimers showed size-dependent adsorption, which was consistent with the expected density of lectins on the surface. The sensitivity of BSI matches or exceeds that of surface plasmon resonance and quartz crystal microbalance techniques, and is sensitive to the number of binding events, rather than changes in mass. The operational simplicity and generality of BSI, along with the near-native conditions under which the target binding proteins are immobilized, make BSI an attractive method for the quantitative characterization of the binding functions of lectins and other proteins.

  14. Aptamer-based polyvalent ligands for regulated cell attachment on the hydrogel surface.

    PubMed

    Gaddes, Erin R; Gydush, Gregory; Li, Shihui; Chen, Niancao; Dong, Cheng; Wang, Yong

    2015-04-13

    Natural biomolecules are often used to functionalize materials to achieve desired cell-material interactions. However, their applications can be limited owing to denaturation during the material functionalization process. Therefore, efforts have been made to develop synthetic ligands with polyvalence as alternatives to natural affinity biomolecules for the synthesis of functional materials and the control of cell-material interactions. This work was aimed at investigating the capability of a hydrogel functionalized with a novel polyvalent aptamer in inducing cell attachment in dynamic flow and releasing the attached cells in physiological conditions through a hybridization reaction. The results show that the polyvalent aptamer could induce cell attachment on the hydrogel in dynamic flow. Moreover, cell attachment on the hydrogel surface was significantly influenced by the value of shear stress. The cell density on the hydrogel was increased from 40 cells/mm(2) to nearly 700 cells/mm(2) when the shear stress was decreased from 0.05 to 0.005 Pa. After the attachment onto the hydrogel surface, approximately 95% of the cells could be triggered to detach within 20 min by using an oligonucleotide complementary sequence that displaced polyvalent aptamer strands from the hydrogel surface. While it was found that the cell activity was reduced, the live/dead staining results show that ≥98% of the detached cells were viable. Therefore, this work has suggested that the polyvalent aptamer is a promising synthetic ligand for the functionalization of materials for regulated cell attachment.

  15. Polyvalent Adult Education Centre (An Integrated Approach to Adult Education for Workers).

    ERIC Educational Resources Information Center

    Koshy, T. A.; And Others

    A project to upgrade the vocational skills of Indian workers is presented. This project is designed to plan and develop integrated educational and training courses of various duration for workers and prospective workers, through the establishment of Polyvalent Centers. These centers are institutions providing opportunity for many-sided education…

  16. Gold glyconanoparticles: synthetic polyvalent ligands mimicking glycocalyx-like surfaces as tools for glycobiological studies.

    PubMed

    Barrientos, Africa G; de la Fuente, Jesús M; Rojas, Teresa C; Fernández, Asunción; Penadés, Soledad

    2003-05-01

    A simple and versatile methodology is described for tailoring sugar-functionalised gold nanoclusters (glyconanoparticles) that have 3D polyvalent carbohydrate display and globular shapes. This methodology allows the preparation of glyconanoparticles with biologically significant oligosaccharides as well as with differing carbohydrate density. Fluorescent glyconanoparticles have been also prepared for labelling cells in biological tests. The materials are water soluble, stable under physiological conditions and present an exceptional small core size. All of them have been characterised by (1)H NMR, UV and IR spectroscopy, TEM and elemental analysis. Their highly polyvalent network can mimic glycosphingolipid clustering and interactions at the plasma membrane, providing an controlled system for glycobiological studies. Furthermore, they are useful building blocks for the design of nanomaterials. PMID:12740837

  17. Stability diagrams for fourfold coordination of polyvalent metal ions in molten mixtures of halide salts

    SciTech Connect

    Akdeniz, Z. Istanbul Univ. . Dept. of Physics); Tosi, M.P. . Dipt. di Fisica Teorica Argonne National Lab., IL )

    1988-11-01

    The stability of local fourfold coordination for divalent and trivalent metal ions in liquid mixtures of polyvalent metal halides and alkali halides is classified by means of structural coordinates obtained from properties of the elements. In parallel with earlier classifications of compound crystal structures and molecular shapes, the elemental properties are taken from first-principles calculations of valence electron orbitals in atoms, in the form of (i) the nodal radii of Andreoni, Baldereschi and Guizzetti or (ii) the pseudopotential radii or Zunger and Cohen. As a third alternative a classification based on Pettifor's phenomenological chemical scale of the elements is also considered. The alternative structural classification schemes that are developed from these elemental properties are generally successfully in distinguishing molten mixtures in which the available experimental evidence indicates long-lived fourfold coordination of polyvalent metal ions. In addition, Pettifor's chemical scale scheme is useful in sorting out finer details of local coordination in the liquid state. 3 figs., 71 refs.

  18. Use of a current varicella vaccine as a live polyvalent vaccine vector.

    PubMed

    Murakami, Kouki; Mori, Yasuko

    2016-01-01

    Varicella-zoster virus (VZV) is the causative agent of varicella and zoster. The varicella vaccine was developed to control VZV infection in children. The currently available Oka vaccine strain is the only live varicella vaccine approved by the World Health Organization. We previously cloned the complete genome of the Oka vaccine strain into a bacterial artificial chromosome vector and then successfully reconstituted the virus. We then used this system to generate a recombinant Oka vaccine virus expressing mumps virus gene(s). The new recombinant vaccine may be an effective polyvalent live vaccine that provides protection against both varicella and mumps viruses. In this review, we discussed about possibility of polyvalent live vaccine(s) using varicella vaccine based on our recent studies.

  19. DNA Nanostructures as Models for Evaluating the Role of Enthalpy and Entropy in Polyvalent Binding

    SciTech Connect

    Nangreave, Jeanette; Yan, Hao; Liu, Yan

    2011-03-30

    DNA nanotechnology allows the design and construction of nanoscale objects that have finely tuned dimensions, orientation, and structure with remarkable ease and convenience. Synthetic DNA nanostructures can be precisely engineered to model a variety of molecules and systems, providing the opportunity to probe very subtle biophysical phenomena. In this study, several such synthetic DNA nanostructures were designed to serve as models to study the binding behavior of polyvalent molecules and gain insight into how small changes to the ligand/receptor scaffolds, intended to vary their conformational flexibility, will affect their association equilibrium. This approach has yielded a quantitative identification of the roles of enthalpy and entropy in the affinity of polyvalent DNA nanostructure interactions, which exhibit an intriguing compensating effect.

  20. Gold glyconanoparticles: synthetic polyvalent ligands mimicking glycocalyx-like surfaces as tools for glycobiological studies.

    PubMed

    Barrientos, Africa G; de la Fuente, Jesús M; Rojas, Teresa C; Fernández, Asunción; Penadés, Soledad

    2003-05-01

    A simple and versatile methodology is described for tailoring sugar-functionalised gold nanoclusters (glyconanoparticles) that have 3D polyvalent carbohydrate display and globular shapes. This methodology allows the preparation of glyconanoparticles with biologically significant oligosaccharides as well as with differing carbohydrate density. Fluorescent glyconanoparticles have been also prepared for labelling cells in biological tests. The materials are water soluble, stable under physiological conditions and present an exceptional small core size. All of them have been characterised by (1)H NMR, UV and IR spectroscopy, TEM and elemental analysis. Their highly polyvalent network can mimic glycosphingolipid clustering and interactions at the plasma membrane, providing an controlled system for glycobiological studies. Furthermore, they are useful building blocks for the design of nanomaterials.

  1. A polyvalent inactivated rhinovirus vaccine is broadly immunogenic in rhesus macaques

    PubMed Central

    Lee, Sujin; Nguyen, Minh Trang; Currier, Michael G.; Jenkins, Joe B.; Strobert, Elizabeth A.; Kajon, Adriana E.; Madan-Lala, Ranjna; Bochkov, Yury A.; Gern, James E.; Roy, Krishnendu; Lu, Xiaoyan; Erdman, Dean D.; Spearman, Paul; Moore, Martin L.

    2016-01-01

    As the predominant aetiological agent of the common cold, human rhinovirus (HRV) is the leading cause of human infectious disease. Early studies showed that a monovalent formalin-inactivated HRV vaccine can be protective, and virus-neutralizing antibodies (nAb) correlated with protection. However, co-circulation of many HRV types discouraged further vaccine efforts. Here, we test the hypothesis that increasing virus input titres in polyvalent inactivated HRV vaccine may result in broad nAb responses. We show that serum nAb against many rhinovirus types can be induced by polyvalent, inactivated HRVs plus alhydrogel (alum) adjuvant. Using formulations up to 25-valent in mice and 50-valent in rhesus macaques, HRV vaccine immunogenicity was related to sufficient quantity of input antigens, and valency was not a major factor for potency or breadth of the response. Thus, we have generated a vaccine capable of inducing nAb responses to numerous and diverse HRV types. PMID:27653379

  2. Concrete shielding housing for receiving and storing a nuclear fuel element container

    SciTech Connect

    Dyck, H.-P.

    1985-07-02

    The invention is directed to a concrete shielding housing for receiving and storing a fuel element container filled with spent nuclear reactor fuel elements. The container is suitable for transport and storage. The clear interior dimensions of the concrete shielding housing are somewhat larger than the outer dimensions of the fuel element container. The concrete shielding housing includes a pallet-type base and in the lower region of the housing there is provided at least one air inlet opening and in the upper region of the housing there is provided at least one air outlet opening. To prevent an uncontrolled conduction of moisture away from the interior of the housing to the ground or to the floor of a storage area or building, there is provided a collection pan arranged under the base plate of the pallet-like base. At least one axial bore extends clear through the base plate of the pallet-like base. With the arrangement of the collection pan, contaminated moisture is collected and prevented from seeping into the ground or floor.

  3. Snakebite by the Shore Pit Viper (Trimeresurus purpureomaculatus) Treated With Polyvalent Antivenom.

    PubMed

    Mong, Rupeng; Tan, Hock Heng

    2016-06-01

    Although snakebites are uncommon, there are several species of medically important venomous snakes native to Singapore. We present a case of envenoming by the shore pit viper (Trimeresurus purpureomaculatus) that showed clinical improvement when treated with the Indian (Haffkine) polyvalent antivenom. A 40-year-old man was bitten on his right hand by a snake, which was identified through photos and his description to be a shore pit viper, which is native to the local mangrove area. Severe swelling and pain developed immediately after the bite, which progressed up the arm. Because of the progression of local swelling, antivenom was started. He was given a total of 6 vials (60 mL) of polyvalent antivenom, with the first vial started 3 hours after the bite. He showed clinical improvement within 24 hours. His subsequent recovery was uneventful, with no other complications as a result of envenomation or antivenom use. Severe envenoming by the shore pit viper can lead to marked local effects such as extensive swelling and tissue necrosis. Antivenom is indicated in the presence of severe local envenomation. Antivenom against the shore pit viper is however not available locally. The Indian (Haffkine) polyvalent antivenom contains antibodies against 4 common venomous snakes in India, namely the Indian cobra, common krait, Russell's viper, and sawscaled viper. The improvement seen in this patient suggests possible cross-neutralizing activity of the Indian vipers' antivenom against the local shore pit viper venom. Further in vivo and in vitro studies should be performed to verify this clinical case.

  4. Controlling the extent of viral genome release by a combination of osmotic stress and polyvalent cations.

    PubMed

    Jin, Yan; Knobler, Charles M; Gelbart, William M

    2015-08-01

    While several in vitro experiments on viral genome release have specifically studied the effects of external osmotic pressure and of the presence of polyvalent cations on the ejection of DNA from bacteriophages, few have systematically investigated how the extent of ejection is controlled by a combination of these effects. In this work we quantify the effect of osmotic pressure on the extent of DNA ejection from bacteriophage lambda as a function of polyvalent cation concentration (in particular, the tetravalent polyamine spermine). We find that the pressure required to completely inhibit ejection decreases from 38 to 17 atm as the spermine concentration is increased from 0 to 1.5 mM. Further, incubation of the phage particles in spermine concentrations as low as 0.15 mM--the threshold for DNA condensation in bulk solution-is sufficient to significantly limit the extent of ejection in the absence of osmolyte; for spermine concentrations below this threshold, the ejection is complete. In accord with recent investigations on the packaging of DNA in the presence of a condensing agent, we observe that the self-attraction induced by the polyvalent cation affects the ordering of the genome, causing it to get stuck in a broad range of nonequilibrated structures.

  5. Controlling the extent of viral genome release by a combination of osmotic stress and polyvalent cations

    NASA Astrophysics Data System (ADS)

    Jin, Yan; Knobler, Charles M.; Gelbart, William M.

    2015-08-01

    While several in vitro experiments on viral genome release have specifically studied the effects of external osmotic pressure and of the presence of polyvalent cations on the ejection of DNA from bacteriophages, few have systematically investigated how the extent of ejection is controlled by a combination of these effects. In this work we quantify the effect of osmotic pressure on the extent of DNA ejection from bacteriophage lambda as a function of polyvalent cation concentration (in particular, the tetravalent polyamine spermine). We find that the pressure required to completely inhibit ejection decreases from 38 to 17 atm as the spermine concentration is increased from 0 to 1.5 mM. Further, incubation of the phage particles in spermine concentrations as low as 0.15 mM—the threshold for DNA condensation in bulk solution—is sufficient to significantly limit the extent of ejection in the absence of osmolyte; for spermine concentrations below this threshold, the ejection is complete. In accord with recent investigations on the packaging of DNA in the presence of a condensing agent, we observe that the self-attraction induced by the polyvalent cation affects the ordering of the genome, causing it to get stuck in a broad range of nonequilibrated structures.

  6. Coloured marking inside glass by laser radiation

    NASA Astrophysics Data System (ADS)

    Ligbado, Grace; Horn, Alexander; Kreutz, Ernst W.; Krauss, Manfred M.; Siedow, Norbert; Hensel, Hartmut

    2005-11-01

    Laser labelling inside glass induces micro-cracks by high energy densities in the focus. The micro-cracks reduce the mechanical stability of glass. Light scattering allows the observer to perceive the cracks as white pixels. Coloured marking of glass in this manner is not possible. Coloured marking inside glass by changing the oxidation state of the metal ions locally in the focus does not weaken the mechanical properties of the glass. Two kind of glass systems, lime-natron-silicate and borosilicate with 0.5 % mass-content of doping are investigated. The simultaneous presence of donators and acceptors allows a transition of electrons between polyvalent ions, and can lead to permanent colour-centres inside the glass, due to the fact that the absorption of the polyvalent ions is changed by the laser-induced conversion process. For this purpose a 3 ω Nd:YAG (wavelength λL = 355 nm, pulse duration t = 10 to 80 ns) and a Ti:Sapphire solid-state laser (wavelength λL = 810 nm, pulse duration t = 200 fs) are used. The radiation parameters and the chemical composition of the glass (mainly doping) are the dominant factors to generate coloured marking. The transmittance as a function of the fluence and the change of the absorption coefficient is measured and gives a statement of the colourshade. Further the difference between lime-natron-silicate and borosilicate glass (same doping variety) is examined. Actually mauve, yellow, red-brown an grey colouring can be produced. Cracks in the microstructure of glass can also be the cause for brown colour-centres generating.

  7. Snakebite by the Shore Pit Viper (Trimeresurus purpureomaculatus) Treated With Polyvalent Antivenom.

    PubMed

    Mong, Rupeng; Tan, Hock Heng

    2016-06-01

    Although snakebites are uncommon, there are several species of medically important venomous snakes native to Singapore. We present a case of envenoming by the shore pit viper (Trimeresurus purpureomaculatus) that showed clinical improvement when treated with the Indian (Haffkine) polyvalent antivenom. A 40-year-old man was bitten on his right hand by a snake, which was identified through photos and his description to be a shore pit viper, which is native to the local mangrove area. Severe swelling and pain developed immediately after the bite, which progressed up the arm. Because of the progression of local swelling, antivenom was started. He was given a total of 6 vials (60 mL) of polyvalent antivenom, with the first vial started 3 hours after the bite. He showed clinical improvement within 24 hours. His subsequent recovery was uneventful, with no other complications as a result of envenomation or antivenom use. Severe envenoming by the shore pit viper can lead to marked local effects such as extensive swelling and tissue necrosis. Antivenom is indicated in the presence of severe local envenomation. Antivenom against the shore pit viper is however not available locally. The Indian (Haffkine) polyvalent antivenom contains antibodies against 4 common venomous snakes in India, namely the Indian cobra, common krait, Russell's viper, and sawscaled viper. The improvement seen in this patient suggests possible cross-neutralizing activity of the Indian vipers' antivenom against the local shore pit viper venom. Further in vivo and in vitro studies should be performed to verify this clinical case. PMID:27061038

  8. [Research on Test Method of Metallic Element Contained in Tea Based on EDXRF Technique].

    PubMed

    Qin, Xu-lei; Li, Ye; Song, Zhong-hua; Wang, Guo-zheng; Li, Shen; Shan, Gao-feng; Duanmu, Qing-duc

    2015-04-01

    As it has been certified by experimental testing that when using the energy-dispersive X-ray fluorescence (EDXRF) method to analyze the metallic elements contained in the tea the energy segment of effective X-ray fluorescence photons is located between 3 and 16 keV. Accordingly the spectral correction element is targeted at the copper elements located near the energy center(8 keV). The copper elements are also used as the picketage to be the standard curve. In the energy segment of effective X-ray fluorescence photons contained in the tea 1.25 mg · kg(-1) of the average detection limit was obtained by using the spiked method to analyze four elements of copper, iron, zinc and lead. Compared with the flame atomic absorption spectrum(FAAS), the actual relative error of the tested value by EDXRF is less than 6%, and the relative standard deviation is less than 5%. The result by T test shows that p > 0.05. The conclusions are that there are no statistically significant differences between EDXRF and FAAS. The measured results gained by the two methods agree with each other. And EDXRF can be used thoroughly to test the metal contents contained in the tea. The result shows that it is feasible to test the metallic contents contained in the tea by EDXRF, and its measured result can meet the requirements of field testing and analysis.

  9. Successful snakebite treatment in three juvenile African wild dogs (Lycaon pictus) with polyvalent antivenom: a Namibian case report.

    PubMed

    Weise, Florian J; van Vuuren, Rudie J; Echement, Katherine E; Cleverley, Matthew P; van Vuuren, Marlice

    2013-01-01

    This article reports the first documented treatment of venomous snakebite with a polyvalent snake antivenom from the South African Institute for Medical Research in endangered African wild dogs (Lycaon pictus). Three juvenile male animals (6.5 months of age) showed clinical signs after being bitten by an unidentified venomous snake. The signs included loss of appetite, disorientation, impaired locomotion, excessive facial swelling, profuse salivation, reduced respiratory effort and an apparent depressed mental state. Intravenous treatment with isotonic Ringer lactate solution, hetastarch 6% and dexamethazone, subcutaneous administration of procaine benzylpenicillin and benzathine benzylpenicillin, and ultimately intravenous administration of the polyvalent snake antivenom resulted in the complete recovery of all three wild dogs.

  10. Polyvalent fuel treatment facility (TCP): shearing and dissolution of used fuel at La Hague facility

    SciTech Connect

    Brueziere, J.; Tribout-Maurizi, A.; Durand, L.; Bertrand, N.

    2013-07-01

    Although many used nuclear fuel types have already been recycled, recycling plants are generally optimized for Light Water Reactor (LWR) UO{sub x} fuel. Benefits of used fuel recycling are consequently restricted to those fuels, with only limited capacity for the others like LWR MOX, Fast Reactor (FR) MOX or Research and Test Reactor (RTR) fuel. In order to recycle diverse fuel types, an innovative and polyvalent shearing and dissolving cell is planned to be put in operation in about 10 years at AREVA's La Hague recycling plant. This installation, called TCP (French acronym for polyvalent fuel treatment) will benefit from AREVA's industrial feedback, while taking part in the next steps towards a fast reactor fuel cycle development using innovative treatment solutions. Feasibility studies and R/Development trials on dissolution and shearing are currently ongoing. This new installation will allow AREVA to propose new services to its customers, in particular in term of MOX fuel, Research Test Reactors fuel and Fast Reactor fuel treatment. (authors)

  11. Improving the safety of Staphylococcus aureus polyvalent phages by their production on a Staphylococcus xylosus strain.

    PubMed

    El Haddad, Lynn; Ben Abdallah, Nour; Plante, Pier-Luc; Dumaresq, Jeannot; Katsarava, Ramaz; Labrie, Steve; Corbeil, Jacques; St-Gelais, Daniel; Moineau, Sylvain

    2014-01-01

    Team1 (vB_SauM_Team1) is a polyvalent staphylococcal phage belonging to the Myoviridae family. Phage Team1 was propagated on a Staphylococcus aureus strain and a non-pathogenic Staphylococcus xylosus strain used in industrial meat fermentation. The two Team1 preparations were compared with respect to their microbiological and genomic properties. The burst sizes, latent periods, and host ranges of the two derivatives were identical as were their genome sequences. Phage Team1 has 140,903 bp of double stranded DNA encoding for 217 open reading frames and 4 tRNAs. Comparative genomic analysis revealed similarities to staphylococcal phages ISP (97%) and G1 (97%). The host range of Team1 was compared to the well-known polyvalent staphylococcal phages phi812 and K using a panel of 57 S. aureus strains collected from various sources. These bacterial strains were found to represent 18 sequence types (MLST) and 14 clonal complexes (eBURST). Altogether, the three phages propagated on S. xylosus lysed 52 out of 57 distinct strains of S. aureus. The identification of phage-insensitive strains underlines the importance of designing phage cocktails with broadly varying and overlapping host ranges. Taken altogether, our study suggests that some staphylococcal phages can be propagated on food-grade bacteria for biocontrol and safety purposes. PMID:25061757

  12. Improving the Safety of Staphylococcus aureus Polyvalent Phages by Their Production on a Staphylococcus xylosus Strain

    PubMed Central

    El Haddad, Lynn; Ben Abdallah, Nour; Plante, Pier-Luc; Dumaresq, Jeannot; Katsarava, Ramaz; Labrie, Steve; Corbeil, Jacques; St-Gelais, Daniel; Moineau, Sylvain

    2014-01-01

    Team1 (vB_SauM_Team1) is a polyvalent staphylococcal phage belonging to the Myoviridae family. Phage Team1 was propagated on a Staphylococcus aureus strain and a non-pathogenic Staphylococcus xylosus strain used in industrial meat fermentation. The two Team1 preparations were compared with respect to their microbiological and genomic properties. The burst sizes, latent periods, and host ranges of the two derivatives were identical as were their genome sequences. Phage Team1 has 140,903 bp of double stranded DNA encoding for 217 open reading frames and 4 tRNAs. Comparative genomic analysis revealed similarities to staphylococcal phages ISP (97%) and G1 (97%). The host range of Team1 was compared to the well-known polyvalent staphylococcal phages phi812 and K using a panel of 57 S. aureus strains collected from various sources. These bacterial strains were found to represent 18 sequence types (MLST) and 14 clonal complexes (eBURST). Altogether, the three phages propagated on S. xylosus lysed 52 out of 57 distinct strains of S. aureus. The identification of phage-insensitive strains underlines the importance of designing phage cocktails with broadly varying and overlapping host ranges. Taken altogether, our study suggests that some staphylococcal phages can be propagated on food-grade bacteria for biocontrol and safety purposes. PMID:25061757

  13. [Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].

    PubMed

    Tovkach, F I; Moroz, S N; Korol', N A; Faĭdiuk, Iu V; Kushkina, A I

    2013-01-01

    Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants.

  14. Test results for composite specimens and elements containing joints and cutouts

    NASA Technical Reports Server (NTRS)

    Sumida, P. T.; Madan, R. C.; Hawley, A. V.

    1988-01-01

    A program was conducted to develop the technology for joints and cutouts in a composite fuselage that meets all design requirements of a large transport aircraft for the 1990s. An advanced trijet derivative of the DC-10 was selected as the baseline aircraft. Design and analysis of a 30-foot-long composite fuselage barrel provided a realistic basis for the test effort. The primary composite material was Hexcel F584 resin on 12 K IM6 fiber, in tape and broadgoods form. Fiberglass broadgoods were used in E-glass and S-glass fiber form in the cutout region of some panels. Additionally, injection-molded chopped graphite fiber/PEEK was used for longeron-to-frame shear clips. The test effort included four groups of test specimens, beginning with coupon specimens of mono-layer and cross-piled laminates, progressing through increasingly larger and more complex specimens, and ending with two 4- by 5-foot curved fuselage side panels. One of the side panels incorporated a transverse skin splice, while the second included two cabin window cutouts.

  15. Solving the Acoustic Problem in Polyvalent Hall at Mauritius: Global Design Challenge Facing Larsen and Toubro, Limited

    ERIC Educational Resources Information Center

    Sankar, Chetan S.; Raju, P. K.; Alur, Ramachandriah; Venkateswaran, Rajan; Elangovan, Rajasekar

    2011-01-01

    The architect for the Mauritius Auditorium project sat in his office at Larsen & Toubro's headquarters in Chennai, India, pondering the phone call he had just received from the vice president, Mr. K.P. Raghavan. The polyvalent hall of the conference center was about to be used to host its first rock concert in February 2005, but during a rehearsal…

  16. Viper and Cobra Venom Neutralization by Alginate Coated Multicomponent Polyvalent Antivenom Administered by the Oral Route

    PubMed Central

    Bhattacharya, Sourav; Chakraborty, Mousumi; Mukhopadhyay, Piyasi; Kundu, P. P.; Mishra, Roshnara

    2014-01-01

    Background Snake bite causes greater mortality than most of the other neglected tropical diseases. Snake antivenom, although effective in minimizing mortality in developed countries, is not equally so in developing countries due to its poor availability in remote snake infested areas as, and when, required. An alternative approach in this direction could be taken by making orally deliverable polyvalent antivenom formulation, preferably under a globally integrated strategy, for using it as a first aid during transit time from remote trauma sites to hospitals. Methodology/Principal Findings To address this problem, multiple components of polyvalent antivenom were entrapped in alginate. Structural analysis, scanning electron microscopy, entrapment efficiency, loading capacity, swelling study, in vitro pH sensitive release, acid digestion, mucoadhesive property and venom neutralization were studied in in vitro and in vivo models. Results showed that alginate retained its mucoadhesive, acid protective and pH sensitive swelling property after entrapping antivenom. After pH dependent release from alginate beads, antivenom (ASVS) significantly neutralized phospholipaseA2 activity, hemolysis, lactate dehydrogenase activity and lethality of venom. In ex vivo mice intestinal preparation, ASVS was absorbed significantly through the intestine and it inhibited venom lethality which indicated that all the components of antivenom required for neutralization of venom lethality were retained despite absorption across the intestinal layer. Results from in vivo studies indicated that orally delivered ASVS can significantly neutralize venom effects, depicted by protection against lethality, decreased hemotoxicity and renal toxicity caused by russell viper venom. Conclusions/Significance Alginate was effective in entrapping all the structural components of ASVS, which on release and intestinal absorption effectively reconstituted the function of antivenom in neutralizing viper and cobra

  17. Successful snakebite treatment in three juvenile African wild dogs (Lycaon pictus) with polyvalent antivenom: a Namibian case report.

    PubMed

    Weise, Florian J; van Vuuren, Rudie J; Echement, Katherine E; Cleverley, Matthew P; van Vuuren, Marlice

    2013-01-01

    This article reports the first documented treatment of venomous snakebite with a polyvalent snake antivenom from the South African Institute for Medical Research in endangered African wild dogs (Lycaon pictus). Three juvenile male animals (6.5 months of age) showed clinical signs after being bitten by an unidentified venomous snake. The signs included loss of appetite, disorientation, impaired locomotion, excessive facial swelling, profuse salivation, reduced respiratory effort and an apparent depressed mental state. Intravenous treatment with isotonic Ringer lactate solution, hetastarch 6% and dexamethazone, subcutaneous administration of procaine benzylpenicillin and benzathine benzylpenicillin, and ultimately intravenous administration of the polyvalent snake antivenom resulted in the complete recovery of all three wild dogs. PMID:23718740

  18. Immunological cross-reactivity and neutralization of the principal toxins of Naja sumatrana and related cobra venoms by a Thai polyvalent antivenom (Neuro Polyvalent Snake Antivenom).

    PubMed

    Leong, Poh Kuan; Fung, Shin Yee; Tan, Choo Hock; Sim, Si Mui; Tan, Nget Hong

    2015-09-01

    The low potency of cobra antivenom has been an area of concern in immunotherapy for cobra envenomation. This study sought to investigate factors limiting the neutralizing potency of cobra antivenom, using a murine model. We examined the immunological reactivity and neutralizing potency of a Thai polyvalent antivenom against the principal toxins of Naja sumatrana (Equatorial spitting cobra) venom and two related Asiatic cobra venom α-neurotoxins. The antivenom possesses moderate neutralizing potency against phospholipases A2 (P, potency of 0.98mg/mL) and moderately weak neutralizing potency against long-chain α-neurotoxins (0.26-0.42mg/mL) but was only weakly effective in neutralizing the short-chain α-neurotoxins and cardiotoxins (0.05-0.08mg/mL). The poor neutralizing potency of the antivenom on the low molecular mass short-chain neurotoxins and cardiotoxins is presumably the main limiting factor of the efficacy of the cobra antivenom. Our results also showed that phospholipase A2, which exhibited the highest ELISA reactivity and avidity, was most effectively neutralized, whereas N. sumatrana short-chain neurotoxin, which exhibited the lowest ELISA reactivity and avidity, was least effectively neutralized by the antivenom. These observations suggest that low immunoreactivity (low ELISA reactivity and avidity) is one of the reasons for poor neutralization of the cobra venom low molecular mass toxins. Nevertheless, the overall results show that there is a lack of congruence between the immunological reactivity of the toxins toward antivenom and the effectiveness of toxin neutralization by the antivenom, indicating that there are other factors that also contribute to the weak neutralization capacity of the antivenom. Several suggestions have been put forward to overcome the low efficacy of the cobra antivenom. The use of a 'proper-mix' formulation of cobra venoms as immunogen, whereby the immunogen mixture used for hyperimmunization contains a mix of various types

  19. [Immunotherapy by polyvalent bacterial antigen (Broncasma Berna) in the prevention of pneumonia in the elderly].

    PubMed

    Suzuki, K; Yamamoto, K; Adachi, S; Yamamoto, T

    1989-03-01

    Pneumonia in the elderly often occurs repeatedly, and the mortality rate from pneumonia continues to remain high today despite the usual use of antibacterial chemotherapy. Therefore, we conducted immunotherapy using a polyvalent bacterial vaccine (broncasma Berna). We treated 54 elderly patients with Broncasma Berna, containing chief bacterial pathogens responsible for pneumonia in the elderly. Clinical results obtained during 2 years were compared with those of 18 subjects not treated with Broncasma Berna. The survival rate was 64.8% for the group treated with Broncasma Berna and 50% for the group not treated. The frequency of contraction of pneumonia decreased significantly in the group treated. Clinical efficacy was obtained in 63% of the group treated to prevent pneumonia. The death rate from pneumonia was 17.6% for the group treated and 44.4% for the group not treated. Immunologically, reinforcement in humoral and cellular immunities was indicated by immunoglobulin values, positive tuberculin skin tests, and an increase in lymphocyte stimulation index values for Broncasma Berna. Significant pathogens in sputum disappeared or decreased in 6 (54.6%) out of 11 patients. Side effects such as pain or redness at the site of injection were observed in 6 patients. From the above results, it may be concluded that Broncasma Berna can be considered to be effective as a long-term immunoprophylactic agent in the prevention of pneumonia in the elderly.

  20. Immobilization of bacteriophage Qbeta on metal-derivatized surfaces via polyvalent display of hexahistidine tags.

    PubMed

    Udit, Andrew K; Brown, Steven; Baksh, Michael M; Finn, M G

    2008-12-01

    Metal-binding peptide motifs are widely used for protein purification, catalysis, and metal-mediated self assembly in the construction of novel materials and multivalent light harvesting complexes. Herein we describe hexahistidine sequences incorporated into the virus-like particle derived from bacteriophage Qbeta via co-expression of the wild-type (WT) and hexahistidine-modified coat proteins in Escherichia coli. The resulting polyvalent display of approximately 37 hexahistidine moieties per virion gave rise to altered properties of Zeta potential and hydrodynamic radius, but no observed change in stability compared to WT. While the resulting display density did not permit hexahistidine chains to cooperate in the coordination of heme, the multiple tags did impart a strong affinity for immobilized metal ions. A dissociation constant for binding to Ni-NTA of approximately 10nM was measured by SPR under non-competitive, physiological conditions. Affinity chromatography over immobilized metal columns was used to purify the particles from both crude cell lysates and after chemical derivatization. These results illustrate the potential of metal-NTA surfaces for the self-assembled presentation of multi-functionalized particles to interrogate systems ranging from small molecule binding to whole cell interactions. PMID:18834633

  1. Preclinical Development of Inactivated Rabies Virus-Based Polyvalent Vaccine Against Rabies and Filoviruses.

    PubMed

    Willet, Mallory; Kurup, Drishya; Papaneri, Amy; Wirblich, Christoph; Hooper, Jay W; Kwilas, Steve A; Keshwara, Rohan; Hudacek, Andrew; Beilfuss, Stefanie; Rudolph, Grit; Pommerening, Elke; Vos, Adriaan; Neubert, Andreas; Jahrling, Peter; Blaney, Joseph E; Johnson, Reed F; Schnell, Matthias J

    2015-10-01

    We previously described the generation of a novel Ebola virus (EBOV) vaccine based on inactivated rabies virus (RABV) containing EBOV glycoprotein (GP) incorporated in the RABV virion. Our results demonstrated safety, immunogenicity, and protective efficacy in mice and nonhuman primates (NHPs). Protection against viral challenge depended largely on the quality of the humoral immune response against EBOV GP.Here we present the extension and improvement of this vaccine by increasing the amount of GP incorporation into virions via GP codon-optimization as well as the addition of Sudan virus (SUDV) and Marburg virus (MARV) GP containing virions. Immunogenicity studies in mice indicate similar immune responses for both SUDV GP and MARV GP compared to EBOV GP. Immunizing mice with multiple antigens resulted in immune responses similar to immunization with a single antigen. Moreover, immunization of NHP with the new inactivated RABV EBOV vaccine resulted in high titer neutralizing antibody levels and 100% protection against lethal EBOV challenge when applied with adjuvant.Our results indicate that an inactivated polyvalent vaccine against RABV filoviruses is achievable. Finally, the novel vaccines are produced on approved VERO cells and a clinical grade RABV/EBOV vaccine for human trials has been produced.

  2. FMD virus isolates: the candidate strains for polyvalent vaccine development in Ethiopia.

    PubMed

    Ayelet, G; Soressa, M; Sisay, T; Belay, A; Gelaye, E; Jembere, S; Skjerve, E; Asmare, K

    2013-06-01

    The study was conducted on foot-and-mouth disease (FMD) viruses with the aim of selecting appropriate vaccinal strain to control of FMD in Ethiopia. The study was conducted in two-dimensional virus neutralization assay to determine the antigenic relationship 'r' value between the candidate vaccine strains and field isolates. A total of 21 serotype O, 7 serotype A, and 8 serotype SAT 2 FMD viruses, which were isolated from cattle and swine. A couple of isolates from each serotype were identified as vaccine candidates in the trial (O-ETH/38/2005, O-ETH/58/2008, A-ETH/7/2008, A-ETH/6/2000, SAT2-ETH/76/2009 and SAT2-ETH/64/2009). The finding revealed all the vaccine candidate depicted high antigenic similarity, above the mean "r" value, to their own serotypes in the studied serotype population except for one serotype A field isolate, A-ETH/13/1981, with "r" value=0.14 and 0.25) which is significantly lower than the minimum requirement. In general, the result indicated that these candidate vaccinal strains can be used for polyvalent vaccine production in the country. PMID:23416124

  3. Alignment of absolute and relative molecular size specifications for a polyvalent pneumococcal polysaccharide vaccine (PNEUMOVAX 23).

    PubMed

    MacNair, John E; Desai, Tejal; Teyral, Jennifer; Abeygunawardana, Chitrananda; Hennessey, John P

    2005-03-01

    An approach was developed to align release and end-expiry specifications for molecular size for the polyvalent pneumococcal polysaccharide vaccine (PNEUMOVAX 23). Each of the 23 polysaccharide components of the vaccine was separately subjected to ultrasonication to produce a series of preparations of decreasing weight-average molecular mass (Mw). These size-reduced polysaccharides were analysed as monovalent solutions by high-performance size exclusion chromatography (HPSEC) with multi-angle laser light scattering (MALLS) and refractive index (RI) detection to measure their Mw. These samples were also analysed by HPSEC with rate nephelometry (RN) detection to measure their relative molecular size (r-MS). The data from the two molecular size measurements established a correlation between Mw and r-MS. For each polysaccharide component of the vaccine, this correlation permits the direct alignment of the r-MS specification in the final formulated product with the Mw specification for the monovalent polysaccharide preparation. The alignment of specifications provides a high level of assurance that the quality control of the final vaccine product is consistent with that of the polysaccharide starting materials.

  4. Identification and purification of immunogenic proteins from nonliving promastigote polyvalent Leishmania vaccine (Leishvacin ).

    PubMed

    Cardoso, Sandra Regina Afonso; da Silva, João Carlos França; da Costa, Roberto Teodoro; Mayrink, Wilson; Melo, Maria Norma; Michalick, Marilene Suzan Marques; Liu, Ibrahim Afrânio Willi; Fujiwara, Ricardo Toshio; Nascimento, Evaldo

    2003-01-01

    Immunogenic proteins from nonliving promastigote polyvalent Leishmania vaccine against American tegumentary leishmaniasis (Leishvacin ), produced by Biobr s (Biochemistry of Brazil ), Montes Claros, State of Minas Gerais, Brazil, were identified and purified by polyacrylamide electrophoresis gel and electroelution. C57BL/10 mice were vaccinated with proteins with estimated molecular weights of 42, 46, 63, 66, 73, 87, 97, and 160kDa in three doses of 30 g of each protein at 15-day intervals combined with 250 microg of Corynebacterium parvum followed by a challenge infection with 10(5) infective promastigotes from Leishmania (Leishmania) amazonensis. The ability of these proteins to induce immune response and protection was analyzed. No statistical difference was observed in the level of IFN-gamma induced by proteins in vaccinated groups in comparison with control groups. Six months after challenge infection, protection levels of 28.57; 42.86; 57.14; 42.86; 42.86, 57.14; 42.86 and 57.14% were demonstrated for each purified protein. PMID:12806454

  5. Protection by attenuated and polyvalent vaccines against highly virulent strains of Marek's disease virus.

    PubMed

    Witter, R L

    1982-01-01

    Tests confirmed that turkey herpesvirus (HVT) vaccine protected chickens poorly against challenge with the highly virulent Md5 strain of Marek's disease (MD) virus, especially in chickens with homologous HVT antibodies. The naturally avirulent SB-1 vaccine virus was likewise poorly protective against challenge with the Md5 strain. Homologous antibodies reduced the protective efficacy of both vaccines, but SB-1 was not affected by HVT antibodies. In order to provide better protection against strains of MD virus poorly protected against by HVT, such as Md5, the Md11 strain of MD virus was attenuated by 75 cell culture passages and evaluated for protective efficacy. This vaccine virus, designated Mdl 1/75C, provided good protection against challenge with Md5 and most other highly virulent MD viruses tested, but was less efficacious against challenge with the JM/102W strain, a prototype MD virus protected against well by HVT and SB-1 vaccines. Furthermore, its efficacy was consistently lower in chicks with HVT antibody. Thus, although HVT, SB-1, and Md11/75C were all efficacious against certain MD viruses, none of these vaccines protected optimally against all MD challenge viruses in all chickens. A polyvalent vaccine composed of Md11/75C, HVT and SB-1 viruses protected chickens better against a battery of five highly virulent MD challenge viruses, including three strains poorly protected against by HVT, than any single vaccine and was not influenced by HVT antibody. These data suggest that vaccinal immunity may be partially viral strain specific.

  6. Method, instruments, and results of the determination of elements contained in Venusian rock by the Vega-2 interplanetary probe

    SciTech Connect

    Surkov, Y.A.; Dudin, A.D.; Kharyukova, V.P.; Manvelyan, O.S.; Moskaleva, L.P.; Shcheglov, O.P.

    1986-04-01

    With an x-ray fluorescent spectrometer installed in the lander of the Vega-2 interplanetary station, elements contained in Venusian rock were determined for the northern part of Terra Aphroditae. The composition proved to be most similar to that of rocks of the anorthosite-norite-troctolite (ANT) group which constitute the basis of the moon's continental crust. The determination of the abundance of basic rock-forming elements from Mg to Fe, and also of some heavier rare elements, was carried out by x-ray-radiometry with the use of instruments installed in the lander. The measuring element included three radioisotope sources (one source of plutonium-238 and two sources of iron-55), four gas-discharge proportional counters, and soil collectors in which was placed the rock material to be analyzed.

  7. Cross-reactivity and neutralization of Indian King cobra (Ophiophagus hannah) venom by polyvalent and monovalent antivenoms.

    PubMed

    Gowtham, Yashonandana J; Mahadeswaraswamy, Y H; Girish, K S; K, Kemparaju

    2014-07-01

    The venom of the largest venomous snake, the king cobra (Ophiophagus hannah), is still out of league for the production of therapeutic polyvalent antivenom nor it is characterized immunologically in the Indian subcontinent. In the present study, the king cobra venom is comparatively studied for the cross-reactivity/reactivity and toxicity neutralization by the locally available equine therapeutic polyvalent BSV and VB antivenoms, and monovalent antivenom (OH-IgG) prepared in rabbit. None of the two therapeutic antivenoms procured from two different firms showed any signs of cross-reactivity in terms of antigen-antibody precipitin lines in immunodouble diffusion assay; however, a weak and an insignificant cross-reactivity pattern was observed in ELISA and Western blot studies. Further, both BSV and VB antivenoms failed to neutralize proteolytic, hyaluronidase and phospholipase activities as well as toxic properties such as edema, myotoxicity and lethality of the venom. As expected, OH-IgG showed strong reactivity in immunodouble diffusion, ELISA and in Western blot analysis and also neutralized both enzyme activities as well as the toxic properties of the venom. Thus, the study provides insight into the likely measures that are to be taken in cases of accidental king cobra bites for which the Indian subcontinent is still not prepared for. PMID:24815989

  8. Cross-reactivity and neutralization of Indian King cobra (Ophiophagus hannah) venom by polyvalent and monovalent antivenoms.

    PubMed

    Gowtham, Yashonandana J; Mahadeswaraswamy, Y H; Girish, K S; K, Kemparaju

    2014-07-01

    The venom of the largest venomous snake, the king cobra (Ophiophagus hannah), is still out of league for the production of therapeutic polyvalent antivenom nor it is characterized immunologically in the Indian subcontinent. In the present study, the king cobra venom is comparatively studied for the cross-reactivity/reactivity and toxicity neutralization by the locally available equine therapeutic polyvalent BSV and VB antivenoms, and monovalent antivenom (OH-IgG) prepared in rabbit. None of the two therapeutic antivenoms procured from two different firms showed any signs of cross-reactivity in terms of antigen-antibody precipitin lines in immunodouble diffusion assay; however, a weak and an insignificant cross-reactivity pattern was observed in ELISA and Western blot studies. Further, both BSV and VB antivenoms failed to neutralize proteolytic, hyaluronidase and phospholipase activities as well as toxic properties such as edema, myotoxicity and lethality of the venom. As expected, OH-IgG showed strong reactivity in immunodouble diffusion, ELISA and in Western blot analysis and also neutralized both enzyme activities as well as the toxic properties of the venom. Thus, the study provides insight into the likely measures that are to be taken in cases of accidental king cobra bites for which the Indian subcontinent is still not prepared for.

  9. Virus-like glycodendrinanoparticles displaying quasi-equivalent nested polyvalency upon glycoprotein platforms potently block viral infection

    PubMed Central

    Ribeiro-Viana, Renato; Sánchez-Navarro, Macarena; Luczkowiak, Joanna; Koeppe, Julia R.; Delgado, Rafael; Rojo, Javier; Davis, Benjamin G.

    2012-01-01

    Ligand polyvalency is a powerful modulator of protein–receptor interactions. Host–pathogen infection interactions are often mediated by glycan ligand–protein interactions, yet its interrogation with very high copy number ligands has been limited to heterogenous systems. Here we report that through the use of nested layers of multivalency we are able to assemble the most highly valent glycodendrimeric constructs yet seen (bearing up to 1,620 glycans). These constructs are pure and well-defined single entities that at diameters of up to 32 nm are capable of mimicking pathogens both in size and in their highly glycosylated surfaces. Through this mimicry these glyco-dendri-protein-nano-particles are capable of blocking (at picomolar concentrations) a model of the infection of T-lymphocytes and human dendritic cells by Ebola virus. The high associated polyvalency effects (β>106, β/N ~102–103) displayed on an unprecedented surface area by precise clusters suggest a general strategy for modulation of such interactions. PMID:23250433

  10. Glass sealing

    SciTech Connect

    Brow, R.K.; Kovacic, L.; Chambers, R.S.

    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.

  11. Growth and performance of Atlantic salmon, Salmo salar L., following administration of a rhabdovirus DNA vaccine alone or concurrently with an oil-adjuvanted, polyvalent vaccine.

    PubMed

    Skinner, L A; Schulte, P M; LaPatra, S E; Balfry, S K; McKinley, R S

    2008-09-01

    This research demonstrates for the first time an absence of growth-related side effects in Atlantic salmon, Salmo salar L., following the injection of a DNA vaccine alone or concurrently with a commercially available, polyvalent, oil-adjuvanted vaccine. Using weight and specific growth rate measurements, individually tagged Atlantic salmon were monitored for 2028 degree days (dd) post-vaccination. During this time, DNA-vaccinated fish did not differ in weight, length, condition factor or specific growth rate compared to unvaccinated control fish. While differences in weight were observed between unvaccinated control and concurrently vaccinated fish, there were no significant differences in weight, length, condition factor or specific growth rate between concurrently vaccinated fish and adjuvant-vaccinated fish, suggesting that only adjuvant vaccination affected growth. To further determine if concurrent injection of a DNA vaccine and a polyvalent, oil-adjuvanted vaccine had a physiological impact on the Atlantic salmon, swimming performance tests were performed at 106 dd post-vaccination with U(crit,1), U(crit,2), the U(crit) recovery ratio (RR) and the normalized RR being similar to values obtained from unvaccinated control fish. In summary, this study shows that concurrent injection of a DNA vaccine and a polyvalent, oil-adjuvanted vaccine does not negatively influence the growth or swimming performance of Atlantic salmon compared to adjuvant vaccination alone.

  12. Glass Artworks

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Several NASA technologies have played part in growth and cost containment of studio glass art, among them a foam type insulation developed to meet a need for lightweight material that would reduce flame spread in aircraft fire. Foam comes in several forms and is widely used by glass artists, chiefly as an insulator for the various types of ovens used in glass working. Another Spinoff is alumina crucibles to contain molten glass. Before alumina crucibles were used, glass tanks were made of firebrick which tended to erode under high temperatures and cause impurities; this not only improved quality but made the process more cost effective. One more NASA technology that found its way into glass art working is a material known as graphite board, a special form of graphite originally developed for rocket motor applications. This graphite is used to exact compound angles and creates molds for poured glass artworks of dramatic design.

  13. Tomato bushy stunt virus (TBSV), a versatile platform for polyvalent display of antigenic epitopes and vaccine design

    SciTech Connect

    Kumar, Shantanu; Ochoa, Wendy; Singh, Pratik; Hsu, Catherine; Schneemann, Anette; Manchester, Marianne; Olson, Mark; Reddy, Vijay

    2009-05-25

    Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of foreign epitopes of interest on their capsid surface to improve their presentation enhancing the antigenicity and host immune response. In the present study, we used the VLPs of Tomato bushy stunt virus (TBSV), an icosahedral plant virus, as a platform to display 180 copies of 16 amino acid epitopes of ricin toxin fused to the C-terminal end of a modified TBSV capsid protein (NDELTA52). Expression of the chimeric recombinant protein in insect cells resulted in spontaneous assembly of VLPs displaying the ricin epitope. Cryo-electron microscopy and image reconstruction of the chimeric VLPs at 22 A resolution revealed the locations and orientation of the ricin epitope exposed on the TBSV capsid surface. Furthermore, injection of chimeric VLPs into mice generated antisera that detected the native ricin toxin. The ease of fusing of short peptides of 15-20 residues and their ability to form two kinds (T = 1, T = 3) of bio-nanoparticles that result in the display of 60 or 180 copies of less constrained and highly exposed antigenic epitopes makes TBSV an attractive and versatile display platform for vaccine design.

  14. Effectiveness of Polyvalent Bacterial Lysate and Autovaccines Against Upper Respiratory Tract Bacterial Colonization by Potential Pathogens: A Randomized Study

    PubMed Central

    Zagólski, Olaf; Stręk, Paweł; Kasprowicz, Andrzej; Białecka, Anna

    2015-01-01

    Background Polyvalent bacterial lysate (PBL) is an oral immunostimulating vaccine consisting of bacterial standardized lysates obtained by lysis of different strains of bacteria. Autovaccines are individually prepared based on the results of smears obtained from the patient. Both types of vaccine can be used to treat an ongoing chronic infection. This study sought to determine which method is more effective against nasal colonization by potential respiratory tract pathogens. Material/Methods We enrolled 150 patients with aerobic Gram stain culture and count results indicating bacterial colonization of the nose and/or throat by potential pathogens. The participants were randomly assigned to each of the following groups: 1. administration of PBL, 2. administration of autovaccine, and 3. no intervention (controls). Results Reduction of the bacterial count in Streptococcus pneumoniae-colonized participants was significant after the autovaccine (p<0.001) and PBL (p<0.01). Reduction of the bacterial count of other β-hemolytic streptococcal strains after treatment with the autovaccine was significant (p<0.01) and was non-significant after PBL. In Haemophilus influenzae colonization, significant reduction in the bacterial count was noted in the PBL group (p<0.01). Methicillin-resistant Staphylococcus aureus colonization did not respond to either treatment. Conclusions The autovaccine is more effective than PBL for reducing bacterial count of Streptococcus pneumoniae and β-hemolytic streptococci, while PBL was more effective against Haemophilus influenzae colonization. PMID:26434686

  15. Biochemical and biological characterization of Naja kaouthia venom from North-East India and its neutralization by polyvalent antivenom

    PubMed Central

    Das, Diganta; Urs, Nanjaraj; Hiremath, Vilas; Vishwanath, Bannikuppe Sannanaik; Doley, Robin

    2013-01-01

    This study describes biochemical and biological properties of Naja kaouthia (Indian monocled cobra) venom of North-East India. The LD50 of the crude venom was found to be 0.148mg/kg and neurotoxicitic symptoms like paralysis of lower limbs and heavy difficulty in breathing at sub-lethal dose in mice was observed. The venom exhibited PLA2, indirect hemolytic and myotoxic activities but showed weak proteolytic and low direct hemolytic activities. It did not exhibit any hemorrhage when injected intradermally to mice. Anticoagulant activity was prominent when recalcification, prothrombin and activated partial thrombinplastin time were tested on platelet poor plasma. Rotem analysis of whole citrated blood in presence of venom showed delay in coagulation time and clot formation time. Fibrinogen of whole citrated blood was depleted by venom when analyzed in Sonoclot. Crude venom at 10µg and after 16hr of incubation was found to degrade α chain of fibrinogen. Neutralization study showed that Indian polyvalent antivenom could neutralize some of the biochemical and biological activities as well as its fibrinogenolytic activity. PMID:24349704

  16. Glass Research

    NASA Technical Reports Server (NTRS)

    Weinberg, M. C.

    1985-01-01

    Research efforts span three general areas of glass science: glass refining, gel-derived glasses, and nucleation and crystallization of glasses. Gas bubbles which are present in a glass product are defects which may render the glass totally useless for the end application. For example, optical glasses, laser host glasses, and a variety of other specialty glasses must be prepared virtually defect free to be employable. Since a major mechanism of bubble removal, buoyant rise, is virtually inoperative in microgravity, glass fining will be especially difficult in space. On the other hand, the suppression of buoyant rise and the ability to perform containerless melting experiments in space allows the opportunity to carry out several unique bubble experiments in space. Gas bubble dissolution studies may be performed at elevated temperatures for large bubbles with negligible bubble motion. Also, bubble nucleation studies may be performed without the disturbing feature of heterogeneous bubble nucleation at the platinum walls. Ground based research efforts are being performed in support of these potential flight experiments.

  17. Metallic glasses.

    PubMed

    Greer, A L

    1995-03-31

    Amorphous metallic alloys, relative newcomers to the world of glasses, have properties that are unusual for solid metals. The metallic glasses, which exist in a very wide variety of compositions, combine fundamental interest with practical applications. They also serve as precursors for exciting new nanocrystalline materials. Their magnetic (soft and hard) and mechanical properties are of particular interest.

  18. D-AKAP2:PKA RII:PDZK1 ternary complex structure: insights from the nucleation of a polyvalent scaffold.

    PubMed

    Sarma, Ganapathy N; Moody, Issa S; Ilouz, Ronit; Phan, Ryan H; Sankaran, Banumathi; Hall, Randy A; Taylor, Susan S

    2015-01-01

    A-kinase anchoring proteins (AKAPs) regulate cAMP-dependent protein kinase (PKA) signaling in space and time. Dual-specific AKAP2 (D-AKAP2/AKAP10) binds with high affinity to both RI and RII regulatory subunits of PKA and is anchored to transporters through PDZ domain proteins. Here, we describe a structure of D-AKAP2 in complex with two interacting partners and the exact mechanism by which a segment that on its own is disordered presents an α-helix to PKA and a β-strand to PDZK1. These two motifs nucleate a polyvalent scaffold and show how PKA signaling is linked to the regulation of transporters. Formation of the D-AKAP2: PKA binary complex is an important first step for high affinity interaction with PDZK1, and the structure reveals important clues toward understanding this phenomenon. In contrast to many other AKAPs, D-AKAP2 does not interact directly with the membrane protein. Instead, the interaction is facilitated by the C-terminus of D-AKAP2, which contains two binding motifs-the D-AKAP2AKB and the PDZ motif-that are joined by a short linker and only become ordered upon binding to their respective partner signaling proteins. The D-AKAP2AKB binds to the D/D domain of the R-subunit and the C-terminal PDZ motif binds to a PDZ domain (from PDZK1) that serves as a bridging protein to the transporter. This structure also provides insights into the fundamental question of why D-AKAP2 would exhibit a differential mode of binding to the two PKA isoforms. PMID:25348485

  19. Administration of a polyvalent mechanical bacterial lysate to elderly patients with COPD: Effects on circulating T, B and NK cells.

    PubMed

    Lanzilli, Giulia; Traggiai, Elisabetta; Braido, Fulvio; Garelli, Valentina; Folli, Chiara; Chiappori, Alessandra; Riccio, Anna Maria; Bazurro, Gyada; Agazzi, Alessia; Magnani, Alessandra; Canonica, Giorgio Walter; Melioli, Giovanni

    2013-01-01

    The modifications of the subsets of circulating lymphocytes were evaluated in a group of patients with COPD undergoing treatment with a polyvalent mechanical bacterial lysate (PMBL), a drug that is able to significantly modify the natural history of these patients. Using multicolor immune-florescence and flow cytometry, T, B subsets and NK cells were extensively studied both in the group of treated patients and in a disease and age matched controls. Despite the age, in treated patients, T and NK cells were significantly increased in numbers of circulating cells, but not in percentages, while B cells remained unmodified. CD3+4+T cells were increased in treated patients, while CD3+CD8T cells were unmodified by the treatment. Activated T cells were increased but Treg, resulted reduced both in percentage than in absolute numbers. Transitional B cells resulted increased (in percentage and in absolute numbers) in their late maturation step (T3), while only early Naïve B cells were increased by the treatment, while other naïve subpopulations were unmodified. Memory B cells were reduced in percentage (but remained unmodified as absolute numbers), while the most immature form of memory B cells was significantly increased. Finally, both switch memory B cells and plasma cells resulted unmodified by the PMBL treatment. These results clearly indicated that the administration of the PMBL, even in elderly patients with COPD, was able to induce a significant immune-stimulation and these results, at cellular level, clearly support the evidence that the mechanism of action of PMBL is strictly related to a direct effect on immune-competent cells. PMID:23206888

  20. Enzyme-linked immunosorbant assay (ELISA) of size-selected crotalid venom antigens by Wyeth's polyvalent antivenom.

    PubMed

    Schaeffer, R C; Randall, H; Resk, J; Carlson, R W

    1988-01-01

    The binding of Antivenom (Crotalidae) Polyvalent to fractions from crude venoms of eight crotalid and one viperid snake, obtained by high performance size-exclusion chromatography, was determined with an indirect enzyme-linked immunosorbent assay (ELISA). Most of the large (greater than 30,000 mol. wt) molecular mass crotalid venom fractions were associated with high (greater than 0.7 absorbance units) ELISA values. Similarly, the medium (13,000-30,000 mol. wt) and small (less than 14,000 mol. wt) molecular mass crotalid venom fractions were coincident with moderate (0.3-0.7 absorbance units) and low (less than 0.3 absorbance units) ELISA levels. Some variability in this pattern was seen with individual venom fractions. A distinctly different pattern of ELISA values were observed with two rattlesnake venoms: the South American (Crotalus durissus terrificus) and Mojave desert (Crotalus scutulatus scutulatus) rattlesnakes. The elution profile from these venoms showed a progression of low to moderate ELISA values within the large molecular mass fractions. This pattern was followed by a decline to low ELISA values throughout the remainder of the elution profile. When saw scaled viper (Echis carinatus leucogaster) venom fractions were tested, only background ELISA values were detected with antivenom. Similarly, background ELISA values were associated with the small molecular mass fractions of all venoms tested. In addition, the elution position for the basic peptides of southern Pacific (Crotalus viridis helleri) and timber (Crotalus h. horridus) rattlesnake venoms showed minimal ELISA values. These data support the view that except for the venom of C. durissus terrificus and C. s. scutulatus, most antivenom antibodies bind large (greater than 30,000 mol. wt) venom fractions. Thus, antivenom contains minimal levels of antibodies to the basic peptides in these venoms. PMID:3347932

  1. [Use of anti-D (Rh) IgG or intramuscular polyvalent human immunoglobulin in the treatment of chronic autoimmune thrombocytopenic purpura].

    PubMed

    Vizcaíno, G; Diez-Ewald, M; Arteaga-Vizcaíno, M; Torres, E

    1992-01-01

    The present study compares the effect of the intramuscular injection of low doses of IgG anti-D or human polyvalent immunoglobulin (Ig) on the platelet count of patients with CATP. Forty patients (14 children, 26 adults), 11 who had undergone splenectomy, were divided in the following groups of treatment: 20 patients received a single injection of 300 micrograms of IgG anti-D, 6 patients received the same dose as above plus 0.5 mg/kg daily of prednisone v.o and 14 patients received 640 mg of polyvalent Ig. Each patient was sequentially studied by measuring peripheral blood parameters, reticulocyte index, direct Coombs' test and C3-C4 determinations. Their blood group and Rh factor had been previously determined. The platelet response was evaluated as refractory (no response) and favorable (platelet increment over 50,000/microliters compared with initial platelet count). Patients with a favorable response over a month were considered as a prolonged remission. The results showed a favorable platelet response in 74% of the patients that received a single injection of IgG anti-D alone (one of the patients was Rh negative) or associated to prednisone, and 42.8% of the cases when polyvalent Ig was used. The patients who had not undergone splenectomy obtained better results than the group with splenectomy (62% vs 45%) and children showed a better response than adults (78.5% vs 46.1%). Forty five percent of prolonged remissions (including the Rh negative patient) were obtained with both schemes of IgG anti-D administration and only 28.5% when polyvalent Ig was used. The remissions were significantly longer with IgG anti-D (p < 0.01). The hematological and serological parameters did not show any significant modifications in all the cases and there was no adverse effects with the treatment. In conclusion, the intramuscular injection of immunoglobulins, especially IgG anti-D, produce an increase in the platelet count in some patients with CATP, several of them can obtain

  2. Glass microspheres

    SciTech Connect

    Day, D.E.; Ehrhardt, G.J.

    1988-12-06

    This patent describes a glass microsphere having a diameter of about 54 micrometers or less and adapted for radiation therapy of a mammal. The glass consists of essentially an yttrium oxide-aluminosilicate glass composition lying substantially within a quadrilateral region of the ternary composition diagram of the yttria-alumina-silica system, the quadrilateral region being defined by its four corners having the following combination of weight proportions of the components: 20% silica, 10% alumina, 70% yttria; 70% silica, 10% alumina, 20% yttria; 70% silica, 20% alumina, 10% yttria; and 20% silica, 45% alumina, 35% yttria, the glass having a chemical durability such that subsequent to irradiation and administration of the microsphere to the mammal, the mircosphere will not release a significant amount of yttrium-90 into the mammal's system.

  3. Glass electrolytes

    SciTech Connect

    Not Available

    1984-06-25

    The objective of this research is a glass electrolyte for use in sodium/sulfur batteries that has a low resistivity (100 ohm-cm at 300/sup 0/C) and is stable in the cell environment. Experiments in this program are focussed on glasses in the quaternary system: soda, alumina, zirconia and silica. The FY 1983 research on glass analogs of NASICON, parallel thermodynamic calculations, and a review of the literature in the areas of glass conductivity and corrosion resistance led to selection of this system for more detailed investigation. The main program elements are: (1) conductivity measurements at 300 to 500/sup 0/C; (2) differential thermal analysis for determination of glass-transition and crystallization temperatures; (3) static corrosion tests at 400/sup 0/C using Na, Na/sub 2/S/sub 4/, and S; (4) mechanical strength and fracture toughness measurements; and (5) sodium/sulfur cell tests at 350/sup 0/C. Elements (1) and (2) are nearly completed; element (3) is being initiated using the glasses prepared for (1) and (2), and elements (4) and (5) will begin in the first and second quarters of FY 1985, respectively. Fourteen quaternary glasses having a broad range of compositions have been made. The resistivities of these glasses at 300/sup 0/C extended from 130 to 3704 ohm-cm; the activation energies for conduction extended from 0.488 to 0.684 eV, and the glass transition temperatures extended from 397 to 685/sup 0/C. Through a multiple linear regression analysis of these data response surfaces were generated for resistivity, activation energy for conduction, and glass transition temperature over the composition region within the quaternary system that is bounded by SiO/sub 2/, Na/sub 2/O/sub 3/, Na/sub 2/AlO/sub 4/ and Na/sub 2/ZrO/sub 3/. These response surfaces indicated a new region of high conductivity and high glass transition temperature in the neighborhood of 42% soda, 31% silica and 27% alumina plus zirconia.

  4. Pinhole Glasses

    NASA Astrophysics Data System (ADS)

    Colicchia, Giuseppe; Hopf, Martin; Wiesner, Hartmut; Zollman, Dean

    2008-01-01

    Eye aberrations are commonly corrected by lenses that restore vision by altering rays before they pass through the cornea. Some modern promoters claim that pinhole glasses are better than conventional lenses in correcting all kinds of refractive defects such as myopia (nearsighted), hyperopia (farsighted), astigmatisms, and presbyopia. Do pinhole glasses really give better vision? Some ways to use this question for motivation in teaching optics have been discussed. For this column we include a series of experiments that students can complete using a model of the eye and demonstrate issues related to pinhole vision correction.

  5. Pinhole Glasses

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Hopf, Martin; Wiesner, Hartmut; Zollman, Dean

    2008-01-01

    Eye aberrations are commonly corrected by lenses that restore vision by altering rays before they pass through the cornea. Some modern promoters claim that pinhole glasses are better than conventional lenses in correcting all kinds of refractive defects such as myopia (nearsighted), hyperopia (farsighted), astigmatisms, and presbyopia. Do pinhole…

  6. Preparation and characterization of novel foamed porous glass-ceramics

    SciTech Connect

    Sasmal, Nibedita; Garai, Mrinmoy; Karmakar, Basudeb

    2015-05-15

    Foamed glass-ceramics without using foaming agent have been synthesized in a novel glass system of SrO-CaO-Al{sub 2}O{sub 3}-TiO{sub 2}-B{sub 2}O{sub 3}-SiO{sub 2}-P{sub 2}O{sub 5}-M{sub x}O{sub y} (where M = Ba, Mg, La, Ce and Ni) by a simple process of powder sintering. The glass and glass-ceramics are characterized by dilatometry, differential scanning calorimetry (DSC), heating stage microscopy (HSM), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), optical microscopy and Fourier transformed infrared spectroscopy (FTIR). All the glasses formed are amorphous and the glass transition temperature and dilatometric softening temperature of these glasses are found to be in the range 673–678 °C and 706–728 °C respectively. The glasses are highly stable as indicated by the DSC evaluated glass stability parameters of the range 195–240 °C. Quantitative sintering study of glass powder compacts revealed swelling in the samples with NiO and CeO{sub 2} corresponding to a geometry change of 75 and 108% around 900 °C respectively. With reference to this finding the glass powder compacts are heated to 900 °C and the foamed glass-ceramics are obtained. Characteristic crystalline silicate phases have been identified in the XRD studies and their microstructures are recorded by FESEM. Optical microscope study of the foamed samples revealed formation of bigger foamed cavity with residual pores in samples with NiO and CeO{sub 2} in comparison to samples with BaO, MgO and La{sub 2}O{sub 3}. The mean pore diameters of the samples with NiO and CeO{sub 2} are determined to be 43 and 32 μm, and their respective porosities are 2.34 and 1.82 cm{sup 3}/g respectively. Thus NiO and CeO{sub 2} are found to be very effective to obtain foamed glass-ceramics without using foaming agent by the viscous flow sintering of fine glass powder compacts along with the reduction of the respective polyvalent ions. - Highlights: • Synthesis of foamed porous glass

  7. Children's Glasses

    NASA Astrophysics Data System (ADS)

    Akerskog, Gunnar; Soderlund, Jan

    1980-07-01

    There is a common opinion among eye specialists and opticians that children's glasses often are not shaped for optimal fitting. A fundamental reason for this is the lack of data for the shaping of the bows, with the result that most children's glasses are reduced copies of adult's glasses. This report describes a photogrammetric method for collection of primary data for manufac-turing bows for children. An ordinary amateur camera was equipped with a stereo-adapter. With a few arrangements, such as projecting a pattern on the face and keeping the hair away from the ears, 600 children were photographed. A calibration photograph was exposed at the beginning and end of each film or when the equipment had been transported or otherwise disturbed. The photographs were measured in a stereocomparator and the coordinates analytically corrected for distortion. After determination of model coordinates the requested geometric information, such as pupillar distance, eye-ear distance, location of the bridge of the nose etc, was calculated. The shapes of average noses were presented as profile plots.

  8. Impact Strength of Glass and Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Bless, Stephan; Tolman, John

    2009-06-01

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning, Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression and the steady-state strength. For both glasses, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic---as opposed to intrinsic---property.

  9. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    SciTech Connect

    KRUGER AA; HRMA PR

    2009-10-08

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

  10. Concurrent injection of a rhabdovirus-specific DNA vaccine with a polyvalent, oil-adjuvanted vaccine delays the specific anti-viral immune response in Atlantic salmon, Salmo salar L.

    PubMed

    Skinner, Lisa A; LaPatra, S E; Adams, A; Thompson, K D; Balfry, S K; McKinley, R S; Schulte, P M

    2010-04-01

    Vaccines are commonly used in salmonid aquaculture as a method of disease prevention. Although there is a substantial amount of published research regarding the immunological and physiological effects following the injection of different polyvalent vaccines and DNA vaccines, there are no published reports examining the physiological and immunological effects of concurrent vaccine injection, which is the situation encountered in aquaculture. Using key immunological parameters such as lysozyme activity and specific antibody titres we examined the short-term activation of the immune response of cultured Atlantic salmon (Salmo salar L.) following concurrent injection with a traditional, polyvalent, oil-adjuvanted vaccine (AV) and an IHNV-specific DNA vaccine (DV). Our results indicate that different aspects of the innate and adaptive immune responses are influenced in either a positive or negative manner. While concurrent vaccine injection elicited an increase in lysozyme activity, changes in antibody titre (Ab) were antigen specific. The production of anti-Aeromonas salmonicida Abs was significantly greater in the combined vaccine group at 296 degree days post-vaccine injection (dd pvi), while the production of anti-Listonella anguillarum Abs was significantly greater at 106 dd pvi in the combined vaccine group. Of even greater interest was the apparent delay in production of IHNV-specific neutralizing antibodies (NAb) when the DV was injected concurrently with the polyvalent AV. The results indicated that concurrent injection of a polyvalent oil-AV and a DV can be beneficial to the production of antibodies; however, the specific anti-viral response may be delayed.

  11. IMPACT STRENGTH OF GLASS AND GLASS CERAMIC

    SciTech Connect

    Bless, S.; Tolman, J.

    2009-12-28

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  12. Impact Strength of Glass and Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Bless, S.; Tolman, J.

    2009-12-01

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  13. Chemical Principles Revisited: The Chemistry of Glass.

    ERIC Educational Resources Information Center

    Kolb, Doris; Kolb, Kenneth E.

    1979-01-01

    Presents a detailed discussion on the chemistry of glass. Topics discussed include: natural glass, early history, modern glass composition, raw materials for glass melting, chemically modified glasses, modern glass forming, glass ceramics, and new developments in glass research. (BT)

  14. Detection of Banana mild mosaic virus and Banana virus X by polyvalent degenerate oligonucleotide RT-PCR (PDO-RT-PCR).

    PubMed

    Teycheney, Pierre-Yves; Acina, Isabelle; Lockhart, Benham E L; Candresse, Thierry

    2007-06-01

    Viruses are important constraints to the movement and propagation of plant germplasm, especially for vegetatively propagated crops such as banana and plantain. Their control relies primarily on the use of virus-free plant material, whose production and certification requires sensitive and reliable detection methods. An existing polyvalent degenerate oligonucleotide RT-PCR (PDO-RT-PCR) assay was adapted to the detection of Banana mild mosaic virus (BanMMV) and Banana virus X, two Flexiviridae infecting Musa spp. PDO inosine-containing primers were found to be well suited to the detection of BanMMV, despite its high molecular diversity, but not to that of the highly conserved BVX, for which species-specific primers were designed. Sampling and sample processing steps were optimized in order to avoid nucleic acid purification prior to the reverse transcription step. A polyclonal anti-BanMMV antiserum was raised and successfully used for the immunocapture (IC) of BanMMV viral particles from leaf extracts, leading to the development of a PDO-IC-RT-nested PCR assay. Although the anti-BanMMV antiserum could to some extent recognize BVX viral particles, direct binding (DB) was shown to be a more efficient method for processing BVX-infected samples and a PDO-DB-RT-nested PCR assay was developed for the detection of BVX from leaf extracts. PMID:17280722

  15. Simultaneous oral immunization of mice with live attenuated Escherichia coli expressing LT192-STa 13 and LT 192-STb fusion immunogen, respectively, for polyvalent vaccine candidate.

    PubMed

    Liu, Wenxin; Li, Jinping; Bao, Jun; Li, Xingyue; Guan, Weikun; Yuan, Chaowen; Tang, Jie; Zhao, Zhiteng; Shi, Dongfang

    2015-05-01

    Previous epidemiological study showed that most of the porcine enterotoxin Escherichia coli (ETEC) strains harbor multiple enterotoxins but lack any of the fimbriae or non-fimbrial adhesion genes. Therefore, effective ETEC vaccines need to aim directly at all the enterotoxin antigens. The objective of this study was to evaluate the simultaneous immune effect of two live attenuated E. coli strains expressing LTR192G-STaA13Q and LTR192G-STb fusion immunogen, respectively. The results showed that both local mucosal and systemic immune responses against LT, STa, STb, and F41 were induced in BALB/c mice immunized orally with the recombinant E. coli strains ER-A and ER-B simultaneously. In addition, results of cellular immune responses showed that stimulation index (SI) values of immunized mice were significantly higher than control mice (P < 0.05) and a marked shift toward type-2 helper T lymphocyte (Th 2) immunity. Moreover, the induced antibodies demonstrated neutralizing effects on LT, STa, and STb producing E. coli infection. These data indicated that the use of recombinant E. coli ER-A and ER-B could be a valuable strategy for future polyvalent vaccine development of ETEC. PMID:25549617

  16. Detection of Banana mild mosaic virus and Banana virus X by polyvalent degenerate oligonucleotide RT-PCR (PDO-RT-PCR).

    PubMed

    Teycheney, Pierre-Yves; Acina, Isabelle; Lockhart, Benham E L; Candresse, Thierry

    2007-06-01

    Viruses are important constraints to the movement and propagation of plant germplasm, especially for vegetatively propagated crops such as banana and plantain. Their control relies primarily on the use of virus-free plant material, whose production and certification requires sensitive and reliable detection methods. An existing polyvalent degenerate oligonucleotide RT-PCR (PDO-RT-PCR) assay was adapted to the detection of Banana mild mosaic virus (BanMMV) and Banana virus X, two Flexiviridae infecting Musa spp. PDO inosine-containing primers were found to be well suited to the detection of BanMMV, despite its high molecular diversity, but not to that of the highly conserved BVX, for which species-specific primers were designed. Sampling and sample processing steps were optimized in order to avoid nucleic acid purification prior to the reverse transcription step. A polyclonal anti-BanMMV antiserum was raised and successfully used for the immunocapture (IC) of BanMMV viral particles from leaf extracts, leading to the development of a PDO-IC-RT-nested PCR assay. Although the anti-BanMMV antiserum could to some extent recognize BVX viral particles, direct binding (DB) was shown to be a more efficient method for processing BVX-infected samples and a PDO-DB-RT-nested PCR assay was developed for the detection of BVX from leaf extracts.

  17. A retrospective study of use of polyvalent anti-snake venom and risk factors for mortality from snake bite in a tertiary care setting

    PubMed Central

    Pore, Shraddha M.; Ramanand, Sunita J.; Patil, Praveenkumar T.; Gore, Alka D.; Pawar, Mayur P.; Gaidhankar, Smita L.; Ghanghas, Ravi R.

    2015-01-01

    Aims: Envenomation with poisonous snakes is associated with considerable morbidity and mortality. The present study was undertaken with the objectives of assessing anti-snake venom (ASV) use, early adverse reactions to ASV, premedication and clinical outcomes in snake bite patients. Association of various risk factors (age, gender, dose of ASV, time gap between snake bite and ASV administration, use of mechanical ventilation and type of snake bite) with mortality was also assessed. Settings and Design: This retrospective study was conducted at two Tertiary Care Teaching Hospitals. Subjects and Methods: The medical records of 176 patients of snake bite with documented use of ASV were retrospectively analyzed to retrieve relevant data. Statistical Analysis: Descriptive statistics was used to express results about ASV use, early adverse reactions to ASV, premedication and clinical outcomes. Univariate and multivariate analysis was performed to find out significant risk factors associated with mortality. Results: The main indication for ASV was vasculotoxic snake bite (75%) followed by neurotoxic snake bite (16%). Mean dose of ASV was 18.63 ± 14.52 vials. Prophylactic premedication with corticosteroids alone or in combination with antihistaminic was used in more than 70% patients. Early adverse reactions to ASV were seen in 4% patients. Neurotoxic snake bite was a significant risk factor associated with mortality in multivariate analysis. Conclusions: Neurotoxic snake bite is an independent predictor of mortality in snake bite patients. Currently used polyvalent ASV may be less effective in treating neurotoxic snake bite. PMID:26069363

  18. Repairing cracked glass

    NASA Technical Reports Server (NTRS)

    Helman, D. D.; Holt, J. W.; Smiser, L. V.

    1979-01-01

    Filing procedure consisting of machined lightweight fused-silica tiles coated with thin-layer of borosilicate glass produces homogeneous seal in thin glass. Procedure is useful in repairing glass envelopes, X-ray tub windows, Dewar flasks, and similar thin glass objects.

  19. Inverted glass harp

    NASA Astrophysics Data System (ADS)

    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.

  20. Inverted glass harp.

    PubMed

    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. PMID:26382336

  1. Glass-silicon column

    DOEpatents

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  2. Sintered porous DP-bioactive glass and hydroxyapatite as bone substitute.

    PubMed

    Lin, F H; Lin, C C; Liu, H C; Huang, Y Y; Wang, C Y; Lu, C M

    1994-10-01

    There is extensive experimental and surgical experience with the use of bone tissue to fill defects in the skeleton, to bridge non-union sites, and to pack defects in bone created from cyst curettage. DP-bioactive glass with a chemical composition of Na2O 8.4%, SiO2 39.6%, P2O5 12% and CaO 40% has been reported as an alternative bone substitute of high mechanical strength, good biocompatibility. and which has a tight bond with living tissue. The bonding layer between DP-bioactive glass and bone tissue was considered to be formed by dissolution of calcium and phosphate ions from the DP-bioactive glass into the surrounding body fluids. The biological hydroxyapatite was suspected to deposit directly onto the bonding layer. In order to confirm the interaction between the DP-bioactive glass and bone tissue, the developed bioactive glass was implanted into rabbit femur condyle for 2-32 weeks. The histological evaluation of DP-bioactive glass as a bone substitute was also investigated in the study. Porous hydroxyapatite bioceramic was used in the control group and the results were compared with those of DP-bioactive glass. The interface between the DP-bioactive glass and bone tissue examined with SEM-EPMA showed that the bioactive glass formed a reaction layer on the surface within 2 weeks after operation and formed a direct bond with natural bone. The elements contained in the bioactive glass apparently interdiffuse with the living bone and biological hydroxyapatite deposited onto the diffusion area, which was proved by EPMA and TEM. After implantation for over 8 weeks, the DP-bioactive glass was gradually biodegraded and absorbed by the living bone. Histological examination using the optical microscope showed that osteocytes grow into the inside of the DP-bioactive glass and the bioactive glass would be expected to be a part of bone.

  3. Picture Wall (Glass Structures)

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Photo shows a subway station in Toronto, Ontario, which is entirely glass-enclosed. The all-glass structure was made possible by a unique glazing concept developed by PPG Industries, Pittsburgh, Pennsylvania, one of the largest U.S. manufacturers of flat glass. In the TVS glazing system, transparent glass "fins" replace conventional vertical support members used to provide support for wind load resistance. For stiffening, silicone sealant bonds the fins to adjacent glass panels. At its glass research center near Pittsburgh, PPG Industries uses the NASTRAN computer program to analyze the stability of enclosures made entirely of glass. The company also uses NASTRAN to simulate stresses on large containers of molten glass and to analyze stress effects of solar heating on flat glass.

  4. Reaction cured glass and glass coatings

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Leiser, D. B.; Katvala, V. W. (Inventor)

    1978-01-01

    The invention relates to reaction cured glass and glass coatings prepared by reacting a compound selected from the group consisting of silicon tetraboride, silicon hexaboride, other boron silicides, boron and mixtures with a reactive glass frit composed of a porous high silica borosilicate glass and boron oxide. The glassy composites of the present invention are useful as coatings on low density fibrous porous silica insulations used as heat shields and for articles such as reaction vessels that are subjected to high temperatures with rapid heating and cooling and that require resistance to temperature and repeated thermal shock at temperatures up to about 1482C (2700PF).

  5. GlassForm

    2011-09-16

    GlassForm is a software tool for generating preliminary waste glass formulas for a given waste stream. The software is useful because it reduces the number of verification melts required to develop a suitable additive composition. The software includes property models that calculate glass properties of interest from the chemical composition of the waste glass. The software includes property models for glass viscosity, electrical conductivity, glass transition temperature, and leach resistance as measured by the 7-daymore » product consistency test (PCT).« less

  6. Cholera toxin-B (ctxB) antigen expressing Salmonella Typhimurium polyvalent vaccine exerts protective immune response against Vibrio cholerae infection.

    PubMed

    Vishwakarma, Vikalp; Sahoo, Sushree Sangita; Das, Susmita; Ray, Shilpa; Hardt, Wolf-Dietrich; Suar, Mrutyunjay

    2015-04-01

    Live attenuated vaccines are cost effective approach for preventing a broad range of infectious diseases, and thus are of great interest. However, immune-defects can predispose the patient to infections by the vaccine candidate itself. So far, few live vaccine candidates have been designed specifically for immune compromised individuals. Recently, we reported a new Salmonella Typhimurium Z234-vaccine strain (Periaswamy et al., PLoS ONE 2012;7:e45433), which was specifically attenuated in the NADPH-oxidase deficient host. In the present study, the Z234-vaccine strain was further engineered to express heterologous antigen (Vibrio cholerae toxin antigen subunit-B, i.e. CtxB) with the intention of creating a vector for simultaneous protection against Cholera and Salmonellosis. The primary aim of this study was to ensure the expression of CtxB antigen by the recombinant vaccine strain Z234-pMS101. The antigen CtxB was expressed through Z234 as a fusion protein with N-terminal signal sequence of Salmonella outer protein (SopE), an effector protein from Salmonella under the control of SopE promoter. The CtxB-expressing plasmid construct pMS101 (pM968-pSopE-ctxB) was found to be stable both in vitro and in vivo. In an oral mouse infection model, the vaccine strain Z234-pMS101 efficiently colonized the host gut. The extent of protection was confirmed after challenging the immunized hosts with live V. cholerae. Vaccinated mice showed reduced gut colonization by V. cholerae. Further assessment of immunological parameters supported the possibility of conferring effective immune response by Z234-pMS101 vaccine strain. Overall, the Z234-pMS101 vaccine strain showed potential as a promising polyvalent vaccine candidate to protect against S. Typhimurium and V. cholerae infection simultaneously.

  7. 6. Looking glass aircraft in the project looking glass historic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Looking glass aircraft in the project looking glass historic district. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Avenue between Comstat Drive & Nightwatch Avenue, Offutt Air Force Base, Bellevue, Sarpy County, NE

  8. Oxynitride glass fibers

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  9. Glass tube splitting tool

    NASA Technical Reports Server (NTRS)

    Klein, J. A.; Murray, C. D.; Stein, J. A.

    1971-01-01

    Tool accurately splits glass tubing so cuts are aligned 180 deg apart and reassembled tube forms low pressure, gastight enclosure. Device should interest industries using cylindrical closed glass containers.

  10. Sublingual therapeutic immunization with a polyvalent bacterial preparation in patients with recurrent respiratory infections: immunomodulatory effect on antigen-specific memory CD4+ T cells and impact on clinical outcome

    PubMed Central

    Alecsandru, D; Valor, L; Sánchez-Ramón, S; Gil, J; Carbone, J; Navarro, J; Rodríguez, J J; Rodríguez-Sainz, C; Fernández-Cruz, E

    2011-01-01

    Recurrent respiratory tract infections (RRTIs) are common clinical conditions in individuals with alterations of the immune function. A prospective open pilot study in a cohort of patients with RRTIs has been performed to assess whether sublingual immunization with a polyvalent bacterial vaccine could exert an immunomodulatory effect on the antigen-specific immunological responses and have an impact on the clinical outcome. Seventeen patients with RRTIs were recruited. An oral polyvalent bacterial preparation (Bactek®) was administered to all patients daily for 6 months. Immunological assessment was performed at baseline and at the end of immunization. Immunological measurements included: T cell-specific proliferations of CD3+CD4+ and CD3+CD8+ to Bactek® antigens, total immunoglobulin levels, antibodies to pneumococcal polysaccharide and tetanus toxoid and B, T and natural killer (NK) cell subsets. There was a significant increase in the proliferative capacity of CD3+CD4+ T cells specific to Bactek® antigens at month 6 in comparison to baseline (P < 0·0001). A significant increase in total CD3+ T cells was also observed (P < 0·05). No significant differences were observed between baseline and month 6 in levels of total immunoglobulins, specific antibodies and B, T or NK cell subsets. A significant reduction in the patient's rate of RRTIs was observed compared with 1 year prior to initiation of therapy (P < 0·0001). The results demonstrate that long-term administration of a sublingual polyvalent bacterial preparation in patients with RRTIs exerts an immune stimulating effect on CD4+ T helper cell responses to bacterial antigens which could be associated with clinical benefit. PMID:21391984

  11. Clinical safety of a polyvalent F(ab')2 equine antivenom in 223 African snake envenomations: a field trial in Cameroon. VAO (Venin Afrique de l'Ouest) Investigators.

    PubMed

    Chippaux, J P; Lang, J; Eddine, S A; Fagot, P; Rage, V; Peyrieux, J C; Le Mener, V

    1998-01-01

    A large-scale clinical trials was conducted, according to World Health Organization Good Clinical Practice guidelines, in 7 centres in north Cameroon to determine the safety and efficacy of a polyvalent antivenom composed of purified F(ab')2. This study included 223 patients presenting clinically with obvious snake bite, predominantly due to Echis ocellatus (viper), the most abundant species in this savannah region. Clinical surveillance was maintained for 5 d in all patients and until the twenty-sixth day in 74% of cases. Two 10 mL ampoules of polyvalent F(ab')2 equine antivenom (Ipser Africa) were administered to each patient by intravenous infusion. If necessary, treatment was repeated 1 h after the end of the first infusion, and then with a frequency determined by the patient's clinical condition. Before initiation of antivenom treatment, the main clinical disorders observed on admission were oedema (93.7%) and haemorrhage (48.9%), with a clotting time longer than 30 min in 65.4% of patients. Clinical cure was obtained in 213 patients (96.8%). No amputation was necessary, and the case fatality rate was only 1.3%. On average, 4.6 (+/- 3.7) ampoules were administered per patient; 43% of subjects recovered after only a single infusion of 2 ampoules. Early adverse reactions, of varying degrees of severity, were observed in 6.3% of patients. A severe early reaction, anaphylactic shock, was observed in only one patient (0.4%). Serum sickness was observed in another patient. Polyvalent F(ab')2 equine antivenom given by repeated 20 mL intravenous infusions is a safe and effective treatment for envenomation caused by African vipers. PMID:10326114

  12. Technique for Machining Glass

    NASA Technical Reports Server (NTRS)

    Rice, S. H.

    1982-01-01

    Process for machining glass with conventional carbide tools requires a small quantity of a lubricant for aluminum applied to area of glass to be machined. A carbide tool is then placed against workpiece with light pressure. Tool is raised periodically to clear work of glass dust and particles. Additional lubricant is applied as it is displaced.

  13. Glass in Class

    ERIC Educational Resources Information Center

    Greaves, Neville

    2005-01-01

    Glass is reviewed from fabrication to application, laying emphasis on the wide-ranging physics involved. This begins with liquids and solids and the way in which glasses are defined and can be demonstrated in the classroom. At the atomic level the regular structure of crystals and their irregular counterparts in glasses are explained through…

  14. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, M.; Watson, E.B.; Acocella, J.

    1986-11-04

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10[sup 7] rad, the coloration resistant glass does not lose transparency. 3 figs.

  15. Oxynitride glass production procedure

    DOEpatents

    Weidner, Jerry R.; Schuetz, Stanley T.; O'Brien, Michael H.

    1991-01-01

    The invention is a process for the preparation of high quality oxynitride glasses without resorting to high pressures. Nitrogen-containing compounds such as Si.sub.3 N.sub.4 are first encapsulated in a low melting temperature glass. Particles of the encapsulated nitrogen-containing compound are mixed with other oxide glass-formers and melted in an atmosphere of flowing nitrogen and in the presence of buffering gas to form the oxynitride glass. Glasses containing up to 15 at % nitrogen have been prepared by this method.

  16. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, Minoru; Watson, E. Bruce; Acocella, John

    1986-01-01

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10.sup.7 rad, the coloration resistant glass does not lose transparency.

  17. Acoustics of glass harmonicas

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.

    2001-05-01

    Glass musical instruments are probably as old as glassmaking. At least as early as the 17th century it was discovered that wine glasses, when rubbed with a wet finger, produced a musical tone. A collection of glasses played in this manner is called a glass harp. Another type of glass harmonica, called the armonica by its inventor Benjamin Franklin, employs glass bowls or cups turned by a horizontal axle, so the performer need only touch the rim of the bowls as they rotate to set them into vibration. We discuss the modes of vibration of both types of glass harmonica, and describe the different sounds that are emitted by rubbing, tapping, or bowing them. Rubbing with a wet finger tends to excite only the (2,0) mode and its harmonics through a ``stick-slip'' process, while tapping excites the other modes as well.

  18. Random pinning glass model.

    PubMed

    Karmakar, Smarajit; Parisi, Giorgio

    2013-02-19

    Glass transition, in which viscosity of liquids increases dramatically upon decrease of temperature without any major change in structural properties, remains one of the most challenging problems in condensed matter physics despite tremendous research efforts in past decades. On the other hand, disordered freezing of spins in magnetic materials with decreasing temperature, the so-called "spin glass transition," is understood relatively better. A previously found similarity between some spin glass models and the structural glasses inspired development of theories of structural glasses based on the scenario of spin glass transition. This scenario, although it looks very appealing, is still far from being well established. One of the main differences between standard spin systems and molecular systems is the absence of quenched disorder and the presence of translational invariance: it often is assumed that this difference is not relevant, but this conjecture still needs to be established. The quantities, which are well-defined and characterized for spin models, are not easily calculable for molecular glasses because of the lack of quenched disorder that breaks the translational invariance in the system. Thus the characterization of the similarity between spin and the structural glass transition remains an elusive subject. In this study, we introduced a model structural glass with built-in quenched disorder that alleviates this main difference between the spin and molecular glasses, thereby helping us compare these two systems: the possibility of producing a good thermalization at rather low temperatures is one of the advantages of this model. PMID:23382186

  19. Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

    PubMed

    Kotz, Frederik; Plewa, Klaus; Bauer, Werner; Schneider, Norbert; Keller, Nico; Nargang, Tobias; Helmer, Dorothea; Sachsenheimer, Kai; Schäfer, Michael; Worgull, Matthias; Greiner, Christian; Richter, Christiane; Rapp, Bastian E

    2016-06-01

    Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals. PMID:27060964

  20. Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

    PubMed

    Kotz, Frederik; Plewa, Klaus; Bauer, Werner; Schneider, Norbert; Keller, Nico; Nargang, Tobias; Helmer, Dorothea; Sachsenheimer, Kai; Schäfer, Michael; Worgull, Matthias; Greiner, Christian; Richter, Christiane; Rapp, Bastian E

    2016-06-01

    Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals.

  1. Diamond turning of glass

    SciTech Connect

    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

  2. Containerless processing of glass

    NASA Technical Reports Server (NTRS)

    Happe, R. A.

    1981-01-01

    Ground-based research on the containerless melting of glass and experiments performed during a flight on the SPAR 6 are described. Experiments leading to selection of the flight sample composition, a silica-modified gallia/calcia glass, and the preparation of a one quarter inch diameter flight sample are described. During the flight experiment, a sample of the glass was containerless melted and cooled to a clear glass in a single axis acoustic positioning apparatus. The functioning of the flight experimental hardware was evaluated. The evaluation of the sample is presented.

  3. Drugstore Reading Glasses

    NASA Astrophysics Data System (ADS)

    Erlichson, Herman

    2006-03-01

    The occasion for this paper was my reading of a paper in the February 2005 issue of TPT. As one gets older the near point of the eye begins to recede.2 This is called presbyopia.3 An alternative to purchasing glasses from an optometrist is to purchase an inexpensive pair of reading glasses in a pharmacy. The pharmacy has these glasses ordered by diopters corresponding to the strength of the lens needed for a particular presbyopic eye. The glasses are, of course, not available for myopic eyes.

  4. Glass--Sand + Imagination

    NASA Astrophysics Data System (ADS)

    Kolb, Kenneth E.; Kolb, Doris K.

    2000-07-01

    Glass is older than recorded history, and yet it is as new as tomorrow! How, when, or where man first learned to make glass is not known, but we do know that the ancient Egyptians were making glass articles as early as 2,600 B.C.E. (The making of glass beads may have begun as much as 3000 years earlier.) They used it to make jewelry and luxury items, such as decorative bowls and perfume bottles, available only to the wealthy.

  5. Apollo 15 green glasses.

    NASA Technical Reports Server (NTRS)

    Ridley, W. I.; Reid, A. M.; Warner, J. L.; Brown, R. W.

    1973-01-01

    The samples analyzed include 28 spheres, portions of spheres, and angular fragments from soil 15101. Emerald green glasses from other soils are identical to those from 15101. The composition of the green glass is unlike that of any other major lunar glass group. The Fe content is comparable to that in mare basalts, but Ti is much lower. The Mg content is much higher than in most lunar materials analyzed to date, and the Cr content is also high. The low Al content is comparable to that of mare basalt glasses.

  6. Getting Started with Glass

    ERIC Educational Resources Information Center

    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…

  7. Glasses and Contact Lenses

    MedlinePlus

    ... Here's Help White House Lunch Recipes Glasses and Contact Lenses KidsHealth > For Kids > Glasses and Contact Lenses Print A A A Text Size What's ... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ...

  8. Surface Conductive Glass.

    ERIC Educational Resources Information Center

    Tanaka, John; Suib, Steven L.

    1984-01-01

    Discusses the properties of surface-conducting glass and the chemical nature of surface-conducting stannic (tin) oxide. Also provides the procedures necessary for the preparation of surface-conducting stannic oxide films on glass substrates. The experiment is suitable for the advanced inorganic chemistry laboratory. (JN)

  9. Glass leaching performance

    SciTech Connect

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

    1983-05-01

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

  10. Defense HLW Glass Degradation Model

    SciTech Connect

    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.

  11. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    NASA Astrophysics Data System (ADS)

    May, J. C.; Rey, L.; Lee, Chi-Jen; Arciniega, Juan

    2004-09-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

  12. Glass electrolyte composition

    DOEpatents

    Kucera, Gene H.; Roche, Michael F.

    1985-01-01

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na.sub.2 O, ZrO.sub.2, Al.sub.2 O.sub.3 and SiO.sub.2 in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2.times.10.sup.-3 (ohm-cm).sup.-1 at 300.degree. C. and a glass transition temperature in excess of 500.degree. C.

  13. Glass electrolyte composition

    DOEpatents

    Kucera, G.H.; Roche, M.F.

    1985-01-08

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na/sub 2/O, ZrO/sub 2/, Al/sub 2/O/sub 3/ and SiO/sub 2/ in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2 x 10/sup -3/ (ohm-cm)/sup -1/ at 300/sup 0/C and a glass transition temperature in excess of 500/sup 0/C.

  14. Waste glass weathering

    SciTech Connect

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

    1993-12-31

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

  15. Super ionic conductive glass

    DOEpatents

    Susman, Sherman; Volin, Kenneth J.

    1984-01-01

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

  16. Super ionic conductive glass

    DOEpatents

    Susman, S.; Volin, K.J.

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

  17. Glass Stronger than Steel

    DOE R&D Accomplishments Database

    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.

  18. Whisker reinforced glass ceramic

    SciTech Connect

    Hirschfeld, D.A.; Brown, J.J. Jr.

    1996-06-03

    The process for making an in-situ whisker reinforced glass-ceramic that is up to 1.5 times as strong as conventional glass-ceramics was developed at Virginia Tech and patented in 1993. This technology has been identified as having commercial potential for use in high temperature heat exchanger applications for the electric power generation field by the National Center for Appropriate Technology (NCAT). This technology was licensed by MATVA, Inc., a small Virginia business, for further development. In particular, the goal of this project was to develop a property database and conduct initial testing of heat exchanger prototypes to demonstrate its potential application. This final report describes how the glass precursor was formed, physical properties of the glass-ceramic, techniques for making heat exchanger prototypes.

  19. THE COLOR GLASS CONDENSATE.

    SciTech Connect

    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.

  20. Frangible glass canisters

    NASA Technical Reports Server (NTRS)

    Seifert, R.

    1972-01-01

    The need for a canister that can release its contents without disturbing the contents dynamically is discussed. The solution of this problem by the use of a frangible glass canister is considered. The basic theory applicable to frangible glass and the method of initiating a command flaw are discussed. A brief description of the test program and the results of a flight test are presented.

  1. Metallic glass composition

    DOEpatents

    Kroeger, Donald M.; Koch, Carl C.

    1986-01-01

    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.

  2. Display innovations through glass

    NASA Astrophysics Data System (ADS)

    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.

  3. Glass fiber insulation

    SciTech Connect

    Griffith, E.J.; Ngo, T.M.

    1993-06-29

    A composition for a glass fiber insulation is described comprising a loose mat of glass fibers having at least a portion of the surface coated with a water insoluble, non-hygroscopic, amorphous aluminum phosphate polymer having a molar ratio of Al[sub 2]O[sub 3] to P[sub 2]O[sub 5] of less than 1 and providing a substantial thermal resistance.

  4. Method for making glass nonfogging

    DOEpatents

    Lord, David E.; Carter, Gary W.; Petrini, Richard R.

    1979-01-01

    A method for rendering glass nonfogging (to condensation fog) by sandwiching the glass between two electrodes such that the glass functions as the dielectric of a capacitor, a large alternating current (AC) voltage is applied across the electrodes for a selected time period causing the glass to absorb a charge, and the electrodes are removed. The glass absorbs a charge from the electrodes rendering it nonfogging. The glass surface is undamaged by application of the AC voltage, and normal optical properties are unaffected. This method can be applied to optical surfaces such as lenses, auto windshields, mirrors, etc., wherever condensation fog on glass is a problem.

  5. Baseline LAW Glass Formulation Testing

    SciTech Connect

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

    2013-06-13

    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.

  6. Volcanic Glasses: Construction Materials

    NASA Astrophysics Data System (ADS)

    Moskowitz, Samuel E.

    1998-01-01

    Natural glass is the product of rapidly cooled molten rock. Two natural sources of the melt are volcanic eruption and meteoritic impact. Pure glass is an amorphous aggregate. Volcanic glass is a material that could be utilized in the construction of extraterrestrial outposts. Pumice and perlite are volcanic glasses currently used in the building industry. Samples of natural volcanic glass found in the lunar regolith were returned to Earth as part of the Apollo and Luna programs. An alpha proton X-ray spectrometer onboard the Pathfinder recently examined martian rocks located in the vicinity of the lander craft. Preliminary results of chemical composition by weight of SiO2 50-55%, Al203 11-13%, K20 1-2%, Na20 2-5%, CaO 4-6%, MgO 3-7%, FeO 12-14%, S03 2-5%, and MnO <1% were given for two rocks. Parenthetically, the values for K and Mn were perhaps too high, and the analysis was based on X-ray data only. The appreciable amount of silica already found on Mars and empirical evidence to support the hypothesis that the planet once had water sufficient to rapidly cool magma imply the possibility of discovering natural glass of volcanic origin in subsequent missions.

  7. Containerless synthesis of interesting glasses

    NASA Technical Reports Server (NTRS)

    Weinberg, Michael C.

    1990-01-01

    One aspect of containerless glass experimentation was thoroughly examined: glass forming ability. It is argued that although containerless processing will abet glass formation, other ground-based methods can do the job better. However, these methods have limitations, such as sample dimensions and concomitant ability to make property measurements. Most importantly, perhaps, is the observation that glass properties are a function of preparation procedure. Thus, it seems as though there still is an argument for use of containerless processing for glass forming.

  8. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    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

  9. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    SciTech Connect

    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. Sol-Gel Glasses

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.

    1985-01-01

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

  11. Glass matrix armor

    DOEpatents

    Calkins, Noel C.

    1991-01-01

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

  12. Jet penetration in glass

    SciTech Connect

    Moran, B.; Glenn, L.A.; Kusubov, A.

    1991-05-01

    We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

  13. Glass strengthening and patterning methods

    DOEpatents

    Harper, David C; Wereszczak, Andrew A; Duty, Chad E

    2015-01-27

    High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

  14. Transient nucleation in glasses

    NASA Technical Reports Server (NTRS)

    Kelton, K. F.

    1991-01-01

    Nucleation rates in condensed systems are frequently not at their steady state values. Such time dependent (or transient) nucleation is most clearly observed in devitrification studies of metallic and silicate glasses. The origin of transient nucleation and its role in the formation and stability of desired phases and microstructures are discussed. Numerical models of nucleation in isothermal and nonisothermal situations, based on the coupled differential equations describing cluster evolution within the classical theory, are presented. The importance of transient nucleation in glass formation and crystallization is discussed.

  15. Containerless processing of fluoride glass

    NASA Technical Reports Server (NTRS)

    Doremus, Robert H.

    1990-01-01

    Ground-based experiments on glass formation, crystallization, surface tension, vaporization, and chemical durability of a zirconium-barium-lanthanum (ZBL) fluoride glass are summarized. In a container large, columnar grains grew out from the container-glass interface during cooling. The main crystalline phase was alpha BaZrF6. A ZBL glass sphere was levitated acoustically during Shuttle flight STS-11. The glass was melted and then cooled while being levitated (containerless). Crystallization in the recovered sample was very fine and mainly beta BaZr2F10, showing the influence of the container on the nucleation and microstructure of crystallization in the glass. Glass formation should be easier for a containerless glass than in a container.

  16. Characterizing glass frits for slurries

    NASA Technical Reports Server (NTRS)

    Nakano, H. N.

    1979-01-01

    Glass frit can be mixed with consistently reproducible properties even from different batches of glass frit using technique to measure one quantity that determines integrated properties of frit for combination with given liquid.

  17. Microexplosions in Tellurite Glasses

    SciTech Connect

    Sundaram, S. K.; Schaffer, C. B.; Mazur, E.

    2003-03-01

    Femtosecond laser pulses were used to initiate microexplosions in baseline, Al2O3-doped, and La2O3-doped sodium tellurite glasses. Single or multiple-shots were used in the experiments. Writing of simple structures (periodic array of voxels as well as lines) was demonstrated. The regions of microexplosion and writing were characterized using scanning electron microscopy (SEM, energy dispersive spectrometer (EDS), and atomic force microscopy (AFM) postmortem. Fingerprints of microexplosions, concentric lines within the region and a concentric ring outside the region due to shock wave generated during the microexplosions were evident. In the case of the baseline glass, no chemistry change was observed within the region of microexplosion. But, Al2O3-doped and La2O3-doped glasses showed depletion of the dopant from the edge to the center of the region of microexplosions, indicating chemistry gradient within the regions. Interrogation of the bulk and laser-treated regions using micro-Raman spectroscopy revealed no structural change due the microexplosions and writing within these glasses. These data were attributed to the localization of the effect to small regions due to tightly focused laser pulses used in the experiments.

  18. Glass ceilings of professionalisation.

    PubMed

    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

  19. "Stained Glass" Landscape Windows

    ERIC Educational Resources Information Center

    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…

  20. Stained-Glass Pastels

    ERIC Educational Resources Information Center

    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…

  1. CADMIUM PHOSPHATE GLASS

    DOEpatents

    Carpenter, H.W.; Johnson, P.D.

    1963-04-01

    A method of preparing a cadmium phosphate glass that comprises providing a mixture of solid inorganic compounds of cadmuim and phosphate having vaporizable components and heating the resulting composition to a temperature of at least 850 un. Concent 85% C is presented. (AEC)

  2. Glass ceilings of professionalisation.

    PubMed

    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.

  3. What Glass Ceiling?

    ERIC Educational Resources Information Center

    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)

  4. Glass and ceramics. [lunar resources

    NASA Technical Reports Server (NTRS)

    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.

  5. Yesterday's Trash Makes Tomorrow's "Glass"

    ERIC Educational Resources Information Center

    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…

  6. Barstow heliostat mirror glass characterization

    SciTech Connect

    Lind, M.A.; Buckwalter, C.Q.

    1980-09-01

    The technical analysis performed on the special run of low iron float glass procured from the Ford Glass Division for the ten megawatt solar thermal/electric pilot power plant to be constructed at Barstow, California is discussed. The topics that are addressed include the optical properties and the relative durability of the glass. Two optical parameters, solar transmittance and optical flatness, were measured as referenced in the specification and found to be better than the stated tolerances. The average solar transmittance exceeded 0.890 transmittance units. The glass also exhibited optical angular flatness deviations less than +-1.0 mrad as required. Both qualitative and quantitative accelerated weathering tests were performed on the glass in order to compare its durability to other soda lime float glass and alternate composition glasses of interest to the solar community. In both the quantitative leaching experiments and the more qualitative room temperature and elevated temperature water vapor exposure experiments the heliostat glass exhibited the same characteristics as the other soda-lime silicate float glasses. As a final test for mirroring compatability, selected samples of the production run of the glass were sent to four different commercial manufacturers for mirror coating. None of the manufacturers reported any difficulty silvering the glass. Based on the tests performed, the glass meets or exceeds all optical specifications for the Barstow heliostat field.

  7. Water's second glass transition.

    PubMed

    Amann-Winkel, Katrin; Gainaru, Catalin; Handle, Philip H; Seidl, Markus; Nelson, Helge; Böhmer, Roland; Loerting, Thomas

    2013-10-29

    The glassy states of water are of common interest as the majority of H2O in space is in the glassy state and especially because a proper description of this phenomenon is considered to be the key to our understanding why liquid water shows exceptional properties, different from all other liquids. The occurrence of water's calorimetric glass transition of low-density amorphous ice at 136 K has been discussed controversially for many years because its calorimetric signature is very feeble. Here, we report that high-density amorphous ice at ambient pressure shows a distinct calorimetric glass transitions at 116 K and present evidence that this second glass transition involves liquid-like translational mobility of water molecules. This "double Tg scenario" is related to the coexistence of two liquid phases. The calorimetric signature of the second glass transition is much less feeble, with a heat capacity increase at Tg,2 about five times as large as at Tg,1. By using broadband-dielectric spectroscopy we resolve loss peaks yielding relaxation times near 100 s at 126 K for low-density amorphous ice and at 110 K for high-density amorphous ice as signatures of these two distinct glass transitions. Temperature-dependent dielectric data and heating-rate-dependent calorimetric data allow us to construct the relaxation map for the two distinct phases of water and to extract fragility indices m = 14 for the low-density and m = 20-25 for the high-density liquid. Thus, low-density liquid is classified as the strongest of all liquids known ("superstrong"), and also high-density liquid is classified as a strong liquid. PMID:24101518

  8. Glass transition and stable glass formation of tetrachloromethane

    NASA Astrophysics Data System (ADS)

    Chua, Y. Z.; Tylinski, M.; Tatsumi, S.; Ediger, M. D.; Schick, C.

    2016-06-01

    Physical vapor deposition (PVD) has been used to prepare organic glasses with very high kinetic stability and it has been suggested that molecular anisotropy is a prerequisite for stable glass formation. Here we use PVD to prepare glasses of tetrachloromethane, a simple organic molecule with a nearly isotropic molecular structure. In situ AC nanocalorimetry was used to characterize the vapor-deposited glasses. Glasses of high kinetic stability were produced by deposition near 0.8 Tg. The isothermal transformation of the vapor-deposited glasses into the supercooled liquid state gave further evidence that tetrachloromethane forms glasses with high kinetic stability, with the transformation time exceeding the structural relaxation time of the supercooled liquid by a factor of 103. The glass transition temperature of liquid-cooled tetrachloromethane is determined as Tg ≈ 78 K, which is different from previously reported values. The frequency dependence of the glass transition was also determined and the fragility was estimated as m ≈ 118. The successful formation of PVD glasses of tetrachloromethane which have high kinetic stability argues that molecular asymmetry is not a prerequisite for stable glass formation.

  9. Volcanic glass as a natural analog for borosilicate waste glass

    SciTech Connect

    Morgenstein, M.E.; Shettel, D.L.

    1994-12-31

    Obsidian and basaltic glass are opposite end-members of natural volcanic glass compositions. Syngenetic and diagenetic tensile failure in basaltic glass (low silica glass) is pervasive and provides abundant alteration fronts deep into the glass structure. Perlitic fracturing in obsidian (high silica glass) limits the alteration zones to an {open_quotes}onion skin{close_quotes} geometry. Borosilicate waste glass behaves similarly to the natural analog of basaltic glass (sideromelane). During geologic time, established and tensile fracture networks form glass cells (a three-dimensional reticulated pattern) where the production of new fracture surfaces increases through time by geometric progression. This suggests that borosilicate glass monoliths will eventually become rubble. Rates of reaction appear to double for every 12C{degrees} of temperature increase. Published leach rates suggest that the entire inventory of certain radionuclides may be released during the 10,000 year regulatory time period. Steam alteration prior to liquid attack combined with pervasive deep tensile failure behavior may suggest that the glass waste form is not license defensible without a metallic- and/or ceramic-type composite barrier as an overpack.

  10. Apollo 12 ropy glasses revisited

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. The administration of a polyvalent mechanical bacterial lysate in elderly patients with COPD results in serological signs of an efficient immune response associated with a reduced number of acute episodes.

    PubMed

    Ricci, Rossella; Palmero, Candida; Bazurro, Gyada; Riccio, Anna Maria; Garelli, Valentina; Di Marco, Eddi; Cirillo, Carmelina; Braido, Fulvio; Canonica, Giorgio Walter; Melioli, Giovanni

    2014-02-01

    The administration of a polyvalent mechanical bacterial lysate (PMBL) in elderly patients with COPD has been shown to reduce the number of exacerbation. This is largely related to the involvement of cells belonging to the innate and the adaptive immune system (including dendritic cells, granulocytes, T and B lymphocytes and NK cells) that actively cooperate inducing the production of specific opsonizing antibodies directed to the antigens of PMBL. We have evaluated the production of antibodies directed to respiratory and systemic pathogens in a group of elderly COPD patients, recruited in a clinical trial, ancillary to a larger multicenter double blind, placebo-controlled, parallel-designed clinical trial in which patients were randomized to daily receive either PMBL or placebo. The treated group not only experienced a reduced number of seroconversion, but also, better controlled the number of infectious episodes and COPD exacerbations. It was thus evident that the administration of PMBL resulted not only effective in inducing the secretion of specific antibodies, but also effective in reducing the infectious episodes trough the potentiation of the antibody-mediated arm of the immune response. PMID:23792312

  12. The performance of Glass GEM

    NASA Astrophysics Data System (ADS)

    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%.

  13. Profiles in garbage glass containers

    SciTech Connect

    Miller, C.

    1997-09-01

    Glass containers are made from sand, limestone, soda ash, cullet (crushed bottles), and various additives, including those used to color brown, green, or blue bottles. Sixty percent of the glass used in the US is clear (flint) and one-fourth is brown (amber). Almost half of the green bottles are imported wind and beer bottles. Other glass products include flat glass such as windows; fiberglass insulation; and glassware. These products use different manufacturing processes and different additives than container glass. This profile covers only container glass. Glass bottles are commonly collected in curb-side programs. Losses due to breakage and the abrasiveness of glass during collection and processing offset their low collection and processing costs. Breakage solutions include installation of interior baffles or nets in the collection trucks, special glass-only truck compartments, and limiting the number of times glass is transferred after collection before final processing. Ten states require deposits on glass bottles for beer and soft drinks and related items.

  14. Fluoride glass: Crystallization, surface tension

    NASA Technical Reports Server (NTRS)

    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.

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

    DOEpatents

    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.

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

    DOEpatents

    Kelly, Michael D.; Kramer, Daniel P.

    1987-11-10

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

  17. Using small glass catalogs

    NASA Astrophysics Data System (ADS)

    Tesar, John C.

    2000-07-01

    Changes in glass catalogs from the major manufacturers, Schott, Ohara, Hoya, Corning, and Summita, are a future certainty. The ongoing efforts of these companies to eliminate arsenic, lead, and other environmentally unfriendly materials may well have an additional effect on the size of their catalogs also. We should not assume a zero-sum game, however. Environmental concerns may not lead to permanently smaller catalogs, though many have speculated that in the near term this might be so. However, from the designer's perspective, very small, abbreviated class catalogs, constructed for special purposes, can speed the glass selection process. Several examples will be discussed, based on derivative libraries suggested by Zhang, Shannon, and Walker. Streamlined libraries tailored for special purposes can be used effectively in the latest lens design software. Future software tools may speed this selection process by the use of algorithms that treat the problem as a `black box' using logic tools derived from probability studies of the patent literature.

  18. Glass matrix armor

    SciTech Connect

    Calkins, N.C.

    1991-09-03

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

  19. Picritic glasses from Hawaii

    USGS Publications Warehouse

    Clague, D.A.; Weber, W.S.; Dixon, J.E.

    1991-01-01

    ESTIMATES of the MgO content of primary Hawaiian tholeiitic melts range from 8wt% to as high as 25wt% (refs 1, 2). In general, these estimates are derived from analysis of the whole-rock composition of lavas, coupled with the compositions of the most magnesian olivine phenocrysts observed. But the best estimate of magma composition comes from volcanic glass, as it represents the liquid composition at the time of quenching; minimal changes occur during the quenching process. Here we report the discovery of tholeiitic basalt glasses, recovered offshore of Kilauea volcano, that contain up to 15.0 wt% MgO. To our knowledge, these are the most magnesian glasses, and have the highest eruption temperatures (??? 1,316 ??C), yet found. The existence of these picritic (high-MgO) liquids provides constraints on the temperature structure of the upper mantle, magma transport and the material and thermal budgets of the Hawaiian volcanoes. Furthermore, picritic melts are affected little by magma-reservoir processes, and it is therefore relatively straightforward to extrapolate back to the composition of the primary melt and its volatile contents.

  20. Mixed polyanion glass cathodes: Glass-state conversion reactions

    SciTech Connect

    Kercher, Andrew K.; Kolopus, James A.; Carroll, Kyler; Unocic, Raymond R.; Kirklin, S.; Wolverton, C.; Stooksbury, Shelby L.; Boatner, Lynn A.; Dudney, Nancy J.

    2015-01-01

    Mixed polyanion (MP) glasses can undergo glass-state conversion (GSC) reactions to provide an alternate class of high-capacity cathode materials. GSC reactions have been demonstrated in phosphate/vanadate glasses with Ag, Co, Cu, Fe, and Ni cations. These MP glasses provided high capacity and good high power performance, but suffer from moderate voltages, large voltage hysteresis, and significant capacity fade with cycling. Details of the GSC reaction have been revealed by x-ray absorption spectroscopy, electron microscopy, and energy dispersive x-ray spectroscopy of ex situ cathodes at key states of charge. Using the Open Quantum Materials Database (OQMD), a computational thermodynamic model has been developed to predict the near-equilibrium voltages of glass-state conversion reactions in MP glasses.

  1. Mixed polyanion glass cathodes: Glass-state conversion reactions

    DOE PAGES

    Kercher, Andrew K.; Kolopus, James A.; Carroll, Kyler; Unocic, Raymond R.; Kirklin, S.; Wolverton, C.; Stooksbury, Shelby L.; Boatner, Lynn A.; Dudney, Nancy J.

    2015-01-01

    Mixed polyanion (MP) glasses can undergo glass-state conversion (GSC) reactions to provide an alternate class of high-capacity cathode materials. GSC reactions have been demonstrated in phosphate/vanadate glasses with Ag, Co, Cu, Fe, and Ni cations. These MP glasses provided high capacity and good high power performance, but suffer from moderate voltages, large voltage hysteresis, and significant capacity fade with cycling. Details of the GSC reaction have been revealed by x-ray absorption spectroscopy, electron microscopy, and energy dispersive x-ray spectroscopy of ex situ cathodes at key states of charge. Using the Open Quantum Materials Database (OQMD), a computational thermodynamic model hasmore » been developed to predict the near-equilibrium voltages of glass-state conversion reactions in MP glasses.« less

  2. Cluster-assembled metallic glasses

    NASA Astrophysics Data System (ADS)

    Kartouzian, Aras

    2013-07-01

    A bottom-up approach to nanofabricate metallic glasses from metal clusters as building blocks is presented. Considering metallic glasses as a subclass of cluster-assembled materials, the relation between the two lively fields of metal clusters and metallic glasses is pointed out. Deposition of selected clusters or collections of them, generated by state-of-the-art cluster beam sources, could lead to the production of a well-defined amorphous material. In contrast to rapidly quenched glasses where only the composition of the glass can be controlled, in cluster-assembled glasses, one can precisely control the structural building blocks. Comparing properties of glasses with similar compositions but differing in building blocks and therefore different in structure will facilitate the study of structure-property correlation in metallic glasses. This bottom-up method provides a novel alternative path to the synthesis of glassy alloys and will contribute to improving fundamental understanding in the field of metallic glasses. It may even permit the production of glassy materials for alloys that cannot be quenched rapidly enough to circumvent crystallization. Additionally, gaining deeper insight into the parameters governing the structure-property relation in metallic glasses can have a great impact on understanding and design of other cluster-assembled materials.

  3. Cluster-assembled metallic glasses.

    PubMed

    Kartouzian, Aras

    2013-07-30

    A bottom-up approach to nanofabricate metallic glasses from metal clusters as building blocks is presented. Considering metallic glasses as a subclass of cluster-assembled materials, the relation between the two lively fields of metal clusters and metallic glasses is pointed out. Deposition of selected clusters or collections of them, generated by state-of-the-art cluster beam sources, could lead to the production of a well-defined amorphous material. In contrast to rapidly quenched glasses where only the composition of the glass can be controlled, in cluster-assembled glasses, one can precisely control the structural building blocks. Comparing properties of glasses with similar compositions but differing in building blocks and therefore different in structure will facilitate the study of structure-property correlation in metallic glasses. This bottom-up method provides a novel alternative path to the synthesis of glassy alloys and will contribute to improving fundamental understanding in the field of metallic glasses. It may even permit the production of glassy materials for alloys that cannot be quenched rapidly enough to circumvent crystallization. Additionally, gaining deeper insight into the parameters governing the structure-property relation in metallic glasses can have a great impact on understanding and design of other cluster-assembled materials.

  4. Analytical Plan for Roman Glasses

    SciTech Connect

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

    2011-01-01

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

  5. Bioactive glass in tissue engineering

    PubMed Central

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

    2011-01-01

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

  6. Bioactive glass in tissue engineering.

    PubMed

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

    2011-06-01

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

  7. Mixed polyanion glass cathodes: Iron phosphate vanadate glasses

    SciTech Connect

    Kercher, Andrew K; Ramey, Joanne Oxendine; Carroll, Kyler J; Kiggans Jr, James O; Veith, Gabriel M; Meisner, Roberta; Boatner, Lynn A; Dudney, Nancy J

    2014-01-01

    Mixed polyanion (MP) glasses have been investigated for use as cathodes in lithium ion batteries. MP glass cathodes are similar in composition to theoretically promising crystalline polyanionic (CP) cathodes (e.g., lithium cobalt phosphate, lithium manganese silicate), but with proper polyanion substitution, they can be designed to overcome the key shortcomings of CP cathodes, such as poor electrical conductivity and irreversible phase changes. Iron phosphate/vanadate glasses were chosen as a first demonstration of the MP glass concept. Polyanion substitution with vanadate was shown to improve the intercalation capacity of an iron phosphate glass from almost zero to full theoretical capacity. In addition, the MP glass cathodes also exhibited an unexpected second high-capacity electrochemical reaction. X-ray absorption near-edge structure (XANES) and x-ray diffraction (XRD) of cathodes from cells having different states of charge suggested that this second electrochemical reaction is a glass-state conversion reaction. With a first demonstration established, MP glass materials utilizing an intercalation and/or glass-state conversion reaction are promising candidates for future high-energy cathode research.

  8. Fracture mechanics of cellular glass

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

  9. Calcium-assisted glass-to-glass bonding for fabrication of glass microfluidic devices.

    PubMed

    Allen, Peter B; Chiu, Daniel T

    2008-09-15

    Glass is a desired material for many microfluidics applications. It is chemically resistant and has desirable characteristics for capillary electrophoresis. The process to make a glass chip, however, is lengthy and inconvenient, with the most difficult step often being the bonding of two planar glass substrates. Here we describe a new glass bonding technique, which requires only washing of the glass surfaces with a calcium solution and 1-2 h of bonding at 115 degrees C. We found calcium uniquely allows for this simple and efficient low-temperature bonding to occur, and none of the other cations we tried (e.g., Na (+), Mg (2+), Mn (3+)) resulted in satisfactory bonding. We determined this bond is able to withstand high applied field strengths of at least up to 4 kV x cm (-1). When intense pressure was applied to a fluid inlet, a circular portion of the coverslip beneath the well exploded outward but very little of the glass-glass interface debonded. In combination with the directed hydrofluoric acid etching of a glass substrate using a poly(dimethylsiloxane) (PDMS) etch guide, we were able to make glass chips with better than 90% yield within 6 h. This technique is compatible with inexpensive unpolished glass and is limited in resolution by the PDMS etch guide used and the intrinsic properties of isotropic etching.

  10. PLZT capacitor on glass substrate

    DOEpatents

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

    2016-03-29

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

  11. Microsheet Glass In Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Richter, Scott W.

    1993-01-01

    Microsheet glass used as highly protective covering material for developmental concentrating reflectors for solar power systems. Together with other materials, possible to fabricate lightweight, highly reflective, accurate, and long-lived concentrators. Desirable properties include durability and smoothness. Glass not affected by ultraviolet radiation, and not degraded by atomic oxygen, found in low orbits around Earth. Though concentrators intended for use in outer space, noteworthy that terrestrial concentrator fabricated with glass sheet 0.7 mm thick.

  12. Electronic structure of metallic glasses

    SciTech Connect

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

    1981-01-01

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

  13. Structural color from colloidal glasses

    NASA Astrophysics Data System (ADS)

    Magkiriadou, Sofia

    When a material has inhomogeneities at a lengthscale comparable to the wavelength of light, interference can give rise to structural colors: colors that originate from the interaction of the material's microstructure with light and do not require absorbing dyes. In this thesis we study a class of these materials, called photonic glasses, where the inhomogeneities form a dense and random arrangement. Photonic glasses have angle-independent structural colors that look like those of conventional dyes. However, when this work started, there was only a handful of colors accessible with photonic glasses, mostly hues of blue. We use various types of colloidal particles to make photonic glasses, and we study, both theoretically and experimentally, how the optical properties of these glasses relate to their structure and constituent particles. Based on our observations from glasses of conventional particles, we construct a theoretical model that explains the scarcity of yellow, orange, and red photonic glasses. Guided by this model, we develop novel colloidal systems that allow a higher degree of control over structural color. We assemble glasses of soft, core-shell particles with scattering cores and transparent shells, where the resonant wavelength can be tuned independently of the reflectivity. We then encapsulate glasses of these core-shell particles into emulsion droplets of tunable size; in this system, we observe, for the first time, angle-independent structural colors that cover the entire visible spectrum. To enhance color saturation, we begin experimenting with inverse glasses, where the refractive index of the particles is lower than the refractive index of the medium, with promising results. Finally, based on our theoretical model for scattering from colloidal glasses, we begin an exploration of the color gamut that could be achieved with this technique, and we find that photonic glasses are a promising approach to a new type of long-lasting, non-toxic, and

  14. Space processing of chalcogenide glass

    NASA Technical Reports Server (NTRS)

    Larsen, D. C.; Ali, M. I.

    1977-01-01

    The manner in which the weightless, containerless nature of in-space processing can be successfully utilized to improve the quality of infrared transmitting chalcogenide glasses is determined. The technique of space processing chalcogenide glass was developed, and the process and equipment necessary to do so was defined. Earthbound processing experiments with As2S3 and G28Sb12Se60 glasses were experimented with. Incorporated into these experiments is the use of an acoustic levitation device.

  15. PLZT capacitor on glass substrate

    DOEpatents

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

    2016-01-05

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

  16. Glass rupture disk

    DOEpatents

    Glass, S. Jill; Nicolaysen, Scott D.; Beauchamp, Edwin K.

    2002-01-01

    A frangible rupture disk and mounting apparatus for use in blocking fluid flow, generally in a fluid conducting conduit such as a well casing, a well tubing string or other conduits within subterranean boreholes. The disk can also be utilized in above-surface pipes or tanks where temporary and controllable fluid blockage is required. The frangible rupture disk is made from a pre-stressed glass with controllable rupture properties wherein the strength distribution has a standard deviation less than approximately 5% from the mean strength. The frangible rupture disk has controllable operating pressures and rupture pressures.

  17. Glass corrosion in natural environment

    NASA Technical Reports Server (NTRS)

    Thorpe, Arthur N.

    1989-01-01

    A series of studies of the effects of solutes which appear in natural aqueous environments, specifically Mg and Al, under controlled conditions, permit characterization of the retardation of silicate glass leaching in water containing such solutes. In the case of Mg the interaction with the glass appears to consist of exchange with alkali ions present in the glass to a depth of several microns. The effect of Al can be observed at much lower levels, indicating that the mechanism in the case of Al involves irreversible formation of aluminosilicate species at the glass surface.

  18. Glass corrosion in natural environments

    NASA Technical Reports Server (NTRS)

    Thorpe, Arthur N.; Barkatt, Aaron

    1992-01-01

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

  19. Infrared-transmitting fluoroaluminate glasses.

    NASA Astrophysics Data System (ADS)

    Feng-Yin, Lin; He-Fang, Hu; Yi-Bo, Yuan

    1990-07-01

    The glass-forming ability in the system of RF2-AlF3-YF3 was studied. The relationships between some physical properties, including refractive index, density, characteristic temperatures and viscosity, and chemical composition are reported. The crystallization kinetics of glass in the melt-cooling and glass-reheating process are investigated. The experimental results show that this fluoroaluminate glass is characterized by a widely transparent region from 0.2 to 7 um, a low refractive index, a high Abbe's value and other good physical and chemical properties.

  20. Crystallization of copper metaphosphate glass

    NASA Technical Reports Server (NTRS)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

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

  1. Compositional threshold for Nuclear Waste Glass Durability

    SciTech Connect

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

    2013-04-24

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

  2. Method for heating a glass sheet

    DOEpatents

    Boaz, Premakaran Tucker

    1998-01-01

    A method for heating a glass sheet includes the steps of heating a glass sheet to a first predetermined temperature and applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature to allow the glass sheet to be formed.

  3. Method for heating a glass sheet

    DOEpatents

    Boaz, P.T.

    1998-07-21

    A method for heating a glass sheet includes the steps of heating a glass sheet to a first predetermined temperature and applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature to allow the glass sheet to be formed. 5 figs.

  4. Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems

    SciTech Connect

    Raley, N.F.; Davidson, J.C.; Balch, J.W.

    1995-10-23

    We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.

  5. POROUS WALL, HOLLOW GLASS MICROSPHERES

    SciTech Connect

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to 'normal glasses of a 1 to 2 order of

  6. Quinary metallic glass alloys

    DOEpatents

    Lin, X.; Johnson, W.L.

    1998-04-07

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3}K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf){sub a}(Al,Zn){sub b}(Ti,Nb){sub c}(Cu{sub x}Fe{sub y}(Ni,Co){sub z}){sub d} wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d{hor_ellipsis}y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  7. Quinary metallic glass alloys

    DOEpatents

    Lin, Xianghong; Johnson, William L.

    1998-01-01

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  8. Spheroidization of glass powders for glass ionomer cements.

    PubMed

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

    2004-08-01

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

  9. The definitive story of Buddy Holly's glasses.

    PubMed

    Goldlist, Gerald I

    2007-06-01

    Buddy Holly's glasses were part of his performing identity. Correspondence with Dr. J. Davis Armistead, the man who prescribed and sold him those striking glasses over 50 years ago, provides the definitive story of Buddy Holly's glasses. PMID:17508046

  10. Method of determining glass durability

    DOEpatents

    Jantzen, Carol Maryanne; Pickett, John Butler; Brown, Kevin George; Edwards, Thomas Barry

    1998-01-01

    A process for determining one or more leachate concentrations of one or more components of a glass composition in an aqueous solution of the glass composition by identifying the components of the glass composition, including associated oxides, determining a preliminary glass dissolution estimator, .DELTA.G.sub.p, based upon the free energies of hydration for the component reactant species, determining an accelerated glass dissolution function, .DELTA.G.sub.a, based upon the free energy associated with weak acid dissociation, .DELTA.G.sub.a.sup.WA, and accelerated matrix dissolution at high pH, .DELTA.G.sub.a.sup.SB associated with solution strong base formation, and determining a final hydration free energy, .DELTA.G.sub.f. This final hydration free energy is then used to determine leachate concentrations for elements of interest using a regression analysis and the formula log.sub.10 (N C.sub.i (g/L))=a.sub.i +b.sub.i .DELTA.G.sub.f. The present invention also includes a method to determine whether a particular glass to be produced will be homogeneous or phase separated. The present invention is also directed to methods of monitoring and controlling processes for making glass using these determinations to modify the feedstock materials until a desired glass durability and homogeneity is obtained.

  11. Method of determining glass durability

    DOEpatents

    Jantzen, C.M.; Pickett, J.B.; Brown, K.G.; Edwards, T.B.

    1998-12-08

    A process is described for determining one or more leachate concentrations of one or more components of a glass composition in an aqueous solution of the glass composition by identifying the components of the glass composition, including associated oxides, determining a preliminary glass dissolution estimator, {Delta}G{sub p}, based upon the free energies of hydration for the component reactant species, determining an accelerated glass dissolution function, {Delta}G{sub a}, based upon the free energy associated with weak acid dissociation, {Delta}G{sub a}{sup WA}, and accelerated matrix dissolution at high pH, {Delta}G{sub a}{sup SB} associated with solution strong base formation, and determining a final hydration free energy, {Delta}G{sub f}. This final hydration free energy is then used to determine leachate concentrations for elements of interest using a regression analysis and the formula log{sub 10}(N C{sub i}(g/L))=a{sub i} + b{sub i}{Delta}G{sub f}. The present invention also includes a method to determine whether a particular glass to be produced will be homogeneous or phase separated. The present invention is also directed to methods of monitoring and controlling processes for making glass using these determinations to modify the feedstock materials until a desired glass durability and homogeneity is obtained. 4 figs.

  12. Holder for rotating glass body

    DOEpatents

    Kolleck, Floyd W.

    1978-04-04

    A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

  13. Refractory Glass Seals for SOFC

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.

    2011-07-01

    One of the critical challenges facing planar solid oxide fuel cell (SOFC) technology is the need for reliable sealing technology. Seals must exhibit long-term stability and mechanical integrity in the high temperature SOFC environment during normal and transient operation. Several different approaches for sealing SOFC stacks are under development, including glass or glass-ceramic seals, metallic brazes, and compressive seals. Among glass seals, rigid glass-ceramics, self-healing glass, and composite glass approaches have been investigated under the SECA Core Technology Program. The U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) has developed the refractory glass approach in light of the fact that higher sealing temperatures (e.g., 930-1000 degrees C) may enhance the ultimate in-service bulk strength and electrical conductivity of contact materials, as well as the bonding strength between contact materials and adjacent SOFC components, such as interconnect coatings and electrodes. This report summarizes the thermal, chemical, mechanical, and electrical properties of the refractory sealing glass.

  14. Making a Better Beer Glass.

    ERIC Educational Resources Information Center

    Hoffer, Alan R.

    1982-01-01

    A class activity is detailed in which alternative designs for glasses are examined. The goal is to design a glass which is built tilted, so that beer can be poured in without creating a foam problem. The activity is viewed as one leading to interesting questions. (MP)

  15. Training Guidelines: Glass Furnace Operators.

    ERIC Educational Resources Information Center

    Ceramics, Glass, and Mineral Products Industry Training Board, Harrow (England).

    Technological development in the glass industry is constantly directed towards producing high quality glass at low operating costs. Particularly, changes have taken place in melting methods which mean that the modern furnace operator has greater responsibilities than any of his predecessors. The complexity of control systems, melting rates, tank…

  16. Space processing of chalcogenide glass

    NASA Technical Reports Server (NTRS)

    Firestone, R. F.; Schramm, S. W.

    1978-01-01

    A program was conducted to develop the technique of space processing for chalcogenide glass, and to define the process and equipment necessary. In the course of this program, successful long term levitation of objects in a 1-g environment was achieved. Glass beads 4 mm diameter were containerless melted and fused together.

  17. Fullerene-doped porous glasses

    NASA Astrophysics Data System (ADS)

    Joshi, M. P.; Kukreja, L. M.; Rustagi, K. C.

    We report the doping of C60 in porous glass by diffusion in solution phase at room temperature. The presence of C60 in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials.

  18. Silicate Glass Corrosion Mechanism revisited

    NASA Astrophysics Data System (ADS)

    Geisler, Thorsten; Lenting, Christoph; Dohmen, Lars

    2015-04-01

    Understanding the mechanism(s) of aqueous corrosion of nuclear waste borosilicate glasses is essential to predict their long-term aqueous durability in a geologic repository. Several observations have been made with compositionally different silicate glasses that cannot be explained by any of the established glass corrosion models. These models are based on diffusion-controlled ion exchange and subsequent structural reorganisation of a leached, hydrated residual glass, leaving behind a so-called gel layer. In fact, the common observation of lamellar to more complex pattern formation observed in experiment and nature, the porous structure of the corrosion layer, an atomically sharp boundary between the corrosion zone and the underlying pristine glass, as well as results of novel isotope tracer and in situ, real time experiments rather support an interface-coupled glass dissolution-silica reprecipitation model. In this model, the congruent dissolution of the glass is coupled in space and time to the precipitation and growth of amorphous silica at an inwardly moving reaction front. We suggest that these coupled processes have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments.

  19. International Congress on Glass XII

    SciTech Connect

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

    1980-01-01

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

  20. Glass-An Environmental Protector

    SciTech Connect

    MARRA, JAMES

    2004-11-01

    From asbestos abatement to lead paint removal to nuclear waste stabilization and even to heavy metal removal using microorganisms, glass has great potential as a solution to many environmental problems. The ability to accommodate an array of chemical elements within the glass structure has facilitated the use of glass as a medium for the stabilization of numerous hazardous substances. The resulting glasses have proven to be durable enough for direct land disposal. In many cases, the stabilized forms have been deemed suitable for re-use in other applications. As recycling and hazardous material treatment become even more important in the global materials cycle, it is a certainty that glass will assume a prominent role.

  1. Consolidated silica glass from nanoparticles

    SciTech Connect

    Mayerhoefer, Thomas G. Shen Zhijian; Leonova, Ekaterina; Eden, Mattias; Kriltz, Antje; Popp, Juergen

    2008-09-15

    A dense silica glass was prepared by consolidating a highly dispersed silicic acid powder (particle size <10 nm) with the Spark Plasma Sintering (SPS) technique. The glass was characterized by ellipsometry, transmission electron microscopy (TEM), infrared reflectance and transmittance spectroscopy, as well as by Raman, UV-Vis-NIR and solid-state nuclear magnetic resonance (NMR) spectroscopy. The prototypic sample showed a transmittance of about 63% compared to silica glass in the UV-Vis spectral range. Based on the results of infrared transmittance spectroscopy this lower transparency is due to the comparably high water content, which is about 40 times higher than that in silica glass. {sup 1}H magic-angle spinning (MAS) NMR confirmed an increase in hydroxyl groups in the sample prepared by SPS relative to that of the conventional SiO{sub 2} reference glass. Aside from the comparably high water content, we conclude from the similarity of the IR-reflectance and the {sup 29}Si MAS NMR spectra of the SPS sample and the corresponding spectra of the conventionally prepared silica glass, that the short- and medium-range order is virtually the same in both materials. Raman spectroscopy, however, suggests that the number of three- and four-membered rings is significantly smaller in the SPS sample compared to the conventionally prepared sample. Based on these results we conclude that it is possible to prepare glasses by compacting amorphous powders by the SPS process. The SPS process may therefore enable the preparation of glasses with compositions inaccessible by conventional methods. - Graphical abstract: We report the preparation of SiO{sub 2} glass by consolidating a highly dispersed silicic acid powder with the Spark Plasma Sintering (SPS) technique. The glass was characterized by ellipsometry, transmission electron microscopy (TEM), infrared reflectance and transmittance spectroscopy, as well as by Raman-, UV-Vis-NIR- and solid-state nuclear magnetic resonance (NMR

  2. Glass Ceramic Formulation Data Package

    SciTech Connect

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

    2012-06-17

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

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

    SciTech Connect

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

    2001-07-24

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

  4. Energetics of glass fragmentation: Experiments on synthetic and natural glasses

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Russell, J. K.; Kennedy, L. A.

    2013-11-01

    Natural silicate glasses are an essential component of many volcanic rock types including coherent and pyroclastic rocks; they span a wide range of compositions, occur in diverse environments, and form under a variety of pressure-temperature conditions. In subsurface volcanic environments (e.g., conduits and feeders), melts intersect the thermodynamically defined glass transition temperature to form glasses at elevated confining pressures and under differential stresses. We present a series of room temperature experiments designed to explore the fundamental mechanical and fragmentation behavior of natural (obsidian) and synthetic glasses (Pyrex™) under confining pressures of 0.1-100 MPa. In each experiment, glass cores are driven to brittle failure under compressive triaxial stress. Analysis of the load-displacement response curves is used to quantify the storage of energy in samples prior to failure, the (brittle) release of elastic energy at failure, and the residual energy stored in the post-failure material. We then establish a relationship between the energy density within the sample at failure and the grain-size distributions (D-values) of the experimental products. The relationship between D-values and energy density for compressive fragmentation is significantly different from relationships established by previous workers for decompressive fragmentation. Compressive fragmentation is found to have lower fragmentation efficiency than fragmentation through decompression (i.e., a smaller change in D-value with increasing energy density). We further show that the stress storage capacity of natural glasses can be enhanced (approaching synthetic glasses) through heat treatment.

  5. Containerless glass fiber processing

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    SciTech Connect

    Kruger, A.A.

    1995-07-01

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

  7. Glass ceramic seals to inconel

    DOEpatents

    McCollister, Howard L.; Reed, Scott T.

    1983-11-08

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

  8. Automated glass-fragmentation analysis

    NASA Astrophysics Data System (ADS)

    Gordon, Gaile G.

    1996-02-01

    This paper describes a novel automated inspection process for tempered safety glass. The system is geared toward the European Community (EC) import regulations which are based on fragment count and dimensions in a fractured glass sample. The automation of this test presents two key challenges: image acquisition, and robust particle segmentation. The image acquisition must perform well both for clear and opaque glass. Opaque regions of glass are common in the American auto industry due to painted styling or adhesives (e.g. defroster cables). The system presented uses a multiple light source, reflected light imaging technique, rather than transmitted light imaging which is often used in manual versions of this inspection test. Segmentation of the glass fragments in the resulting images must produce clean and completely connected crack lines in order to compute the correct particle count. Processing must therefore be robust with respect to noise in the imaging process such as dust and glint on the glass. The system presented takes advantage of mathematical morphology algorithms, in particular the watershed algorithm, to perform robust preprocessing and segmentation. Example images and image segmentation results are shown for tempered safety glass which has been painted on the outside edges for styling purposes.

  9. Glass microspheres for medical applications

    NASA Astrophysics Data System (ADS)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in <1 week, without causing any detectable joint damage. The combination of dysprosium lithium borate glass microspheres and EDTA chelation therapy provides an unique "tool" for the medical community, which can deliver a large dose (>100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass

  10. Method for manufacturing glass frit

    DOEpatents

    Budrick, Ronald G.; King, Frank T.; Nolen, Jr., Robert L.; Solomon, David E.

    1977-01-01

    A method of manufacturing a glass frit for use in the manufacture of uniform glass microspheres to serve as containers for laser fusion fuel to be exposed to laser energy which includes the formation of a glass gel which is then dried, pulverized, and very accurately sized to particles in a range of, for example, 125 to 149 micrometers. The particles contain an occluded material such as urea which expands when heated. The sized particles are washed, dried, and subjected to heat to control the moisture content prior to being introduced into a system to form microspheres.

  11. Zirconia solubility in boroaluminosilicate glass

    SciTech Connect

    Raman, S.V.; Bopp, R.; Batcheller, T.A.; Yan, Q.

    1995-12-31

    In the Idaho Chemical Processing Plant (ICPP) waste streams, zirconia is often the waste load limiting species. It modifies the glass network, enhances durability, increases viscosity and induces crystallization. The limits of its dissolution in boroaluminosilicate glass, with magnesia and soda additions were experimentally determined. A ternary compositional surface is evolved to present the isothermal regimes of liquid, liquid + zircon, liquid + forsterite, and liquid phase sintered ceramic. The potential of partitioning the transuranics, transition elements and solutes in these regimes is discussed. The visible Raman spectroscopic results are presented to elucidate the dependence among glass composition, structure and chemical durability.

  12. Zirconia solubility in boroaluminosilicate glass

    SciTech Connect

    Raman, S.V.; Bopp, R.; Batcheller, T.A.; Yan, Q.

    1996-08-01

    In the Idaho Chemical Processing Plant (ICPP) waste streams, zirconia is often the waste load limiting species. It modifies the glass network, enhances durability, increases viscosity and induces crystallization. The limits of its dissolution in boroaluminosilicate glass, with magnesia and soda additions were experimentally determined. A ternary compositional surface is evolved to present the isothermal regimes of liquid, liquid+zircon, liquid+forsterite, and liquid phase sintered ceramic. The potential of partitioning the transuranics, transition elements and solutes in these regimes is discussed. The visible Raman spectroscopic results are presented to elucidate the dependence among glass composition, structure and chemical durability.

  13. Complexity of vector spin glasses.

    PubMed

    Yeo, J; Moore, M A

    2004-08-13

    We study the annealed complexity of the m-vector spin glasses in the Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of the Thouless-Anderson-Palmer free energy is found to consist of a continuous band of positive eigenvalues in addition to an isolated eigenvalue and (m-1) null eigenvalues due to rotational invariance. Rather surprisingly, the band does not extend to zero at any finite temperature. The isolated eigenvalue becomes zero in the thermodynamic limit, as in the Ising case (m=1), indicating that the same supersymmetry breaking recently found in Ising spin glasses occurs in vector spin glasses.

  14. Recent developments in laser glasses

    SciTech Connect

    Weber, M.J.

    1983-01-10

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

  15. Polyamine triggering of exocytosis in Paramecium involves an extracellular Ca(2+)/(polyvalent cation)-sensing receptor, subplasmalemmal Ca-store mobilization and store-operated Ca(2+)-influx via unspecific cation channels.

    PubMed

    Klauke, N; Blanchard, M; Plattner, H

    2000-03-15

    The polyamine secretagogue, aminoethyldextran (AED), causes a cortical [Ca(2+)] transient in Paramecium cells, as analyzed by fluorochrome imaging. Our most essential findings are: (i) Cortical Ca(2+) signals also occur when AED is applied in presence of the fast Ca(2+) chelator, BAPTA. (ii) Extracellular La(3+) application causes within seconds a rapid, reversible fluorescence signal whose reversibility can be attributed to a physiological [Ca(2+)](i) transient (while injected La(3+) causes a sustained fluorescence signal). (iii) Simply increasing [Ca(2+)](o) causes a similar rapid, short-lived [Ca(2+)](i) transient. All these phenomena, (i-iii), are compatible with activation of an extracellular "Ca(2+)/(polyvalent cation)-sensing receptor" known from some higher eukaryotic systems, where this sensor (responding to Ca(2+), La(3+) and some multiply charged cations) is linked to cortical calcium stores which, thus, are activated. In Paramecium, such subplasmalemmal stores ("alveolar sacs") are physically linked to the cell membrane and they can also be activated by the Ca(2+) releasing agent, 4-chloro-m-cresol, just like in Sarcoplasmic Reticulum. Since this drug causes a cortical Ca(2+) signal also in absence of Ca(2+)(o) we largely exclude a "Ca(2+)-induced Ca(2+) release" (CICR) mechanism. Our finding of increased cortical Ca(2+) signals after store depletion and re-addition of extracellular Ca(2+) can be explained by a "store-operated Ca(2+) influx" (SOC), i.e., a Ca(2+) influx superimposing store activation. AED stimulation in presence of Mn(2+)(o) causes fluorescence quenching in Fura-2 loaded cells, indicating involvement of unspecific cation channels. Such channels, known to occur in Paramecium, share some general characteristics of SOC-type Ca(2+) influx channels. In conclusion, we assume the following sequence of events during AED stimulated exocytosis: (i) activation of an extracellular Ca(2+)/polyamine-sensing receptor, (ii) release of Ca(2+) from

  16. Comparison of Montanide adjuvants, IMS 3012 (Nanoparticle), ISA 206 and ISA 35 (Emulsion based) along with incomplete Freund's adjuvant for hyperimmunization of equines used for production of polyvalent snake antivenom.

    PubMed

    Waghmare, Arun; Deopurkar, R L; Salvi, Nitin; Khadilkar, Milind; Kalolikar, Milind; Gade, S K

    2009-02-11

    The use of adjuvant is of fundamental importance in vaccines formulations and antisera production. Currently selection and use of adjuvant systems in snake antivenom preparation has become a major issue in terms of animal welfare as well as economics. In order to minimize disadvantages associated with traditionally used Freund's adjuvant (FA) in equines and to produce potent polyvalent antivenom against four Indian snake venoms in minimum possible period, a comparison was made between various commercially available non-emulsion/emulsion based adjuvants like IMS 3012, ISA 206 and ISA 35 with Incomplete Freund's adjuvant (IFA) for their immunopotentiation capacity and safety in donor animals. The present study was conducted in 33 new horses, randomly divided into four groups and hyperimmunized using crude mixture of snake venoms, viz.; Cobra venom (CV), Russell's viper venom (RV), Krait venom (KV) and Saw-scaled viper (EV) along with four above mentioned adjuvants through subcutaneous (s.c.) route at intervals of two weeks. Periodic standard safety assessments were done. Immunopotentiation ability of each adjuvant group in terms of percent responders were estimated at 14th, 21st, 30th and 43rd week. The neutralization activity (ED(50)) of pooled sera samples by 43(rd) week, obtained with IMS 3012 group for CV, RV, KV and EV venoms were 0.133, 0.143, 0.070 and 0.270 mg venom/ml of serum respectively. The antivenom potency with IMS 3012 and overall responding horses (100%) even against weak immunogen like CV was significantly higher (p<0.05) than other three adjuvants studied. The horses of IMS 3012 group showed minimum local reactions at injection site, while horses from other three groups exhibited moderate (++) reactions; 66.7% in ISA 206, 12.5% in ISA 35 and 14.3% in IFA respectively, however these were transient and reabsorbed or healed subsequently. Finally, we conclude that, nanoparticle adjuvant IMS 3012 could be a possible alternative to the emulsion adjuvants

  17. Galactic Hearts of Glass

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Click on image for larger graph

    This artist's concept shows delicate greenish crystals sprinkled throughout the violent core of a pair of colliding galaxies. The white spots represent a thriving population of stars of all sizes and ages. NASA's Spitzer Space Telescope detected more than 20 bright and dusty galactic mergers like the one depicted here, all teeming with the tiny gem-like crystals.

    When galaxies collide, they trigger the birth of large numbers of massive stars. Astronomers believe these blazing hot stars act like furnaces to produce silicate crystals in the same way that glass is made from sand. The stars probably shed the crystals as they age, and as they blow apart in supernovae explosions.

    At the same time the crystals are being churned out, they are also being destroyed. Fast-moving particles from supernova blasts easily convert silicates crystals back to their amorphous, or shapeless, form.

    How is Spitzer seeing the crystals if they are rapidly disappearing? Astronomers say that, for a short period of time at the beginning of galactic mergers, massive stars might be producing silicate crystals faster than they are eliminating them. When our own galaxy merges with the Andromeda galaxy in a few billion years, a similar burst of massive stars and silicate crystals might occur.

    Crystal Storm in Distant Galaxy The graph (see inset above) of infrared data from NASA's Spitzer Space Telescope tells astronomers that a distant galaxy called IRAS 08752+3915 is experiencing a storm of tiny crystals made up of silicates. The crystals are similar to the glass-like grains of sand found on Earth's many beaches.

    The data were taken by Spitzer's infrared spectrograph, which splits light open to reveal its rainbow-like components. The resulting spectrum shown here reveals the signatures of both crystalline (green) and non-crystalline (brown) silicates.

    Spitzer detected the same

  18. Characterization of electrostatic glass actuators

    NASA Astrophysics Data System (ADS)

    Moser, R.; Wüthrich, R.; Sache, L.; Higuchi, T.; Bleuler, H.

    2003-06-01

    Electrostatic glass actuators are a promising concept for various applications. The use of the interaction between glassy substances and electrostatic fields allows synchronous propulsion akin to the electret actuator. Even though some properties of electrostatic glass motors have been observed and described, a characterization is still missing. The authors would like to present the experimental work leading to the determination of the optimal glass blend and to the optimal electrode pattern in order to maximize the exploitable forces. An analytical model is also presented, satisfactorily close to the measured data. These measurements and models constitute a tool to design electrostatic glass actuators such as, for example, a miniature disk drive, which is presented as one of several promising applications.

  19. Turning nuclear waste into glass

    SciTech Connect

    Pegg, Ian L.

    2015-02-15

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

  20. Taylor impact of glass bars

    NASA Astrophysics Data System (ADS)

    Murray, Natalie; Bourne, Neil; Field, John

    1997-07-01

    Brar and Bless pioneeered the use of plate impact upon bars as a technique for investigating the 1D stress loading of glass. We wish to extend this technique by applying VISAR and embedded stress gauge measurements to a symmetrical version of the test. In this configuration two rods impact one upon the other in a symmetrical version of the Taylor test geometry in which the impact is perfectly rigid in the centre of mass frame. Previous work in the laboratory has characterised the three glass types (float, borosilicate and a high density lead glass). These experiments will identify the 1D stress failure mechanisms from high-speed photography and the stress and particle velocity histories will be interpreted in the light of these results. The differences in response of the three glasses will be highlighted.

  1. High Tech Art: Chameleon Glass

    NASA Technical Reports Server (NTRS)

    1993-01-01

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

  2. Fast Crystals and Strong Glasses

    SciTech Connect

    Weitz, David

    2009-11-04

    This talk describes new results on model colloid systems that provide insight into the behavior of fundamental problems in colloid physics, and more generally, for other materials as well. By visualizing the nucleation and growth of colloid crystals, we find that the incipient crystallites are much more disordered than expected, leading to a larger diversity of crystal morphologies. When the entropic contribution of these diverse morphologies is included in the free energy, we are able to describe the behavior very well, and can predict the nucleation rate surprisingly accurately. The talk also describes the glass transition in deformable colloidal particles, and will show that when the internal elasticity of the particles is included, the colloidal glass transition mimics that of molecular glass formers much more completely. These results also suggest that the elasticity at the scale of the fundamental unit, either colloid particle or molecule, determines the nature of the glass transition, as described by the "fragility."

  3. Injuring potential of drinking glasses.

    PubMed

    Sterzik, Vera; Kneubuehl, Beat P; Ropohl, Dirk; Bohnert, Michael

    2008-08-01

    At a party of a sports club, an argument started between two groups of young men, in the course of which one of the persons involved threw a beer glass hitting a young man of the other group, who collapsed with a profusely bleeding wound. Although resuscitation measures were initiated immediately, the victim died at the scene due to exsanguination from the completely severed left external carotid artery in combination with the aspiration of blood. Tests with drinking glasses thrown at a skull-neck model suggested that an undamaged beer glass thrown at the head of the victim could not cause the fatal injuries on the neck because of its splintering behaviour. In fact, it seemed that the beer glass had been damaged prior to throwing it and that its sharp edges perforated the skin on hitting the neck. PMID:18524515

  4. 2012 Problem 13: Misty Glass

    NASA Astrophysics Data System (ADS)

    Huang, Shan; Li, Xiao; Gao, Wenli; Zhou, Huijun

    2015-10-01

    Based on diffraction theory, we propose a model to explain the formation of colorful rings created by a misty glass. The model is verified by examining the relation between the size of the ring and size of the droplets.

  5. Surface reactions of natural glasses

    SciTech Connect

    White, A.F.

    1986-12-31

    Reactions at natural glass surfaces are important in studies involving nuclear waste transport due to chemical control on ground water in host rocks such as basalt and tuff, to potential diffusion into natural hydrated glass surfaces and as natural analogs for waste glass stability. Dissolution kinetics can be described by linear surface reaction coupled with cation interdiffusion with resulting rates similar to those of synthetic silicate glasses. Rates of Cs diffusion into hydrated obsidian surfaces between 25{sup 0} and 75{sup 0}C were determined by XPS depth profiles and loss rates from aqueous solutions. Calculated diffusion coefficients were ten others of magnitude more rapid than predicted from an Arrhenius extrapolation of high temperature tracer diffusion data due to surface hydration reactions.

  6. Glass Furnace Model Version 2

    2003-05-06

    GFM2.0 is a derivative of the GFM code with substantially altered and enhanced capabilities. Like its predecessor, it is a fully three-dimensional, furnace simulation model that provides a more accurate representation of the entire furnace, and specifically, the glass melting process, by coupling the combustion space directly to the glass batch and glass melt via rigorous radiation heat transport models for both the combustion space and the glass melt. No assumptions are made with regardmore » to interfacial parameters of heat, flux, temperature distribution, and batch coverage as must be done using other applicable codes available. These critical parameters are calculated. GFM2.0 contains a processor structured to facilitate use of the code, including the entry of teh furnace geometry and operating conditions, the execution of the program, and display of the computational results. Furnace simulations can therefore be created in a straightforward manner.« less

  7. Inorganic glass ceramic slip rings

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  8. Porous glasses for optical sensors

    NASA Astrophysics Data System (ADS)

    Dorosz, Dominik; Procyk, Bernadeta

    2006-03-01

    Microporous glasses from the Na II0-B II0 3-Si0 II system can be obtained by appropriate thermal and chemical treatment. During the thermal treatment the separation of the borate phase from the silicon skeleton has been occurred. The borates are in the form small drops joined to each other. In the course of chemical treatment the borates become leached in water, water solutions of acids or basis and the glass becomes porous. Microporous glasses may find application in many branches of science and engineering. The applications depend on the internal arrangement, size and shape of pores. These parameters may be in a wide range modified by a change of the chemical composition. The received porous glass was used as an element in optical fibre NO II sensor. The specific coloration reaction between organic reagents and NO II in the pores was occurred. It is possible to detection of 10-50 ppm NO II level.

  9. Ion implantation in silicate glasses

    SciTech Connect

    Arnold, G.W.

    1993-12-01

    This review examines the effects of ion implantation on the physical properties of silicate glasses, the compositional modifications that can be brought about, and the use of metal implants to form colloidal nanosize particles for increasing the nonlinear refractive index.

  10. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  11. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  12. Properties Of Soda/Yttria/Silica Glasses

    NASA Technical Reports Server (NTRS)

    Angel, Paul W.; Hann, Raiford E.

    1994-01-01

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

  13. Containerless Manufacture of Glass Optical Fibers

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  14. Luminescence of powdered uranium glasses

    NASA Technical Reports Server (NTRS)

    Eubanks, A. G.; Mcgarrity, J. M.; Silverman, J.

    1974-01-01

    Measurement of cathodoluminescence and photoluminescence efficiencies in powdered borosilicate glasses having different particle size and different uranium content. Excitation with 100 to 350 keV electrons and with 253.7 nm light was found to produce identical absolute radiant exitance spectra in powdered samples. The most efficient glass was one containing 29.4 wt% B2O3, 58.8 wt% SiO2, 9.8 wt% Na2O and 2.0 wt% UO2.

  15. Comparison of Macedon and Darwin glass

    USGS Publications Warehouse

    Chapman, D.R.; Keil, Klaus; Annell, C.

    1967-01-01

    Chemical analyses are presented for major and minor elements in two specimens of natural glass reported from Macedon, Victoria, and are compared with new analyses of glass from Mt. Darwin, Tasmania. One specimen of Macedon glass is dark, the other light; both are spongy with relatively large cavities of size uncommon in Darwin glass. Some of the new analyses of Darwin glass extend considerably the compositional range previously reported for Mg, Ni and Co. The chemical composition of Macedon glass cannot be distinguished from that of Darwin glass for any of twenty-five elements investigated. It appears possible that the two specimens of glass reported from Macedon may represent either two mislabelled pieces of Darwin glass, or else a separate natural occurrence of Darwin glass 560 km north of Mt. Darwin. ?? 1967.

  16. BNFL Report Glass Formers Characterization

    SciTech Connect

    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.

  17. BNFL Report Glass Formers Characterization

    SciTech Connect

    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.

  18. Space processing of chalcogenide glass

    NASA Technical Reports Server (NTRS)

    Ali, M. A.; Larsen, D. C.

    1976-01-01

    The manner in which the weightless, containerless nature of in-space processing can be successfully utilized to improve the quality of infrared transmitting chalcogenide glasses was investigated. The following conclusions were reached: (1) Laboratory experiments have established the techniques, processes and equipment necessary for the production of high purity chalcogenide glasses. (2) Processing techniques have been successfully adopted for Ge28Sb12Se60 glass in a 1-g environment. (3) The Ge28Sb12Se60 glasses that have been processed have optical transmission around 63% (5 mm thick). (4) Laboratory experiments have established that the use of precursor materials in powdered form increases the oxygen contamination of the processed glass. This indicates that high purity precursor materials in bar or pellet form should be used. (5) Modifications were made on the MSFC acoustic levitator in an attempt to improve levitation stability during long-time experiments. Room temperature experiments on As2S3 glasses and high temperature experiments on polystyrene were conducted.

  19. Glasses for nuclear waste immobilization

    SciTech Connect

    Ojovan, M.I.; Batyukhnova, O.G.

    2007-07-01

    Vitrification of nuclear wastes 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 waste form. Vitrification is a mature technology and has been used for high level nuclear waste (HLW) immobilisation for more than 40 years in France, Germany and Belgium, Russia, UK, Japan and the USA. 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 (GCM). Both borosilicate and phosphate glasses are currently used to immobilise nuclear wastes, moreover in addition to relatively homogeneous glasses novel GCM are used to immobilise problematic waste streams. The spectrum of wastes which are currently vitrified increases from HLW to low and intermediate wastes (LILW) such as legacy wastes in Hanford, USA and nuclear power plant operational wastes in Russia and Korea. (authors)

  20. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, William E.

    1984-01-01

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  1. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, W.E.

    1982-09-30

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  2. Glass Membrane For Controlled Diffusion Of Gases

    DOEpatents

    Shelby, James E.; Kenyon, Brian E.

    2001-05-15

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

  3. A Cosmic Magnifying Glass

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Scanning the heavens for the first time since the successful December 1999 servicing mission, NASA's Hubble Space Telescope imaged a giant, cosmic magnifying glass, a massive cluster of galaxies called Abell 2218. This 'hefty' cluster resides in the constellation Draco, some 2 billion light-years from Earth. The cluster is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. This phenomenon, called gravitational lensing, magnifies, brightens, and distorts images from faraway objects. The cluster's magnifying powers provides a powerful 'zoom lens' for viewing distant galaxies that could not normally be observed with the largest telescopes. The picture is dominated by spiral and elliptical galaxies. Resembling a string of tree lights, the biggest and brightest galaxies are members of the foreground cluster. Researchers are intrigued by a tiny red dot just left of top center. This dot may be an extremely remote object made visible by the cluster's magnifying powers. Further investigation is needed to confirm the object's identity. The color picture already reveals several arc-shaped features that are embedded in the cluster and cannot be easily seen in the black-and- white image. The colors in this picture yield clues to the ages, distances, and temperatures of stars, the stuff of galaxies. Blue pinpoints hot young stars. The yellow-white color of several of the galaxies represents the combined light of many stars. Red identifies cool stars, old stars, and the glow of stars in distant galaxies. This view is only possible by combining Hubble's unique image quality with the rare lensing effect provided by the magnifying cluster.

  4. [Hospital auxiliary staff, between polyvalence and invisibility].

    PubMed

    Veissier, Pascale

    2016-01-01

    Often underestimated, hospital auxiliary staff carry out on a daily basis a professional activity that may be difficult to define and/or recognize. What does their work consist in and what are the boundaries of the scope of their activity? Faced with a growing rate of absenteeism among these members of staff in a nursing home for elderly people attached to a hospital, an issue emerges: does the content of their professional activity have an impact on the causes and evolution of this phenomenon? PMID:26976318

  5. Commodifying the polyvalent good of health care.

    PubMed

    Kaveny, M C

    1999-06-01

    This essay serves as an introduction to this issue of the Journal of Medicine and Philosophy on commodification and health care. The essay attempts to sharpen the articulation of generally expressed worries about the commodification of health care. It does so by defining commodification, analyzing three components of the good of health care, and attempting to assess how commodification might distort the shape of each of those components. Next, it explores how the good of health care might be distorted by the market-based principle of distributive justice, "to each according to ability to pay." Finally, it identifies two basic questions about the relationship of medicine and the market that merit further exploration. (1) How does the market-based language of "incentives" so pervasive in the world of managed care distort the complex patterns of virtue and vice that motivate actors in the health care arena? (2) If we recognize that we cannot eliminate the influence of money from the health care system, how can we insure that the good of health care remains, in Radin's terms, "incompletely commodified"?

  6. HIGH-LEVEL WASTE GLASS FORMULATION MODEL SENSITIVITY STUDY 2009 GLASS FORMULATION MODEL VERSUS 1996 GLASS FORMULATION MODEL

    SciTech Connect

    BELSHER JD; MEINERT FL

    2009-12-07

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

  7. Natural analogues of nuclear waste glass corrosion.

    SciTech Connect

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

    1999-01-06

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

  8. Calorimetric Study of Kinetic Glass Transition in Metallic Glasses

    SciTech Connect

    Hiki, Y.; Takahashi, H.

    2008-02-21

    Differential scanning calorimetry (DSC) experiments were carried out for a bulk metallic glass (BMG), Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10.0}Be{sub 22.5}, below and above the glass transition temperature T{sub g}. The T{sub g} values were determined from the DSC curves. A wide range of heating rate, q = dT/dt = 0.1-100 K/min, was adopted for the experiment, and the q dependence of the apparent T{sub g} was investigated. As q was decreased, the value of T{sub g} decreased rapidly, then more slowly, and seemed to approach a constant value at low q. The experimental result of this kinetic glass transition phenomenon was analyzed on the basis of the relaxation process occurring in the transition temperature range.

  9. Mechanisms of Rhyolitic Glass Hydration Below the Glass Transition

    SciTech Connect

    Anovitz, Lawrence {Larry} M; Cole, David R; Fayek, Mostafa

    2008-01-01

    Although a great deal is known about the interaction between water and rhyolitic glasses and melts at temperatures above the glass transition, the nature of this interaction at lower temperatures is much more obscure. Comparisons between high- and low-temperature diffusion studies suggest that several factors play important roles under lower-temperature conditions that are not significant at higher temperatures. Water concentrations in rhyolitic glasses hydrated at low temperatures are significantly greater than in those hydrated at high temperatures and low pressures. Surface concentrations, which equilibrate quickly with the surrounding environment at high temperature, change far more slowly as temperature decreases, and may not equilibrate at room temperature for hundreds or thousands of years. Temperature extrapolations of high- and low-temperature diffusion data are not consistent, suggesting that a change in mechanism occurs. These differences may be due to the inability of "self-stress," caused by the in-diffusing species, to relax at lower temperature. Preliminary calculations suggest that the level of stress caused by glass-water interaction may be greater than the tensile strength of the glass. On a microstuctural scale, extrapolations of high-temperature Fourier transform infrared spectroscopy (FTIR) data to lower temperatures suggests that there should be little or no hydroxyl present in glasses hydrated at low temperature. Comparisons of low-temperature hydration results among SiO2, obsidian, and albite compositions show distinct differences, and features are present in the spectra that do not occur at high temperature. Analysis of H2O and D2O diffusion also suggest that mechanistic differences occur between low- and high-temperature diffusive processes.

  10. Database for waste glass composition and properties

    SciTech Connect

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

    1993-12-31

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

  11. Bioactive Glasses: Frontiers and Challenges

    PubMed Central

    Hench, Larry L.; Jones, Julian R.

    2015-01-01

    Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong, and stable bond with host tissues. This article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass–ceramics. In the 1980s, it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass®. The four eras are (a) discovery, (b) clinical application, (c) tissue regeneration, and (d) innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs. PMID:26649290

  12. Underwater implosion of glass spheres.

    PubMed

    Turner, Stephen E

    2007-02-01

    Underwater implosion experiments were conducted with thin-wall glass spheres to determine the influence that structural failure has on the pressure pulse. Four experiments were conducted with glass spheres having an outside diameter of 7.62 cm, thickness of 0.762 mm, and an estimated buckling pressure of 7.57 MPa. The experiments were performed in a pressure vessel at a hydrostatic pressure of 6.996 MPa. The average peak pressure of the implosion pressure pulse was 26.1 MPa, measured at a radial distance of 10.16 cm from the sphere center. A computational fluid structure interaction model was developed to assess how the failure rate of the glass structure influences the pressure time history. The model employed a specified glass failure sequence that is uniform in time and space. It was found that for the conditions of the test, a glass failure rate of 275 m/s provided a reasonable representation of the test data. The test data and the model results show that the failure time history of the structure has a significant influence on an implosion pressure pulse. Computational prediction of an implosion pressure pulse needs to include the failure time history of the structure; otherwise it will overpredict the pressure time history.

  13. Communication: An obligatory glass surface

    NASA Astrophysics Data System (ADS)

    Ashtekar, S.; Nguyen, D.; Zhao, K.; Lyding, J.; Wang, W. H.; Gruebele, M.

    2012-10-01

    Theory predicts, and experiments have shown, that dynamics is faster at glass surfaces than in the bulk, allowing the glass to settle into deeper energy landscape minima, or "age more." Is it possible that a glass surface could survive at temperatures where the bulk crystallizes, or that it could remain glassy after the bulk is heated all the way to its melting temperature and re-cooled? We image in real-time and with sub-nanometer resolution the two-state surface dynamics on a cerium-based glass surface, from deep within the glassy regime to above the crystallization temperature. Unlike other surfaces that we have studied, this glass surface remains amorphous even after the bulk re-crystallizes. The surface retains non-crystalline structure and two state dynamics of cooperatively rearranging regions even after heat annealing to just below the bulk melting temperature. The heat-annealed cooperatively rearranging regions are larger than originally, a sign that the surface is well aged. The surface dynamics depends weakly on temperature, showing no sign of the superexponential increase in bulk dynamics expected near Tg.

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

    SciTech Connect

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

    2012-04-02

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

  15. Study Of Phase Separation In Glass

    NASA Technical Reports Server (NTRS)

    Neilson, George F.; Weinberg, Michael C.; Smith, Gary L.

    1989-01-01

    Report describes an experimental study of effect of hydroxide content on phase separation in soda/silica glasses. Ordinary and gel glasses melted at 1,565 degree C, and melts stirred periodically. "Wet" glasses produced by passing bubbles of N2 saturated with water through melts; "dry" glasses prepared in similar manner, except N2 dried before passage through melts. Analyses of compositions of glasses performed by atomic-absorption and index-of-refraction measurements. Authors conclude hydroxide speeds up phase separation, regardless of method (gel or ordinary) by which glass prepared. Eventually helps material scientists to find ways to control morphology of phase separation.

  16. Electron anions and the glass transition temperature.

    PubMed

    Johnson, Lewis E; Sushko, Peter V; Tomota, Yudai; Hosono, Hideo

    2016-09-01

    Properties of glasses are typically controlled by judicious selection of the glass-forming and glass-modifying constituents. Through an experimental and computational study of the crystalline, molten, and amorphous [Ca12Al14O32](2+) ⋅ (e(-))2, we demonstrate that electron anions in this system behave as glass modifiers that strongly affect solidification dynamics, the glass transition temperature, and spectroscopic properties of the resultant amorphous material. The concentration of such electron anions is a consequential control parameter: It invokes materials evolution pathways and properties not available in conventional glasses, which opens a unique avenue in rational materials design. PMID:27559083

  17. Honeycomb mirrors of borosilicate glass

    NASA Technical Reports Server (NTRS)

    Angel, J. R. P.; Hill, J. M.

    1982-01-01

    The fabrication of different types of honeycomb mirrors with various kinds of borosilicate glass is discussed. Borosilicate glass is much less expensive to make than zero expansion glass, and can be used for ground-based applications. A mirror 60 cm in diameter made with a slotted strut or egg-crate honeycomb of 6 mm polished Pyrex plate is shown. The faceplates are 12 mm thick, laminated from the same 6 mm sheet. The result of an interferometric test is shown, with residual errors of about wavelength/8 RMS. An alternative fabrication technique for very large mirrors which require high quality bonds between separate sheets of thick Pyrex is described. The result of a recent test casting of a 60 cm honeycomb structure made in a mold with towers 14 cm square and 6 mm gaps between is shown, and methods to cast an entire mirror in one operation are discussed.

  18. Disaster medicine through Google Glass.

    PubMed

    Carenzo, Luca; Barra, Federico Lorenzo; Ingrassia, Pier Luigi; Colombo, Davide; Costa, Alessandro; Della Corte, Francesco

    2015-06-01

    Nontechnical skills can make a difference in the management of disasters and mass casualty incidents and any tool helping providers in action might improve their ability to respond to such events. Google Glass, released by Google as a new personal communication device, could play a role in this field. We recently tested Google Glass during a full-scale exercise to perform visually guided augmented-reality Simple Triage and Rapid Treatment triage using a custom-made application and to identify casualties and collect georeferenced notes, photos, and videos to be incorporated into the debriefing. Despite some limitations (battery life and privacy concerns), Glass is a promising technology both for telemedicine applications and augmented-reality disaster response support to increase operators' performance, helping them to make better choices on the field; to optimize timings; and finally represents an excellent option to take professional education to a higher level.

  19. Space processing of chalcogenide glasses

    NASA Technical Reports Server (NTRS)

    Larsen, D. C.; Ali, M. A.

    1975-01-01

    Chalcogenide glasses are discussed as good infrared transmitters, possessing the strength, corrosion resistance, and scale-up potential necessary for large 10.6-micron windows. The disadvantage of earth-produced chalcogenide glasses is shown to be an infrared absorption coefficient which is unacceptably high relative to alkali halides. This coefficient is traced to optical nonhomogeneities resulting from environmental and container contamination. Space processing is considered as a means of improving the infrared transmission quality of chalcogenides and of eliminating the following problems: optical inhomogeneities caused by thermal currents and density fluctuation in the l-g earth environment; contamination from the earth-melting crucible by oxygen and other elements deleterious to infrared transmission; and, heterogeneous nucleation at the earth-melting crucible-glass interface.

  20. Glasses for seeing beyond visible.

    PubMed

    Zhang, XiangHua; Bureau, Bruno; Lucas, Pierre; Boussard-Pledel, Catherine; Lucas, Jacques

    2008-01-01

    Conventional glasses based on oxides have a transparency limited by phonon absorption in the near IR region and have a limited interest for analyzing information located far beyond the visible. The IR spectral domain is nevertheless of prime interest, since it covers fundamental wavelength ranges used for thermal imaging as well as molecular vibrational signatures. Besides spectacular advances in the field of IR detectors, the main significant progresses are related to the development of IR glass optics, such as lenses or IR optical fibres. The field of IR glasses is almost totally dominated by glasses formed from heavy atoms such as the chalcogens S, Se and Te. Their transparency extends up to 12, 16 and 28 microm for sulfide-, selenide- and the new generation of telluride-based glasses, respectively. They cover the atmospheric transparency domains, 3-5 and 8-13 microm, respectively, at which the IR radiation can propagate allowing thermal imaging and night-vision operations through thick layers of atmosphere. The development of new glass compositions will be discussed on the basis of structural consideration with the objective of moulding low-cost lenses for IR cameras used, for instance, in car-driving assistance. Additionally, multimode, single-index, optical fibres operating in the 3 to 12 microm window developed for in situ remote evanescent-wave IR spectroscopy will also be mentioned. The detection of molecular IR signatures is applied to environmental monitoring for investigating the pollution of underground water with toxic molecules. The extension of this technique to the investigation of biomolecules in three different studies devoted to liver tissues analysis, bio-film formation, and cell metabolism will also be discussed. Finally we will mention the developments in the field of single-mode fibres operating around 10 mum for the Darwin space mission, which is aiming at discovering, signs of biological life in telluric earth-like exoplanets throughout

  1. Crystallization of niobium germanosilicate glasses

    SciTech Connect

    Santos, Rodrigo; Wondraczek, Lothar

    2010-01-15

    Niobium germanosilicate glasses are potential candidates for the fabrication of transparent glass ceramics with interesting non-linear optical properties. A series of glasses in the (Ge,Si)O{sub 2}-Nb{sub 2}O{sub 5}-K{sub 2}O system were prepared by melting and casting and their characteristic temperatures were determined by differential thermal analysis. Progressive replacement of GeO{sub 2} by SiO{sub 2} improved the thermal stability of the glasses. Depending on the composition and the crystallization heat-treatment, different nanocrystalline phases-KNbSi{sub 2}O{sub 7}, K{sub 3}Nb{sub 3}Si{sub 2}O{sub 13} and K{sub 3.8}Nb{sub 5}Ge{sub 3}O{sub 20.4} could be obtained. The identification and characterization of these phases were performed by X-ray diffraction and Raman spectroscopy. The 40 GeO{sub 2}-10 SiO{sub 2}-25 Nb{sub 2}O{sub 5}-25 K{sub 2}O (mol%) composition presented the higher ability for volume crystallization and its nucleation temperature was determined by the Marotta's method. An activation energy for crystal growth of {approx}529 kJ/mol and a nucleation rate of 9.7x10{sup 18} m{sup -3} s{sup -1} was obtained, for this composition. Transparent glass ceramics with a crystalline volume fraction of {approx}57% were obtained after a 2 h heat-treatment at the nucleation temperature, with crystallite sizes of {approx}20 nm as determined by transmission electron microscopy. - Abstract: TEM image and XRD pattern of the glass ceramic produced (circles indicate nanocrystals).

  2. Experimental studies of glass refining

    NASA Technical Reports Server (NTRS)

    Subramanian, R. S.; Cole, R.; Kondos, P.

    1984-01-01

    The basic components of the experimental apparatus were selected and acquired. Techniques were developed for the fabrication of the special crucibles necessary for the experiments. Arrangements were made for the analysis of glass and gas bubble samples for composition information. Donations of major equipment were received for this project from Owens, Illinois where a similar study had been conducted a few year ago. Decisions were made regarding the actual glass composition to be used, the gas to be used in the first experiments, and the temperatures at which the experiments should be conducted. A microcomputer was acquired, and work was begun on interfacing the video analyzer to it.

  3. Antiferromagnetic inclusions in lunar glass

    USGS Publications Warehouse

    Thorpe, A.N.; Senftle, F.E.; Briggs, Charles; Alexander, Corrine

    1974-01-01

    The magnetic susceptibility of 11 glass spherules from the Apollo 15, 16, and 17 fines and two specimens of a relatively large glass spherical shell were studied as a function of temperature from room temperature to liquid helium temperatures. All but one specimen showed the presence of antiferromagnetic inclusions. Closely spaced temperature measurements of the magnetic susceptibility below 77 K on five of the specimens showed antiferromagnetic temperature transitions (Ne??el transitions). With the exception of ilmenite in one specimen, these transitions did not correspond to any transitions in known antiferromagnetic compounds. ?? 1974.

  4. Molecular random tilings as glasses

    PubMed Central

    Garrahan, Juan P.; Stannard, Andrew; Blunt, Matthew O.; Beton, Peter H.

    2009-01-01

    We have recently shown that p-terphenyl-3,5,3′,5′-tetracarboxylic acid adsorbed on graphite self-assembles into a two-dimensional rhombus random tiling. This tiling is close to ideal, displaying long-range correlations punctuated by sparse localized tiling defects. In this article we explore the analogy between dynamic arrest in this type of random tilings and that of structural glasses. We show that the structural relaxation of these systems is via the propagation–reaction of tiling defects, giving rise to dynamic heterogeneity. We study the scaling properties of the dynamics and discuss connections with kinetically constrained models of glasses. PMID:19720990

  5. Manufacturing unique glasses in space

    NASA Technical Reports Server (NTRS)

    Happe, R. P.

    1976-01-01

    An air suspension melting technique is described for making glasses from substances which to date have been observed only in the crystalline condition. A laminar flow vertical wind tunnel was constructed for suspending oxide melts that were melted using the energy from a carbon dioxide laser beam. By this method it is possible to melt many high-melting-point materials without interaction between the melt and crucible material. In addition, space melting permits cooling to suppress crystal growth. If a sufficient amount of under cooling is accompanied by a sufficient increase in viscosity, crystallization will be avoided entirely and glass will result.

  6. High modulus high temperature glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1973-01-01

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

  7. Glass microstructure capping and bonding techniques.

    PubMed

    Mazurczyk, Radoslaw; Mansfield, Colin D; Lygan, Marcin

    2013-01-01

    The capping of microfluidic features fabricated in glass substrates is achievable by various technological methods. Of the entire spectrum of possibilities (gluing, glass bonding via intermediate layers, pressure or plasma-assisted glass bonding, etc.) a detailed description of three techniques is presented here. The first is a low temperature PDMS-glass adhesion bonding, the second is medium temperature pressure assisted glass-glass bonding, and finally, high temperature glass-glass fusion bonding. All these protocols allow completion of the manufacturing process for a fully enclosed microfluidic chip. Nevertheless, as they are complementary rather than competing methods, they effectively extend the range of tools available to fabricate lab-on-a-chip microdevices. Each has its own merits and each could feasibly be used at different developmental stages of a given microfluidic device.

  8. Measurement and Control of Glass Feedstocks

    SciTech Connect

    2005-08-01

    Laser-induced breakdown spectroscopy (LIBS) promises a new way for glass manufacturers to significantly increase productivity. By measuring the chemical makeup in raw materials and recycled glass cullet, LIBS can quickly detect contaminants and batch non...

  9. High-Intensity Plasma Glass Melter

    SciTech Connect

    2004-01-01

    Modular high-intensity plasma melter promises improved performance, reduced energy use, and lower emissions. The glass industry has used the same basic equipment for melting glass for the past 100 years.

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

    SciTech Connect

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

    2014-03-21

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

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

    PubMed

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

    2014-03-21

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

  12. BZT: A Soft Pseudospin Glass.

    PubMed

    Sherrington, David

    2013-11-27

    In an attempt to understand the origin of relaxor ferroelectricity, it is shown that interesting behavior of the onset of nonergodicity and of precursor nanodomains, found in first-principles simulations of the relaxor alloy Ba(Zr(1-x)Ti(x))O(3), can easily be understood within a simple mapping to a soft pseudospin glass.

  13. BZT: A Soft Pseudospin Glass

    NASA Astrophysics Data System (ADS)

    Sherrington, David

    2013-11-01

    In an attempt to understand the origin of relaxor ferroelectricity, it is shown that interesting behavior of the onset of nonergodicity and of precursor nanodomains, found in first-principles simulations of the relaxor alloy Ba(Zr1-xTix)O3, can easily be understood within a simple mapping to a soft pseudospin glass.

  14. Passing through the Glass Ceiling.

    ERIC Educational Resources Information Center

    McGinty, Robert L.

    This paper describes personal and professional networking, discusses data on women and networking skills, and argues that women should exercise these skills in their efforts to shatter the "glass ceiling" and achieve their career potential. An introductory discussion notes that women, though they do network, may develop ties primarily with other…

  15. Digimarc Discover on Google Glass

    NASA Astrophysics Data System (ADS)

    Rogers, Eliot; Rodriguez, Tony; Lord, John; Alattar, Adnan

    2015-03-01

    This paper reports on the implementation of the Digimarc® Discover platform on Google Glass, enabling the reading of a watermark embedded in a printed material or audio. The embedded watermark typically contains a unique code that identifies the containing media or object and a synchronization signal that allows the watermark to be read robustly. The Digimarc Discover smartphone application can read the watermark from a small portion of printed image presented at any orientation or reasonable distance. Likewise, Discover can read the recently introduced Digimarc Barcode to identify and manage consumer packaged goods in the retail channel. The Digimarc Barcode has several advantages over the traditional barcode and is expected to save the retail industry millions of dollars when deployed at scale. Discover can also read an audio watermark from ambient audio captured using a microphone. The Digimarc Discover platform has been widely deployed on the iPad, iPhone and many Android-based devices, but it has not yet been implemented on a head-worn wearable device, such as Google Glass. Implementing Discover on Google Glass is a challenging task due to the current hardware and software limitations of the device. This paper identifies the challenges encountered in porting Discover to the Google Glass and reports on the solutions created to deliver a prototype implementation.

  16. Hollow glass for insulating layers

    NASA Astrophysics Data System (ADS)

    Merticaru, Andreea R.; Moagar-Poladian, Gabriel

    1999-03-01

    Common porous materials, some of which will be considered in the chapters of this book, include concrete, paper, ceramics, clays, porous semiconductors, chromotography materials, and natural materials like coral, bone, sponges, rocks and shells. Porous materials can also be reactive, such as in charcoal gasification, acid rock dissolution, catalyst deactivation and concrete. This study continues the investigations about the properties of, so-called, hollow glass. In this paper is presented a computer simulation approach in which the thermo-mechanical behavior of a 3D microstructure is directly computed. In this paper a computer modeling approach of porous glass is presented. One way to test the accuracy of the reconstructed microstructures is to computed their physical properties and compare to experimental measurement on equivalent systems. In this view, we imagine a new type of porous type of glass designed as buffer layer in multilayered printed boards in ICs. Our glass is a variable material with a variable pore size and surface area. The porosity could be tailored early from the deposition phases that permitting us to keep in a reasonable balance the dielectric constant and thermal conductivity.

  17. Volcanic glasses, their origins and alteration processes

    USGS Publications Warehouse

    Friedman, I.; Long, W.

    1984-01-01

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

  18. Crystallization of a barium-aluminosilicate glass

    NASA Technical Reports Server (NTRS)

    Drummond, C. H., III; Lee, W. E.; Bansal, N. P.; Hyatt, M. J.

    1989-01-01

    The crystallization of a celsian glass composition was investigated as a possible high-temperature ceramic matrix material. Heat treatments invariably resulted in crystallization of the hexaclesian phase unless a flux, such as lithia, was added or a nucleating agent used (e.g., celsian seeds). TEM analysis revealed complex microstructures. Glasses with Mo additions contained hexacelsian, mullite, and an Mo-rich glass. Li2O additions stabilized celsian but mullite and Mo-rich glass were still present.

  19. Fracture of Silicate Glasses: Ductile or Brittle?

    NASA Astrophysics Data System (ADS)

    Guin, Jean-Pierre; Wiederhorn, Sheldon M.

    2004-05-01

    Atomic force microscopy is used to investigate the possibility of cavity formation during crack growth in silicate glasses. Matching areas on both fracture surfaces were mapped and then compared. For silica glass, and soda-lime-silicate glass, the fracture surfaces matched to a resolution of better than 0.3 nm normal to the surface and 5 nm parallel to the surface. We could find no evidence for cavity formation in our study and suggest that completely brittle fracture occurs in glass.

  20. 3. General view showing rear of looking glass aircraft. View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. General view showing rear of looking glass aircraft. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  1. 5. Headon view of looking glass aircraft. View to southwest. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Head-on view of looking glass aircraft. View to southwest. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  2. 4. View showing underside of wing, looking glass aircraft. View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. View showing underside of wing, looking glass aircraft. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  3. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  4. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  5. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  6. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  7. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  8. Grinding Glass Disks On A Belt Sander

    NASA Technical Reports Server (NTRS)

    Lyons, James J., III

    1995-01-01

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

  9. DURABLE GLASS FOR THOUSANDS OF YEARS

    SciTech Connect

    Jantzen, C.

    2009-12-04

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

  10. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  11. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  12. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  13. Classification of oxide glasses: A polarizability approach

    SciTech Connect

    Dimitrov, Vesselin; Komatsu, Takayuki . E-mail: komatsu@chem.nagaokaut.ac.jp

    2005-03-15

    A classification of binary oxide glasses has been proposed taking into account the values obtained on their refractive index-based oxide ion polarizability {alpha}{sub O2-}(n{sub 0}), optical basicity {lambda}(n{sub 0}), metallization criterion M(n{sub 0}), interaction parameter A(n{sub 0}), and ion's effective charges as well as O1s and metal binding energies determined by XPS. Four groups of oxide glasses have been established: glasses formed by two glass-forming acidic oxides; glasses formed by glass-forming acidic oxide and modifier's basic oxide; glasses formed by glass-forming acidic and conditional glass-forming basic oxide; glasses formed by two basic oxides. The role of electronic ion polarizability in chemical bonding of oxide glasses has been also estimated. Good agreement has been found with the previous results concerning classification of simple oxides. The results obtained probably provide good basis for prediction of type of bonding in oxide glasses on the basis of refractive index as well as for prediction of new nonlinear optical materials.

  14. Jagged Edges of the Glass Ceiling

    ERIC Educational Resources Information Center

    Robinson, Victoria L.

    2004-01-01

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

  15. Optical limiting in semiconductor-doped glasses

    NASA Astrophysics Data System (ADS)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1996-02-01

    We report optical limiting at 527 nm in two Schott semiconductor-doped glasses OG530 and OG515. These two glasses show quite contrasting nonlinear optical behaviour. The glass OG515 shows strong clamping while OG530 shows no clamping in optical limiting inspite of having much larger nonlinear refractive index. Similarly OG530 exhibits saturation of absorption while OG515 does not.

  16. Method for milling and drilling glass

    NASA Technical Reports Server (NTRS)

    Rice, S. H. (Inventor)

    1980-01-01

    A process for machining glass by placing a rotating carbide working surface under minimum pressure against an area of glass to be worked is described. Concurrently the region between the working surface and the area of glass is wet with a lubricant consisting essentially of a petroleum carrier, a complex mixture of esters and a complex mixture of naturally occurring aromatic oils.

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

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1973-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Šmit, Žiga; Knific, Timotej; Jezeršek, David; Istenič, Janka

    2012-05-01

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

  19. Alu element-containing RNAs maintain nucleolar structure and function.

    PubMed

    Caudron-Herger, Maïwen; Pankert, Teresa; Seiler, Jeanette; Németh, Attila; Voit, Renate; Grummt, Ingrid; Rippe, Karsten

    2015-11-12

    Non-coding RNAs play a key role in organizing the nucleus into functional subcompartments. By combining fluorescence microscopy and RNA deep-sequencing-based analysis, we found that RNA polymerase II transcripts originating from intronic Alu elements (aluRNAs) were enriched in the nucleolus. Antisense-oligo-mediated depletion of aluRNAs or drug-induced inhibition of RNA polymerase II activity disrupted nucleolar structure and impaired RNA polymerase I-dependent transcription of rRNA genes. In contrast, overexpression of a prototypic aluRNA sequence increased both nucleolus size and levels of pre-rRNA, suggesting a functional link between aluRNA, nucleolus integrity and pre-rRNA synthesis. Furthermore, we show that aluRNAs interact with nucleolin and target ectopic genomic loci to the nucleolus. Our study suggests an aluRNA-based mechanism that links RNA polymerase I and II activities and modulates nucleolar structure and rRNA production.

  20. Glass needs for a growing photovoltaics industry

    SciTech Connect

    Burrows, Keith; Fthenakis, Vasilis

    2014-10-18

    With the projected growth in photovoltaics, the demand for glass for the solar industry will far exceed the current supply, and thousands of new float-glass plants will have to be built to meet its needs over the next 20 years. Such expansion will provide an opportunity for the solar industry to obtain products better suited to their needs, such as low-iron glass and borosilicate glass at the lowest possible price. While there are no significant technological hurdles that would prevent the flat glass industry from meeting the solar industry’s projected needs, to do so will require advance planning and substantial investments.

  1. Dynamics of Glass Relaxation at Room Temperature

    NASA Astrophysics Data System (ADS)

    Welch, Roger C.; Smith, John R.; Potuzak, Marcel; Guo, Xiaoju; Bowden, Bradley F.; Kiczenski, T. J.; Allan, Douglas C.; King, Ellyn A.; Ellison, Adam J.; Mauro, John C.

    2013-06-01

    The problem of glass relaxation under ambient conditions has intrigued scientists and the general public for centuries, most notably in the legend of flowing cathedral glass windows. Here we report quantitative measurement of glass relaxation at room temperature. We find that Corning® Gorilla® Glass shows measurable and reproducible relaxation at room temperature. Remarkably, this relaxation follows a stretched exponential decay rather than simple exponential relaxation, and the value of the stretching exponent (β=3/7) follows a theoretical prediction made by Phillips for homogeneous glasses.

  2. Radiotracer investigation in a glass production unit.

    PubMed

    Pant, H J; Goswami, Sunil; Biswal, Jayashree; Samantaray, J S; Sharma, V K; Singhal, Sorabh

    2016-10-01

    A radiotracer investigation was carried out in a glass production unit in a glass industry. Lanthanum-140 as lanthanium oxide mixed with silica was used as a radiotracer to trace the molten glass in various sections of the unit. Residence time distributions of molten glass were measured and analyzed to identify the flow abnormities. The flow parameters such as breakthrough time, mean residence time, homogenization time, dead volume and flow patterns in different sections of the unit were obtained from the measured RTD data. The results of the investigation were used to improve and optimize the operation of the glass production unit. PMID:27474905

  3. Production of glass balloons for laser targets

    SciTech Connect

    Hendricks, C.D.; Dressler, J.L.

    1982-09-28

    An apparatus for producing small quantities of glass balloons for use as laser fusion targets is described. To produce precise quantities of the ingredients of one glass balloon, a jet of an aqueous solution of the glass constituents and a blowing agent is metered into uniformly sized drops by Rayleigh breakup. A small fraction of these uniform drops is then passed through an oven where the water is evaporated, the remaining solid material is fused into glass, and a blowing agent decomposes or water of hydration evolves as a vapor to blow the drop into a balloon. Photographs of the resulting glass balloons are presented.

  4. Major element composition of Luna 20 glasses.

    NASA Technical Reports Server (NTRS)

    Warner, J.; Reid, A. M.; Ridley, W. I.; Brown, R. W.

    1972-01-01

    Ten per cent of the 50 to 150-micron size fraction of Luna 20 soil is glass. A random suite of 270 of these glasses has been analyzed by electron microprobe techniques. The major glass type forms a strong cluster around a mean value corresponding to Highland basalt (anorthositic gabbro) with 70% normative feldspar. Minor glass groups have the compositions of mare basalts and of low-K Fra Mauro type basalts. The glass data indicate that Highland basalt is the major rock type in the highlands north of Mare Fecunditatis.

  5. Molecular glasses for nuclear waste encapsulation

    SciTech Connect

    Ropp, R.C.

    1982-09-28

    A molecular glass based upon a phosphate of aluminum, or other trivalent metal, provides significant improvement over prior art glasses for encapsulation of high level radioactive nuclear waste. When containing a controlled amount of those elemental oxides found in a typical nuclear waste, the waste-glass would not devitrify under conditions which produced devitrification in the non-nuclear-waste-containing glass, exhibited hydrolysis losses lower by an order of magnitude, had high solvency power for those elemental oxides, exhibited little tendency for internal crystallite formation, and possessed other desirable physical characteristics, all in direct antithesis to the properties of the best prior-known glasses used for this application.

  6. Evaluation of Behaviours of Laminated Glass

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  7. Identifying glass compositions in fly ash

    NASA Astrophysics Data System (ADS)

    Aughenbaugh, Katherine; Stutzman, Paul; Juenger, Maria

    2016-01-01

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

  8. Recirculation bubbler for glass melter apparatus

    DOEpatents

    Guerrero, Hector; Bickford, Dennis

    2007-06-05

    A gas bubbler device provides enhanced recirculation of molten glass within a glass melter apparatus. The bubbler device includes a tube member disposed within a pool of molten glass contained in the melter. The tube member includes a lower opening through which the molten glass enters and upper slots disposed close to (above or below) the upper surface of the pool of molten glass and from which the glass exits. A gas (air) line is disposed within the tube member and extends longitudinally thereof. A gas bubble distribution device, which is located adjacent to the lower end of the tube member and is connected to the lower end of the gas line, releases gas through openings therein so as to produce gas bubbles of a desired size in the molten glass and in a distributed pattern across the tube member.

  9. Pressurized heat treatment of glass ceramic

    DOEpatents

    Kramer, D.P.

    1984-04-19

    A method of producing a glass-ceramic having a specified thermal expansion value is disclosed. The method includes the step of pressurizing the parent glass material to a predetermined pressure during heat treatment so that the glass-ceramic produced has a specified thermal expansion value. Preferably, the glass-ceramic material is isostatically pressed. A method for forming a strong glass-ceramic to metal seal is also disclosed in which the glass-ceramic is fabricated to have a thermal expansion value equal to that of the metal. The determination of the thermal expansion value of a parent glass material placed in a high-temperature environment is also used to determine the pressure in the environment.

  10. glass chemistry: structure-property relationships

    NASA Astrophysics Data System (ADS)

    Smedskjaer, Morten M.; Youngman, Randall E.; Mauro, John C.

    2014-08-01

    Pyrex® glass was one of the first commercial boroaluminosilicate glass compositions, selected in 1915 from thousands of compositions due to its ability to sustain mechanical and thermal shock. While the microscopic structure of Pyrex® glass has recently been investigated, the microscopic origins of its macroscopic properties are not well understood, i.e., the atomic scale foundation of the original empirical invention of Pyrex® glass has yet to be established. In this work, we have tackled this problem by investigating the effects of varying Si/Al and Na/B ratios on the boron and aluminum speciation and a range of physical and rheological properties in the Pyrex® glass family. We show that the canonical Pyrex® boroaluminosilicate composition is indeed optimal for attaining relatively high values of glass transition temperature and elastic moduli and a low coefficient of thermal expansion, while simultaneously maintaining a high glass-forming ability.

  11. Combinatorial development of bulk metallic glasses.

    PubMed

    Ding, Shiyan; Liu, Yanhui; Li, Yanglin; Liu, Ze; Sohn, Sungwoo; Walker, Fred J; Schroers, Jan

    2014-05-01

    The identification of multicomponent alloys out of a vast compositional space is a daunting task, especially for bulk metallic glasses composed of three or more elements. Despite an increasing theoretical understanding of glass formation, bulk metallic glasses are predominantly developed through a sequential and time-consuming trial-and-error approach. Even for binary systems, accurate quantum mechanical approaches are still many orders of magnitude away from being able to simulate the relatively slow kinetics of glass formation. Here, we present a high-throughput strategy where ∼3,000 alloy compositions are fabricated simultaneously and characterized for thermoplastic formability through parallel blow forming. Using this approach, we identified the composition with the highest thermoplastic formability in the glass-forming system Mg-Cu-Y. The method provides a versatile toolbox for unveiling complex correlations of material properties and glass formation, and should facilitate a drastic increase in the discovery rate of metallic glasses.

  12. Recycled crushed glass in road work applications.

    PubMed

    Disfani, M M; Arulrajah, A; Bo, M W; Hankour, R

    2011-11-01

    A comprehensive suite of geotechnical laboratory tests was undertaken on samples of recycled crushed glass produced in Victoria, Australia. Three types of recycled glass sources were tested being coarse, medium and fine sized glass. Laboratory testing results indicated that medium and fine sized recycled glass sources exhibit geotechnical behavior similar to natural aggregates. Coarse recycled glass was however found to be unsuitable for geotechnical engineering applications. Shear strength tests indicate that the fine and medium glass encompass shear strength parameters similar to that of natural sand and gravel mixtures comprising of angular particles. Environmental assessment tests indicated that the material meets the requirements of environmental protection authorities for fill material. The results were used to discuss potential usages of recycled glass as a construction material in geotechnical engineering applications particularly road works.

  13. Glasses, ceramics, and composites from lunar materials

    NASA Technical Reports Server (NTRS)

    Beall, George H.

    1992-01-01

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

  14. Neutron diffraction studies of natural glasses

    SciTech Connect

    Wright, A.C.; Erwin Desa, J.A.; Weeks, R.A.; Sinclair, R.N.; Bailey, D.K.

    1983-08-01

    A neutron diffraction investigation has been carried out of the structures of several naturally occurring glasses, viz. Libyan Desert glass, a Fulgurite, Wabar glass, Lechatelierite from Canon Diablo, a Tektite, Obsidian (3 samples), and Macusani glass. Libyan Desert sand has also been examined, together with crystalline ..cap alpha..-quartz and ..cap alpha..-cristobalite. A comparison of data for the natural glasses and synthetic vitreous silica (Spectrosil B) in both reciprocal and real space allows a categorisation into Silicas, which closely resemble synthetic vitreous silica, and Silicates, for which the resemblance to silica is consistently less striking. The data support the view that Libyan Desert glass and sand have a common origin, while the Tektite has a structure similar to that of volcanic glasses.

  15. A universal description of ultraslow glass dynamics

    PubMed Central

    Martinez-Garcia, Julio Cesar; Rzoska, Sylwester J.; Drozd-Rzoska, Aleksandra; Martinez-Garcia, Jorge

    2013-01-01

    The dynamics of glass is of importance in materials science but its nature has not yet been fully understood. Here we report that a verification of the temperature dependencies of the primary relaxation time or viscosity in the ultraslowing/ultraviscous domain of glass-forming systems can be carried out via the analysis of the inverse of the Dyre–Olsen temperature index. The subsequent analysis of experimental data indicates the possibility of the self-consistent description of glass-forming low-molecular-weight liquids, polymers, liquid crystals, orientationally disordered crystals and Ising spin-glass-like systems, as well as the prevalence of equations associated with the ‘finite temperature divergence’. All these lead to a new formula for the configurational entropy in glass-forming systems. Furthermore, a link to the dominated local symmetry for a given glass former is identified here. Results obtained show a new relationship between the glass transition and critical phenomena. PMID:23652011

  16. Low-thermal expansion infrared glass ceramics

    NASA Astrophysics Data System (ADS)

    Lam, Philip

    2009-05-01

    L2 Tech, Inc. is in development of an innovative infrared-transparent glass ceramic material with low-thermal expansion (<0.5 ppm/°C) and high thermal-shock resistance to be used as windows and domes for high speed flight. The material is an inorganic, non-porous glass ceramic, characterized by crystalline phases of evenly distributed nano-crystals in a residual glass phase. The major crystalline phase is zirconium tungstate (ZrW2O8) which has Negative Thermal Expansion (NTE). The glass phase is the infrared-transparent germanate glass which has positive thermal expansion (PTE). Then glass ceramic material has a balanced thermal expansion of near zero. The crystal structure is cubic and the thermal expansion of the glass ceramic is isotropic or equal in all directions.

  17. Durability of Silicate Glasses: An Historical Approach

    SciTech Connect

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

    2007-01-02

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

  18. Characterization of Savannah River Plant waste glass

    SciTech Connect

    Plodinec, M J

    1985-01-01

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

  19. Crystallization of cerium containing iron borophosphate glasses/glass-ceramics and their spectral properties

    NASA Astrophysics Data System (ADS)

    Wang, Fu; Liao, Qilong; Zhu, Hanzhen; Dai, Yunya; Wang, Hong

    2016-04-01

    The crystallization behaviors of CeO2 containing 36Fe2O3-10B2O3-54P2O5 glasses/glass-ceramics (IBP glasses/glass-ceramics) and the effect of CeO2 addition on the structure of the IBP glasses/glass-ceramics annealed at 850 °C for 10 h were investigated by XRD, SEM and FTIR. The results show that Fe4(PO4)2O and Fe2(PO4)O phases are detected in the IBP glasses/glass-ceramics annealed at 650 °C for 10 h, and traces of FePO4 crystal is also detected when the CePO4 crystallite pre-exists in the unannealed IBP glass-ceramics. When the glasses/glass-ceramics are heat-treated at 850 °C for 10 h, Fe4(PO4)2O, Fe2(PO4)O and a small amount of FePO4 phase are detected. Meanwhile, CePO4 phase also appears in the crystallized IBP glasses/glass-ceramics containing more than 6 mol% (including 6 mol%) CeO2. Moreover, the main structural units of the crystallized glasses/glass-ceramics are [PO4] and [BO4] tetrahedron. [CeO4] tetrahedron also exists in the structure of the crystallized IBP glasses/glass-ceramics containing CeO2. CeO2 addition and the pre-existing CePO4 crystallite improve the resistance of the IBP glasses/glass-ceramics to crystallization, which makes the infrared bands associated with the vibration of [PO4] group increase in intensity and shift to high wave number.

  20. Glasses in coarse-grained micrometeorites

    NASA Astrophysics Data System (ADS)

    Varela, M. E.; Kurat, G.

    2009-06-01

    Micrometeorites (MMs, interplanetary dust particles with 25 - 500 μm diameters) carry the main mass of extraterrestrial matter that is captured by Earth. The coarse-grained MMs mainly consist of olivine aggregates, which - as their counterparts in CC chondrites - also contain pyroxenes and glass. We studied clear glasses in four coarse-grained crystalline MMs (10M12, M92-6b, AM9, and Mc7-10), which were collected from the ice at Cap Prudhomme, Antarctica. Previous studies of glasses (e.g., glass inclusions trapped in olivine and clear mesostasis glass) in carbonaceous and ordinary chondrites showed that these phases could keep memory of the physical-chemical conditions to which extraterrestrial matter was exposed. Here we compare the chemical compositions of MM glasses and glasses from CM chondrites with that in experimentally heated objects from the Allende CV chondrite and with glasses from cometary particles. Our results show that MMs were heated to variable degrees (during entry through the terrestrial atmosphere), which caused a range from very little chemical modification of the glass to total melting of the precursor object. Such modifications include dissolution of minerals in the melted glass precursor and some loss of volatile alkali elements. The chemical composition of all precursor glasses in the MMs investigated is not primitive such as glasses in CM and CR chondrite objects. It shows signs of pre-terrestrial chemical modification, e.g., metasomatic enrichments in Na and Fe 2+ presumably in the solar nebula. Glasses of MMs heated to very low degree have a chemical composition indistinguishable from that of glasses in comet Wild 2 particles; giving additional evidence that interplanetary dust (e.g., Antarctic MMs) possibly represents samples from comets.

  1. Bare Bones of Bioactive Glass

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Bioactive glass particles (left) with a microporous surface (right) are widely accepted as a synthetic material for periodontal procedures. Using the particles to grow three-dimensional tissue cultures may one day result in developing an improved, more rugged bone tissue that may be used to correct skeletal disorders and bone defects. The work is sponsored by NASA's Office of Biological and Physical Research.

  2. Gold based bulk metallic glass

    NASA Astrophysics Data System (ADS)

    Schroers, Jan; Lohwongwatana, Boonrat; Johnson, William L.; Peker, Atakan

    2005-08-01

    Gold-based bulk metallic glass alloys based on Au-Cu-Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5mm in the best glassformer. Au49Ag5.5Pd2.3Cu26.9Si16.3 has a liquidus temperature of 644K, a glass transition temperature of 401K, and a supercooled liquid region of 58K. The Vickers hardness of the alloys in this system is ˜350Hv, twice that of conventional 18-karat crystalline gold alloys. This combination of properties makes the alloys attractive for many applications including electronic, medical, dental, surface coating, and jewelry.

  3. Glass shell manufacturing in space

    NASA Technical Reports Server (NTRS)

    Nolen, R. L.; Downs, R. L.; Ebner, M. A.

    1982-01-01

    Highly-uniform, hollow glass spheres, which are used for inertial-confinement fusion targets, are formed from metal-organic gel powder feedstock in a drop-tower furnace. The modelling of this gel-to-sphere transformation has consisted of three phases: gel thermochemistry, furnance-to-gel heat transfer, and gravity-driven degradation of the concentricity of the molten shell. The heat transfer from the furnace to the free-falling gel particle was modelled with forced convection. The gel mass, dimensions, and specific heat as well as furnace temperature profile and furnace gas conductivity, were controlled variables. This model has been experimentally verified. In the third phase, a mathematical model was developed to describe the gravity-driven degradation of concentricity in molten glass shells.

  4. Lid heater for glass melter

    DOEpatents

    Phillips, Terrance D.

    1993-01-01

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

  5. Lid heater for glass melter

    DOEpatents

    Phillips, T.D.

    1993-12-14

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

  6. Nanoporous glass films on liquids.

    PubMed

    Zuber, Kamil; Evans, Drew; Murphy, Peter

    2014-01-01

    Glass-like thin films are used in many applications as dielectric layers, barrier coatings, abrasion-resistant films, and/or transparent films. We report the first direct application of such materials to liquid substrates using a plasma-deposition process at atmospheric pressure. The study demonstrates the broader utilization of these materials, for example, as robust membranes for water harvesting or drug delivery.

  7. Melter Glass Removal and Dismantlement

    SciTech Connect

    Richardson, BS

    2000-10-31

    The U.S. Department of Energy (DOE) has been using vitrification processes to convert high-level radioactive waste forms into a stable glass for disposal in waste repositories. Vitrification facilities at the Savannah River Site (SRS) and at the West Valley Demonstration Project (WVDP) are converting liquid high-level waste (HLW) by combining it with a glass-forming media to form a borosilicate glass, which will ensure safe long-term storage. Large, slurry fed melters, which are used for this process, were anticipated to have a finite life (on the order of two to three years) at which time they would have to be replaced using remote methods because of the high radiation fields. In actuality the melters useable life spans have, to date, exceeded original life-span estimates. Initial plans called for the removal of failed melters by placing the melter assembly into a container and storing the assembly in a concrete vault on the vitrification plant site pending size-reduction, segregation, containerization, and shipment to appropriate storage facilities. Separate facilities for the processing of the failed melters currently do not exist. Options for handling these melters include (1) locating a facility to conduct the size-reduction, characterization, and containerization as originally planned; (2) long-term storing or disposing of the complete melter assembly; and (3) attempting to refurbish the melter and to reuse the melter assembly. The focus of this report is to look at methods and issues pertinent to size-reduction and/or melter refurbishment in particular, removing the glass as a part of a refurbishment or to reduce contamination levels (thus allowing for disposal of a greater proportion of the melter as low level waste).

  8. Crystallization of lithium borate glasses

    NASA Technical Reports Server (NTRS)

    Goktas, A. A.; Neilson, G. F.; Weinberg, M. C.

    1992-01-01

    The glass-forming ability and crystallization behavior of lithium borate compositions, in the diborate-to-metaborate-range, were studied. In particular, the nature and sequence of formation of crystalline phases and the tendency toward devitrification were investigated as functions of temperature, thermal history and batch composition. It was found that the sequence of crystalline phase formation was sensitive to all of the three latter factors, and it was observed that under certain conditions metastable defect structures of the metaborate can appear.

  9. Mozart, dice, and glass selection

    NASA Astrophysics Data System (ADS)

    Tesar, John C.

    2000-10-01

    In a perfect world a good starting point should not be required. A Genetic Algorithm in powerful lens design software should find an optimum solution for us. As a practical matter a good starting point does matter. Time and resources may not be sufficient to generate a good design in a global optimizer quickly. In lens design a small glass catalog combined with the Hammer algorithm in ZEMAX moves the glass selection process in a search around the glass map forcing the design to consider many radically different forms in a short amount of time. From this starting point an expanded search can be undertaken by conventional design methods or in a global search algorithm. There are precedents in other fields for a narrow search method that still yields near infinite numbers of solutions. Mozart invented a game that narrows a search from a blank sheet paper and a set of notes to a single voice minuet by rolling dice. The results can be played and the dynamics manipulated to form the starting points for future compositions. Music composition software has, like lens design software, incorporated many powerful algorithms and search techniques. A simple comparison will be made. It is a long way from a protoplasm to Christie Brinkley. A good starting point means a lot whether you are an optical designer, a composer, or running the universe.

  10. Taylor impact of glass rods

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

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

  11. Structural Aspects of Metallic Glasses

    SciTech Connect

    Miracle, Daniel; Egami, Takeshi; Flores, Katharine M; Kelton, Kenneth

    2007-01-01

    A recent structural model reconciles apparently conflicting features of randomness, short-range order, and medium-range order that coexist in metallic glasses. In this efficient cluster packing model, short-range order can be described by efficiently packed solute-centered clusters, producing more than a dozen established atomic clusters, including icosahedra. The observed preference for icosahedral short-range order in metallic glasses is consistent with the theme of efficient atomic packing and is further favored by solvent-centered clusters. Driven by solute-solute avoidance, medium-range order results from the organization in space of overlapping, percolating (via connected pathways), quasi-equivalent clusters. Cubic-like and icosahedral-like organization of these clusters are consistent with measured medium-range order. New techniques such as fluctuation electron microscopy now provide more detailed experimental studies of medium-range order for comparison with model predictions. Microscopic free volume in the efficient cluster packing model is able to represent experimental and computational results, showing free volume complexes ranging from subatomic to atomic-level sizes. Free volume connects static structural models to dynamic processes such as diffusion and deformation. New approaches dealing with 'free' and 'anti-free' microscopic volume and coordinated atomic motion show promise for modeling the complex dynamics of structural relaxations such as the glass transition. Future work unifying static and dynamic structural views is suggested.

  12. Taylor impact of glass rods

    SciTech Connect

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

    2005-05-01

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

  13. Manufacturing laser glass by continuous melting

    SciTech Connect

    Campbell, J H; Suratwala, T; krenitsky, S; Takeuchi, K

    2000-07-01

    A novel, continuous melting process is being used to manufacture meter-sized plates of laser glass at a rate 20-times faster, 5-times cheaper, and with 2-3 times better optical quality than with previous one-at-a-time, ''discontinuous'' technology processes. This new technology for manufacturing laser glass, which is arguably the most difficult continuously-melted optical material ever produced, comes as a result of a $60 million, six-year joint R&D program between government and industry. The glasses manufactured by the new continuous melting process are Nd-doped phosphate-based glasses and are marketed under the product names LG-770 (Schott Glass Technologies) and LHG-8 (Hoya Corporation USA). With this advance in glass manufacturing technology, it is now possible to construct high-energy, high-peak-power lasers for use in fusion energy development, national defense, and basic physics research that would have been impractical to build using the old melting technology. The development of continuously melted laser glass required technological advances that have lead to improvements in the manufacture of other optical glass products as well. For example, advances in forming, annealing, and conditioning steps of the laser glass continuous melting process are now being used in manufacture of other large-size optical glasses.

  14. Spectroscopic study of biologically active glasses

    NASA Astrophysics Data System (ADS)

    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.

  15. Specialty glass raw materials: Status and developments

    SciTech Connect

    Bauer, R.J.; Gray, S.L.

    1996-12-31

    The authors highlight several key raw materials used in the specialty glass industry. The focus here is to update changes and shifts underway in the worldwide availability and processes that will impact both costs and efficient use of these products. The glass types that use these materials generally are those other than container, float, and fiber glass. Those high-volume consumers of glass raw materials are discussed in a companion paper in this volume. In the specialty glass field, the batch materials involve minerals, and the chemicals derived from them, which are less readily available domestically. These are much more critically defined by specifications of assay, contamination, and particle size, resulting in their being more expensive. They are seldom commodity products. The scope of materials for this fragmented industry includes those for leads, borosilicates, aluminosilicates, opals, sealing and frit glasses, optical glass, ophthalmic glass, cathode ray tubes (CRTs) for TV and display, and glass-ceramics as major segments. They use lead oxides, nearly all the alkalies and alkaline earth portions of the periodic table, as well as rare earths, transition element oxides, phosphates, boron minerals and chemicals, zircon, zinc, most of the halogens, and many of the anions. They often require very special particle size specifications. The requirements for these batch materials are often based on chemistry, the absence of contaminants that impact melting, very wide ranges of the electromagnetic spectrum, glass homogeneity, and freedom from solid and gaseous inclusions down to ppm levels in both size and number.

  16. Precise dispersion equations of absorbing filter glasses

    NASA Astrophysics Data System (ADS)

    Reichel, S.; Biertümpfel, Ralf

    2014-05-01

    The refractive indices versus wavelength of optical transparent glasses are measured at a few wavelengths only. In order to calculate the refractive index at any wavelength, a so-called Sellmeier series is used as an approximation of the wavelength dependent refractive index. Such a Sellmeier representation assumes an absorbing free (= loss less) material. In optical transparent glasses this assumption is valid since the absorption of such transparent glasses is very low. However, optical filter glasses have often a rather high absorbance in certain regions of the spectrum. The exact description of the wavelength dependent function of the refractive index is essential for an optimized design for sophisticated optical applications. Digital cameras use an IR cut filter to ensure good color rendition and image quality. In order to reduce ghost images by reflections and to be nearly angle independent absorbing filter glass is used, e.g. blue glass BG60 from SCHOTT. Nowadays digital cameras improve their performance and so the IR cut filter needs to be improved and thus the accurate knowledge of the refractive index (dispersion) of the used glasses must be known. But absorbing filter glass is not loss less as needed for a Sellmeier representation. In addition it is very difficult to measure it in the absorption region of the filter glass. We have focused a lot of effort on measuring the refractive index at specific wavelength for absorbing filter glass - even in the absorption region. It will be described how to do such a measurement. In addition we estimate the use of a Sellmeier representation for filter glasses. It turns out that in most cases a Sellmeier representation can be used even for absorbing filter glasses. Finally Sellmeier coefficients for the approximation of the refractive index will be given for different filter glasses.

  17. Method for heating, forming and tempering a glass sheet

    DOEpatents

    Boaz, P.T.; Sitzman, G.W.

    1998-10-27

    A method for heating, forming and tempering a glass sheet is disclosed including the steps of heating at least one glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration, and cooling an outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet. 2 figs.

  18. Method for heating, forming and tempering a glass sheet

    DOEpatents

    Boaz, Premakaran Tucker; Sitzman, Gary W.

    1998-01-01

    A method for heating, forming and tempering a glass sheet including the steps of heating at least one glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration, and cooling an outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet.

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

    PubMed Central

    Khoroushi, Maryam; Keshani, Fateme

    2013-01-01

    Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the “smart” materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI) cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA). Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications. PMID:24130573

  20. Unusual fast secondary relaxation in metallic glass

    PubMed Central

    Wang, Q.; Zhang, S.T.; Yang, Y.; Dong, Y.D.; Liu, C.T.; Lu, J.

    2015-01-01

    The relaxation spectrum of glassy solids has long been used to probe their dynamic structural features and the fundamental deformation mechanisms. Structurally complicated glasses, such as molecular glasses, often exhibit multiple relaxation processes. By comparison, metallic glasses have a simple atomic structure with dense atomic packing, and their relaxation spectra were commonly found to be simpler than those of molecular glasses. Here we show the compelling evidence obtained across a wide range of temperatures and frequencies from a La-based metallic glass, which clearly shows two peaks of secondary relaxations (fast versus slow) in addition to the primary relaxation peak. The discovery of the unusual fast secondary relaxation unveils the complicated relaxation dynamics in metallic glasses and, more importantly, provides us the clues which help decode the structural features serving as the ‘trigger' of inelasticity on mechanical agitations. PMID:26204999

  1. Load Bearing Innovative Construction from Glass

    NASA Astrophysics Data System (ADS)

    Kalamar, R.; Eliášová, M.

    2015-11-01

    Glass plays an exceptional role in the modern architecture due to the optical properties and transparency. Structural elements from glass like beams, facades and roofs are relatively frequent in common practice [1]. Although glass has significantly higher compressive strength in comparison with tensile strength, load bearing glass elements are relatively rare. This opens up new opportunities for application of glass in such structures as transparent columns loaded by the axial force. This paper summarizes the experimental results of the tests on glass columns loaded by centric pressure, which were performed in the laboratories of the CTU in Prague, Faculty of Civil Engineering. The first set of experiments was composed of three specimens in a reduced scale 1:2 to verify real behaviour of the specimens with enclosed hollow cross-section. The main goal of the experiment was to determine force at the first breakage and consequently the maximal force at the collapse of this element.

  2. Integral assembly of photovoltaic arrays using glass

    NASA Technical Reports Server (NTRS)

    Younger, P. R.; Kirkpatrick, A. R.; Maxwell, H. G.; Holtze, R. F.

    1978-01-01

    For a number of reasons glass is an excellent material for encapsulation of solar cell arrays. Glass can be readily available at relatively low cost. It exhibits excellent stability against degradation by solar ultraviolet illumination and atmospheric pollutants. A superior approach results if glass is employed directly as an integral encapsulant without secondary organic materials. A description is presented of a electrostatic bonding process which is being developed for integral assembly of glass encapsulated arrays. Solar cells are placed in contact with the glass surface, temperature is raised until the glass becomes ionically conductive, and an electric field is applied to initiate the bonding action. Silicon solar cells up to 3 inches in diameter have been integrally bonded without degradation.

  3. Shear Adhesive Connections for Glass Structures

    NASA Astrophysics Data System (ADS)

    Machalická, K.; Horčičková, I.; Eliášová, M.

    2015-11-01

    Unique aesthetical properties of glass - not only transparency but also smooth, glossy and primarily reflective surface - give this material special importance in the contemporary architecture. In every structural application of glass it is necessary to solve the problem associated with connections between glass pane and other part from a different material or between two glass elements. Moreover, there are many types of hybrid structures that combine glass and different materials to achieve safe failure behaviour and high degree of transparency at the same time. Connection of brittle glass and reinforcing material is an essential part of these structures, where composite action between two parts is beneficially ensured by a glued joint. The current paper deals with the experimental analysis focused on the determination of mechanical characteristics of adhesives applied in planar connections under shear loading.

  4. Origin of embrittlement in metallic glasses.

    PubMed

    Garrett, Glenn R; Demetriou, Marios D; Launey, Maximilien E; Johnson, William L

    2016-09-13

    Owing to their glassy nature, metallic glasses demonstrate a toughness that is extremely sensitive to the frozen-in configurational state. This sensitivity gives rise to "annealing embrittlement," which is often severe and in many respects limits the technological advancement of these materials. Here, equilibrium configurations (i.e., "inherent states") of a metallic glass are established around the glass transition, and the configurational properties along with the plane-strain fracture toughness are evaluated to associate the intrinsic glass toughness with the inherent state properties and identify the fundamental origin of embrittlement. The established correlations reveal a one-to-one correspondence between toughness and shear modulus continuous over a broad range of inherent states, suggesting that annealing embrittlement is controlled almost solely by an increasing resistance to shear flow. This annealing embrittlement sensitivity is shown to vary substantially between metallic glass compositions, and appears to correlate well with the fragility of the metallic glass. PMID:27573817

  5. Origin of embrittlement in metallic glasses.

    PubMed

    Garrett, Glenn R; Demetriou, Marios D; Launey, Maximilien E; Johnson, William L

    2016-09-13

    Owing to their glassy nature, metallic glasses demonstrate a toughness that is extremely sensitive to the frozen-in configurational state. This sensitivity gives rise to "annealing embrittlement," which is often severe and in many respects limits the technological advancement of these materials. Here, equilibrium configurations (i.e., "inherent states") of a metallic glass are established around the glass transition, and the configurational properties along with the plane-strain fracture toughness are evaluated to associate the intrinsic glass toughness with the inherent state properties and identify the fundamental origin of embrittlement. The established correlations reveal a one-to-one correspondence between toughness and shear modulus continuous over a broad range of inherent states, suggesting that annealing embrittlement is controlled almost solely by an increasing resistance to shear flow. This annealing embrittlement sensitivity is shown to vary substantially between metallic glass compositions, and appears to correlate well with the fragility of the metallic glass.

  6. Coulomb Glass: a Mean Field Study

    NASA Astrophysics Data System (ADS)

    Mandra, Salvatore; Palassini, Matteo

    2012-02-01

    We study the Coulomb glass model of disordered localized electrons with long-range Coulomb interaction, which describes systems such as disordered insulators, granular metals, amorphous semiconductors, or doped crystalline semiconductors. Long ago Efros and Shklovskii showed that the long-range repulsion induces a soft Coulomb gap in the single particle density of states at low temperatures. Recent works suggested that this gap is associated to a transition to a glass phase, similar to the Almeida-Thouless transition in spin glasses. In this work, we use a mean field approach to characterize several physical properties of the Coulomb glass. In particular, following a seminal work of Bray and Moore, we show that the Edward-Anderson parameter qEA and the spin glass susceptibility χSG are directly related to spectrum distribution of the Hessian matrix around free energy minima. Using this result, we show that no glass transition is associated to the gap formation.

  7. Surface self-diffusion of organic glasses.

    PubMed

    Brian, Caleb W; Yu, Lian

    2013-12-19

    Surface self-diffusion coefficients have been determined for the organic glass Nifedipine using the method of surface grating decay. The flattening of 1000 nm surface gratings occurs by viscous flow at 12 K or more above the glass transition temperature and by surface diffusion at lower temperatures. Surface diffusion is at least 10(7) times faster than bulk diffusion, indicating a highly mobile surface. Nifedipine glasses have faster surface diffusion than the previously studied Indomethacin glasses, despite their similar bulk relaxation times. Both glasses exhibit fast surface crystal growth, and its rate scales with surface diffusivity. The observed rate of surface diffusion implies substantial surface rearrangement during the preparation of low-energy glasses by vapor deposition. The Random First Order Transition Theory and the Coupling Model successfully predict the large surface-enhancement of mobility and its increase on cooling, but disagree with the experimental observation of the faster surface diffusion of Nifedipine.

  8. Porosity in metal-organic framework glasses.

    PubMed

    Thornton, A W; Jelfs, K E; Konstas, K; Doherty, C M; Hill, A J; Cheetham, A K; Bennett, T D

    2016-03-01

    The porosity of a glass formed by melt-quenching a metal-organic framework, has been characterized by positron annihilation lifetime spectroscopy. The results reveal porosity intermediate between the related open and dense crystalline frameworks ZIF-4 and ZIF-zni. A structural model for the glass was constructed using an amorphous polymerization algorithm, providing additional insight into the gas-inaccessible nature of porosity and the possible applications of hybrid glasses.

  9. Process for preparing improved silvered glass mirrors

    DOEpatents

    Buckwalter, C.Q. Jr.

    1980-01-28

    Glass mirrors having improved weathering properties are prepared by an improvement in the process for making the mirrors. The glass surface after it has been cleaned but before it is silvered, is contacted with a solution of lanthanide rare earths in addition to a sensitization solution of tin or palladium. The addition of the rare earths produces a mirror which has increased resistance to delamination of the silver from the glass surface in the presence of water.

  10. Surface Coatings on Lunar Volcanic Glasses

    NASA Technical Reports Server (NTRS)

    Wentworth, Susan J.; McKay, D. S.; Thomas,-Keprta, K. L.; Clemett, S. J.

    2007-01-01

    We are undertaking a detailed study of surface deposits on lunar volcanic glass beads. These tiny deposits formed by vapor condensation during cooling of the gases that drove the fire fountain eruptions responsible for the formation of the beads. Volcanic glass beads are present in most lunar soil samples in the returned lunar collection. The mare-composition beads formed as a result of fire-fountaining approx.3.4-3.7 Ga ago, within the age range of large-scale mare volcanism. Some samples from the Apollo 15 and Apollo 17 landing sites are enriched in volcanic spherules. Three major types of volcanic glass bead have been identified: Apollo 15 green glass, Apollo 17 orange glass, and Apollo 17 "black" glass. The Apollo 15 green glass has a primitive composition with low Ti. The high-Ti compositions of the orange and black glasses are essentially identical to each other but the black glasses are opaque because of quench crystallization. A poorly understood feature common to the Apollo 15 and 17 volcanic glasses is the presence of small deposits of unusual materials on their exterior surfaces. For example, early studies indicated that the Apollo 17 orange glasses had surface enrichments of In, Cd, Zn, Ga, Ge, Au, and Na, and possible Pb- and Zn-sulfides, but it was not possible to characterize the surface features in detail. Technological advances now permit us to examine such features in detail. Preliminary FE-TEM/X-ray studies of ultramicrotome sections of Apollo 15 green glass indicate that the surface deposits are heterogeneous and layered, with an inner layer consisting of Fe with minor S and an outer layer of Fe and no S, and scattered Zn enrichments. Layering in surface deposits has not been identified previously; it will be key to defining the history of lunar fire fountaining.

  11. Process for preparing improved silvered glass mirrors

    DOEpatents

    Buckwalter, Jr., Charles Q.

    1981-01-01

    Glass mirrors having improved weathering properties are prepared by an improvement in the process for making the mirrors. The glass surface after it has been cleaned but before it is silvered, is contacted with a solution of lanthanide rare earths in addition to a sensitization solution of tin or palladium. The addition of the rare earths produces a mirror which has increased resistance to delamination of the silver from the glass surface in the presence of water.

  12. Fascinating optics in a glass of water

    NASA Astrophysics Data System (ADS)

    de Waele, A. T. A. M.

    2016-04-01

    In Ref. [1] Jo Hermans discussed how the image of a horizontal arrow behind a glass of water reverses direction when it is moved away from the glass. The present paper deals with some other interesting effects that can be observed when looking at a drawing (source) taped tightly onto the back of a cylindrical glass of water, or beer, or white wine, whatever the reader prefers.

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

    SciTech Connect

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

    2009-10-05

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe3+/Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300-700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass.

  15. Healing of lithographically introduced flaws in glass and glass containing ceramics

    SciTech Connect

    Ackler, H.D.

    1992-12-01

    The morphological evolution of cylindrical pores or ``channels`` and crack-like cavities in glass and glass-containing ceramics at elevated temperatures was studied. The systems studied were: Coming 7056 alkali borosilicate glass, soda-lime glass (microscope slides), a commercially available 96% Al{sub 2}O{sub 3}with {approx}5--10% intergranular glass, 96% Al{sub 2}O{sub 3} bonded to sapphire, and a model sapphire/glass/sapphire system fabricated by diffusion bonding etched and unetched pieces of sapphire onto which 30--50 nm of SiO{sub 2} had been sputter deposited. These systems span a broad range of glass contents, and permit observation of healing behavior with varying glass content. The results were compared with analytical models and results of similar studies in completely crystalline systems.

  16. Healing of lithographically introduced flaws in glass and glass containing ceramics

    SciTech Connect

    Ackler, H.D.

    1992-12-01

    The morphological evolution of cylindrical pores or channels'' and crack-like cavities in glass and glass-containing ceramics at elevated temperatures was studied. The systems studied were: Coming 7056 alkali borosilicate glass, soda-lime glass (microscope slides), a commercially available 96% Al[sub 2]O[sub 3]with [approx]5--10% intergranular glass, 96% Al[sub 2]O[sub 3] bonded to sapphire, and a model sapphire/glass/sapphire system fabricated by diffusion bonding etched and unetched pieces of sapphire onto which 30--50 nm of SiO[sub 2] had been sputter deposited. These systems span a broad range of glass contents, and permit observation of healing behavior with varying glass content. The results were compared with analytical models and results of similar studies in completely crystalline systems.

  17. Dipolar ferromagnets and glasses (invited)

    SciTech Connect

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

    1991-11-15

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

  18. Simple aging in molecular glasses

    NASA Astrophysics Data System (ADS)

    Niss, Kristine

    2015-03-01

    The glass transition takes place when the structural (alpha) relaxation freezes in and the liquid enters a non-equilibrium solid state. This usually happens when the relaxation time, τ, reaches a timescale of 1000 seconds, and τ = 1000 s is pragmatically used as a definition of the glass transition temperature Tg. However, if the glass is studied on a long enough time scale then relaxation is still seen as physical aging. Aging is a non-linear signature of the alpha relaxation in which the relaxation dynamics changes as a function of how far the system has relaxed. If the system is studied well below Tg then equilibrium will not be achieved, but just below or around Tg it is possible to systematically monitor the non-linear relaxation all the way to equilibrium. We have developed a micro crystat which is optimized for making fast changes in temperature and keeping temperature stable over days and even weeks. Combining this micro cryostat with a small dielectric cell it is possible to monitor non-linear relaxation in a dynamical range of more than 4 decades from 10 seconds to a 105 seconds. The aging is monitored after a fast temperature jump. This means that the aging itself is isotherm, and the data therefore directly shows, how the relaxation-rate changes as volume and structure change on the isotherm. We have studied several molecular liquids and find that the data to a very large extend can be understood in terms of a TNM formalism. This implies time-aging-time superposition and suggests a simple picture where the out of equlibrium ``states'' correspond to equilibrium states - at an other temperature. If the alpha relaxation is dynamically heterogeneous as it is commonly believed, then the aging results show that fast and slow ``modes'' of the relaxation are governed in the same way by structure and volume. We hypothesize that aging according to TNM formalism is an intrinsic property of Roskilde Simple liquids.

  19. Glass-windowed ultrasound transducers.

    PubMed

    Yddal, Tostein; Gilja, Odd Helge; Cochran, Sandy; Postema, Michiel; Kotopoulis, Spiros

    2016-05-01

    In research and industrial processes, it is increasingly common practice to combine multiple measurement modalities. Nevertheless, experimental tools that allow the co-linear combination of optical and ultrasonic transmission have rarely been reported. The aim of this study was to develop and characterise a water-matched ultrasound transducer architecture using standard components, with a central optical window larger than 10 mm in diameter allowing for optical transmission. The window can be used to place illumination or imaging apparatus such as light guides, miniature cameras, or microscope objectives, simplifying experimental setups. Four design variations of a basic architecture were fabricated and characterised with the objective to assess whether the variations influence the acoustic output. The basic architecture consisted of a piezoelectric ring and a glass disc, with an aluminium casing. The designs differed in piezoelectric element dimensions: inner diameter, ID=10 mm, outer diameter, OD=25 mm, thickness, TH=4 mm or ID=20 mm, OD=40 mm, TH=5 mm; glass disc dimensions OD=20-50 mm, TH=2-4 mm; and details of assembly. The transducers' frequency responses were characterised using electrical impedance spectroscopy and pulse-echo measurements, the acoustic propagation pattern using acoustic pressure field scans, the acoustic power output using radiation force balance measurements, and the acoustic pressure using a needle hydrophone. Depending on the design and piezoelectric element dimensions, the resonance frequency was in the range 350-630 kHz, the -6 dB bandwidth was in the range 87-97%, acoustic output power exceeded 1 W, and acoustic pressure exceeded 1 MPa peak-to-peak. 3D stress simulations were performed to predict the isostatic pressure required to induce material failure and 4D acoustic simulations. The pressure simulations indicated that specific design variations could sustain isostatic pressures up to 4.8 MPa.The acoustic simulations were able to

  20. Glass-bead peen plating

    NASA Technical Reports Server (NTRS)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  1. Glass-windowed ultrasound transducers.

    PubMed

    Yddal, Tostein; Gilja, Odd Helge; Cochran, Sandy; Postema, Michiel; Kotopoulis, Spiros

    2016-05-01

    In research and industrial processes, it is increasingly common practice to combine multiple measurement modalities. Nevertheless, experimental tools that allow the co-linear combination of optical and ultrasonic transmission have rarely been reported. The aim of this study was to develop and characterise a water-matched ultrasound transducer architecture using standard components, with a central optical window larger than 10 mm in diameter allowing for optical transmission. The window can be used to place illumination or imaging apparatus such as light guides, miniature cameras, or microscope objectives, simplifying experimental setups. Four design variations of a basic architecture were fabricated and characterised with the objective to assess whether the variations influence the acoustic output. The basic architecture consisted of a piezoelectric ring and a glass disc, with an aluminium casing. The designs differed in piezoelectric element dimensions: inner diameter, ID=10 mm, outer diameter, OD=25 mm, thickness, TH=4 mm or ID=20 mm, OD=40 mm, TH=5 mm; glass disc dimensions OD=20-50 mm, TH=2-4 mm; and details of assembly. The transducers' frequency responses were characterised using electrical impedance spectroscopy and pulse-echo measurements, the acoustic propagation pattern using acoustic pressure field scans, the acoustic power output using radiation force balance measurements, and the acoustic pressure using a needle hydrophone. Depending on the design and piezoelectric element dimensions, the resonance frequency was in the range 350-630 kHz, the -6 dB bandwidth was in the range 87-97%, acoustic output power exceeded 1 W, and acoustic pressure exceeded 1 MPa peak-to-peak. 3D stress simulations were performed to predict the isostatic pressure required to induce material failure and 4D acoustic simulations. The pressure simulations indicated that specific design variations could sustain isostatic pressures up to 4.8 MPa.The acoustic simulations were able to

  2. Apparatus Splits Glass Tubes Longitudinally

    NASA Technical Reports Server (NTRS)

    Shaw, Ernest; Manahan, Robert O'neil

    1993-01-01

    Tubes split into half cylinders by hot-wire/thermal-shock method. Tube to be cut placed on notched jig in apparatus. Nichrome wire stretched between arms of pivoted carriage and oriented parallel to notch. Wire heated by electrical current while resting on tube. After heating for about 1 minute for each millimeter of thickness of glass, tube quenched in water and split by resulting thermal shock. Apparatus used to split tubes in sizes ranging from 3/8 in. in diameter by 1 in. long to 1 1/2 in. in diameter by 4 in. long.

  3. Momentum deficit in quantum glasses

    SciTech Connect

    Andreev, A. F.

    2009-07-15

    Using the concept of tunneling two-level systems, we explain the reduction of rotational inertia of disordered solid {sup 4}He observed in the torsional oscillator experiments. The key point is a peculiar quantum phenomenon of momentum deficit for two-level systems in moving solids. We show that an unusual state that is essentially different from both normal and superfluid solid states can be realized in quantum glasses. This state is characterized by reduced rotational inertia in oscillator experiments, by the absence of a superflow, and by the normal behavior in steady rotation.

  4. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, Paul A.; Bloom, Ira D.; Roche, Michael F.

    1987-01-01

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

  5. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, P.A.; Bloom, I.D.; Roche, M.F.

    1986-04-17

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

  6. Electrochemical cell with high conductivity glass electrolyte

    DOEpatents

    Nelson, P.A.; Bloom, I.D.; Roche, M.F.

    1987-04-21

    A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material. 6 figs.

  7. Compliant Glass Seals for SOFC Stacks

    SciTech Connect

    Chou, Y. S.; Choi, Jung-Pyung; Xu, Wei; Stephens, Elizabeth V.; Koeppel, Brian J.; Stevenson, Jeffry W.; Lara-Curzio, Edgar

    2014-04-01

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

  8. Thermal Analysis Of Reluctant Glass Formers

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin C.; Curreri, Peter A.

    1989-01-01

    Thermocouple holds sample and monitors temperature during cooling. Ellipsoidal furnace provides controlled cooling rates for studies of thermal properties of reluctant glass formers. Glass tube inserted into furnace and used to blow helium on specimen to cool rapidly. Cooling curve analyzed to determine rate of cooling and such properties of sample as nucleation and recalescence temperatures at cooling rate. Continuous-cooling-crystallization boundaries determined empirically from plots of nucleation time vs. nucleation temperature from runs at large number of different rates of cooling. Apparatus used to examine glass-formation ability of material and critical cooling rate to form glass.

  9. Systems approach to nuclear waste glass development

    SciTech Connect

    Jantzen, C M

    1986-01-01

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

  10. Research on graphite reinforced glass matrix composites

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    The results of research for the origination of graphite-fiber reinforced glass matrix composites are presented. The method selected to form the composites consisted of pulling the graphite fiber through a slurry containing powdered glass, winding up the graphite fiber and the glass it picks up on a drum, drying, cutting into segments, loading the tape segment into a graphite die, and hot pressing. During the course of the work, composites were made with a variety of graphite fibers in a glass matrix.

  11. Boron Nitride Nanotubes-Reinforced Glass Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam; Hurst, Janet B.; Choi, Sung R.

    2005-01-01

    Boron nitride nanotubes of significant lengths were synthesized by reaction of boron with nitrogen. Barium calcium aluminosilicate glass composites reinforced with 4 weight percent of BN nanotubes were fabricated by hot pressing. Ambient-temperature flexure strength and fracture toughness of the glass-BN nanotube composites were determined. The strength and fracture toughness of the composite were higher by as much as 90 and 35 percent, respectively, than those of the unreinforced glass. Microscopic examination of the composite fracture surfaces showed pullout of the BN nanotubes. The preliminary results on the processing and improvement in mechanical properties of BN nanotube reinforced glass matrix composites are being reported here for the first time.

  12. The mechanism of borosilicate glass corrosion revisited

    NASA Astrophysics Data System (ADS)

    Geisler, Thorsten; Nagel, Thorsten; Kilburn, Matt R.; Janssen, Arne; Icenhower, Jonathan P.; Fonseca, Raúl O. C.; Grange, Marion; Nemchin, Alexander A.

    2015-06-01

    Currently accepted mechanistic models describing aqueous corrosion of borosilicate glasses are based on diffusion-controlled hydrolysis, hydration, ion exchange reactions, and subsequent re-condensation of the hydrolyzed glass network, leaving behind a residual hydrated glass or gel layer. Here, we report results of novel oxygen and silicon isotope tracer experiments with ternary Na borosilicate glasses that can be better explained by a process that involves the congruent dissolution of the glass, which is spatially and temporally coupled to the precipitation and growth of an amorphous silica layer at an inwardly moving reaction interface. Such a process is thermodynamically driven by the solubility difference between the glass and amorphous silica, and kinetically controlled by glass dissolution reactions at the reaction front, which, in turn, are controlled by the transport of water and solute elements through the growing corrosion zone. Understanding the coupling of these reactions is the key to understand the formation of laminar or more complex structural and chemical patterns observed in natural corrosion zones of ancient glasses. We suggest that these coupled processes also have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments.

  13. Optical Properties of Silver Nanoparticulate Glasses

    NASA Astrophysics Data System (ADS)

    Evans, Rachel N.; Cannavino, Sarah A.; King, Christy A.; Lamartina, Joseph A.; Magruder, Robert H.; Ferrara, Davon W.

    The ion exchange method of embedding metal nanoparticles (NPs) into float glass is an often used technique of fabricating colored glasses and graded-index waveguides. The depth and size of NP formation in the glass depends on the concentration and temperature of metal ions in the molten bath. In this study we explore the dichroic properties of silver metal ion exchange restricted to only one side of a glass microscope slide using reflection and transmission spectroscopy and its dependence on temperature, concentration of silver ions, and length of time in the molten bath.

  14. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    SciTech Connect

    W. Ebert

    2001-09-20

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

  15. Prediction of glass durability as a function of glass composition and test conditions: Thermodynamics and kinetics

    SciTech Connect

    Jantzen, C M

    1988-01-01

    The long-term durability of nuclear waste glasses can be predicted by comparing their performance to natural and ancient glasses. Glass durability is a function of the kinetic and thermodynamic stability of glass in solution. The relationship between the kinetic and thermodynamic aspects of glass durability can be understood when the relative contributions of glass composition and imposed test conditions are delineated. Glass durability has been shown to be a function of the thermodynamic hydration free energy which can be calculated from the glass composition. Hydration thermodynamics also furnishes a quantitative frame of reference to understand how various test parameters affect glass durability. Linear relationships have been determined between the logarithmic extent of hydration and the calculated hydration free energy for several different test geometries. Different test conditions result in different kinetic reactivity parameters such as the exposed glass surface area (SA), the leachant solution volume (V), and the length of time that the glass is in the leachant (t). Leachate concentrations are known to be a function of the kinetic test parameter (SAV)t. The relative durabilities of glasses, including pure silica, obsidians, nuclear waste glasses, medieval window glasses, and frit glasses define a plane in three dimensional ..delta..G/sub hyd/-concentration-(SAV)t space. At constant kinetic conditions, e.g., test geometry and test duration, the three dimensional plane is intersected at constant (SAV)t and the ..delta..G/sub hyd/-concentration plots have similar slopes. The slope represents the natural logarithm of the theoretical slope, (12.303 RT), for the rate of glass dissolution. 53 refs., 4 figs.

  16. 49 CFR 230.52 - Water glass valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be...

  17. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Glass and glazed openings. 3280.113... Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass doors shall meet the requirements of § 3280.403 the “Standard for Windows and Sliding Glass Doors Used...

  18. 49 CFR 230.52 - Water glass valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be...

  19. 49 CFR 230.56 - Water glass lamps.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Water glass lamps. 230.56 Section 230.56... Water Glasses and Gauge Cocks § 230.56 Water glass lamps. All water glasses must be supplied with a suitable lamp properly located to enable the engine crew to easily see the water in the glass....

  20. 49 CFR 230.52 - Water glass valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be...

  1. 49 CFR 230.56 - Water glass lamps.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Water glass lamps. 230.56 Section 230.56... Water Glasses and Gauge Cocks § 230.56 Water glass lamps. All water glasses must be supplied with a suitable lamp properly located to enable the engine crew to easily see the water in the glass....

  2. 49 CFR 230.52 - Water glass valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be...

  3. 49 CFR 230.52 - Water glass valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be...

  4. 49 CFR 230.56 - Water glass lamps.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Water glass lamps. 230.56 Section 230.56... Water Glasses and Gauge Cocks § 230.56 Water glass lamps. All water glasses must be supplied with a suitable lamp properly located to enable the engine crew to easily see the water in the glass....

  5. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Glass and glazed openings. 3280.113... Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass doors shall meet the requirements of § 3280.403 the “Standard for Windows and Sliding Glass Doors Used...

  6. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Glass and glazed openings. 3280.113... Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass doors shall meet the requirements of § 3280.403 the “Standard for Windows and Sliding Glass Doors Used...

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  8. 49 CFR 230.56 - Water glass lamps.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Water glass lamps. 230.56 Section 230.56... Water Glasses and Gauge Cocks § 230.56 Water glass lamps. All water glasses must be supplied with a suitable lamp properly located to enable the engine crew to easily see the water in the glass....

  9. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Glass and glazed openings. 3280.113... Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass doors shall meet the requirements of § 3280.403 the “Standard for Windows and Sliding Glass Doors Used...

  10. 49 CFR 230.56 - Water glass lamps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Water glass lamps. 230.56 Section 230.56... Water Glasses and Gauge Cocks § 230.56 Water glass lamps. All water glasses must be supplied with a suitable lamp properly located to enable the engine crew to easily see the water in the glass....

  11. Reinforcement of conventional glass-ionomer restorative material with short glass fibers.

    PubMed

    Hammouda, Ibrahim M

    2009-01-01

    This study investigated the strengthening effect of glass fibers when added to conventional glass-ionomer restorative material. Glass fibers were incorporated into glass-ionomer powder in 3 wt% and 5 wt%. The fibers used had 1 mm length and 10 microm thickness. These criteria of fiber length, diameter, and concentration represent a new approach for reinforcing conventional glass-ionomer [Medifill, conventional restorative glass-ionomer]. The mechanical properties tested were diametral tensile strength, hardness, flexural strength, flexural modulus and fracture toughness after 24-h and 7-days of storage in deionized water. Glass short fibers were mixed thoroughly into the glass-ionomer powder before mixing with the cement liquid. Samples of specific dimensions were prepared for each time interval and fiber loading according to the manufacturer's instructions and international standards. Hardness was measured using a micro-hardness tester at 100 gram applied load for 15 s. The other mechanical properties were measured using a Lloyd universal testing machine. The results showed increased diametral tensile strength, flexural strength, flexural modulus, and fracture toughness by the addition of glass fibers. There was an appreciable increase of the tested mechanical properties of glass-ionomer restorative material as a result of increasing fiber loading and water storage for 1 week. It was concluded that conventional glass-ionomer can be reinforced by the addition of short glass fibers.

  12. Glass shell manufacturing in space

    NASA Technical Reports Server (NTRS)

    Downs, R. L.; Ebner, M. A.; Nolen, R. L., Jr.

    1981-01-01

    Highly-uniform, hollow glass spheres (shells), which are used for inertial confinement fusion targets, were formed from metal-organic gel powder feedstock in a vertical furnace. As a result of the rapid pyrolysis caused by the furnace, the gel is transformed to a shell in five distinct stages: (a) surface closure of the porous gel; (b) generation of a closed-cell foam structure in the gel; (c) spheridization of the gel and further expansion of the foam; (d) coalescence of the closed-cell foam to a single-void shell; and (e) fining of the glass shell. The heat transfer from the furnace to the falling gel particle was modeled to determine the effective heating rate of the gel. The model predicts the temperature history for a particle as a function of mass, dimensions, specific heat, and absorptance as well as furnace temperature profile and thermal conductivity of the furnace gas. A model was developed that predicts the gravity-induced degradation of shell concentricity in falling molten shells as a function of shell characteristics and time.

  13. Optically responsive supramolecular polymer glasses

    NASA Astrophysics Data System (ADS)

    Balkenende, Diederik W. R.; Monnier, Christophe A.; Fiore, Gina L.; Weder, Christoph

    2016-03-01

    The reversible and dynamic nature of non-covalent interactions between the constituting building blocks renders many supramolecular polymers stimuli-responsive. This was previously exploited to create thermally and optically healable polymers, but it proved challenging to achieve high stiffness and good healability. Here we present a glass-forming supramolecular material that is based on a trifunctional low-molecular-weight monomer ((UPyU)3TMP). Carrying three ureido-4-pyrimidinone (UPy) groups, (UPyU)3TMP forms a dynamic supramolecular polymer network, whose properties are governed by its cross-linked architecture and the large content of the binding motif. This design promotes the formation of a disordered glass, which, in spite of the low molecular weight of the building block, displays typical polymeric behaviour. The material exhibits a high stiffness and offers excellent coating and adhesive properties. On account of reversible dissociation and the formation of a low-viscosity liquid upon irradiation with ultraviolet light, rapid optical healing as well as (de)bonding on demand is possible.

  14. Optically responsive supramolecular polymer glasses.

    PubMed

    Balkenende, Diederik W R; Monnier, Christophe A; Fiore, Gina L; Weder, Christoph

    2016-01-01

    The reversible and dynamic nature of non-covalent interactions between the constituting building blocks renders many supramolecular polymers stimuli-responsive. This was previously exploited to create thermally and optically healable polymers, but it proved challenging to achieve high stiffness and good healability. Here we present a glass-forming supramolecular material that is based on a trifunctional low-molecular-weight monomer ((UPyU)3TMP). Carrying three ureido-4-pyrimidinone (UPy) groups, (UPyU)3TMP forms a dynamic supramolecular polymer network, whose properties are governed by its cross-linked architecture and the large content of the binding motif. This design promotes the formation of a disordered glass, which, in spite of the low molecular weight of the building block, displays typical polymeric behaviour. The material exhibits a high stiffness and offers excellent coating and adhesive properties. On account of reversible dissociation and the formation of a low-viscosity liquid upon irradiation with ultraviolet light, rapid optical healing as well as (de)bonding on demand is possible. PMID:26983805

  15. Optically responsive supramolecular polymer glasses

    PubMed Central

    Balkenende, Diederik W. R.; Monnier, Christophe A.; Fiore, Gina L.; Weder, Christoph

    2016-01-01

    The reversible and dynamic nature of non-covalent interactions between the constituting building blocks renders many supramolecular polymers stimuli-responsive. This was previously exploited to create thermally and optically healable polymers, but it proved challenging to achieve high stiffness and good healability. Here we present a glass-forming supramolecular material that is based on a trifunctional low-molecular-weight monomer ((UPyU)3TMP). Carrying three ureido-4-pyrimidinone (UPy) groups, (UPyU)3TMP forms a dynamic supramolecular polymer network, whose properties are governed by its cross-linked architecture and the large content of the binding motif. This design promotes the formation of a disordered glass, which, in spite of the low molecular weight of the building block, displays typical polymeric behaviour. The material exhibits a high stiffness and offers excellent coating and adhesive properties. On account of reversible dissociation and the formation of a low-viscosity liquid upon irradiation with ultraviolet light, rapid optical healing as well as (de)bonding on demand is possible. PMID:26983805

  16. SRNL POROUS WALL GLASS MICROSPHERES

    SciTech Connect

    Wicks, G; Leung Heung, L; Ray Schumacher, R

    2008-04-15

    The Savannah River National Laboratory (SRNL) has developed a new medium for storage of hydrogen and other gases. This involves fabrication of thin, Porous Walled, Hollow Glass Microspheres (PW-HGMs), with diameters generally in the range of 1 to several hundred microns. What is unique about the glass microballons is that porosity has been induced and controlled within the thin, one micron thick walls, on the scale of 10 to several thousand Angstroms. This porosity results in interesting properties including the ability to use these channels to fill the microballons with special absorbents and other materials, thus providing a contained environment even for reactive species. Gases can now enter the microspheres and be retained on the absorbents, resulting in solid-state and contained storage of even reactive species. Also, the porosity can be altered and controlled in various ways, and even used to filter mixed gas streams within a system. SRNL is involved in about a half dozen different programs involving these PW-HGMs and an overview of some of these activities and results emerging are presented.

  17. Bare Bones of Bioactive Glass

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Even in normal gravity, bioactive glass particles enhance bone growth in laboratory tests with flat tissue cultures. Ducheyne and his team believe that using the bioactive microcarriers in a rotating bioreactor in microgravity will produce improved, three-dimensional tissue cultures. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and University of Pennsylvania Center for Bioactive Materials and Tissue Engineering.

  18. Crystallization Kinetics in Fluorochloroziroconate Glass-Ceramics

    NASA Astrophysics Data System (ADS)

    Alvarez, Carlos J.

    Annealing fluorochlorozirconate (FCZ) glasses nucleates BaCl2 nanocrystals in the glass matrix, resulting in a nanocomposite glass-ceramic that has optical properties suitable for use as a medical X-ray imaging plate. Understanding the way in which the BaCl¬2 nanocrystal nucleation, growth and phase transformation processes proceed is critical to controlling the optical behavior. However, there is a very limited amount of information about the formation, morphology, and distribution of the nanocrystalline particles in FCZ glass-ceramics. In this thesis, the correlation between the microstructure and the crystallization kinetics of FCZ glass-ceramics, are studied in detail. In situ X-ray diffraction and transmission electron microscopy annealing experiments are used to analyze the crystal structure, size and distribution of BaCl 2 nanocrystals in FCZ glass-ceramics as a function of annealing rate and temperature. Microstructural analysis of the early stages on nucleation identified the formation of both BaCl2 and BaF2 nanocrystals. Annealing FCZ glass-ceramics above 280°C can cause the formation of additional glass matrix phase crystals, their microstructure and the annealing parameters required for their growth are identified. As the crystalline phases grow directly from the glass, small variations in processing of the glass can have a profound influence on the crystallization process. The information obtained from these experiments improves the understanding of the nucleation, growth and phase transformation process of the BaCl¬2 nanocrystals and additional crystalline phases that form in FCZ glass-ceramics, and may help expedite the implementation of FCZ glass-ceramics as next-generation X-ray detectors. Lastly, as these glass-ceramics may one day be commercialized, an investigation into their degradation in different environmental conditions was also performed. The effects of direct contact with water or prolonged exposure to humid environments on the

  19. Control of radioactive waste-glass melters

    SciTech Connect

    Bickford, D.F. ); Hrma, P. ); Bowan, B.W. II )

    1990-01-01

    Slurries of simulated high level radioactive waste and glass formers have been isothermally reacted and analyzed to identify the sequence of the major chemical reactions in waste vitrification, their effect on glass production rate, and the development of leach resistance. Melting rates of waste batches have been increased by the addition of reducing agents (formic acid, sucrose) and nitrates. The rate increases are attributable in part to exothermic reactions which occur at critical stages in the vitrification process. Nitrates must be balanced by adequate reducing agents to avoid the formation of persistent foam, which would destabilize the melting process. The effect of foaming on waste glass production rates is analyzed, and melt rate limitations defined for waste-glass melters, based upon measurable thermophysical properties. Minimum melter residence times required to homogenize glass and assure glass quality are much smaller than those used in current practice. Thus, melter size can be reduced without adversely affecting glass quality. Physical chemistry and localized heat transfer of the waste-glass melting process are examined, to refine the available models for predicting and assuring glass production rate. It is concluded that the size of replacement melters and future waste processing facilities can be significantly decreased if minimum heat transfer requirements for effective melting are met by mechanical agitation. A new class of waste glass melters has been designed, and proof of concept tests completed on simulated High Level Radioactive Waste slurry. Melt rates have exceeded 155 kg m{sup {minus}2} h{sup {minus}1} with slurry feeds (32 lb ft{sup {minus}2} h{sup {minus}1}), and 229 kg kg m{sup {minus}2} h{sup {minus}1} with dry feed (47 lb ft{sup {minus}2} h{sup {minus}1}). This is about 8 times the melt rate possible in conventional waste- glass melters of the same size. 39 refs., 5 figs., 9 tabs.

  20. Protein adsorption to multi-component glasses

    NASA Astrophysics Data System (ADS)

    Hall, Matthew Micah

    2003-07-01

    The adsorption of human serum albumin (HSA) to sodium silicate, soda lime silicate (SLS), and sodium aluminosilicate (SAS) glass microspheres was investigated using sodiumdodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in conjunction with a colloidal silver stain for visualization. The 30 Na2O·70 SiO2 composition could not be evaluated due to an apparent chemical interference that occurred during silver staining. This inhibitory effect was attributed to the extensive corrosion that occurred during the protein elution and caused an elevation in the pH of the solution. The remaining glass compositions were sufficiently durable for further study. The HSA adsorption capacity of SLS glass microspheres containing 70 and 80 mol% SiO2 increased as CaO was substituted for Na2O. An abrupt decrease in the HSA adsorption capacity was observed for SLS glasses containing 60 mol% SiO2. A similar trend was observed for the SAS glass microspheres, although the SAS glasses adsorbed less HSA than the SLS glasses containing equivalent molar percentages of SiO2. The initial increase in HSA adsorption capacity for SLS and SAS glasses containing 70 and 80 MOM SiO2 was attributed to the introduction of positive charges into the glass surfaces via Ca2+ and Al3+ cations. The decrease in HSA adsorption capacity for SLS and SAS glasses containing 60 mol% SiO2 may be due to an enhanced affinity between the glasses and HSA, resulting in a "flattened" conformation that limits the total accessible area for adsorption.

  1. Borosilicate glass alteration driven by magnesium carbonates

    NASA Astrophysics Data System (ADS)

    Debure, M.; Frugier, P.; De Windt, L.; Gin, S.

    2012-01-01

    The alteration of simplified synthetic glass, representative of the French reference nuclear glass R7T7, in presence of hydromagnesite has been experimentally investigated and modeled. Magnesium in solution is known to potentially enhance glass alteration; nuclear glass clayed host rocks contain magnesium and can dissolve to maintain the concentration of magnesium in solution. For modeling purposes, it was suitable to study a simple system. Hydromagnesite was therefore chosen as a simple model mineral in order to check the influence of an Mg-rich mineral on glass alteration. Since the models use thermodynamic and kinetic parameters measured in pure water and pH-buffered solutions, changing the solution composition or adding minerals is a key step towards the validation of the modeling assumptions before using the model for predictive purposes. Experiments revealed that glass alteration is enhanced in presence of hydromagnesite. Modeling was performed using the GRAAL model implemented within the CHESS/HYTEC reactive transport code. Modeling proved useful both for explaining the mechanisms involved and quantifying the impact on glass alteration: Mg coming from hydromagnesite dissolution reacts with Si provided by the glass in order to form magnesium silicates. This reaction decreases the pH down to neutral conditions where magnesium silicates are more soluble than at the natural alkali pH imposed by glass or hydromagnesite dissolution. The driving force of the magnesium silicate precipitation is eventually the interdiffusion of alkali within the altered amorphous glass layer as this mechanism consumes protons. The model's ability to describe the concentrations of elements in solution and formed solids whatever the glass/hydromagnesite ratio strongly supports the basic modeling hypothesis.

  2. Compositional-tailoring of optical properties in IR transparent chalcogenide glasses for precision glass molding

    NASA Astrophysics Data System (ADS)

    Gleason, B.; Wachtel, P.; Musgraves, J. D.; Qiao, A.; Anheier, N.; Richardson, K.

    2013-09-01

    The structural and optical properties of AsSe chalcogenide glass, starting with As40Se60, were studied as a function of Ge or Se additions. These elements provide broad glass forming options when combined with the host matrix to allow for compositional tuning of properties. Optimization of glass composition has been shown to produce bulk glasses with a thermoptic coefficient (dn/dT) equal to zero, as well as a composition which could demonstrate a net zero change in index after precision glass molding (PGM). The bulk glass density, coefficient of thermal expansion (CTE), refractive index, and dn/dT were measured for all bulk compositions, as was the refractive index after PGM. For the bulk glasses examined, both the refractive index (measured at discrete laser wavelengths from 3.4 to10.6 μm) and dn/dT were observed to decrease as the molecular percentage of either Ge or Se is increased. Compared to the starting glass' network, additions of either Ge or Se lead to a deviation from the "optimally constrained" binary glass' average coordination number = 2.4. Additions of Se or Ge serve to decrease or increase the average coordination number (CN) of the glass, respectively, while also changing the network's polarizability. After a representative PGM process, glasses exhibited an "index drop" consistent with that seen for oxide glasses.1 Based on our evaluation, both the Gecontaining and Ge-free tielines show potential for developing unique compositions with either a zero dn/dT for the unmolded, bulk glass, as well as the potential for a glass that demonstrates a net zero "index drop" after molding. Such correlation of glass chemistry, network, physical and optical properties will enable the tailoring of novel compositions suitable for prototyping towards targeted molding behavior and final properties.

  3. Offutt Air Force Base, Looking Glass Airborne Command Post, Hydraulic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Offutt Air Force Base, Looking Glass Airborne Command Post, Hydraulic Fluid Buildings, Northeast of Looking Glass Avenue at southwest side of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  4. Surface layer effects on waste glass corrosion

    SciTech Connect

    Feng, X.

    1993-12-31

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

  5. Monitoring and analyzing waste glass compositions

    DOEpatents

    Schumacher, R.F.

    1994-03-01

    A device and method are described for determining the viscosity of a fluid, preferably molten glass. The apparatus and method use the velocity of rising bubbles, preferably helium bubbles, within the molten glass to determine the viscosity of the molten glass. The bubbles are released from a tube positioned below the surface of the molten glass so that the bubbles pass successively between two sets of electrodes, one above the other, that are continuously monitoring the conductivity of the molten glass. The measured conductivity will change as a bubble passes between the electrodes enabling an accurate determination of when a bubble has passed between the electrodes. The velocity of rising bubbles can be determined from the time interval between a change in conductivity of the first electrode pair and the second, upper electrode pair. The velocity of the rise of the bubbles in the glass melt is used in conjunction with other physical characteristics, obtained by known methods, to determine the viscosity of the glass melt fluid and, hence, glass quality. 2 figures.

  6. Antibacterial properties of laser spinning glass nanofibers.

    PubMed

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

    2014-12-30

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

  7. The Glass Ceiling: Progress and Persistent Challenges

    ERIC Educational Resources Information Center

    McLlwain, Wendy M.

    2012-01-01

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

  8. Monitoring and analyzing waste glass compositions

    DOEpatents

    Schumacher, Ray F.

    1994-01-01

    A device and method for determining the viscosity of a fluid, preferably molten glass. The apparatus and method uses the velocity of rising bubbles, preferably helium bubbles, within the molten glass to determine the viscosity of the molten glass. The bubbles are released from a tube positioned below the surface of the molten glass so that the bubbles pass successively between two sets of electrodes, one above the other, that are continuously monitoring the conductivity of the molten glass. The measured conductivity will change as a bubble passes between the electrodes enabling an accurate determination of when a bubble has passed between the electrodes. The velocity of rising bubbles can be determined from the time interval between a change in conductivity of the first electrode pair and the second, upper electrode pair. The velocity of the rise of the bubbles in the glass melt is used in conjunction with other physical characteristics, obtained by known methods, to determine the viscosity of the glass melt fluid and, hence, glass quality.

  9. Cluster size distribution in Gaussian glasses

    NASA Astrophysics Data System (ADS)

    Novikov, S. V.

    2011-03-01

    A simple method for the estimation of the asymptotics of the cluster numbers in Gaussian glasses is described. Validity of the method was tested by the comparison with the exact analytic result for the non-correlated field and simulation data for the distribution of random energies in strongly spatially correlated dipolar glass model.

  10. Viscous Glass Sealants for SOFC Applications

    SciTech Connect

    Scott Misture

    2012-09-30

    Two series of silicate glasses that contain gallium as the primary critical component have been identified and optimized for viscous sealing of solid oxide fuel cells operating from 650 to 850°C. Both series of glass sealants crystallize partially upon heat treatment and yield multiphase microstructures that allow viscous flow at temperatures as low as 650°C. A fully amorphous sealant was also developed by isolating, synthesizing and testing a silicate glass of the same composition as the remnant glassy phase in one of the two glass series. Of ~40 glasses tested for longer than 500 hours, a set of 5 glasses has been further tested for up to 1000h in air, wet hydrogen, and against both yttria-stabilized zirconia and aluminized stainless steel. In some cases the testing times reached 2000h. The reactivity testing has provided new insight into the effects of Y, Zr, and Al on bulk and surface crystallization in boro-gallio-silicate glasses, and demonstrated that at least 5 of the newly-developed glasses are viable viscous sealants.

  11. Glass tubes for protecting solar cells

    NASA Technical Reports Server (NTRS)

    Shelpuk, B.

    1978-01-01

    Protecting solar cells against environmental effects is accomplished by putting them inside glass tubes instead of hermetically sealing them between pairs of flat glass sheets. If cells are coupled with storage battery integrated into tube, freestanding power source could be built.

  12. Rapid Glass Refiner Development Program, Final report

    SciTech Connect

    1995-02-20

    A rapid glass refiner (RGR) technology which could be applied to both conventional and advanced class melting systems would significantly enhance the productivity and the competitiveness of the glass industry in the United States. Therefore, Vortec Corporation, with the support of the US Department of Energy (US DOE) under Cooperative Agreement No. DE-FC07-90ID12911, conducted a research and development program for a unique and innovative approach to rapid glass refining. To provide focus for this research effort, container glass was the primary target from among the principal glass types based on its market size and potential for significant energy savings. Container glass products represent the largest segment of the total glass industry accounting for 60% of the tonnage produced and over 40% of the annual energy consumption of 232 trillion Btu/yr. Projections of energy consumption and the market penetration of advanced melting and fining into the container glass industry yield a potential energy savings of 7.9 trillion Btu/yr by the year 2020.

  13. Oxide glasses for mid-infrared lasers

    NASA Astrophysics Data System (ADS)

    Richards, Billy D. O.; Jha, Animesh; Jose, Gin; Jiang, Xin

    2011-06-01

    We present an overview of rare-earth doped heavy metal oxide and oxy-fluoride glasses which show promise as host materials for lasers operating in the 2-5 μm spectral region for medical, military and sensing applications. By engineering glass composition and purity, tellurite and germanate glasses can support transmission up to and beyond 5 μm and can have favourable thermal, mechanical and environmental stability compared to fluoride glasses. We discuss techniques for glass purification and water removal for enhanced infrared transmission. By comparing the material properties of the glass, and spectroscopic performance of selected rare-earth dopant ions we can identify promising compositions for fibre and bulk lasers in the mid-infrared. Tellurite glass has recently been demonstrated to be a suitable host material for efficient and compact lasers in the {2 μm spectral region in fibre and bulk form and the next challenge is to extend the operating range further into the infrared region where silica fibre is not sufficiently transparent, and provide an alternative to fluoride glass and fibre.

  14. Method and apparatus for melting glass batch

    DOEpatents

    Fassbender, Alexander G.; Walkup, Paul C.; Mudge, Lyle K.

    1988-01-01

    A glass melting system involving preheating, precalcining, and prefluxing of batch materials prior to injection into a glass furnace. The precursors are heated by convection rather than by radiation in present furnaces. Upon injection into the furnace, batch materials are intimately coated with molten flux so as to undergo or at least begin the process of dissolution reaction prior to entering the melt pool.

  15. Glass electrolytes for sodium/sulfur cells

    NASA Astrophysics Data System (ADS)

    Roche, M. F.; Kucera, G. H.

    A glass electrolyte for use in sodium/sulfur batteries that has a low resistivity (100 ohm-cm at 300 (0)C) ans is stable in the cell environment was investigated. Glasses in the quaternary system: soda, alumina, zirconia and silica were studied. The main program elements are: (1) conductivity measurements at 300 to 500(0)C; (2) differential thermal analysis for determination of glass transition and crystallization temperatures; (3) static corrosion tests at 400(0)C using Na, Na2S4, and S; (4) mechanical strength and fracture toughness measurements; and (5) sodium/sulfur cell tests at 350(0)C. Fourteen quaternary glasses with a broad range of compositions were made. The resistivities of these glasses at 300(0)C extended from 130 to 3704 ohm-cm; the activation energies for conduction extended from 0.48 to 0.684 eV, and the glass transition temperatures extended from 397 to 685(0)C. Through a multiple linear regression analysis of these data response surfaces were generated for resistivity, activation energy for conduction, and glass transition temperture over the composition region within the quaternary system that is bounded by SiO2, Na2O3, Na2AlO4 and Na2ZrO3. The response surfaces indicate a new region of high conductivity and high glass transition temperature in the neighborhood of 42% soda, 31% silica and 27% alumina plus zirconia.

  16. The Glass Ceiling Initiative. A Report.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC.

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

  17. An Interview with Gene V. Glass

    ERIC Educational Resources Information Center

    Robinson, Daniel H.

    2004-01-01

    Gene V. Glass is presently Regents' Professor of both Educational Leadership and Policy Studies and Psychology in Education at Arizona State University. He won the Palmer O. Johnson Award for best article in the "American Educational Research Journal" in both 1968 and 1970. Dr. Glass has also served on the editorial boards of 13 journals and has…

  18. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; Watkins, R.D.

    1988-01-21

    Glass compositions containing CaO, Al/sub 2/O/sub 3/, B/sub 2/O/sub 3/, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  19. Phase Stability Determinations of DWPF Waste Glasses

    SciTech Connect

    Marra, S.L.

    1999-10-22

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. To fulfill this requirement, glass samples were heat treated at various times and temperatures. These results will provide guidance to the repository program about conditions to be avoided during shipping, handling and storage of DWPF canistered waste forms.

  20. Insertion of neptunium in borosilicate glasses

    NASA Astrophysics Data System (ADS)

    Petit-Maire, D.; Petiau, J.; Calas, G.; Jacquet-Francillon, N.

    1989-06-01

    Neptunium environment are studied in borosilicate glasses modelling those used to confine the high-level radioactive waste solution of fission products. Valence states III, IV and V are analysed and the local structures are compared to those of uranium and thorium in the same glasses.

  1. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1992-01-01

    Glass compositions containing CaO, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  2. Metallic function of lithium phosphate glass electrodes

    SciTech Connect

    Kochetova, T.I.; Bobrov, V.S.

    1995-05-20

    Specificity of metallic functions of lithium phosphate glasses toward univalent cations over a wide concentration range and their correlation with cation size have been studied. In the present work, the authors extended the spectrum of phosphate glass compositions: a study has been made how additions of gallium, titanium, and vanadium oxides influence electrode properties.

  3. Modification of resin modified glass ionomer cement by addition of bioactive glass nanoparticles.

    PubMed

    Valanezhad, Alireza; Odatsu, Tetsuro; Udoh, Koichi; Shiraishi, Takanobu; Sawase, Takashi; Watanabe, Ikuya

    2016-01-01

    In the present study, sol-gel derived nanoparticle calcium silicate bioactive glass was added to the resin-modified light cure glass-ionomer cement to assess the influence of additional bioactive glass nanoparticles on the mechanical and biological properties of resin-modified glass-ionomer cement. The fabricated bioactive glass nanoparticles added resin-modified glass-ionomer cements (GICs) were immersed in the phosphate buffer solution for 28 days to mimic real condition for the mechanical properties. Resin-modified GICs containing 3, 5 and 10 % bioactive glass nanoparticles improved the flexural strength compared to the resin-modified glass-ionomer cement and the samples containing 15 and 20 % bioactive glass nanoparticles before and after immersing in the phosphate buffer solution. Characterization of the samples successfully expressed the cause of the critical condition for mechanical properties. Cell study clarified that resin-modified glass-ionomer cement with high concentrations of bioactive glass nanoparticles has higher cell viability and better cell morphology compare to control groups. The results for mechanical properties and toxicity approved that the considering in selection of an optimum condition would have been a more satisfying conclusion for this study.

  4. Nanocrystallization in Fluorochlorozirconate Glass-Ceramics.

    PubMed

    Alvarez, Carlos J; Liu, Yuzi; Leonard, Russell L; Johnson, Jacqueline A; Petford-Long, Amanda K

    2013-11-01

    Heat treating fluorochlorozirconate (FCZ) glasses nucleates nanocrystals in the glass matrix, resulting in a nanocomposite glass-ceramic that has optical properties suitable for use as a medical imaging plate. Understanding the way in which the nanocrystal nucleation proceeds is critical to controlling the optical behavior. The nucleation and growth of nanocrystals in FCZ glass-ceramics was investigated with in situ transmission electron microscopy heating experiments. The experiments showed the nucleation and growth of previously unreported BaF2 nanocrystals in addition to the expected BaCl2 nanocrystals. Chemical analysis of the BaF2 nanocrystals shows an association with the optically active dopant previously thought only to interact with BaCl2 nanocrystals. The association of the dopant with BaF2 crystals suggests that it plays a role in the photoluminescent (PL) properties of FCZ glass-ceramics.

  5. Glass needs for a growing photovoltaics industry

    DOE PAGES

    Burrows, Keith; Fthenakis, Vasilis

    2014-10-18

    With the projected growth in photovoltaics, the demand for glass for the solar industry will far exceed the current supply, and thousands of new float-glass plants will have to be built to meet its needs over the next 20 years. Such expansion will provide an opportunity for the solar industry to obtain products better suited to their needs, such as low-iron glass and borosilicate glass at the lowest possible price. While there are no significant technological hurdles that would prevent the flat glass industry from meeting the solar industry’s projected needs, to do so will require advance planning and substantialmore » investments.« less

  6. Glass heat pipe evacuated tube solar collector

    DOEpatents

    McConnell, Robert D.; Vansant, James H.

    1984-01-01

    A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

  7. Fabrication of long lasting phosphorescence glass spheres

    NASA Astrophysics Data System (ADS)

    Lv, Hao; Liu, Aimei; Tong, Jufang; Yi, Xunong; Li, Qianguang

    2008-12-01

    The long lasting phosphorescence glass spheres doped with Eu2O3 and Dy2O3 were prepared under the reducing atmosphere and characterized. XRD analysis indicated the glass spheres exhibited the typical diffraction peaks of SrAl2O4: Eu2+, Dy3+. The emission spectra of the glass spheres showed broad bands peaking at 510nm. The excitation spectra of the glass spheres showed broad bands ranging from 300 to 480nm. These are believed due to the 5d4f-->4f transitions of Eu2+ in the SrAl2O4: Eu2+, Dy3+ phosphors. The afterglow luminescence of the glass spheres excited by a 40W fluorescence lamp for 30min can be observed in the dark for about 15h with the naked eye.

  8. Bioactive glass coatings for orthopedic metallic implants

    SciTech Connect

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

    2003-06-30

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

  9. Crystallization in heat-treated fluorochlorozirconate glasses

    PubMed Central

    Johnson, JA; Weber, JKR; Kolesnikov, AI; Schweizer, S

    2009-01-01

    Crystallization phenomena of fluorochlorozirconate glasses were investigated by means of differential scanning calorimetry and inelastic neutron scattering. The precipitation of barium chloride nanoparticles from the glass matrix upon heat treatment was found to be suppressed when re-melting the glass with a reducing agent but not if the agent was present in the initial synthesis. Addition of small amounts of oxide to the predominantly fluoride melt was found to maintain the presence of nanoparticles but not to induce the predicted phase transition of the barium chloride nanoparticles from hexagonal to orthorhombic structure. Inelastic neutron scattering performed on an ‘as-made’ glass and a heat-treated glass showed an increase in ‘hardness’, consistent with a more ordered structure. PMID:19789720

  10. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-12-02

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La{sub 2}O{sub 3}, B{sub 2}O{sub 3}, TiO{sub 2} and Al{sub 2}O{sub 3} in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 2 figs.

  11. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La.sub.2 O.sub.3, B.sub.2 O.sub.3, TiO.sub.2 and Al.sub.2 O.sub.3 in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  12. Considerations of Glass Sealing SOFC Stacks

    SciTech Connect

    Yang, Z Gary; Weil, K. Scott; Meinhardt, Kerry D.; Paxton, Dean M.; Stevenson, Jeffry W.

    2003-08-31

    Due to their TEC matching to PEN components, excellent oxidation resistance, low cost and good fabricability, stainless steels have been used as the interconnect materials in planar SOFC. For being hermetical, the stainless steel interconnect ought to be sealed to YSZ electrolyte and/or another piece of metallic interconnect, usually using a sealing glass. The seal performance, which is critical factor to determine the reliability and durability of SOFC stack, largely depends on the chemical compatibility between the sealing glass and stainless steel. In this work, the ferritic stainless steel 446 and a barium-aluminosilicate base glass have been taken as an example for metallic interconnects and sealing glass, respectively, and the corrosion at the interface of metal and sealing glass has been investigated and understood. The methodology and results of the microscopic analysis and thermodynamic modeling will be presented, and the mechanism of corrosion at the interface will be discussed as well.

  13. Designing aluminum sealing glasses for manufacturability

    SciTech Connect

    Kovacic, L.; Crowder, S.V.; Brow, R.K.

    1995-08-01

    Hermetically sealed aluminum electronic components have advantages over steel components from a manufacturing standpoint. They are lighter weight, cost less to machine, and can be sealed at lower temperatures. We have developed a family of new phosphate glasses, the ALSG series, that have the necessary thermal and chemical properties for producing reliable hermetic seals to aluminum alloys. The development of this glass family has included predictive techniques to minimize the time and effort required to integrate the technology into production environments. We will describe the developmental design matrix used to predict glass properties as a function of composition, thereby enabling the optimization of glasses for use in specific applications. We will also introduce a statistical model which is being investigated to optimize processing parameters of new glasses, decreasing the number of sealing runs required to achieve a quality hermetic component.

  14. Joining of silicon nitrides using oxynitride glasses

    SciTech Connect

    O`Brien, M.H.

    1993-03-01

    This report presents a study on commercial silicon nitrides that were successfully joined using oxynitride glasses. Sintered silicon nitride was joined by either closed or glass-filled joints. Glass-filled joints were successfully used on hot-pressed silicon nitrides and were comparable in fast fracture strength to unjoined silicon nitrides up to approximately 1000C. Above that temperature, strengths decreased rapidly and glass flow failure began. The study observed that time-dependent failure currently limits the service temperatures of glass-filled joints. Creep failure occurred in excess of 1000C. Between 900 and 1000C, slow crack growth failure was observed. Cavitation (or viscous deformation) was the rate-controlling mechanism of slow crack growth.

  15. Experimental design of a waste glass study

    SciTech Connect

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

    1995-04-01

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

  16. Glass heat pipe evacuated tube solar collector

    SciTech Connect

    McConnell, R.D.; Vansant, J.H.

    1984-10-02

    A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

  17. Gaseous Sulfate Solubility in Glass: Experimental Method

    SciTech Connect

    Bliss, Mary

    2013-11-30

    Sulfate solubility in glass is a key parameter in many commercial glasses and nuclear waste glasses. This report summarizes key publications specific to sulfate solubility experimental methods and the underlying physical chemistry calculations. The published methods and experimental data are used to verify the calculations in this report and are expanded to a range of current technical interest. The calculations and experimental methods described in this report will guide several experiments on sulfate solubility and saturation for the Hanford Waste Treatment Plant Enhanced Waste Glass Models effort. There are several tables of sulfate gas equilibrium values at high temperature to guide experimental gas mixing and to achieve desired SO3 levels. This report also describes the necessary equipment and best practices to perform sulfate saturation experiments for molten glasses. Results and findings will be published when experimental work is finished and this report is validated from the data obtained.

  18. Atomic Dynamics in Metallic Liquids and Glasses

    SciTech Connect

    Egami, Takeshi; Levashov, Valentin A; Aga, Rachel S; Morris, James R

    2007-01-01

    How atoms move in metallic glasses and liquids is an important question in discussing atomic transport, glass formation, structural relaxation and other properties of metallic glasses. While the concept of free-volume has long been used in describing atomic transport, computer simulations and isotope measurements have shown that atomic transport occurs by a much more collective process than assumed in the free-volume theory. We introduce a new approach to describe the atomic dynamics in metallic glasses, in terms of local energy landscapes related to fluctuations in the topology of atomic connectivity. This approach may form the basis for a new paradigm for discussing the structure-properties relationship in metallic glasses.

  19. Nanocrystallization in Fluorochlorozirconate Glass-Ceramics

    PubMed Central

    Alvarez, Carlos J.; Liu, Yuzi; Leonard, Russell L.; Johnson, Jacqueline A.; Petford-Long, Amanda K.

    2014-01-01

    Heat treating fluorochlorozirconate (FCZ) glasses nucleates nanocrystals in the glass matrix, resulting in a nanocomposite glass-ceramic that has optical properties suitable for use as a medical imaging plate. Understanding the way in which the nanocrystal nucleation proceeds is critical to controlling the optical behavior. The nucleation and growth of nanocrystals in FCZ glass-ceramics was investigated with in situ transmission electron microscopy heating experiments. The experiments showed the nucleation and growth of previously unreported BaF2 nanocrystals in addition to the expected BaCl2 nanocrystals. Chemical analysis of the BaF2 nanocrystals shows an association with the optically active dopant previously thought only to interact with BaCl2 nanocrystals. The association of the dopant with BaF2 crystals suggests that it plays a role in the photoluminescent (PL) properties of FCZ glass-ceramics. PMID:24707056

  20. A consortium approach to glass furnace modeling.

    SciTech Connect

    Chang, S.-L.; Golchert, B.; Petrick, M.

    1999-04-20

    Using computational fluid dynamics to model a glass furnace is a difficult task for any one glass company, laboratory, or university to accomplish. The task of building a computational model of the furnace requires knowledge and experience in modeling two dissimilar regimes (the combustion space and the liquid glass bath), along with the skill necessary to couple these two regimes. Also, a detailed set of experimental data is needed in order to evaluate the output of the code to ensure that the code is providing proper results. Since all these diverse skills are not present in any one research institution, a consortium was formed between Argonne National Laboratory, Purdue University, Mississippi State University, and five glass companies in order to marshal these skills into one three-year program. The objective of this program is to develop a fully coupled, validated simulation of a glass melting furnace that may be used by industry to optimize the performance of existing furnaces.

  1. Glass ionomer restorative cement systems: an update.

    PubMed

    Berg, Joel H; Croll, Theodore P

    2015-01-01

    Glass ionomer cements have been used in pediatric restorative dentistry for more than two decades. Their usefulness in clinical dentistry is preferential to other materials because of fluoride release from the glass component, biocompatibility, chemical adhesion to dentin and enamel, coefficient of thermal expansion similar to that of tooth structure, and versatility. The purpose of this paper was to review the uses of glass ionomer materials in pediatric dentistry, specifically as pit and fissure sealants, dentin and enamel replacement repair materials, and luting cements, and for use in glass ionomer/resin-based composite stratification tooth restoration (the sandwich technique). This article can also be used as a guide to research and clinical references regarding specific aspects of the glass ionomer systems and how they are used for young patients.

  2. Glass Formation Ability and Kinetics of the Gd55Al20Ni25 Bulk Metallic Glass

    NASA Astrophysics Data System (ADS)

    Jo, Chol-Lyong; Xia, Lei; Ding, Ding; Dong, Yuan-Da

    2006-03-01

    We report a new bulk glass-forming alloy Gd55Al20Ni25. The bulk sample of the alloy is prepared in the shape of rods in diameter 2 mm by suction casting. The rod exhibits typical amorphous characteristics in the x-ray diffraction pattern, paramagnetic property at 300 K, distinct glass transition and multi-step crystallization behaviour in differential scanning calorimetry traces. The glass formation ability of the alloy is investigated by using the reduced glass transition temperature Trg and the parameter γ. Kinetics of glass transition and primary crystallization is also studied. The fragility parameter m obtained from the Vogel-Fulcher-Tammann dependence of glass transition temperature Tg on ln phi (phi is the heating rate) classifies the bulk metallic glasses into the intermediate category according to Angell's classification.

  3. Glass formation and physical properties of chalcogenide glasses in Ge-S-Pb system

    NASA Astrophysics Data System (ADS)

    Qu, Guoshun; Lin, Changgui; Li, Zhuobin; Zhai, Sumin; Gu, Shaoxuan; Tao, Haizheng; Xu, Tiefeng

    2014-03-01

    Chalcogenide glasses based on Ge-S-Pb system were prepared, and the compositional dependence of their physic-chemical properties and glass structure were investigated. Up to 23 mol% Pb can be dissolved in this glass system and the glass-formation region like a small isolated island was found. The effect of the introduction of Pb on the glass structure is discussed by employing Raman spectra. It is shown that the substitution of Pb for Ge decreases the number of [GeS4] and [S3Ge-GeS3] units, leading to the variation of properties, such as Tg, H‧, and Hv. The knowledge of this structure-properties relationship of Ge-S-Pb glasses would be of significance to select or to design suitable host glass for optoelectronic applications.

  4. Raman and Infrared Spectroscopy of Yttrium Aluminum Borate Glasses and Glass-ceramics

    NASA Technical Reports Server (NTRS)

    Bradley, J.; Brooks, M.; Crenshaw, T.; Morris, A.; Chattopadhyay, K.; Morgan, S.

    1998-01-01

    Raman spectra of glasses and glass-ceramics in the Y2O3-Al2O3-B2O3 system are reported. Glasses with B2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400 C for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 800 C were performed in order to induce nucleation and crystallization. It was found that Na2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl3(BO3)4.

  5. Method for heating and forming a glass sheet

    DOEpatents

    Boaz, P.T.

    1997-08-12

    A method for heating and forming a glass sheet includes the steps of heating a glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, cooling an outer surface of the glass sheet to at least a third predetermined temperature and forming the glass sheet using forming rollers to a predetermined configuration. 5 figs.

  6. Method for heating and forming a glass sheet

    DOEpatents

    Boaz, Premakaran Tucker

    1997-01-01

    A method for heating and forming a glass sheet includes the steps of heating a glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, cooling an outer surface of the glass sheet to at least a third predetermined temperature and forming the glass sheet using forming rollers to a predetermined configuration.

  7. Direct conversion of halogen-containing wastes to borosilicate glass

    SciTech Connect

    Forsberg, C.W.; Beahm, E.C.; Rudolph, J.C.

    1996-12-09

    Glass has become a preferred waste form worldwide for radioactive wastes: however, there are limitations. Halogen-containing wastes can not be converted to glass because halogens form poor-quality waste glasses. Furthermore, halides in glass melters often form second phases that create operating problems. A new waste vitrification process, the Glass Material Oxidation and dissolution System (GMODS), removes these limitations by converting halogen-containing wastes into borosilicate glass and a secondary, clean, sodium-halide stream.

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

    PubMed

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

    2011-10-01

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

  9. Glass dissolution rate measurement and calculation revisited

    NASA Astrophysics Data System (ADS)

    Fournier, Maxime; Ull, Aurélien; Nicoleau, Elodie; Inagaki, Yaohiro; Odorico, Michaël; Frugier, Pierre; Gin, Stéphane

    2016-08-01

    Aqueous dissolution rate measurements of nuclear glasses are a key step in the long-term behavior study of such waste forms. These rates are routinely normalized to the glass surface area in contact with solution, and experiments are very often carried out using crushed materials. Various methods have been implemented to determine the surface area of such glass powders, leading to differing values, with the notion of the reactive surface area of crushed glass remaining vague. In this study, around forty initial dissolution rate measurements were conducted following static and flow rate (SPFT, MCFT) measurement protocols at 90 °C, pH 10. The international reference glass (ISG), in the forms of powders with different particle sizes and polished monoliths, and soda-lime glass beads were examined. Although crushed glass grains clearly cannot be assimilated with spheres, it is when using the samples geometric surface (Sgeo) that the rates measured on powders are closest to those found for monoliths. Overestimation of the reactive surface when using the BET model (SBET) may be due to small physical features at the atomic scale-contributing to BET surface area but not to AFM surface area. Such features are very small compared with the thickness of water ingress in glass (a few hundred nanometers) and should not be considered in rate calculations. With a SBET/Sgeo ratio of 2.5 ± 0.2 for ISG powders, it is shown here that rates measured on powders and normalized to Sgeo should be divided by 1.3 and rates normalized to SBET should be multiplied by 1.9 in order to be compared with rates measured on a monolith. The use of glass beads indicates that the geometric surface gives a good estimation of glass reactive surface if sample geometry can be precisely described. Although data clearly shows the repeatability of measurements, results must be given with a high uncertainty of approximately ±25%.

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

    PubMed

    Schibille, Nadine

    2011-01-01

    The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East. In order to elucidate the supply and consumption of glass during this transitional period, 31 glass samples from the assemblage found at Pergamon (Turkey) that date to the fourth to fourteenth centuries CE were analysed by electron microprobe analysis (EPMA) and by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The statistical evaluation of the data revealed that the Byzantine glasses from Pergamon represent at least three different glass production technologies, one of which had not previously been recognised in the glass making traditions of the Mediterranean. While the chemical characteristics of the late antique and early medieval fragments confirm the current model of glass production and distribution at the time, the elemental make-up of the majority of the eighth- to fourteenth-century glasses from Pergamon indicate the existence of a late Byzantine glass type that is characterised by high alumina levels. Judging from the trace element patterns and elevated boron and lithium concentrations, these glasses were produced with a mineral soda different to the Egyptian natron from the Wadi Natrun, suggesting a possible regional Byzantine primary glass production in Asia Minor. PMID:21526144

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

    PubMed

    Schibille, Nadine

    2011-04-19

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

  12. Late Byzantine Mineral Soda High Alumina Glasses from Asia Minor: A New Primary Glass Production Group

    PubMed Central

    Schibille, Nadine

    2011-01-01

    The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East. In order to elucidate the supply and consumption of glass during this transitional period, 31 glass samples from the assemblage found at Pergamon (Turkey) that date to the fourth to fourteenth centuries CE were analysed by electron microprobe analysis (EPMA) and by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The statistical evaluation of the data revealed that the Byzantine glasses from Pergamon represent at least three different glass production technologies, one of which had not previously been recognised in the glass making traditions of the Mediterranean. While the chemical characteristics of the late antique and early medieval fragments confirm the current model of glass production and distribution at the time, the elemental make-up of the majority of the eighth- to fourteenth-century glasses from Pergamon indicate the existence of a late Byzantine glass type that is characterised by high alumina levels. Judging from the trace element patterns and elevated boron and lithium concentrations, these glasses were produced with a mineral soda different to the Egyptian natron from the Wadi Natrun, suggesting a possible regional Byzantine primary glass production in Asia Minor. PMID:21526144

  13. Glass for sealing lithium cells

    DOEpatents

    Leedecke, C.J.

    1981-08-28

    Glass compositions resistant to corrosion by lithium cell electrolyte and having an expansion coefficient of 45 to 85 x 10/sup -70/C/sup -1/ have been made with SiO/sub 2/, 25 to 55% by weight; B/sub 2/O/sub 3/, 5 to 12%; Al/sub 2/O/sub 3/, 12 to 35%; CaO, 5 to 15%; MgO, 5 to 15%; SrO, 0 to 10%; and La/sub 2/O/sub 3/, 0 to 5%. Preferred compositions within that range contain 3 to 8% SrO and 0.5 to 2.5% La/sub 2/O/sub 3/.

  14. Shock temperatures in anorthite glass

    NASA Technical Reports Server (NTRS)

    Boslough, M. B.; Ahrens, T. J.; Mitchell, A. C.

    1983-01-01

    Temperatures of CaAl2Si2O8 (anorthite glass) shocked to pressures between 48 and 117 GPa were measured in the range from 2500 to 5600 K, using optical pyrometry techniques. The pressure dependence of the shock temperatures deviates significantly from predictions based on a single high pressure phase. At least three phase transitions, at pressures of about 55, 85, and 100 GPa and with transition energies of about 0.5 MJ/kg each (approximately 1.5 MJ/kg total) are required to explain the shock temperature data. The phase transition at 100 GPa can possibly be identified with the stishovite melting transition. Theoretical models of the time dependence of the thermal radiation from the shocked anorthite based on the geometry of the experiment and the absorptive properties of the shocked material yields good agreement with observations, indicating that it is not necessary to invoke intrinsic time dependences to explain the data in many cases.

  15. KT boundary impact glasses from the Gulf of Mexico region

    NASA Technical Reports Server (NTRS)

    Claeys, Philippe; Alvarez, Walter; Smit, Jan; Hildebrand, A. R.; Montanari, Alessandro

    1993-01-01

    Cretaceous-Tertiary boundary (KTB) tektite glasses occur at several sites around the Gulf of Mexico. Contrary to rumor among KTB workers, glass fragments have been found by several researchers in the base of the spherule bed at Arroyo el Mimbral in NE Mexico. The presence of green, red, and transparent glass fragments at Mimbral only, demonstrates that the Mimbral glass is not a laboratory contamination by Beloc glass. The chemistry and ages of the glass are consistent with an origin from the Chixculub impact crater in Yucatan. No evidence supports a volcanic origin for the KTB glasses. A discussion of tektite glass from the KT boundary is presented.

  16. Refractive index of glass and its dipersion for visible light.

    SciTech Connect

    Smith, D. Y.; Karstens, W.

    2010-01-01

    The classification of optical glass and empirical relations between the refractive index and its dispersion are discussed in terms of moments of the glass's IR and UV absorption spectra. The observed linear dependence of index on dispersion within glass families is shown to arise primarily from the approximately linear superposition of the electronic absorptions of glass former and glass modifiers. The binary classification into crown and flint glasses is also based primarily on electronic spectra: Crown glasses are 'wide-gap' materials with excitation energies greater than {approx}12.4 eV, while flint glasses are their 'narrow-gap' counterpart.

  17. Soft-sphere soft glasses

    NASA Astrophysics Data System (ADS)

    Heyes, D. M.; Clarke, S. M.; Brańka, A. C.

    2009-11-01

    Molecular dynamics simulations have been used to compute physical properties of model fluids in which the particles interacted via the soft-sphere pair potential (SSP) ϕ(r )=ɛ(σ /r)n, where ɛ and σ are the characteristic energy and distance, respectively. The emphasis is on small values of n, tending to the lower theromodynamically allowed bound of 3+. An accurate equation of state for the SSP fluid is obtained, consisting of two terms, and as n→3+, the compressibility factor, Z tends to Z =B2ζn /3 for ζ >0, where B2 is the second virial coefficient, and ζ =πNσ3/6V is a nominal packing fraction for N particles in volume V. A simple formula for the position of the first peak in the radial distribution function in the soft particle limit is proposed and shown to agree with the simulation data. The fluid phase velocity autocorrelation function at fluid-solid coexistence becomes more oscillatory as n decreases. Values for the self-diffusion coefficient D and shear viscosity η were calculated as a function of n and density, and these were used to estimate the n-dependence of an ideal glass transition. The glass transition shifts relatively further into the solid part of the phase diagram as softness (˜1/n) increases. D decreases by ca. 75% and η increases by about a factor of 3 along the fluid-solid coexistence line from n =∞ to 3.25. Non-Gaussian behavior was calculated from the particle displacements as a function of particle softness. A screened soft-sphere potential, SSSP, was introduced to explore the effects for small n of the long range part of the potential in relation to the scale of the local structure. The SSSP with suitable analytic form and parameters can give statistically indistinguishable results from the full SSP for the static properties, D and η.

  18. Dynamic Fatigue of ULE Glass

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Nettles, Alan T.; Brantley, Lott W. (Technical Monitor)

    2001-01-01

    Ultra Low Expansion (ULE) glass is used in a number of applications which require a low thermal expansion coefficient. One such application is telescope mirror elements. An allowable stress can be calculated for this material based upon modulus of rupture data; however, this does not take into account the problem of delayed failure. Delayed failure, due to stress corrosion can significantly shorten the lifetime of a glass article. Knowledge of the factors governing the rate of subcritical flaw growth in a given environment enables the development of relations between lifetime, applied stress and failure probability for the material under study. Dynamic fatigue is one method of obtaining the necessary information to develop these relationships. In this study, the dynamic fatigue method was used to construct time-to-failure diagrams for both 230/270 ground and optically polished samples. The grinding and polishing process reduces the surface flaw size and subsurface damage, and relieves residual stress by removing materials with successively smaller grinding media. This resulted in an increase in the strength of the optic during the grinding and polishing sequence. There was also an increase in the lifetime due to grinding and polishing. It was found that using the fatigue parameters determined from the 230/270 grit surface are not significantly different from the optically polished values. Although the lower bound of the polished samples is more conservative, neither time-to-failure curves lie beyond the upper or lower bound of the confidence limits. Therefore, designers preferring conservative limits could use samples without residual stress present (polished samples) to determine the fatigue parameters and inert Weibull parameters from samples with the service condition surface, to determine time-to-failure of the optical element.

  19. Nanophase glass ceramics for capacitive energy storage

    NASA Astrophysics Data System (ADS)

    Rangarajan, Badri

    Glass ceramics are candidate dielectric materials for high energy storage capacitors. Since energy density depends primarily on dielectric permittivity and breakdown strength, glass ceramics with interconnected nano-crystalline particles and low porosity, which leads to high breakdown strength, are expected to have high energy density values. Three glass ceramic systems were investigated. Barium/lead sodium niobate glass ceramics, designated as PNNS (PbO-Na 2O-Nb2O5-SiO2) and BNNS (BaONa 2O- Nb2O5-SiO2), and barium titanate silicate glass ceramic, designated as BTS (BaOTiO2-SiO2), belonging to medium (epsilonr ~ 400-700) and low (epsilon r ~ 20) permittivity regimes, respectively, were fabricated by roller quenching and controlled crystallization. The overall properties of the glass ceramics were controlled by connectivity and volume fraction of crystallites. PNNS and BNNS developed perovskite and tungsten-bronze phases during crystallization with permittivity values between 400 and 700. Microstructural analysis of PNNS glass ceramic revealed grain sizes of the order of 50 nm. The calculated breakdown strengths were ~0.7 and ~075 MV/cm for PNNS and BNNS respectively. The resulting energy densities at breakdown were ~4.5 and ~6.5 J/cm3 for PNNS and BNNS respectively. However, the disadvantages, such as difficult glass formability, less control over crystallization due to multiphase formation and low dielectric breakdown strength values due to high dielectric contrast between the glass and crystal phases, associated with PNNS and BNNS glass ceramics served as the motivating factor for exploring BTS glass ceramic. The major advantage of studying BTS glass ceramic over the other systems is that a single crystalline phase, fresnoite (Ba2TiSi2O 8), grows from the quenched glass and properties can be explored over the whole spectrum ranging from fully amorphous to fully crystalline. Crystallization kinetics of the BTS glass is explored to control the relative volume

  20. HGMS: Glasses and Nanocomposites for Hydrogen Storage.

    SciTech Connect

    Lipinska, Kris; Hemmers, Oliver

    2013-02-17

    The primary goal of this project is to fabricate and investigate different glass systems and glass-derived nanocrystalline composite materials. These glass-based, two-phased materials will contain nanocrystals that can attract hydrogen and be of potential interest as hydrogen storage media. The glass materials with intrinsic void spaces that are able to precipitate functional nanocrystals capable to attract hydrogen are of particular interest. Proposed previously, but never practically implemented, one of promising concepts for storing hydrogen are micro-containers built of glass and shaped into hollow microspheres. The project expanded this concept to the exploration of glass-derived nanocrystalline composites as potential hydrogen storage media. It is known that the most desirable materials for hydrogen storage do not interact chemically with hydrogen and possess a high surface area to host substantial amounts of hydrogen. Glasses are built of disordered networks with ample void spaces that make them permeable to hydrogen even at room temperature. Glass-derived nanocrystalline composites (two-phased materials), combination of glasses (networks with ample voids) and functional nanocrystals (capable to attract hydrogen), appear to be promising candidates for hydrogen storage media. Key advantages of glass materials include simplicity of preparation, flexibility of composition, chemical durability, non-toxicity and mechanical strength, as well as low production costs and environmental friendliness. This project encompasses a fundamental research into physics and chemistry of glasses and nanocrystalline composite materials, derived from glass. Studies are aimed to answer questions essential for considering glass-based materials and composites as potential hydrogen storage media. Of particular interest are two-phased materials that combine glasses with intrinsic voids spaces for physisorption of hydrogen and nanocrystals capable of chemisorption. This project does not

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

    PubMed

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

    2015-01-01

    The physical modification of glass transition temperature (T(g)) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of T(g) for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low T(g)s have become available only recently. PMID:25666949

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

    SciTech Connect

    Christian, J. H.

    2015-08-18

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

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

    SciTech Connect

    Christian, J. H.

    2015-08-01

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

  4. Enhancement effect of pre-reacted glass on strength of glass-ionomer cement.

    PubMed

    Monmaturapoj, Naruporn; Soodsawang, Wiwaporn; Tanodekaew, Siriporn

    2012-02-01

    In this paper, we report on the enhanced strength of glass ionomer cement (GIC) by using the process of pre acid-base reaction and spray drying in glass preparation. The pre acid-base reaction was induced by prior mixing of the glass powder with poly(alkenoic acid). The weight ratios of glass powder to poly(alkenoic acid) were varied to investigate the extent of the pre acid-base reaction of the glass. The effect of the spray drying process which produced spherical glass particles on cement strength was also studied and discussed. The results show that adding 2%-wt of poly(alkenoic acid) liquid in the pre-reacted step improved cement strength. GICs prepared using a mixture of pre-reacted glass with both spherical and irregular powders at 60:40 by weight exhibited the highest compressive strength at 138.64±7.73 MPa. It was concluded that glass ionomer cements containing pre-reacted glass with mixed glass morphology using both spherical and irregular forms are promising as restorative dental materials with improved mechanical properties and handling characteristics.

  5. Current status of photoprotection by window glass, automobile glass, window films, and sunglasses.

    PubMed

    Almutawa, Fahad; Vandal, Robert; Wang, Steven Q; Lim, Henry W

    2013-04-01

    Ultraviolet radiation (UVR) has known adverse effects on the skin and eyes. Practitioners are becoming more aware of the importance of outdoor photoprotection. However, little attention is directed to the exposure of the skin and eyes to UVR through the window glass or sunglasses. The amount of ultraviolet transmission through glass depends mainly on the type of the glass. All types of commercial and automobile glass block the majority of ultraviolet-B; however, the degree of ultraviolet-A transmission depends on the type of glass. Laminated glass offers better UVA protection than tempered glass; new safety regulations for automobiles may result in increased use of laminated glass for side windows. Window films can be applied to glass to increase UVR protection. Sunglasses need to be compliant with one of the national standards; a wraparound style or side shields offer the best protection. Increased understanding by practitioners on the transmission of UVR through glass, window films, and sunglasses would allow them to better educate the public and to better manage photosensitive patients.

  6. Glass-ferroic composite caused by the crystallization of ferroic glass

    NASA Astrophysics Data System (ADS)

    Ji, Yuanchao; Ding, Xiangdong; Wang, Dong; Otsuka, Kazuhiro; Ren, Xiaobing

    2015-12-01

    We report a glass-ferroic composite (in short "glass-ferroic") in ferroic materials, an analog of the composite of glassy and crystalline phases (glass-crystal composite, e.g., semicrystalline polymer). The formation of glass-ferroic (i.e., the existence of residual ferroic glass) stems from a time-dependent crystallization of the ferroic glass. Moreover, glass-ferroics show two types of transition characteristics depending on the thermal hysteresis of crystallization transition as exemplified in T i48.7N i51.3 and P b0.87L a0.13Z r0.4T i0.6O3 . Based on experimental results, a generic phase diagram is established to include all ferroic states, i.e., ferroic crystal, ferroic glass, and glass-ferroic. Being the third class of ferroic materials, glass-ferroics may open a new avenue for achieving novel properties and designing ferroic phase-change memory devices.

  7. Bubble formation in additive manufacturing of glass

    NASA Astrophysics Data System (ADS)

    Luo, Junjie; Gilbert, Luke J.; Peters, Daniel C.; Bristow, Douglas A.; Landers, Robert G.; Goldstein, Jonathan T.; Urbas, Augustine M.; Kinzel, Edward C.

    2016-05-01

    Bubble formation is a common problem in glass manufacturing. The spatial density of bubbles in a piece of glass is a key limiting factor to the optical quality of the glass. Bubble formation is also a common problem in additive manufacturing, leading to anisotropic material properties. In glass Additive Manufacturing (AM) two separate types of bubbles have been observed: a foam layer caused by the reboil of the glass melt and a periodic pattern of bubbles which appears to be unique to glass additive manufacturing. This paper presents a series of studies to relate the periodicity of bubble formation to part scan speed, laser power, and filament feed rate. These experiments suggest that bubbles are formed by the reboil phenomena why periodic bubbles result from air being trapped between the glass filament and the substrate. Reboil can be detected using spectroscopy and avoided by minimizing the laser power while periodic bubbles can be avoided by a two-step laser melting process to first establish good contact between the filament and substrate before reflowing the track with higher laser power.

  8. Glass ceramic-to-metal seals

    DOEpatents

    Not Available

    1982-04-19

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

  9. Critical review of glass performance modeling

    SciTech Connect

    Bourcier, W.L.

    1994-07-01

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

  10. Wood burning stove having glass cleaning system

    SciTech Connect

    Ferguson, R.W.; Andors, D.K.; Reed, E.S. Jr.

    1987-08-04

    A heating apparatus is described for burning solid fuels comprising: a frame assembly enclosing a combustion chamber, the frame assembly including front, side and rear walls, a top and a bottom; a transparent glass panel mounted in one of the walls to permit viewing of combustion in the combustion chamber; and glass panel cleaning means for supplying a curtain of hot air flowing uniformly and downwardly over the interior surface of the transparent glass panel for maintaining the glass panel at an elevated interior temperature and for forming a barrier to prevent soot and creosote buildup. The glass panel cleaning means includes: a first manifold for providing a reservoir of low turbulence air. The first manifold is positioned above the glass panel and has an aperture for directing hot air downwardly. A means supplies hot air to the first manifold. A second manifold positioned below the first manifold, the second manifold receives air from the aperture of the first manifold. This further reduces the turbulence of the air. The second manifold provides an exit slot for directing the curtain of hot air downwardly over the glass panel.

  11. Energy implications of glass-container recycling

    SciTech Connect

    Gaines, L L; Mintz, M M

    1994-03-01

    This report addresses the question of whether glass-container recycling actually saves energy. Glass-container production in 1991 was 10{sup 7} tons, with cullet making up about 30% of the input to manufacture. Two-thirds of the cullet is postconsumer waste; the remainder is in-house scrap (rejects). Most of the glass recycled is made into new containers. Total primary energy consumption includes direct process-energy use by the industry (adjusted to account for the efficiency of fuel production) plus fuel and raw-material transportation and production energies; the grand total for 1991 is estimated to be about 168 {times} 10{sup 12} Btu. The total primary energy use decreases as the percent of glass recycled rises, but the maximum energy saved is only about 13%. If distance to the landfill is kept fixed and that to the recovery facility multiplied by about eight, to 100 mi, a break-even point is reached, and recycling saves no energy. Previous work has shown that to save energy when using glass bottles, reuse is the clear choice. Recycling of glass does not save much energy or valuable raw material and does not reduce air or water pollution significantly. The most important impacts are the small reduction of waste sent to the landfill and increased production rates at glass plants.

  12. Temperature effects on waste glass performance

    SciTech Connect

    Mazer, J.J.

    1991-02-01

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

  13. Viscosity properties of tellurite-based glasses

    SciTech Connect

    Tincher, B.; Massera, J.; Petit, L.; Richardson, K.

    2010-12-15

    The viscosity behavior of glasses with the composition (90-x)TeO{sub 2}-10Bi{sub 2}O{sub 3}-xZnO with x = 15, 17.5, and 20 (TBZ glasses) and 80TeO{sub 2}-(20-y)Na{sub 2}O-yZnO system with y = 0, 5, and 10 (TNZ glasses) have been measured as a function of temperature using a beam-bending (BBV) and a parallel-plate (PPV) viscometer. The structure of the glass' network has been characterized using Raman spectroscopy and has been related to the viscosity temperature behavior and the fragility parameter (m) of the glasses. As the concentration of ZnO in the TBZ system (x) increases, the fragility parameter of the glass increases, whereas it decreases with an increase of the ZnO concentration (y) in the TNZ system. In both glasses, these variations in m have been related to the partial depolymerization of the tellurite network associated with the level of modifier content. The depolymerization of the tellurite network is believed to be the result of a reduction in the number of [TeO{sub 4}] units and the formation of [TeO{sub 3}] and [TeO{sub 3+1}] units that occurs with a change in TeO{sub 2} content in the TBZ system and modifier content in the TNZ system.

  14. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-01-01

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  15. Accelerated glass reaction under PCT conditions

    SciTech Connect

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

    1992-12-31

    Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

  16. Solid oxide fuel cell having a glass composite seal

    SciTech Connect

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

    2013-04-16

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

  17. Relationship between topological order and glass forming ability in densely packed enstatite and forsterite composition glasses.

    PubMed

    Kohara, S; Akola, J; Morita, H; Suzuya, K; Weber, J K R; Wilding, M C; Benmore, C J

    2011-09-01

    The atomic structures of magnesium silicate melts are key to understanding processes related to the evolution of the Earth's mantle and represent precursors to the formation of most igneous rocks. Magnesium silicate compositions also represent a major component of many glass ceramics, and depending on their composition can span the entire fragility range of glass formation. The silica rich enstatite (MgSiO(3)) composition is a good glass former, whereas the forsterite (Mg(2)SiO(4)) composition is at the limit of glass formation. Here, the structure of MgSiO(3) and Mg(2)SiO(4) composition glasses obtained from levitated liquids have been modeled using Reverse Monte Carlo fits to diffraction data and by density functional theory. A ring statistics analysis suggests that the lower glass forming ability of the Mg(2)SiO(4) glass is associated with a topologically ordered and very narrow ring distribution. The MgO(x) polyhedra have a variety of irregular shapes in MgSiO(3) and Mg(2)SiO(4) glasses and a cavity analysis demonstrates that both glasses have almost no free volume due to a large contribution from edge sharing of MgO(x)-MgO(x) polyhedra. It is found that while the atomic volume of Mg cations in the glasses increases compared to that of the crystalline phases, the number of Mg-O contacts is reduced, although the effective chemical interaction of Mg(2+) remains similar. This unusual structure-property relation of Mg(2)SiO(4) glass demonstrates that by using containerless processing it may be possible to synthesize new families of dense glasses and glass ceramics with zero porosity. PMID:21873237

  18. Relationship between topological order and glass forming ability in densely packed enstatite and forsterite composition glasses.

    PubMed

    Kohara, S; Akola, J; Morita, H; Suzuya, K; Weber, J K R; Wilding, M C; Benmore, C J

    2011-09-01

    The atomic structures of magnesium silicate melts are key to understanding processes related to the evolution of the Earth's mantle and represent precursors to the formation of most igneous rocks. Magnesium silicate compositions also represent a major component of many glass ceramics, and depending on their composition can span the entire fragility range of glass formation. The silica rich enstatite (MgSiO(3)) composition is a good glass former, whereas the forsterite (Mg(2)SiO(4)) composition is at the limit of glass formation. Here, the structure of MgSiO(3) and Mg(2)SiO(4) composition glasses obtained from levitated liquids have been modeled using Reverse Monte Carlo fits to diffraction data and by density functional theory. A ring statistics analysis suggests that the lower glass forming ability of the Mg(2)SiO(4) glass is associated with a topologically ordered and very narrow ring distribution. The MgO(x) polyhedra have a variety of irregular shapes in MgSiO(3) and Mg(2)SiO(4) glasses and a cavity analysis demonstrates that both glasses have almost no free volume due to a large contribution from edge sharing of MgO(x)-MgO(x) polyhedra. It is found that while the atomic volume of Mg cations in the glasses increases compared to that of the crystalline phases, the number of Mg-O contacts is reduced, although the effective chemical interaction of Mg(2+) remains similar. This unusual structure-property relation of Mg(2)SiO(4) glass demonstrates that by using containerless processing it may be possible to synthesize new families of dense glasses and glass ceramics with zero porosity.

  19. Relationship between topological order and glass forming ability in densely packed enstatite and forsterite composition glasses

    PubMed Central

    Kohara, S.; Akola, J.; Morita, H.; Suzuya, K.; Weber, J. K. R.; Wilding, M. C.; Benmore, C. J.

    2011-01-01

    The atomic structures of magnesium silicate melts are key to understanding processes related to the evolution of the Earth’s mantle and represent precursors to the formation of most igneous rocks. Magnesium silicate compositions also represent a major component of many glass ceramics, and depending on their composition can span the entire fragility range of glass formation. The silica rich enstatite (MgSiO3) composition is a good glass former, whereas the forsterite (Mg2SiO4) composition is at the limit of glass formation. Here, the structure of MgSiO3 and Mg2SiO4 composition glasses obtained from levitated liquids have been modeled using Reverse Monte Carlo fits to diffraction data and by density functional theory. A ring statistics analysis suggests that the lower glass forming ability of the Mg2SiO4 glass is associated with a topologically ordered and very narrow ring distribution. The MgOx polyhedra have a variety of irregular shapes in MgSiO3 and Mg2SiO4 glasses and a cavity analysis demonstrates that both glasses have almost no free volume due to a large contribution from edge sharing of MgOx-MgOx polyhedra. It is found that while the atomic volume of Mg cations in the glasses increases compared to that of the crystalline phases, the number of Mg-O contacts is reduced, although the effective chemical interaction of Mg2+ remains similar. This unusual structure-property relation of Mg2SiO4 glass demonstrates that by using containerless processing it may be possible to synthesize new families of dense glasses and glass ceramics with zero porosity. PMID:21873237

  20. Characterisation of Erbium Doped Phosphate Glass

    NASA Astrophysics Data System (ADS)

    Rasid, A. A.; Rohani, M. S.; Sahar, M. R.; Kasim, A.

    2010-03-01

    A series of erbium doped phosphate glass has been successfully fabricated, and the determination of their density and luminescence properties has been carried out. It is particularly interesting to study the effect of modifying oxides to the properties of the glass. The glass density reduces with the increasing content of Na2O. The emission spectra from luminescence spectroscopy resolved six emission peaks from the excitation wavelength of 336.8 nm (3.69 eV). The emission of 4F7/2 gives two emission peaks, where the peak near 482 nm shows a higher intensity and the peak near 491 nm gives a weak emission spectra.

  1. Glass melter off-gas system

    DOEpatents

    Jantzen, Carol M.

    1997-01-01

    Apparatus and method for melting glass in a glass melter in such a way as to reduce deposition of particulates in the off-gas duct. Deposit accumulation is reduced by achieving an off-gas velocity above approximately 15 meters/second and an off-gas temperature as close as possible to, but not higher than, the glass softening point. Because the deposits are largely water-soluble, those that do form on the interior surface of the duct can be readily removed by injecting water or steam directly into the off-gas duct from its entrance or exit.

  2. Novel lead-iron phosphate glass

    DOEpatents

    Boatner, Lynn A.; Sales, Brian C.

    1989-01-01

    The invention described and claimed in the specification relates to the discovery that effective addition of Fe.sub.2 O.sub.3 to a lead phosphate glass results in a glass having enhanced chemical durability and physical stability, and consists essentially of the glass resulting from melting a mixture consisting essentially of, in weight percent, 40-66 percent PbO, 30-55 percent P.sub.2 O.sub.5 and an effective concentration up to 12 percent Fe.sub.2 O.sub.3.

  3. Microstructure fabrication on glasses for microfluidics

    NASA Astrophysics Data System (ADS)

    Chen, Qiuping; Chen, Qiuling; Liao, Guihua; Milanese, Daniel

    2008-12-01

    Micro-channels were fabricated in sodalime glass through imprinting, and then joined to a glass slab by thermal assisted direct bonding (TADB). These techniques are simple and low cost, suitable for mass production of micro-fluidic devices. The joined samples were characterized before and after TADB by optical microscopy, profilometer, SEM, shear strength test and Vickers hardness test. The integrity of channels is maintained also after the TADB. The interface between the two glass slabs was found to be without impurities, bubbles and cracks. The bonding strength was also measured to be 31.94MPa.

  4. Effects of Gravity on ZBLAN Glass Crystallization

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Ethridge, Edwin C.; Smith, Guy A.; Workman, Gary

    2004-01-01

    The effects of gravity on the crystallization of ZrF(4)-BaF(2)-LaF(3)-AlF(3)-NaF glasses have been studied using the NASA KC-135 and a sounding rocket. Fibers and cylinders of ZBLAN glass were heated to the crystallization temperature in unit and reduced gravity. When processed in unit gravity the glass crystallized, but when processed in reduced gravity, crystallization was suppressed. A possible explanation involving shear thinning is presented to explain these results.

  5. Ultrahigh stability of atomically thin metallic glasses

    SciTech Connect

    Cao, C. R.; Huang, K. Q.; Zhao, N. J.; Sun, Y. T.; Bai, H. Y.; Gu, L. E-mail: dzheng@iphy.ac.cn Zheng, D. N. E-mail: dzheng@iphy.ac.cn Wang, W. H. E-mail: dzheng@iphy.ac.cn

    2014-07-07

    We report the fabrication and study of thermal stability of atomically thin ZrCu-based metallic glass films. The ultrathin films exhibit striking dynamic properties, ultrahigh thermal stability, and unique crystallization behavior with discrete crystalline nanoparticles sizes. The mechanisms for the remarkable high stability and crystallization behaviors are attributed to the dewetting process of the ultrathin film. We demonstrated a promising avenue for understanding some fundamental issues such as glassy structure, crystallization, deformation, and glass formation through atomic resolution imaging of the two dimensional like metallic glasses.

  6. Effects of Gravity on ZBLAN Glass Crystallization

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Ethridge, Edwin C.; Smith, G. A.; Workman, G.

    2003-01-01

    The effects of gravity on the crystallization of ZrF4-BaF2-LaF3-AlF3- NaF glasses have been studied utilizing NASA's KC135 and a sounding rocket, Fibers and cylinders of ZBLAN glass were heated to the crystallization temperature in unit and reduced gravity. When processed in unit gravity the glass crystallized, but when processed in reduced gravity, crystallization was suppressed. A possible explanation involving shear thinning is presented to explain these results.

  7. Designing aluminum sealing glasses for manufacturability

    SciTech Connect

    Kovacic, L.; Crowder, S.V.; Brow, R.K.; Bencoe, D.N.

    1993-12-31

    Manufacturability issues involved in the development of new sealing glasses include tailoring glass compositions to meet material and component requirements and determining the optimum seal processing parameters. For each of these issues, statistical analysis can be used to shorten the time between concept and product in the development of what is essentially a new manufacturing technology. We use the development of our new family of phosphate-based glasses for aluminum/stainless steel and aluminum/CuBe hermetic sealing, the ALSG family, to illustrate the statistical approach.

  8. GLASS COMPOSITION AND PROCESS OF MAKING

    DOEpatents

    Bishay, A.M.

    1962-09-01

    Glass compositions are described which are suitable for scintillators of thermal-neutron counters. The glass consists of from 70 to 75 mole% of B/sub 2/O/ sub 3/, from 7 to 9 mole% of Ce/sub 2/O/sub 3/, and from 23 to 16 mole% of Al/sub 2/O/sub 3/ plus Na/sub 2 /O in a mole ratio of 1 to 1.5. The process of making the glass from cerous oxalate, ammonium pentaborate, sodium carbonate, and hydrated alumina in a nonoxidizing atmosphere at 1400-1500 deg C is given. (AEC)

  9. Integral glass encapsulation for solar arrays

    NASA Technical Reports Server (NTRS)

    Young, P. R.

    1977-01-01

    Electrostatic bonding has been used to join silicon solar cells to borosilicate glass without the aid of any organic binders or adhesives. The results of this investigation have been to demonstrate, without question, the feasibility of this process as an encapsulation technique. The potential of ESB for terrestrial solar arrays was clearly shown. The process is fast, reproducible, and produces a permanent bond between glass and silicon that is stronger than the silicon itself. Since this process is a glass sealing technique requiring no organics it makes moisture tight sealing of solar cells possible.

  10. Novel lead-iron phosphate glass

    DOEpatents

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

    1989-07-11

    The invention described and claimed in the specification relates to the discovery that effective addition of Fe[sub 2]O[sub 3] to a lead phosphate glass results in a glass having enhanced chemical durability and physical stability, and consists essentially of the glass resulting from melting a mixture consisting essentially of, in weight percent, 40--66 percent PbO, 30--55 percent P[sub 2]O[sub 5] and an effective concentration up to 12 percent Fe[sub 2]O[sub 3].

  11. Statistics of silicate units in binary glasses

    NASA Astrophysics Data System (ADS)

    Gaddam, Anuraag; Montagne, Lionel; Ferreira, José M. F.

    2016-09-01

    In this paper, we derive a new model to determine the distribution of silicate units in binary glasses (or liquids). The model is based on statistical mechanics and assumes grand canonical ensemble of silicate units which exchange energy and network modifiers from the reservoir. This model complements experimental techniques, which measure short range order in glasses such as nuclear magnetic resonance (NMR) spectroscopy. The model has potential in calculating the amounts of liquid-liquid phase segregation and crystal nucleation, and it can be easily extended to more complicated compositions. The structural relaxation of the glass as probed by NMR spectroscopy is also reported, where the model could find its usefulness.

  12. New glass developments for fiber optics

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  13. 'Work-Hardenable' Ductile Bulk Metallic Glass

    SciTech Connect

    Das, Jayanta; Eckert, Juergen; Tang Meibo; Wang Weihua; Kim, Ki Buem; Baier, Falko; Theissmann, Ralf

    2005-05-27

    Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<1%) at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive 'work hardening' and large ductility of 18%. Significant increase in the flow stress was observed during deformation. The 'work-hardening' capability and ductility of this class of metallic glass is attributed to a unique structure correlated with atomic-scale inhomogeneity, leading to an inherent capability of extensive shear band formation, interactions, and multiplication of shear bands.

  14. Thulium-based bulk metallic glass

    SciTech Connect

    Yu, H. B.; Yu, P.; Wang, W. H.; Bai, H. Y.

    2008-04-07

    We report the formation and properties of a thulium-based bulk metallic glass (BMG). Compared with other known rare-earth (RE) based BMGs, Tm-based BMGs show features of excellent glass formation ability, considerable higher elastic modulus, smaller Poisson's ratio, high mechanical strength, and intrinsic brittleness. The reasons for the different properties between the Tm-based and other RE-based BMGs are discussed. It is expected that the Tm-based glasses with the unique properties are appropriate candidates for studying some important issues in BMGs.

  15. Applicability of glass for transmission LED optics

    NASA Astrophysics Data System (ADS)

    Hellwig, Ansgar; Geyer, Ulf; Heßling, Thomas; Hübner, Marc C.

    2012-10-01

    For LED lighting applications, Fresnel lenses or TIR lenses are frequently made of optical plastics. Glass, however, can offer a number of advantages, including higher resistance to heat, to UV light, and to chemicals like solvents. In this work, several glass materials for transmission optics are compared. The transmittances are evaluated, including Fresnel losses and absorption, as well as shifts of the chromaticity coordinates and of the color rendering index. TIR lenses made of Suprax borosilicate glass and polycarbonate are compared concerning their contour accuracies and their resulting photometric properties like luminous intensity distributions, luminous fluxes, and chromaticity distributions.

  16. Bleaching versus poling: Comparison of electric field induced phenomena in glasses and glass-metal nanocomposites

    NASA Astrophysics Data System (ADS)

    Lipovskii, A. A.; Melehin, V. G.; Petrov, M. I.; Svirko, Yu. P.; Zhurikhina, V. V.

    2011-01-01

    By examining the electric field induced processes in glasses and glass-metal nanocomposites (GMN) we propose mechanism of the electric field assisted dissolution (EFAD) of metal nanoparticles in glass. We show that in both glass poling and EFAD processes, the strong (up to 1 V/nm) local electric field in the subanodic region is due to the presence of "slow" hydrogen ions bonded to nonbridging oxygen atoms in glass matrix. However, the origin of these hydrogen ions in glass and GMN is different. Specifically, when we apply the electric field to a virgin glass, the enrichment of the glass with hydrogen species takes place in the course of the poling. In GMN, the hydrogen ions have been incorporated into the glass matrix during metal nanoparticles formation via reduction in a metal by hydrogen, i.e., before the electric field was applied. The EFAD of metal nanoparticles resembles the electric field stimulated diffusion of metal film in glass (the important difference however is that in GMN, there is no direct contact of dissolving metal entity with anodic electrode). This similarity makes it possible to estimate the energy of thermal activated transition of silver atoms from a nanoparticle to glass matrix as ˜1.3 eV. Electroneutrality of the GMN requires emission of electrons from nanoparticles. Photoconductivity spectra of soda-lime glasses and the results of numerical calculations of band structure of fused silica, sodium disilicate and sodium-calcium-silicate glass enable us to evaluate the bandgap and the position of electron mobility edge in soda-lime glass. The evaluated values are ˜6 eV and ˜1.2 eV below vacuum level, respectively. The bent of the glass band structure in strong electric field permits a direct tunneling of Fermi electrons from silver nanoparticle (4.6 eV below the vacuum level) to the glass conductivity band. Evaluated in accordance with the Fowler-Nordheim equation the magnitude of electric field necessary to establish comparable electron

  17. SLUDGE BATCH 7B GLASS VARIABILITY STUDY

    SciTech Connect

    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 predictable

  18. High-Entropy Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Wang, W. H.

    2014-10-01

    The high-entropy alloys are defined as solid-solution alloys containing five or more than five principal elements in equal or near-equal atomic percent. The concept of high mixing entropy introduces a new way for developing advanced metallic materials with unique physical and mechanical properties that cannot be achieved by the conventional microalloying approach based on only a single base element. The metallic glass (MG) is the metallic alloy rapidly quenched from the liquid state, and at room temperature it still shows an amorphous liquid-like structure. Bulk MGs represent a particular class of amorphous alloys usually with three or more than three components but based on a single principal element such as Zr, Cu, Ce, and Fe. These materials are very attractive for applications because of their excellent mechanical properties such as ultrahigh (near theoretical) strength, wear resistance, and hardness, and physical properties such as soft magnetic properties. In this article, we review the formation and properties of a series of high-mixing-entropy bulk MGs based on multiple major elements. It is found that the strategy and route for development of the high-entropy alloys can be applied to the development of the MGs with excellent glass-forming ability. The high-mixing-entropy bulk MGs are then loosely defined as metallic glassy alloys containing five or more than five elements in equal or near-equal atomic percent, which have relatively high mixing entropy compared with the conventional MGs based on a single principal element. The formation mechanism, especially the role of the mixing entropy in the formation of the high-entropy MGs, is discussed. The unique physical, mechanical, chemical, and biomedical properties of the high-entropy MGs in comparison with the conventional metallic alloys are introduced. We show that the high-mixing-entropy MGs, along the formation idea and strategy of the high-entropy alloys and based on multiple major elements, might provide

  19. A chemical study of individual green glasses and brown glasses from 15426 - Implications for their petrogenesis

    NASA Technical Reports Server (NTRS)

    Ma, M.-S.; Liu, Y.-G.; Schmitt, R. A.

    1982-01-01

    Systematic chemical analyses of individual Apollo 15 green glasses were performed in order to: (1) study chemical variations among them; (2) understand their petrogenesis and source region; and (3) study their possible relationships with mare basalts in general. Brown glasses were also analyzed in order to study their chemical variations and their petrogenetic relationships to green glasses and mare basalts. The chemical composition of green and brown glasses is shown and variation diagrams of Sc, Cr2O3, FeO, and Co abundances in green glasses are presented. Igneous fractionation, two component magma mixing, and partial melting of heterogeneous source materials are alternate scenarios to explain strong observed correlations. The composition of green glasses indicates that they were derived by partial melting of the fractionated cumulate source materials formed from a magma ocean which had experienced certain degrees of olivine and plagioclase fractional crystallization.

  20. PsyGlass: Capitalizing on Google Glass for naturalistic data collection.

    PubMed

    Paxton, Alexandra; Rodriguez, Kevin; Dale, Rick

    2015-09-01

    As commercial technology moves further into wearable technologies, cognitive and psychological scientists can capitalize on these devices to facilitate naturalistic research designs while still maintaining strong experimental control. One such wearable technology is Google Glass (Google, Inc.: www.google.com/glass), which can present wearers with audio and visual stimuli while tracking a host of multimodal data. In this article, we introduce PsyGlass, a framework for incorporating Google Glass into experimental work that is freely available for download and community improvement over time (www.github.com/a-paxton/PsyGlass). As a proof of concept, we use this framework to investigate dual-task pressures on naturalistic interaction. The preliminary study demonstrates how designs from classic experimental psychology may be integrated in naturalistic interactive designs with emerging technologies. We close with a series of recommendations for using PsyGlass and a discussion of how wearable technology more broadly may contribute to new or adapted naturalistic research designs.