Note: This page contains sample records for the topic r7t7-type nuclear glass from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Analytic implementation of the GRAAL model: Application to a R7T7-type glass package in a geological disposal environment  

NASA Astrophysics Data System (ADS)

The Glass Reactivity with Allowance for the Alteration Layer Model (GRAAL) was proposed in 2008 to describe borosilicate nuclear glass alteration based on coupling an affinity law with the formation and dissolution of a passivating reactive interface. It is examined here in a simplified form in which only the affinity with respect to silicon is taken into account with a concentration at saturation Csat, and the precipitation of neoformed phases is described by an affine relation for silicon above a precipitation threshold Csat'. This simplified "analytical GRAAL" model is capable of predicting the quantities of altered glass and the silicon and boron concentration variations in analytical or semi-analytical form, and thereby identify the main characteristic quantities of the system. The model was tested against a series of laboratory experiments lasting from a few days to a few years; its sensitivity to the parameter values was examined, and the model was validated with respect to SON68 glass alteration in initially pure water. It was then applied to the alteration of a glass package in a repository over periods of up to a million years, by means of exploratory calculations comprising a sensitivity study of the internal model parameters and extrapolation to the temperatures expected in a geological repository in order to identify the parameters and mechanisms having the greatest impact on the residual alteration rate. Alteration is controlled by the precipitation of neoformed phases in every case. The transient conditions are of very limited duration with respect to either silicon or boron (no more than a 100 years, with less than 0.01% alteration of the package). In the precipitation law used in the model, the residual alteration rate and total package lifetime are determined primarily by two parameters: k' (the precipitation kinetics) and ?' (the precipitate surface area per unit volume in the geological barrier). The package lifetime is about 3 × 10 5 years at 30 °C assuming a reasonable value for ?' (10 6 m -1), and would be increased by a factor 3-6 if precipitation in the barrier were disregarded. This cursory description of precipitation will be validated and refined through specific laboratory tests at 50 °C and lower temperatures, coordinated with the development of the "geochemical GRAAL" model and with integral tests in contact with clay and canister corrosion products.

Minet, Y.; Bonin, B.; Gin, S.; Frugier, P.

2010-09-01

2

Helium mobility in SON68 borosilicate nuclear glass: A nuclear reaction analysis approach  

NASA Astrophysics Data System (ADS)

The 3He behavior in the non active R7T7 type borosilicate glass called SON68 has been investigated using the implantation method to introduce helium in the material. Nuclear Reaction Analysis (NRA) was performed to follow the helium concentration depth profile evolution as a function of annealing time and temperature. In addition, in situ Transmission Electron Microscopy (TEM) has been implemented to study the formation of helium bubbles during both implantation and annealing processes. Numerical modeling with two different approaches is proposed and discussed to investigate the helium mobility mechanisms. Our study reveals for helium incorporation by implantation at low temperature the presence of several helium populations with disparate diffusivities. The most mobile helium fraction would be attributed to atomic diffusion. The corresponding activation energy value (0.61 eV) extracted from Arrhenius graphs is in good agreement with literature data. The results also highlight that the damages associated to helium sursaturation are the source of small helium clusters formation, with a reduced mobility instead of the atomic mobility measured by the infusion technique. Small cavities that support this assumption have been observed by TEM at low temperature.

Bès, R.; Sauvage, T.; Peuget, S.; Haussy, J.; Chamssedine, F.; Oliviero, E.; Fares, T.; Vincent, L.

2013-11-01

3

SON68 nuclear glass dissolution kinetics: Current state of knowledge and basis of the new GRAAL model  

NASA Astrophysics Data System (ADS)

This article summarizes the present state of knowledge concerning aqueous alteration of R7T7-type nuclear containment glasses, represented mainly by the inactive reference glass designated SON68. Based on this review, we propose to describe the glass alteration kinetics up to and including the final residual rate regime by means of a new mechanistic model known as GRAAL ( glassreactivitywithallowanceforthealterationlayer). Phenomenological analysis findings are reviewed for the various glass alteration regimes: interdiffusion, initial rate, rate drop, residual rate and, under very particular circumstances, resumption of alteration. These alteration regimes are associated with predominant mechanisms. Published work interpreting and modeling these mechanisms was examined in detail. There is a broad consensus on the general mechanisms of the initial rate and even the interdiffusion regime, whereas the mechanisms controlling the rate drop remain a subject of dispute not only with regard to nuclear glasses but also for the dissolution of silicate minerals. The reaction affinity responsible for the rate drop is expressed differently by different authors and depending on the underlying theories. The disagreement concerns the nature of the phase (glass or gel) or the activated complex controlling the rate drop, which in turn determines the elements that must be taken into account in the overall affinity term. Progress in recent years, especially in identifying the mechanisms responsible for the residual rate, has shed new light on these issues, allowing us to propose new theoretical foundations for modeling the different kinetic regimes of SON68 nuclear glass dissolution. The GRAAL model considers that water diffusion in the passivating reaction zone (the gel formed under saturation conditions) is a rate-limiting step in the overall glass dissolution kinetics. Moreover, this passivation zone is a soluble phase whose stability is directly dependent on the nature of the secondary phases likely to precipitate and on the solution renewal conditions.

Frugier, P.; Gin, S.; Minet, Y.; Chave, T.; Bonin, B.; Godon, N.; Lartigue, J.-E.; Jollivet, P.; Ayral, A.; De Windt, L.; Santarini, G.

2008-10-01

4

Microwave Processing of Simulated Nuclear Waste Glass.  

National Technical Information Service (NTIS)

The objective of this study was to determine the effect of microwave processing on nuclear waste glass properties. Several experiments were carried out using microwave heating techniques using borosilicate glass frit containing simulated nuclear waste mat...

R. L. Schulz Z. Fathi D. E. Clark

1992-01-01

5

Crystallization during processing of nuclear waste glass  

SciTech Connect

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 glassmaking are reviewed.

Hrma, Pavel R.

2010-12-01

6

Thermochemical modeling of nuclear waste glass  

SciTech Connect

The development of assessed and consistent phase equilibria and thermodynamic data for major glass constituents used to incorporate high-level nuclear waste is discussed in this paper. The initial research has included the binary Na{sub 2}O-SiO{sub 2}, Na{sub 2}O-Al{sub 2}O{sub 3}, and SiO{sub 2}-Al{sub 2}O{sub 3} systems. The nuclear waste glass is assumed to be a supercooled liquid containing the constituents in the glass at temperatures of interest for nuclear waste storage. Thermodynamic data for the liquid solutions were derived from mathematical comparisons of phase diagram information and the thermodynamic data available for crystalline solid phases. An associate model is used to describe the liquid solution phases. Utilizing phase diagram information provides very stringent limits on the relative thermodynamic stabilities of all phases which exist in a given system.

Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States); Besmann, T.M.; Beahm, E.C. [Oak Ridge National Lab., TN (United States)

1998-06-01

7

Element speciation during nuclear glass alteration  

NASA Astrophysics Data System (ADS)

Assessing the long-term behavior of nuclear glasses implies the prediction of their long-term performance. An important controlling parameter is their evolution during interaction with water under conditions simulating geological repositories. After briefly recalling the major characteristics of the local and medium-range structure of borosilicate glasses of nuclear interest, we will present some structural features of this evolution. Specific structural tools used to determine the local structure of glass surfaces include synchrotron-radiation x-ray absorption spectroscopy with total electron yield detection. The evolution of the structure of glass surface has been determined at the Zr-, Fe-, Si- and Al-K edges and U-LIII edge. During alteration in near- or under-saturated conditions, some elements such as Fe change coordination, as other elements such as Zr only suffer structural modifications in under-saturated conditions. Uranium exhibits a modification of its speciation from an hexa-coordinated U(VI) in the borosilicate glass to an uranyl group in the gel. These structural modifications may explain the chemical dependence of the initial alteration rate and the transition to the residual regime. They also illustrate the molecular-scale origin of the processes at the origin of the glass-to-gel transformation. Eventually, they explain the provisional trapping of U by the alteration gel: the uranium retention factors in the gel depend on the alteration conditions, and thus on the nature of the resulting gel and on the trapping conditions.

Galoisy, L.; Calas, G.; Bergeron, B.; Jollivet, P.; Pelegrin, E.

2011-12-01

8

Extrapolation of nuclear waste glass aging  

SciTech Connect

Increased confidence is provided to the extrapolation of long-term waste form behavior by comparing the alteration of experimentally aged natural basaltic glass to the condition of the same glass as it has been geologically aged. The similarity between the laboratory and geologic alterations indicates that important aging variables have been identified and incorporated into the laboratory experiments. This provides credibility to the long-term predictions made for waste form borosilicate glasses using similar experimental procedures. In addition, these experiments have demonstrated that the aging processes for natural basaltic glass are relevant to the alteration of nuclear waste glasses, as both appear to react via similar processes. The alteration of a synthetic basaltic glass was measured in MCC-1 tests done at 90/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 182 days. Tests were also done using (1) MCC-2 procedures at 190/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 91 days and (2) hydration tests in saturated water vapor at 240/sup 0/C, a SA/V of approx. 10/sup 6/ cm/sup -1/, and time periods up to 63 days. These results are compared to alteration observed in natural basaltic glasses of great age. 6 references, 6 figures, 1 table.

Byers, C.D.; Ewing, R.C.; Jercinovic, M.J.; Keil, K.

1984-01-01

9

Glass produced by underground nuclear explosions. [Rainier  

SciTech Connect

Detonation of an underground nuclear explosive produces a strong shock wave which propagates spherically outward, vaporizing the explosive and nearby rock and melting, the surrounding rock. The vaporized material expands adiabatically, forming a cavity. As the energy is dissipated during the cavity formation process, the explosive and rock debris condense and mix with the melted rock. The melt flows to the bottom of the cavity where it is quenched by fractured rock fragments falling from above as the cavity collapses. Measurements indicate that about 740 tonnes of rock and/or soil are melted for every kiloton (10/sup 12/ calories) of explosive energy, or about 25% of the explosive energy goes to melting rock. The resulting glass composition reflects the composition of the unaltered rock with explosive debris. The appearance ranges from white pumice to dense, dark lava. The bulk composition and color vary with the amount of explosive iron incorporated into the glass. The refractory explosion products are mixed with the solidified melt, although the degree of mixing is variable. Electron microprobe studies of glasses produced by Rainier in welded tuff have produced the following results: glasses are dehydrated relative to the host media, glasses are extremely heterogeneous on a 20 ..mu..m scale, a ubiquitous feature is the presence of dark marble-cake regions in the glass, which were locally enriched in iron and may be related to the debris, optically amorphous regions provide evidence of shock melting, only limited major element redistribution and homogenization occur within the cavity.

Schwartz, L.; Piwinskii, A.; Ryerson, F.; Tewes, H.; Beiriger, W.

1983-01-01

10

Microwave processing of simulated nuclear-waste glass  

SciTech Connect

The objective of this study was to determine the effect of microwave processing on nuclear waste glass properties. Several experiments were carried out using microwave heating techniques using borosilicate glass frit containing simulated nuclear waste material and borosilicate glass frit without waste products. A time study was conducted to determine whether or not microwave processing can produce a homogeneous glass melt (in less time) when compared with conventional heating methods. Surface analysis techniques such as FTIRRS and SEM were conducted to determine the quality of the glasses. Some preliminary short-term leaching experiments were run to begin determination of the durability of waste glasses processed using microwave heating.

Schulz, R.L.; Fathi, Z.; Clark, D.E.

1992-04-27

11

Hydration process of nuclear-waste glass: an interim report  

SciTech Connect

Aging of simulated nuclear waste glass by contact with a controlled-temperature, humid atmosphere results in the formation of a double hydration layer penetrating the glass, as well as the formation of minerals on the glass surface. The hydration process can be described by Arrhenius behavior between 120 and 240/sup 0/C. Results suggest that simulated aging reactions are necessary for demonstrating that nuclear waste forms can meet projected Nuclear Regulatory Commission regulations. 16 figures, 4 tables.

Bates, J.K.; Jardine, L.J.; Steindler, M.J.

1982-07-01

12

Compositional threshold for Nuclear Waste Glass Durability  

SciTech Connect

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.

Kruger, Albert A. [Pacific Northwest National Lab., Richland, WA (United States); Farooqi, Rahmatullah [Pohang Univ. of Science and Technology, (Korea, Republic of); Hrma, Pavel R. [Pacific Northwest National Lab., Richland, WA (United States), Pohang Univ. of Science and Technology, (Korea, Republic of)

2013-04-24

13

Spectroscopic investigation of U, Np and Th in nuclear glasses  

NASA Astrophysics Data System (ADS)

Vitrification of high-level radioactive waste in borosilicate glasses is currently used on an industrial scale in several countries. The fundamental properties of the waste forms are their chemical and mechanical durability against the forcing conditions represented by chemical alteration or internal/external irradiation. The waste immobilized in glass is composed of over 30 different nuclear fission and activation products, as well as minor actinides. The oxidation state and local atomic coordination of long-lived radionuclides are important parameters to understand the long-term evolution of the glass. We present an overview of the local structure around actinides in glasses similar to the French nuclear glass. X-Ray absorption spectroscopy has been used to probe the local environment around uranium, neptunium and thorium in these glasses. It is combined with with UV-visible spectroscopy, used to get selective information on the surrounding of U(IV), U(V) and U(VI) in glasses. Our spectroscopic data show that U, Np and Th occur in nuclear glasses in a peculiar surrounding showing significant differences with the crystal chemistry of these elements in crystalline compounds. Element speciation may be used as a pertinent parameter to follow the long-term stability of nuclear glasses, either under irradiation or during the alteration of the glass.

Calas, G.; Galoisy, L. V.; Petit-Maire, D.

2011-12-01

14

Nuclear Waste Glasses: Beautiful Simplicity of Complex Systems  

SciTech Connect

The behavior of glasses with a large number of components, such as waste glasses, is not more complex than the behavior of simple glasses. On the contrary, the presence of many components restricts the composition region of these glasses in a way that allows approximating composition-property relationships by linear functions. This has far-reaching practical consequences for formulating nuclear waste glasses. On the other hand, processing high-level and low-activity waste glasses presents various problems, such as crystallization, foaming, and salt segre-gation in the melter. The need to decrease the settling of solids in the melter to an acceptable level and to maximize the rate of melting presents major challenges to processing technology. However, the most important property of the glass product is its chemical durability, a somewhat vague concept in lieu of the assessment of the glass resistance to aqueous attack while the radioactivity decays over tens of thousands of years.

Hrma, Pavel R.

2009-01-01

15

Control of Nepheline Crystallization in Nuclear Waste Glass  

SciTech Connect

Glass frits with a high B{sub 2}O{sub 3} concentration have been designed which, when combined with high-alumina concentration nuclear waste streams, will form glasses with durabilities that are acceptable for repository disposal and predictable using a free energy of hydration model. Two glasses with nepheline discriminator values closest to 0.62 showed significant differences in normalized boron release between the quenched and heat treated versions of each glass. X-ray diffraction confirmed that nepheline crystallized in the glass with the lowest nepheline discriminator value, and nepheline may also exist in the second glass as small nanocrystals. The high-B{sub 2}O{sub 3} frit was successful in producing simulated waste glasses with no detectable nepheline crystallization at waste loadings of up to 45 wt%. The melt rate of this frit was also considerably better than other frits with increased concentrations of Na{sub 2}O.

Fox, Kevin

2008-07-01

16

Nuclear quadrupole resonance of boron in borate glasses  

NASA Astrophysics Data System (ADS)

A continuous wave nuclear quadrupole resonance spectrometer that has a high sensitivity even at low frequencies has been built. Boron and aluminum NQR has been detected in the region 200 kHz to 1.4 MHz. For the first time, boron NQR has been detected in a glass. The NQR spectrum of pure B 20 3 glass is consistent with 85 ± 2% of the boron atoms belonging to boroxol rings. In sodium borate glasses, the number of borons in boroxol rings decreases with increasing sodium content, until when sodium oxide comprises 20 mol% of the glass less than 2% of the borons are in boroxol rings.

Gravina, Samuel J.; Bray, Phillip J.

17

Extrapolation of Nuclear Waste Glass Aging.  

National Technical Information Service (NTIS)

Increased confidence is provided to the extrapolation of long-term waste form behavior by comparing the alteration of experimentally aged natural basaltic glass to the condition of the same glass as it has been geologically aged. The similarity between th...

C. D. Byers R. C. Ewing M. J. Jercinovic K. Keil

1984-01-01

18

Nuclear Waste Glasses: Continuous Melting and Bulk Vitrification  

SciTech Connect

This contribution addresses various aspects of nuclear waste vitrification. Nuclear wastes have a variety of components and composition ranges. For each waste composition, the glass must be formulated to possess acceptable processing and product behavior defined in terms of physical and chemical properties that guarantee that the glass can be easily made and resist environmental degradation. Glass formulation is facilitated by developing property-composition models, and the strategy of model development and application is reviewed. However, the large variability of waste compositions presents numerous additional challenges: insoluble solids and molten salts may segregate; foam may hinder heat transfer and slow down the process; molten salts may accumulate in container refractory walls; on cooling, the glass may precipitate crystalline phases. These problems need targeted exploratory research. Examples of specific problems and their possible solutions are discussed.

Hrma, Pavel R.; Kruger, Albert A.

2008-02-25

19

NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON  

SciTech Connect

This contribution addresses various aspects of nuclear waste vitrification. Nuclear wastes have a variety of components and composition ranges. For each waste composition, the glass must be formulated to possess acceptable processing and product behavior defined in terms of physical and chemical properties that guarantee the glass can be easily made and resist environmental degradation. Glass formulation is facilitated by developing property-composition models, and the strategy of model development and application is reviewed. However, the large variability of waste compositions presents numerous additional challenges: insoluble solids and molten salts may segregate; foam may hinder heat transfer and slow down the process; molten salts may accumulate in container refractory walls; the glass on cooling may precipitate crystalline phases. These problems need targeted exploratory research. Examples of specific problems and their possible solutions are discussed.

KRUGER AA; HRMA PR

2008-03-24

20

Nuclear waste glass Product Consistency Test (PCT), Version 3. 0  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Product Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples.

Jantzen, C.M.; Bibler, N.E.

1990-11-01

21

Nuclear waste glass product consistency test (PCT), Version 5. 0  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

1992-06-01

22

Immobilization of spent nuclear fuel in iron phosphate glass  

NASA Astrophysics Data System (ADS)

Twenty-four iron phosphate compositions (15 wt% wasteloading) were evaluated to determine their suitability for vitrifying Al-clad, highly enriched uranium, spent nuclear fuel (SNF). In half the compositions melted, 80 wt% of the Al 2O 3 in the simulated SNF was removed prior to vitrification. All twenty-four compositions formed homogeneous glasses, many at temperatures as low as 1150°C. As little as 2.5 wt% Na 2O decreased melt viscosity and increased alumina solubility in those glasses of higher alumina contents (7.2 wt% Al 2O 3). None of the glasses contained undissolved uranium compounds as has been found in borosilicate glasses containing as little 4.4 wt% UO 2. The chemical durability (measured by the product consistency test (PCT)) of the iron phosphate wasteforms is as good as, and in many cases up to 15 times better than the approved reference material (ARM-1) borosilicate glass.

Mesko, M. G.; Day, D. E.

23

Spectroscopic investigations on glasses, glass-ceramics and ceramics developed for nuclear waste immobilization  

NASA Astrophysics Data System (ADS)

Highly radioactive nuclear waste must be immobilized in very durable matrices such as glasses, glass-ceramics and ceramics in order to avoid their dispersion in the biosphere during their radioactivity decay. In this paper, we present various examples of spectroscopic investigations (optical absorption, Raman, NMR, EPR) performed to study the local structure of different kinds of such matrices used or envisaged to immobilize different kinds of radioactive wastes. A particular attention has been paid on the incorporation and the structural role of rare earths—both as fission products and actinide surrogates—in silicate glasses and glass-ceramics. An example of structural study by EPR of a ceramic (hollandite) irradiated by electrons (to simulate the effect of the ?-irradiation of radioactive cesium) is also presented.

Caurant, D.

2014-05-01

24

Redox of Simulated Nuclear Waste Glass Forming Melts  

SciTech Connect

Glasses are found in most reduction-oxidation (redox) items that are used everyday; from automobiles to planes. With stability of most glasses, they are being used to store hazardous waste materials. Many elements have different oxidation states and are found in multiple states in glasses. Redox of glasses has significant effect on processing of waste glass melts in melters as well as properties of the waste forms. Nuclear waste glasses generally have complex chemistry (including several redox ions) and form corrosive melts. Basic objective: study the redox of the glasses containing Fe and Ni with square wave voltammetry. A basic simulated frit glass was used for vitrification. The frit composition used was 57.90% SiO2, 17.70% Na2O, 14.70% B2O3, 5.70% Li2O, 2.00% MgO, 1.00% TiO2, 0.50% ZrO2, and 0.50% La2O3. Batch glasses were synthesized and then dopants of Fe2O3 , NiO, and a combination of Fe2O3-NiO were added in 1-wt % amounts. The glass was melted at 1150 C and held for 24 hours. It was poured to the top of a medium sized Pt/Rh crucible and placed in a furnace at 1150 C. The glass powder was allowed to melt for five minutes before the testing apparatus was placed in the melt. The testing apparatus was composed of a Pt/Rh working electrode, Pt/Rh counter electrode, and a Zr/Al reference electrode. The counter electrode is placed in the melt until it is touching the bottom of the crucible creating a closed circuit. Both the reference electrode and working electrode are located half way down the counter electrode. The test showed that melt resistivity was high indicating the amount of conductivity in the melt. Sample melt volume and area of the working electrode were high. Adjusting the crucible size and sizing other electrodes will improve the measurements. Future work: testing NiO glass and Fe2O3-NiO glass to see the interaction between the Fe and the Ni and synthesis of 2 wt %, 3 wt %, and 5-wt % Fe2O3 doped glasses to study effects of Fe concentration.

Vick, Sara C.; Sundaram, S. K.

2001-12-01

25

Redox reaction and foaming in nuclear waste glass melting  

SciTech Connect

This document was prepared by Pacific Northwest Laboratory (PNL) and is an attempt to analyze and estimate the effects of feed composition variables and reducing agent variables on the expected chemistry of reactions occurring in the cold cap and in the glass melt in the nuclear waste glass Slurry-fed, joule-heated melters as they might affect foaming during the glass-making process. Numerous redox reactions of waste glass components and potential feed additives, and the effects of other feed variables on these reactions are reviewed with regard to their potential effect on glass foaming. A major emphasis of this report is to examine the potential positive or negative aspects of adjusting feed with formic acid as opposed to other feed modification techniques including but not limited to use of other reducing agents. Feed modification techniques other than the use of reductants that should influence foaming behavior include control of glass melter feed pH through use of nitric acid. They also include partial replacement of sodium salts by lithium salts. This latter action (b) apparently lowers glass viscosity and raises surface tension. This replacement should decrease foaming by decreasing foam stability.

Ryan, J.L.

1995-08-01

26

Systems Approach to Nuclear Waste Glass Development.  

National Technical Information Service (NTIS)

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 sys...

C. M. Jantzen

1986-01-01

27

Observations of Nuclear Explosive Melt Glass Textures and Surface Areas  

SciTech Connect

This memo report summarizes our current knowledge of the appearance of melt glass formed and subsequently deposited in the subsurface after an underground nuclear test. We have collected archived pictures and melt glass samples from a variety of underground nuclear tests that were conducted at the Nevada Test Site (NTS) during the U.S. nuclear testing program. The purpose of our work is to better determine the actual variation in texture and surface area of the melt glass material. This study is motivated by our need to better determine the rate at which the radionuclides incorporated in the melt glass are released into the subsurface under saturated and partially saturated conditions. The rate at which radionuclides are released from the glass is controlled by the dissolution rate of the glass. Glass dissolution, in turn, is a strong function of surface area, glass composition, water temperature and water chemistry (Bourcier, 1994). This work feeds into an ongoing experimental effort to measure the change in surface area of analog glasses as a function of dissolution rate. The conclusions drawn from this study help bound the variation in the textures of analog glass samples needed for the experimental studies. The experimental work is a collaboration between Desert Research Institute (DRI) and Earth and Environmental Sciences-Lawrence Livermore National Laboratory (EES-LLNL). On March 4, 1999 we hosted a meeting at LLNL to present and discuss our findings. The names of the attendees appear at the end of this memo. This memo report further serves to outline and summarize the conclusions drawn from our meeting. The United States detonated over 800 underground nuclear tests at the NTS between 1951 and 1992. In an effort to evaluate the performance of the nuclear tests, drill-back operations were carried out to retrieve samples of rock in the vicinity of the nuclear test. Drill-back samples were sent to Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL) and analyzed for diagnostic purposes. As a result of these activities, a body of knowledge consisting of personal accounts, photos, reports and archived solid samples was gained regarding the physical nature of the melt glass that formed during an underground nuclear test. In this memo report, we summarize previously published reports, compile archived photos, document and describe melt glass samples and summarized discussions from former field engineers and radiochemists who had direct knowledge of drill-back samples. All the information presented in the report was gathered from unclassified sources. We have included as wide a variation of samples as we could document. Unfortunately, as part of the drill-back and diagnostic efforts, it was not common practice to photograph or physically describe the material returned to the surface.

Kersting, A B; Smith, D K

2006-01-17

28

Vanadium and Chromium Redox Behavior in borosilicate Nuclear Waste Glasses  

SciTech Connect

X-ray absorption spectroscopy (XAS) was used to characterize vanadium (V) and chromium (Cr) environments in low activity nuclear waste (LAW) glasses synthesized under a variety of redox conditions. V{sub 2}O{sub 5} was added to the melt to improve sulfur incorporation from the waste; however, at sufficiently high concentrations, V increased melt foaming, which lowered melt processing rates. Foaming may be reduced by varying the redox conditions of the melt, while small amounts of Cr are added to reduce melter refractory corrosion. Three parent glasses were studied, where CO-CO{sub 2} mixtures were bubbled through the corresponding melt for increasing time intervals so that a series of redox-adjusted-glasses was synthesized from each parent glass. XAS data indicated that V and Cr behaviors are significantly different in these glasses with respect to the cumulative gas bubbling times: V{sup 4+}/V{sub total} ranges from 8 to 35%, while Cr{sup 3+}/Cr{sub total} can range from 15 to 100% and even to population distributions including Cr{sup 2+}. As Na-content decreased, V, and especially, Cr became more reduced, when comparing equivalent glasses within a series. The Na-poor glass series show possible redox coupling between V and Cr, where V{sup 4+} populations increase after initial bubbling, but as bubbling time increases, V{sup 4+} populations drop to near the level of the parent glass, while Cr becomes more reduced to the point of having increasing Cr{sup 2+} populations.

D McKeown; I Muller; H Gan; Z Feng; C Viragh; I Pegg

2011-12-31

29

The Role of Biofilm on the Alteration of Glasses: Example of Basaltic and Nuclear Glasses  

NASA Astrophysics Data System (ADS)

It is generally accepted that alterations of rocks and anthropogenic products are not exclusively driven by the interaction with water or mineral aqueous solutions. Organic compounds as well as microorganisms are important in mineral degradation processes, together with secondary mineralization. However, the exact role of biofilms in these processes remains unclear. In our study we tested two materials, a tholeiitic basaltic glass and the reference French nuclear glass SON68 17 LIDC2A2Z1. Experiments were carried out for 19 weeks using a modified soxhlet's device at 25°C. We developed a specific growth medium which allows both the growth of Pseudomonas bacterium and a precise measurement, using ICP-MS, of trace elements solubilized from the two glass materials. The thickness of biofilms, analyzed by confocal laser microscopy was 40?m for both materials. These biofilms are able to efficiently trap most of the glass constituents, some of them being potentially toxic. They also form a protective barrier at the solid/solution interface. Alteration rates were determined at the end of the experiments. The basaltic glass deteriorated with a rate of 18.3 10-4g.m-2.d-1 in biotic conditions and 29.8 10-4g.m-2.d-1 in the sterile system. The nuclear glass had a dissolution rate of 17.6 10^{- 4}g.m-2.d-1 in the biotic experiment and 25.0 10-4g.m-2.d-1in the sterile medium.

Aouad, G.; Crovisier, J.; Meyer, J.; Stille, P.; Damidot, D.; Hutchens, E.; Vuilleumier, S.; Geoffroy, V.

2006-12-01

30

Processing glass pyrochlore composites for nuclear waste encapsulation  

NASA Astrophysics Data System (ADS)

Glass matrix composites have been developed as alternative materials to immobilize nuclear solid waste, in particular actinides. These composites are made of soda borosilicate glass matrix, into which particles of lanthanum zirconate pyrochlore are encapsulated in concentrations of 30 vol.%. The fabrication process involves powder mixing followed by hot-pressing. At the relatively low processing temperature used (620 °C), the pyrochlore crystalline structure of the zirconate, which is relevant for containment of radioactive nuclei, remains unaltered. The microstructure of the composites exhibits a homogeneous distribution of isolated pyrochlore particles in the glass matrix and strong bonding at the matrix-particle interfaces. Hot-pressing was found to lead to high densification (95% th.d.) of the composite. The materials are characterized by relatively high elastic modulus, flexural strength, hardness and fracture toughness. A numerical approach using a microstructure-based finite element solver was used in order to investigate the mechanical properties of the composites.

Pace, S.; Cannillo, V.; Wu, J.; Boccaccini, D. N.; Seglem, S.; Boccaccini, A. R.

2005-05-01

31

Properties and FTIR spectra of lead phosphate glasses for nuclear waste immobilization  

Microsoft Academic Search

The properties of lead phosphate glasses incorporated with the mixed metal oxides, which may act as the simulated nuclear waste, were studied. All the glasses can be melted under 1000°C and 20wt.% loadings of mixed oxides were achieved. The glass transition temperature increases, while the thermal expansion coefficient and dissolution rate of the waste glasses decreases with increasing incorporated amount

P. Y Shih

2003-01-01

32

The characterization of glass inclusions through nuclear microprobe  

NASA Astrophysics Data System (ADS)

In the last decade, nuclear microanalytical methods have been developed in order to study the distribution of elements of specific interest in natural glasses involving melt (or glass) inclusions trapped in minerals of magmatic origin. The study of these small objects represent a very original application of the microbeam techniques in general. With the nuclear microprobe, we have focused our research in two main directions: (1) the determination of light elements by nuclear reaction analysis (C, N, F, Li, B) and elastic recoil detection analysis in transmission mode (H), contributing to the knowledge of the magmatic thermodynamic conditions (pressure, temperature, gas solubility), to the quantification of volatile budget and to the volcanoes atmospheric contribution; (2) the determination of trace elements as geochemical markers with PIXE, contributing to the knowledge of magmatic processes. In this paper, after a brief review of the methods developed for light elements and their application in volcanology, we present with more details simultaneous use of microPIXE-microPIGE to characterize strontium and fluorine in melt inclusions. The experiments were carried out both with the Bruyères Le Châtel nuclear microprobe (of first generation) and with the new nuclear microprobe of the Pierre Süe laboratory.

Mosbah, M.; Clocchiatti, R.; Métrich, N.; Piccot, D.; Rio, S.; Tirira, J.

1995-09-01

33

Resumption of nuclear glass alteration: State of the art  

NASA Astrophysics Data System (ADS)

Studies of nuclear glass alteration kinetics have shown that after the beginning of a rate drop due to the approach of silica saturation of the solution and the formation of a passivating layer, a resumption of alteration is possible. This phenomenon corresponding to an acceleration of the glass dissolution rate is systematically associated with the precipitation of zeolites and, to a lesser extent, calcium silicate hydrates. Secondary phases which precipitate from the major glass network-forming elements (Si, Al) strongly impact the dissolution kinetics. The literature data are generally consistent and the results are reproducible, showing that the resumption of alteration is observed at high pH, temperature, and S/V ratio during laboratory experiments. The studies also show that the resumption of alteration is strongly dependent on the composition of the glass and the leaching solutions. The wide range of glass compositions studied (about 60 glasses in the articles reviewed) and the variable test conditions (temperature, pH, and solution composition) make it extremely difficult to compare and compile the data, or to decorrelate the effects of the composition on the time before the resumption of alteration and on its magnitude. The observations to date have led to a proposed macroscopic mechanism based on the loss of the passivating properties of the alteration layer after consumption of a fraction of the network-forming elements by precipitation of zeolites. No multiscale mechanistic approach exists, however, to account for the nucleation and growth of zeolites at the expense of the glass. For example, the effect of aluminum in the gel or in solution on the glass alteration kinetics is not sufficiently understood today. Although thermodynamic models have been proposed to delimit the ranges of glass compositions subject to a resumption of alteration, their development is hampered by inadequate knowledge of the newly formed phases and their nucleation-growth mechanism, and by gaps in the thermodynamic databases. Their development is also constrained by the capability of the models to take Si-Al-Ca interactions into account in the alteration gels.

Fournier, Maxime; Gin, Stéphane; Frugier, Pierre

2014-05-01

34

MILLIMETER-WAVE MONITORING OF NUCLEAR WASTE GLASS MELTS - AN OVERVIEW  

EPA Science Inventory

Molten glass characteristics of temperature, resistivity, and viscosity can be monitored reliably in the high temperature and chemically corrosive environment of nuclear waste glass melters using millimeter-wave sensor technology. Millimeter-waves are ideally suited for such meas...

35

Influence of Penetrating gamma Radiation on the Reaction of Simulated Nuclear Waste Glass in Tuff Groundwater.  

National Technical Information Service (NTIS)

Static leaching experiments have been performed to determine the influence of penetrating gamma radiation on the reaction of simulated nuclear waste glass in tuff groundwater at 90(degree)C. Both the leachates and the reacted glass monoliths were analyzed...

W. L. Ebert J. K. Bates T. A. Abrajano T. J. Gerding

1989-01-01

36

Basalt glass: an analogue for the evaluation of the long-term stability of nuclear waste form borosilicate glasses  

SciTech Connect

The long-term stability of nuclear waste form borosilicate glasses can be evaluated by understanding the processes that effect the long-term alteration of glass and by comparing laboratory alteration of synthetic basalt and borosilicate glasses with the observed stability of naturally occurring basaltic glasses in diverse geologic environments. This paper presents detailed electron microprobe analyses of naturally altered basaltic glasses (with maximum ages of 10,000 to 20 million years) from low-temperature environments. These results are compared to laboratory data on the corrosion of a synthetic basaltic glass in MCC-1 tests (90/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 182 days), MCC-2 tests (190/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 210 days) and hydration tests in saturated water vapor (240/sup 0/C, an estimated SA/V of approx. 10/sup 6/ cm/sup -1/ and time periods up to 63 days). Additionally, laboratory-induced hydration alteration of synthetic basalt and borosilicate glasses is compared. These preliminary experiments provide evidence that the alteration processes observed for natural basalt glasses are relevant to understanding the alteration of nuclear waste glass, as both appear to react via similar processes. 12 references, 6 figures, 1 table.

Byers, C.D.; Jercinovic, M.J.; Ewing, R.C.; Keil, K.

1984-01-01

37

Fluorine in silicate glasses: A multinuclear nuclear magnetic resonance study  

SciTech Connect

Anhydrous nepheline, jadeite, and albite glasses doped with F as well as hydrous F-containing haplogranitic glasses were investigated using {sup 19}F combined rotation and multiple-pulse spectroscopy; {sup 19}F {yields} {sup 29}Si cross-polarization/magic angle spinning (MAS); and high-power {sup 19}F decoupled {sup 29}Si, {sup 23}Na, and {sup 27}Al MAS nuclear magnetic resonance methods. Fluorine preferentially coordinates with Al to form octahedral AlF{sub 6}{sup 3{minus}} complexes in all glasses studied. In addition, F anions bridging two Al cations, units containing octahedral Al coordinated by both O and F, or tetrahedral Al-F complexes might be present. The presence of Si-F bonds cannot be entirely ruled out but appears unlikely on the basis of the {sup 19}F {yields} {sup 29}Si CP/MAS spectra. There is no evidence for any significant coordination of F with alkalis in the glasses studied. Over the range of F contents studied (up to 5 wt.%), there seems to be hardly any dependence of F speciation on the concentration of F in the samples. The spectroscopic results explain the decrease of the viscosity of silicate melts with increasing F content by removal of Al from bridging AlO{sub 4}-units due to complexing with F, which causes depolymerization of the melt. The same mechanism can account for the shift of the eutectic point in the haplogranite system to more feldspar-rich compositions with increasing F content, and for the peraluminous composition of most F-rich granites. Liquid immiscibility in F-rich granitic melts might be caused by formation of (Na,K){sub 3}AlF{sub 6} units in the melt with little or no interaction with the silicate component. The presence of F in granitic melts might increase the solubility of high field strength cations by making nonbridging O atoms available which form complexes with these cations.

Schaller, T.; Dingwell, D.B.; Keppler, H.; Merwin, L.; Sebald, A. (Univ. Bayreuth (West Germany)); Knoeller, W. (Bruker Analytische Messtechnik, Rheinstetten (West Germany))

1992-02-01

38

Solubility interpretations of leach tests on nuclear waste glass  

SciTech Connect

A one-year leach test at 90/sup 0/C was conducted on specimens of PNL 76-68 borosilicate glass, a simulated nuclear waste glass. The experimental method was MCC-1, one of the standard leach tests developed by the Materials Characterization Center (MCC). The leachant solutions included deionized water, a silicic acid/sodium bicarbonate solution, and a concentrated K-Mg-Na-Cl brine. Phase characterization techniques and geochemical codes were used to identify possible solubility and sorption controls for the constituents dissolved in the final leach solutions. In the non-brine solutions, an alteration layer of 30-50 ..mu..m is formed that consists mainly of an amorphous Fe(OH)/sub 3/. In addition, a zinc silicate phase precipitated on the glass surface and appears to control the concentrations of dissolved Cs and Si. Calculations with the MINTEQ geochemical code identified possible equilbrium solubility controls for dissolved Fe, Ca, Si, Zn, Pb, P, and F. These calculations also permitted an estimation of the pH at the temperature of the leach experiments. The PHREEQE geochemical code was used to predict the steady state concentrations of Ca/sup 2 +/ and Sr/sup 2 +/ in the final leachates by assuming their sorption on solid amorphous Fe(OH)/sub 3/. For the leach tests completed in the brine solution, a magnesium silicate phase precipitated on the glass surface and may have been responsible for the observed decrease in the concentration of the dissolved Si. This solid phase was tentatively identified as sepiolite and/or possibly talc. These results were compared to mineral solubilities calculated from the MINTEQ geochemical code.

Strachan, D.M.; Krupka, K.M.

1984-01-01

39

Development of glass vitrification at SRL as a waste treatment technique for nuclear weapon components  

SciTech Connect

This report discusses the development of vitrification for the waste treatment of nuclear weapons components at the Savannah River Site. Preliminary testing of surrogate nuclear weapon electronic waste shows that glass vitrification is a viable, robust treatment method.

Coleman, J.T.; Bickford, D.F.

1991-12-31

40

Development of glass vitrification at SRL as a waste treatment technique for nuclear weapon components  

SciTech Connect

This report discusses the development of vitrification for the waste treatment of nuclear weapons components at the Savannah River Site. Preliminary testing of surrogate nuclear weapon electronic waste shows that glass vitrification is a viable, robust treatment method.

Coleman, J.T.; Bickford, D.F.

1991-01-01

41

Final technical report: Effects of water on properties of the simulated nuclear waste glasses  

SciTech Connect

For isolation of nuclear wastes through the vitrification process, waste slurry is mixed with borosilicate based glass and remelted at high temperature. During these processes, water can enter into the final waste glass. It is known that water in silica and silicate glasses changes various glass properties, such as chemical durability, viscosity and electrical conductivity. These properties are very important for processing and assuring the quality and safety controls of the waste glasses. The objective of this project was to investigate the effect of water in the simulated nuclear waste glasses on various glass properties, including chemical durability, glass transition temperature, liquidus temperature, viscosity and electrical conductivity. This report summarizes the results of this investigation conducted at Rensselaer during the past one year.

Li, H.; Tomozawa, M.

1996-02-01

42

Gadolinium Borosilicate Glass-Bonded Gd-Silicate Apatite: A Glass-Ceramic Nuclear Waste Form for Actinides  

SciTech Connect

A Gd-rich crystalline phase precipitated in a sodium gadolinium alumino-borosilicate glass during synthesis. The glass has a chemical composition of 45.39-31.13 wt% Gd2O3, 28.80-34.04 wt% SiO2, 10.75-14.02 wt% Na2O, 4.30-5.89 wt% Al2O3, and 10.75-14.91 wt% B2O3. Backscattered electron images revealed that the crystals are hexagonal, elongated, acicular, prismatic, skeletal or dendritic, tens of mm in size, some reaching 200 mm in length. Electron microprobe analysis confirmed that the crystals are chemically homogeneous and have a formula of NaGd9(SiO4)6O2 with minor B substitution for Si. The X-ray diffraction pattern of this phase is similar to that of lithium gadolinium silicate apatite. Thus, this hexagonal phase is a rare earth silicate with the apatite structure. We suggest that this Gd-silicate apatite in a Gd-borosilicate glass is a potential glass-ceramic nuclear waste form for actinide disposition. Am, Cm and other actinides can easily occupy the Gd-sites. The potential advantages of this glass-ceramic waste form include: (1) both the glass and apatite can be used to immobilize actinides, (2) silicate apatite is thermodynamically more stable than the glass, (3) borosilicate glass-bonded Gd-silicate apatite is easily fabricated, and (4) the Gd is an effective neutron absorber.

Zhao, Donggao (Michigan, Univ Of - Ann Arbor); Li, Liyu (BATTELLE (PACIFIC NW LAB)); Davis, Linda L. (ASSOC WESTERN UNIVERSITY); Weber, William J. (BATTELLE (PACIFIC NW LAB)); Ewing, Rodney C. (Michigan, Univ Of - Ann Arbor); KP Hart and GR Lumpkin

2001-01-01

43

ALKALI/ AKALINE-EARTH CONTENT EFFECTS ON PROPERTIES OF HIGH-ALUMINA NUCLEAR WASTE GLASSES  

SciTech Connect

A series of high alumina (>20 mass %) borosilicate glasses have been made and characterized based on the assumption that the primary modifier cation field strength plays a significant role in mediating glass structure of nuclear waste glasses. Any crystallization upon quenching or after heat treatment at 950 °C for 24 hours was identified and quantified by X-ray diffraction. Particular note was take of any aluminosilicates formed, such as those in the nepheline group (MAlSiO4 where M=K, Na, Li), as these remove multiple glass-formers from the network upon crystallization. The relative roles of potassium, sodium, lithium, calcium, and magnesium on glass structure and crystallization in high alumina glasses were explored using Raman and infrared vibrational spectroscopy. Strong evidence was found for the importance of 4 membered rings in glasses with 10 mol % alkaline earths (Ca, Mg).

McCloy, John S.; Rodriguez, Carmen P.; Windisch, Charles F.; Leslie, Clifford J.; Schweiger, Michael J.; Riley, Brian J.; Vienna, John D.

2010-10-01

44

Leaching of actinide-doped nuclear waste glass in a tuff-dominated system  

Microsoft Academic Search

A laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples were placed in water inside tuff vessels, and then the tuff vessels were placed in water inside Teflon containers. Glass-component leach rates and migration through the

F. Bazan; J. Rego; R. D. Aines

1987-01-01

45

ASSESSMENT OF NEPHELINE PRECIPITATION IN NUCLEAR WASTE GLASS VIA THERMOCHEMICAL MODELING  

EPA Science Inventory

A thermochemical representation of the Na-Al-Si-B-O system relevant for nuclear waste glass has been developed based on the associate species approach for the glass solution phase. Thermochemical data were assessed and associate species data determined for binary and ternary sub...

46

Design and Test of the Borosilicate Glass Burnable Poison Rod for Qinshan Nuclear Power Plant Core.  

National Technical Information Service (NTIS)

Material for the burnable poison of Qinshan Nuclear Power Plant core is GG-17 borosilicate glass. The chemical composition and physico-chemical properties of GG-17 is very close to Pyrex-7740 glass used by Westinghouse. It is expected from the results of ...

J. Huang H. Sun

1988-01-01

47

Cerium, uranium, and plutonium behavior in glass-bonded sodalite, a ceramic nuclear waste form.  

National Technical Information Service (NTIS)

Glass-bonded sodalite is being developed as a ceramic waste form (CWF) to immobilize radioactive fission products, actinides, and salt residues from electrometallurgical treatment of spent nuclear reactor fuel. The CWF consists of about 75 mass % sodalite...

M. A. Lewis D. Lexa L. R. Morss M. K. Richmann

1999-01-01

48

Leaching behavior of glass ceramic nuclear waste forms  

SciTech Connect

Glass ceramic waste forms have been investigated as alternatives to borosilicate glasses for the immobilization of high-level radioactive waste at Pacific Northwest Laboratory (PNL). Three glass ceramic systems were investigated, including basalt, celsian, and fresnoite, each containing 20 wt % simulated high-level waste calcine. Static leach tests were performed on seven glass ceramic materials and one parent glass (before recrystallization). Samples were leached at 90/sup 0/C for 3 to 28 days in deionized water and silicate water. The results, expressed in normalized elemental mass loss, (g/m/sup 2/), show comparable releases from celsian and fresnoite glass ceramics. Basalt glass ceramics demonstrated the lowest normalized elemental losses with a nominal release less than 2 g/m/sup 2/ when leached in polypropylene containers. The releases from basalt glass ceramics when leached in silicate water were nearly identical with those in deionized water. The overall leachability of celsian and fresnoite glass ceramics was improved when silicate water was used as the leachant.

Lokken, R.O.

1981-11-01

49

The effect of chromium oxide on the properties of simulated nuclear waste glasses  

SciTech Connect

A study of the effect of chromium on the properties of selected glasses was performed in the frame of a Contract between Battelle, Pacific Northwest Laboratories and Nuclear Research Institute, ReZ. In the period from July 1994 to June 1995 two borosilicate glasses of special composition were prepared according to the PNL procedure and their physical and structural characteristics of glasses were studied. This Final Report contains a vast documentation on the properties of all glasses studied. For the preparation of the respective technology more detailed study of physico-chemical properties and crystallinity of investigated systems would be desirable.

Vojtech, O.; Sussmilch, J.; Urbanec, Z. [and others] [and others

1996-02-01

50

Simulation of Self-Irradiation of High-Sodium Content Nuclear Waste Glasses  

SciTech Connect

Alkali-borosilicate glasses are widely used in nuclear industry as a matrix for immobilisation of hazardous radioactive wastes. Durability or corrosion resistance of these glasses is one of key parameters in waste storage and disposal safety. It is influenced by many factors such as composition of glass and surrounding media, temperature, time and so on. As these glasses contain radioactive elements most of their properties including corrosion resistance are also impacted by self-irradiation. The effect of external gamma-irradiation on the short-term (up to 27 days) dissolution of waste borosilicate glasses at moderate temperatures (30 deg. to 60 deg. C) was studied. The glasses studied were Magnox Waste glass used for immobilisation of HLW in UK, and K-26 glass used in Russia for ILW immobilisation. Glass samples were irradiated under {gamma}-source (Co-60) up to doses 1 and 11 MGy. Normalised rates of elemental release and activation energy of release were measured for Na, Li, Ca, Mg, B, Si and Mo before and after irradiation. Irradiation up to 1 MGy results in increase of leaching rate of almost all elements from both MW and K-26 with the exception of Na release from MW glass. Further irradiation up to a dose of 11 MGy leads to the decrease of elemental release rates to nearly initial value. Another effect of irradiation is increase of activation energies of elemental release. (authors)

Pankov, Alexey S.; Ojovan, Michael I. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom); Batyukhnova, Olga G. [International Education Training Centre, SUE SIA 'Radon', The 7-th Rostovsky Lane 2/14, Moscow, 119121 (Russian Federation); Lee, William E. [Department of Materials, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ (United Kingdom)

2007-07-01

51

A comparison of the performance of nuclear waste glasses by modeling  

SciTech Connect

Through a combination of data collection and computer modeling, the dissolution mechanism of nuclear waste glasses has been investigated and more clearly defined. Glass dissolution can be described as a dissolution/precipitation process in which glass dissolves in aqueous solution and solids precipitate as the solubility products are exceeded. The dissolution process is controlled by activity of the rate-limiting specie H/sub 4/SiO/sub 4/. As a concentration of H/sub 4/SiO/sub 4/ increases, the rate of dissolution decreases until a final reaction rate is reached. Between the forward reaction rate (early time) and final reaction rate (very long time), glasses may exhibit an intermediate root time dependence caused by a transport resistance for the diffusion of H/sub 4/SiO/sub 4/ within the gel layer on the glass surface. In this report, three glasses are studied: JSS-A, PNL 76-68, and SRL-131. Data from static and dynamic leach tests are assembled, plotted, and successfully modeled. The kinetic parameters for these glasses are reported. With four parameters derived from experiments for each glass, the model can be used to calculate the effects of changes in the initial composition of the water contacting the glass. The effects of convective flow can also be modeled. Furthermore, glasses of different compositions can be readily compared. 49 refs., 27 figs., 5 tabs.

Grambow, B.; Strachan, D.M.

1988-12-01

52

Production and dissolution of nuclear explosive melt glasses at underground test sites in the Pacific Region  

SciTech Connect

From 1975 to 1996 the French detonated 140 underground nuclear explosions beneath the atolls of Mururoa and Fangataufa in the South Pacific; from 1965 to 1971 the United States detonated three high yield nuclear tests beneath Amchitka Island in the Aleutian chain. Approximately 800 metric tons of basalt is melted per kiloton of nuclear yield; almost lo7 metric tons of basalt were melted in these tests. Long-lived and toxic radionuclides are partitioned into the melt glass at the time of explosion and are released by dissolution with seawater under saturated conditions. A glass dissolution model predicts that nuclear melt glasses at these sites will dissolve in lo6 to lo7 yea

Bourcier, W.L.; Smith, D.K.

1998-11-06

53

EELS Spectrum Imaging and Tomography Studies of Simulated Nuclear Waste Glasses  

SciTech Connect

Electron energy loss spectroscopy (EELS) fine structure is a powerful technique for analyzing oxidation levels of rare-earth oxides and coordination numbers in glasses and ceramics, especially for boron. To exploit the unique advantage of EELS over x-ray absorption spectroscopy (XAS)/x-ray absorption near edge structure (XANES), namely nm-scale spatial resolution, EELS spectrum imaging across precipitates in glasses has been employed to detect lateral changes of EELS fine structure. Alkali borosilicate (ABS) glasses doped with Cr{sub 2}O{sub 3}, CeO{sub 2} and ZrO{sub 2} or Fe{sub 2}O{sub 3} were melted to simulate high level radionuclide immobilization glasses. Precipitates with diameter in the range of {approx}20 nm to {approx}500 nm were found homogeneously distributed in the glasses. Ce valence was found to be mainly +3 in the glass matrix, and +4 in crystalline precipitates, while some amorphous particles show +3 as well. Another powerful TEM technique for the analysis of glass-nano-composites is electron tomography, as it is up to now the only technique for the three-dimensional reconstruction of nano-particles. A 3D reconstructed nuclear waste glass is presented in this paper by using a tilt series of ADF STEM images covering a glass fragment of {approx}3{mu}m field of view containing several tens of nano-particles distributed throughout its volume. (authors)

Yang, Guang; Saghi, Zineb; Xu, Xiaojing; Hand, Russell; Moebus, Guenter [Engineering Materials, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2007-07-01

54

Progress toward bridging from atomistic to continuum modeling to predict nuclear waste glass dissolution.  

SciTech Connect

This report summarizes research performed for the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Subcontinuum and Upscaling Task. The work conducted focused on developing a roadmap to include molecular scale, mechanistic information in continuum-scale models of nuclear waste glass dissolution. This information is derived from molecular-scale modeling efforts that are validated through comparison with experimental data. In addition to developing a master plan to incorporate a subcontinuum mechanistic understanding of glass dissolution into continuum models, methods were developed to generate constitutive dissolution rate expressions from quantum calculations, force field models were selected to generate multicomponent glass structures and gel layers, classical molecular modeling was used to study diffusion through nanopores analogous to those in the interfacial gel layer, and a micro-continuum model (K{mu}C) was developed to study coupled diffusion and reaction at the glass-gel-solution interface.

Zapol, Peter (Argonne National Laboratory, Argonne, IL); Bourg, Ian (Lawrence Berkeley National Laboratories, Berkeley, CA); Criscenti, Louise Jacqueline; Steefel, Carl I. (Lawrence Berkeley National Laboratories, Berkeley, CA); Schultz, Peter Andrew

2011-10-01

55

Nuclear waste glass product consistency test (PCT), Version 5.0. Revision 2  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

1992-06-01

56

Effects of composition on properties in an 11-component nuclear waste glass system  

SciTech Connect

Ninety simplified nuclear waste glass compositions within an 11-component oxide composition matrix were tested for crystallinity, viscosity, volatility, and chemical durability. Empirical models of property response as a function of glass composition were developed using statistical experimental design and modeling techniques. A new statistical technique was developed to calculate the effects of oxide components on each property. Independent melts were used to check the prediction accuracy of the models.

Chick, L.A.; Piepel, G.F.; Mellinger, G.B.; May, R.P.; Gray, W.J.; Buckwalter, C.Q.

1981-09-01

57

Molecular diffusion and nuclear-magnetic-resonance relaxation of water in unsaturated porous silica glass  

Microsoft Academic Search

Measurements have been performed of the nuclear-magnetic-resonance longitudinal and transverse relaxation and the self-diffusion coefficient of deionized water confined in the porous space of a silica glass. The average pore diameter of the glass is 3.5 nm, and the experiments were conducted with different degrees of fluid filling. All three physical quantities were found to be linearly dependent on filling

Franco D'orazio; Sankar Bhattacharja; William P. Halperin; Kiyohisa Eguchi; Takao Mizusaki

1990-01-01

58

Measurement of leaching from simulated nuclear-waste glass using radiotracers  

SciTech Connect

The use of radiotracer spiking as a method of measuring the leaching from simulated nuclear-waste glass is shown to give results comparable with other analytical detection methods. The leaching behavior of /sup 85/Sr, /sup 106/Ru, /sup 133/Ba, /sup 137/Cs, /sup 141/Ce, /sup 152/Eu, and other isotopes is measured for several defense waste glasses. These tests show that radiotracer spiking is a sensitive, multielement technique that can provide leaching data, for actual waste elements, that are difficult to obtain by other methods. Additionally, a detailed procedure is described that allows spiked glass to be prepared with a suitable distribution of radionuclides.

Bates, J.K.; Jardine, L.J.; Steindler, M.J.

1982-09-01

59

Leaching of Natural and Nuclear Waste Glasses in Sea Water: Progress Report, CY 85, 86 and 87.  

National Technical Information Service (NTIS)

Microtektites found in sea-bed sediments provide a valuable natural analog in studies of long-term glass durability relevant to evaluation of nuclear waste glass performance. Measurements carried out on a bottle-green microtektite glass composition in de-...

S. Alterescu

1987-01-01

60

Radiation damage of alkali borate glasses for application in safe nuclear waste disposal  

NASA Astrophysics Data System (ADS)

The Electron Paramagnetic Resonance technique has been used to study the time decay of paramagnetic species induced by gamma irradiation and the radiation hardness of different alkali borate glasses for their application in safe nuclear waste disposal. Glasses with different composition have been prepared by conventional melt-quenching. Glass compositions have been chosen to elucidate the role of different alkali cations and of aluminium oxide on the borate glass network. The paramagnetic states detected in these glasses have been attributed, according to the literature, to the formation of hole centers associated with threefold coordinated boron. The results indicate that the time decay trend of the different glasses is slow and that the constant decay does not appear related to the chemical composition. Moreover, the undesired strong fading of the radiation-induced signal during the first 24 h after irradiation, observable in silicate glasses has not been detected. Although no species detectable by a X band spectrometer have been generated, the interaction of lithium borate glasses with air seem to accelerate the system decay rate. Annealing was finally performed and optimized, investigating the correlation between the chemical composition and the radiation damage recovery.

Baccaro, S.; Catallo, N.; Cemmi, A.; Sharma, G.

2011-01-01

61

Predicting liquid immiscibility in multicomponent nuclear waste glasses  

SciTech Connect

Taylor`s model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the US Department of Energy`s Hanford site. Taylor`s model is primarily based on additions of modifying cations to a Na{sub 2}O-B{sub 2}O{sub 3}-SiO{sub 2} (NBS) submixture of the multicomponent glass. The position of the submixture relative to the miscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor`s, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li{sub 2}O to the ``alkali`` corner of the NBS submixture.

Peeler, D.K.; Hrma, P.R.

1994-04-01

62

AN APPROACH TO THERMOCHEMICAL MODELING OF NUCLEAR WASTE GLASS  

EPA Science Inventory

This initial work is aimed at developing a basic understanding of the phase equilibria and solid solution behavior of the constituents of waste glass. Current, experimentally determined values are less than desirable since they depend on measurement of the leach rate under non-r...

63

Solid-State NMR Examination of Alteration Layers on a Nuclear Waste Glasses  

SciTech Connect

Solid-state NMR is a powerful tool for probing the role and significance of alteration layers in determining the kinetics for the corrosion of nuclear waste glass. NMR methods are used to probe the chemical structure of the alteration layers to elucidate information about their chemical complexity, leading to increased insight into the mechanism of altered layer formation. Two glass compositions were examined in this study: a glass preliminarily designed for nuclear waste immobilization (called AFCI) and a simplified version of this AFCI glass (which we call SA1R). Powdered glasses with controlled and known particles sizes were corroded at 90 °C for periods of one and five months with a surface-area to solution-volume ratio of 100,000 m-1. 1H-29Si CP-CPMG MAS NMR, 1H-27Al CP-MAS NMR, 1H-11B CP-MAS NMR, and 1H-23Na CP-MAS NMR experiments provide isolated structural information about the alteration layers, which differ in structure from that of the pristine glass. Both glasses studied here develop alteration layers composed primarily of [IV]Si species. Aluminum is also retained in the alteration layers, perhaps facilitated by the observed increase in coordination from [IV]Al to [VI]Al, which correlates with a loss of charge balancing cations. 1H-11B CP-MAS NMR observations indicated a retention of boron in hydrated glass layers, which has not been characterized by previous work. For the AFCI glass, secondary phase formation begins during the corrosion times considered here, and these neophases are detected within the alteration layers. We identify precursor phases as crystalline sodium metasilicates. An important finding is that layer thickness depends on the length of the initial alteration stages and varies only with respect to silicon species during the residual rate regime.

Murphy, Kelly A.; Washton, Nancy M.; Ryan, Joseph V.; Pantano, Carlo G.; Mueller, Karl T.

2013-06-01

64

An approach to thermochemical modeling of nuclear waste glass  

SciTech Connect

This initial work is aimed at developing a basic understanding of the phase equilibria and solid solution behavior of the constituents of waste glass. Current, experimentally determined values are less than desirable since they depend on measurement of the leach rate under non-realistic conditions designed to accelerate processes that occur on a geologic time scale. The often-used assumption that the activity of a species is either unity or equal to the overall concentration of the metal can also yield misleading results. The associate species model, a recent development in thermochemical modeling, will be applied to these systems to more accurately predict chemical activities in such complex systems as waste glasses.

Besmann, T.M.; Beahm, E.C. [Oak Ridge National Lab., TN (United States); Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States)

1998-11-01

65

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

EPA Science Inventory

Borosilicate glass is the only material currently approved and being used to vitrify high level nuclear waste. Unfortunately, many high level nuclear waste feeds in the U.S. contain components which are chemically incompatible with borosilicate glasses. Current plans call for vit...

66

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

DOEpatents

Disclosed are lead-iron phosphate glasses containing a high level of Fe/sub 2/O/sub 3/ for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste

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

1984-04-11

67

Glass Making Technology for High-Level Nuclear Waste  

SciTech Connect

This paper addresses specific and unique chemical engineering aspects of the Defense Waste Processing Facility (DWPF) at the Savannah River Plant. This paper also addresses the glass melter and those processes that are directly coupled to it. A somewhat disproportionate emphasis is given to sludge pretreatment, for the sake of completeness in this session. We have attempted to focus on those features of the DWPF that may be of general interest or even useful to the practicing chemical engineer.

Boersma, M.D.

1986-07-10

68

Borosilicate and lead silicate glass matrix composites containing pyrochlore phases for nuclear waste encapsulation  

NASA Astrophysics Data System (ADS)

Glass matrix composites intended for the immobilisation of plutonium bearing nuclear legacy waste have been manufactured. Two different matrices, a soda borosilicate glass and a lead silicate glass, are proposed for encapsulating lanthanum and gadolinium zirconates having pyrochlore crystalline structure. The fabrication of the composites involves powder mixing followed by cold pressing and pressureless sintering or hot-pressing at relatively low temperatures (<620 °C). The hot-pressing route is found to be the most convenient, since it leads to relatively high densification even with substantial loading of pyrochlore phase (40 vol.%). The absence of microcracks, due to the close matching of thermal expansion coefficients of the composite constituents, together with the strong pyrochlore particle/glass matrix interfacial bonding, suggests that the composites have good mechanical properties. The innovative introduction of gadolinium zirconate in a lead silicate matrix represents an attractive approach, since the composites reach reasonably high densities both by pressureless sintering and hot-pressing.

Boccaccini, A. R.; Bernardo, E.; Blain, L.; Boccaccini, D. N.

2004-05-01

69

Multicomponent leach tests in Standard Canadian Shield Saline Solution on glasses containing simulated nuclear waste  

SciTech Connect

Leaching experiments on borosilicate glass frit and simulated nuclear waste glasses were performed as a preliminary to leaching experiments on glasses incorporating radioactive waste. The experimental design included (1) simulated waste glass, (2) ASTM Grade-2 titanium container material, (3) clay buffer material, (4) Standard Canadian Shield Saline Solution, and (5) granitic rock. Cumulative fractions of release for boron were determined, as well as the solution concentrations of silicon, iron, strontium and cesium. The leach rates for boron after 28 d were approximately 5 x 10/sup -6/ kg x m/sup -2/ x s/sup -1/ in Hastelloy vessels. There is an apparently strong relationship between the clay/groundwater ratio, the concentration of iron in the solution, and the concentrations of silicon, strontium, and cesium.

Heimann, R.B.; Wood, D.D.; Hamon, R.F.

1984-01-01

70

Current Understanding and Remaining Challenges in Modeling Long-Term Degradation of Borosilicate Nuclear Waste Glasses  

SciTech Connect

Chemical durability is not a single material property that can be uniquely measured. Instead it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment, and modeling. High-level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long-term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near-field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time-scales. This article summarizes the current state of understanding of surface reactions, transport properties, and ion exchange along with the near-field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps.

Vienna, John D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Ryan, Joseph V. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Gin, Stephane [CEA Marcoule, DTCD SECM, Bagnols-sur-Ceze (France); Inagaki, Yaohiro [Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoda (Japan)

2013-12-05

71

Leaching of Actinide-Doped Nuclear Waste Glass in a Tuff-Dominated System.  

National Technical Information Service (NTIS)

A laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples were placed in water inside tuff vessels, and then t...

F. Bazan J. Rego R. D. Aines

1987-01-01

72

ANNUAL PROGRESS REPORT. IRON PHOSPHATE GLASSES: AN ALTERNATIVE FOR VITRIFYING CERTAIN NUCLEAR WASTES  

EPA Science Inventory

A high priority has been given to investigating the vitrification of three specific nuclear wastes in iron phosphate glasses (IPG). These wastes, which were recommended by the Tank Focus Area (TFA) group of Hanford, are poorly suited for vitrification in the currently DOE-approve...

73

Inmovilizacion de residuos nucleares de alta actividad en vidrios sinterizados. Evaluacion del grado de desvitrificacion producido con diferentes tratamientos termicos. (Immobilization of high level nuclear wastes in sintered glasses. Devitrification evaluation produced with different thermal treatments).  

National Technical Information Service (NTIS)

This work describes immobilization of high level nuclear wastes in sintered glass, as alternative way to melting glass. Different chemical compositions of borosilicate glass with simulated waste were utilized and satisfactory results were obtained at labo...

N. B. Messi de Bernasconi D. O. Russo M. E. Bevilacqua M. E. Sterba A. D. Heredia

1990-01-01

74

Nuclear waste glass product consistency test (PCT): Version 7.0. Revision 3  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Product Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Product Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 7.0 of the PCT procedure is attached. This draft version has been submitted to ASTM for full committee (C26, Nuclear Fuel Cycle) ballot after being balloted successfully through subcommittee C26.13 on Repository Waste Package Materials Testing.

Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.

1994-06-01

75

Characteristics of colloids generated during the corrosion of nuclear waste glasses in groundwater  

SciTech Connect

Aqueous colloidal suspensions were generated by reacting nuclear waste glasses with groundwater at 90{degrees}C at different ratios of the glass surface area to solution volume (S/V). The colloids have been characterized in terms of size, charge, identity, and stability with respect to salt concentration, pH, and time, by examination using dynamic light scattering, electrophoretic mobility, and transmission electron microscopy. The colloids are predominately produced by precipitation from solution, possibly with contribution from reacted layers that have spallated from the glass. These colloids are silicon-rich minerals. The colloidal suspensions agglomerate when the salinity of the solutions increase. The following implications for modeling the colloidal transport of contaminants have been derived from this study: (1) The sources of the colloids are not only solubility-limited real colloids and the pseudo colloids formed by adsorption of radionuclides onto a groundwater colloid, but also from the spalled surface layers of reacted waste glasses. (2) In a repository, the local environment is likely to be glass-reaction dominated and the salt concentration is likely to be high, leading to rapid colloid agglomeration and settling; thus, colloid transport may be insignificant. (3) If large volumes of groundwater contact the glass reaction site, the precipitated colloids may become resuspended, and colloid transport may become important. (4) Under most conditions, the colloids are negatively charged and will deposit readily on positively charged surfaces. Negatively charged surfaces will, in general, facilitate colloid stability and transport.

Feng, X.; Buck, E.C.; Mertz, C.; Bates, J.K.; Cunnane, J.C.; Chaiko, D.

1993-10-01

76

Interaction study between nuclear waste-glass melt and ceramic melter bellow liner materials  

NASA Astrophysics Data System (ADS)

Identification of proper materials for plant scale vitrification furnaces, engaged in immobilization of high level nuclear waste has always been a great challenge. Fast degradation of pour spout materials very often cause problem towards smooth pouring of waste-glass melt in canister and damages bellow kept in between. The present experimental study describes the various reaction products that form due to interaction between waste-glass melt and potential bellow liner materials such as copper, stainless steel and nickel based Superalloys (Alloy 690, 625). The results indicate that copper based material has lesser tendency to form adherent glassy layer.

Sengupta, Pranesh

2011-04-01

77

Water diffusion in the simulated French nuclear waste glass SON 68 contacting silica rich solutions: Experimental and modeling  

Microsoft Academic Search

To understand the role of water diffusion on the long-term nuclear waste glass alteration, dynamic experiments were conducted with the borosilicate SON 68 glass in synthetic solutions enriched in Si, Na and B at 50 and 90°C. The water entering the glass exists to 80% in the form of molecular H2O and to 20% in the form of SiOH. The

K. Ferrand; A. Abdelouas; B. Grambow

2006-01-01

78

Properties of nuclear waste melts and glasses: Contact-refractory corrosion and vapor phase hydration  

NASA Astrophysics Data System (ADS)

Control of refractory corrosion in waste glass melts and meeting vapor phase hydration test (VHT) requirement for Hanford low-activity waste (LAW) glass product are two critical issues among many technical challenges of nuclear waste vitrification. In this study, refractory corrosion was treated as a complex non-equilibrium, multi-component and multi-phase reactive transport process and studied both thermodynamically and kinetically. Dissolution tests of granular refractory materials into under-saturated melts coupled with crystallization tests from supersaturated melts were used to determine the possible equilibrium points. The test results show that spinet phase is the most stable phase of K-3 refractory. Solubility of glass-refractory interface material controls the long term refractory corrosion rate and protects refractory from further corrosion. Therefore, refractory corrosion rate can be possibly adjusted by controlling the underlying solubility of the interface material. A set of monolithic refractory corrosion and dissolution tests was carried out to study the kinetic effects of refractory porosity and glass melt viscosity, the two major kinetic factors associated with reactive transport process. The test results show that temperature and glass melt viscosity have intensive effects on refractory material dissolution rate. Fast closure of channels near the glass-refractory interface during corrosion reaction by fast transformation of solid solution to spinel and spinel re-crystallization helps stop further corrosion reaction. Glass composition can be "passivated" by engineering the formulation to maximizing the beneficial alteration process. For the study of VHT kinetics, data from simulated LAW glasses studied previously at Pacific Northwest National Laboratory and Vitreous State Laboratory was modeled based on Avrami equation and its variant, the so-called generalized Avrami equation for better modeling of the VHT data. The results show that the kinetics of the complex vapor hydration process is described satisfactorily by the generalized Avrami equation. The generalized Avrami equation allows the characterization of vapor phase hydration data obtained at different times and temperatures quantitatively on a common basis. The three parameters associated with the generalized Avrami equation depend strongly on glass composition. It seems that both compositional mismatch and incompatibility of a host glass to the transformed hydrous crystalline phases slow down the vapor hydration rate.

Lu, Xiaodong

79

Nuclear Magnetic Resonance Study of Hydrogen Deuteride in Rare Gas Solids, Zeolite, and Porous Vycor Glass  

Microsoft Academic Search

Pulsed nuclear magnetic resonance has been used to measure the spin-lattice(T_1) and transverse(T_2) relaxation times of HD in rare gas solids(argon and krypton) and adsorbed on zeolites(3A and 4A) and Vycor glass. T_1 decreases with increasing T as the molecular DeltaJ rate for thermally excited HD(J > 0) increases. The DeltaJ rate contributes significantly more than Delta m_{rm J} rate.

Jonghun Lyou

1991-01-01

80

High-Resolution Nuclear Magnetic Resonance Studies of Alkali Silicate and Mixed-Alkali Silicate Glasses  

Microsoft Academic Search

High-field (7.1 T) ^{29} Si nuclear magnetic resonance studies with and without magic-angle sample spinning (MASS) are used to determine the structural units present in alkali silicate glasses: R_2OcdotNSiO _2, where R = Li, Na, K, Rb, Cs and N = 1, 2, 4. Previously unreported sites are resolved in the static spectra, contrary to predictions of the binary model

Jane Fulton Emerson

1991-01-01

81

Obsidians and tektites: Natural analogues for water diffusion in nuclear waste glasses  

SciTech Connect

Projected scenarios for the proposed Yucca Mountain repository include significant periods of time when high relative humidity atmospheres will be present, thus the reaction processes of interest will include those known to occur under these conditions. The ideal natural analog for the proposed Yucca Mountain repository would consist of natural borosilicate glasses exposed to expected repository conditions for thousands of years; however, the prospects for identifying such an analog are remote, but an important caveat for using natural analog studies is to relate the reaction processes in the analog to those in the system of interest, rather than a strict comparison of the glass compositions. In lieu of this, identifying natural glasses that have reacted via reaction processes expected in the repository is the most attractive option. The goal of this study is to quantify molecular water diffusion in the natural analogs obsidian and tektites. Results from this study can be used in assessing the importance of factors affecting molecular water diffusion in nuclear waste glasses, relative to other identified reaction processes. In this way, a better understanding of the long-term reaction mechanism can be developed and incorporated into performance assessment models. 17 refs., 4 figs.

Mazer, J.J.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States); Stevenson, C.M. [Archaeological Services Consultants, Inc., Columbus, OH (United States)

1991-11-01

82

Fibrous-glass aerosols: a literature review. Special report. [On nuclear submarines  

SciTech Connect

The submarine atmospheric is a topic of interest, considering that once submerged, the craft relies on its own electrostatic precipitators (ESP's), scrubbers, and filters to create, ideally, an environment with minimal aerosolized toxic materials and other by-products. Historically, atmosphere sampling aboard nuclear submarines has shown contaminants. Other contaminants include: ozone, (major source: by-product of the ESP's); freon, (major source: ship's refrigeration system and air-conditioning plants); hydrogen, (major source: ship's batteries); carbon dioxide, (major source: human respiration); and carbon monoxide, (major source: cigarette smoking). Contaminants tested for but not found were elemental mercury and asbestos. Considering that asbestos is no longer recommended for use, secondary to its carcinogenic and co-carcinogenic qualities, fibrous glass has become a common substitute. One use of fibrous glass aboard the Ohio class submarine is acoustic and thermal insulation around perforated ducting, which runs through many exposed, high traffic spaces, i.e. crew's berthing spaces. Although the raw fibrous glass is protected from the environment it is possible, through natural wear and tear of the housing material, that at some time the insulating material may become exposed and mechanically aerosolized. Obvious questions then are: a) do submarine aerosols contain fiber glass, and b) are there health hazards related to the inhalation of these fibers. This paper reviews the current knowledge as to the health hazard of exposure.

Laverty, B.R.

1987-10-02

83

Molecular diffusion and nuclear-magnetic-resonance relaxation of water in unsaturated porous silica glass  

SciTech Connect

Measurements have been performed of the nuclear-magnetic-resonance longitudinal and transverse relaxation and the self-diffusion coefficient of deionized water confined in the porous space of a silica glass. The average pore diameter of the glass is 3.5 nm, and the experiments were conducted with different degrees of fluid filling. All three physical quantities were found to be linearly dependent on filling provided this was in excess of the amount of water corresponding to one monolayer, in agreement with theoretical predictions based on geometrical considerations. However, a deviation is observed below one monolayer, which is interpreted as a modification of the liquid-solid interface interaction, which causes the water molecules to become less mobile.

D'Orazio, F.; Bhattacharja, S.; Halperin, W.P. (Department of Physics and Astronomy, Northwestern University, Evanston, IL (USA)); Eguchi, K. (Government Industrial Research Institute, Osaka, Ikeda (Japan)); Mizusaki, T. (Department of Physics, Kyoto University, Kyoto (Japan))

1990-12-01

84

Nuclear Magnetic Resonance Study of Hydrogen Deuteride in Rare Gas Solids, Zeolite, and Porous Vycor Glass  

NASA Astrophysics Data System (ADS)

Pulsed nuclear magnetic resonance has been used to measure the spin-lattice(T_1) and transverse(T_2) relaxation times of HD in rare gas solids(argon and krypton) and adsorbed on zeolites(3A and 4A) and Vycor glass. T_1 decreases with increasing T as the molecular DeltaJ rate for thermally excited HD(J > 0) increases. The DeltaJ rate contributes significantly more than Delta m_{rm J} rate. In the first experiment on HD in rare gas solids there occur decreases in both T_1(H) and T_1(D) by factors near 3 and 30, which are predicted for self diffusion modulated by intermolecular nuclear dipolar interaction, above a concentration -dependent temperature (between 40 and 65 K). From comparison of T_1(D) with T_1 (H), the crystal field symmetry appears to be cubic for HD molecular relaxation although it is known to be non-symmetric from other measurements because Omega_{rm Q} << Gamma(DeltaJ), and thus we conclude that 1 times 10 ^{10} sec^ {-1} < Omega _{rm Q} < 7 times 10^{10 } sec^{-1}. In the second experiment on HD adsorbed on porous materials, a distinct-configurational model is favored over a bulk -surface model because of observed similar relaxation of fast and slow T_1 components. Deuteron HD multiple echoes have not been observed from any zeolite sample or Vycor glass, perhaps because of paramagnetic impurities on the surface of these materials. The temperature dependence of T_1 reflects relaxation via both EQQ and phonon interaction. A higher melting temperature of HD in zeolites compared to Vycor glass suggests that zeolites have larger surface fields than does Vycor glass.

Lyou, Jonghun

85

Interstitial sites for He incorporation in nuclear glasses and links to the structure: Results from numerical investigation  

NASA Astrophysics Data System (ADS)

To investigate rare gases incorporation in glasses in relation with nuclear waste confinement, a wide range of borosilicate glasses have been studied by means of molecular dynamics simulations. The rare gases solubility is related to the number of interstitial sites accessible for these gases. To elucidate any relation between the number of interstitial sites and the glass composition, a large set of glass compositions that contain the most representative components in nuclear glasses is considered. We are mainly interested in SBN glasses (SiO2–B2O3–Na2O). A composition dependent force field was used to model the interactions between the atoms. Delaunay tessellation method was used to characterize the different topologies accessible for rare gases and analyze the interstitial sites distribution. In order to investigate irradiation effects by nuclear energy deposition on the number of interstitial sites accessible for He, disordered glasses representative of structures submitted to series of displacement cascades, were prepared by modifying the preparation procedure and the number of interstitial site changes were analyzed.

Kerrache, Ali; Delaye, Jean-Marc

2014-05-01

86

Raman Spectra, Structural Units and Durability of Nuclear Waste Glasses With Variations in Composition and Crystallization: Implications for Intermediate Order in the Glass Network  

SciTech Connect

The Raman spectra of nuclear waste glasses are composed of large variations in half-width and intensity for the commonly observed bridging (Q0) and nonbridging (Q1 to Q4) bands in silicate structures. With increase in waste concentration in a boroaluminosilicate melt, the bands of quenched glasses are distinctly localized with half-width and intensity indicative of increase in atomic order. Since the nuclear waste glasses contain disparate components, and since the bands depart from the typical random network, a systematic study for the origin of these bands as a function of composition and crystallization was undertaken. From a comparative study of Raman spectra of boroaluminosilicate glasses containing Na2O-ZrO2, Na2O-MgO, MgO-Na2O-ZrO2, Na2O-CaO-ZrO2, Na2O-CaO, and Na2O-MgO-CaF2 component sets and orthosilicate crystals of zircon and forsterite, intermediate order is inferred. An edge-sharing polyhedral structural unit is proposed to account for narrow bandwidth and high intensity for Q2 antisymmetric modes, and decreased leaching of sodium with ZrO2 concentration in glass. The intense Q4 band in nuclear waste glass is similar to the intertetrahedral antisymmetric modes in forsterite. The Raman spectra of zircon contains intratetrahedral quartz-like peaks and intertetrahedral non-bridging silicate peaks. The quartz-like peaks nearly vanish in the background of forsterite spectrum. This difference between the Raman spectra of the two orthosilicate crystals presumably results from their biaxial and uniaxial effects on polarizability ellipsoids. The results also reveal formation of 604, 956 and 961 cm-1 defect bands with composition and crystallization.

Raman, Swaminathan Venkat

2002-11-01

87

Assay of nuclear estradiol receptor by exchange on glass fiber filters.  

PubMed

A glass fiber filter exchange assay for nuclear estradiol receptor in human endometrium has been developed. It permits both exchange and measurement of bound radioactivity to be performed without any transfer of the nuclear preparations. Suspensions of nuclei containing estradiol-receptor complexes are adsorbed onto glass fiber filters. Receptor sites, both empty and occupied by endogenous hormone, are labelled by incubation with 20 nM [3H]estradiol without (total binding) or with 2 microM radioinert estradiol (nonspecific binding). Buffer containing unbound radioactive estradiol is then drained, the filters washed, transferred into vials and counted in toluene-based scintillator. Following removal from the scintillator, DNA content of the filters can be measured by the Burton procedure. This exchange technique is easy and specific, with accuracy and precision similar to those of the technique of Bayard et al. (Bayard, F., Damilano, S., Robel, P. and Baulieu, E.E. (1978) J.Clin. Endocrinol. Metab. 46, 635-648). It offers the advantage of increased sensitivity, allowing receptor determinations on nuclear samples containing more than 10 microgram DNA. Approximately 20 measurements can be made from 50 mg tissue (wet weight). PMID:6248131

Levy, C; Eychenne, B; Robel, P

1980-06-19

88

Nuclear Magnetic Resonance Studies of Binary and Ternary Oxide Glass Systems Using BORON-11 and Silicon -29  

NASA Astrophysics Data System (ADS)

The Si('29) nuclear magnetic resonance spectra for glasses and polycrystalline materials in the potassium silicate system have been observed. An anisotropic chemical shift is present in these materials and the first ever detections of these shifts are presented. Resultant NMR lineshapes for materials at selected compositions are correlated with the structural groupings proposed as present in both glasses and crystalline materials. The B('11) NMR spectra in several zinc borate crystalline compounds and glasses have been used to study the structures present in these materials. The NMR spectra in conjunction with computer-generated spectra were used to make structural inferences for these materials. Correlations are made between the structures found using NMR and the crystalline structures proposed in the literature for these materials. Zinc borate glasses spanning the reported glass formation range were studied and values for N(,4) in the glasses are given. The NMR spectra for B('11) in glasses of the Li(,2)O -TeO(,2)-B(,2)O(,3) and TeO(,2)-B(,2)O(,3)-Al(,2)O(,3) systems were secured and used to study the behavior of N(,4), the fraction of boron atoms in four-coordination, as a function of glass composition. The appearance of non-zero values for N(,4) in the TeO(,2)-B(,2)O(,3)-Al(,2)O(,3) glasses and the enhancement of N(,4) in the Li(,2)O-TeO(,2)-B(,2)O(,3) glasses above that obtained for the binary Li(,2)O-B(,2)O(,3) glass system indicates that the TeO(,2) in the glasses contributes to the formation of four-coordinated boron atoms. A mechanism which accounts for the N(,4) behavior is presented. Relations describing the behavior of N(,4) for the binary TeO(,2)-B(,2)O(,3) system are inferred from the results secured.

Harris, Isaac Anthony, Jr.

89

GdBr3: CE in a glass wafer as a nuclear radiation monitor.  

PubMed

A glass wafer that contains cerium-activated gadolinium-based scintillator has been tested as a nuclear radiation monitor. The detector is prepared by mixing powdered gadolinium and cerium (3+) bromides with alumina, silica, and lithium fluoride, melting the mixture at 1,400°C, and then quenching and annealing the glass. The resulting clear glass matrix emits stimulated blue light that can be collected by a conventional photomultiplier tube. Spectral analysis of radionuclides with this detector shows the energy peaks for alpha particles, the energy continuum for beta particles, the Compton continuum and full-energy peaks for gamma rays, and an energy continuum with specific reaction-product peaks for neutrons. Energy resolution for the 5.5-MeV alpha particle and 0.662-MeV gamma-ray peaks is about 20%. This resolution, although threefold poorer than for single-crystal NaI(Tl) scintillators, contributes to radionuclide identification and quantification. Application of this detector to radiation monitoring is proposed, as well as approaches for improving light collection and energy resolution that will facilitate radionuclide identification and monitoring, especially for alpha particles, beta particles, and low-energy gamma rays. PMID:23532079

Kang, Zhitao; Rosson, Robert; Barta, M Brooke; Nadler, Jason; Wagner, Brent; Kahn, Bernd

2013-05-01

90

Investigation of alkali ion exchange processes in waste glasses using Rutherford backscattering spectrometry and nuclear reaction analysis  

Microsoft Academic Search

A series of dissolution experiments using isotopic labeled (D2 18O) aqueous solution were carried out to investigate the ion exchange mechanism in Na2O-Al2O3-SiO2 glasses with fixed Na2O and variable Al2O3 concentrations. The sodium removal and the deuterium and oxygen uptake in the glass coupons were measured using ion beam methods such as Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis

V. Shutthanandan; Suntharampillai Thevuthasan; Donald R. Baer; Evan M. Adams; Saravanamuthu Maheswaran; Mark H. Engelhard; Jonathan P. Icenhower; B. Peter McGrail

2001-01-01

91

Apatite- and monazite-bearing glass-crystal composites for the immobilization of low-level nuclear and hazardous wastes  

SciTech Connect

This study demonstrates that glass-crystal composite waste forms can be produced from waste streams containing high proportions of phosphorus, transition metals, and/or halides. The crystalline phases produced in crucible-scale melts include apatite, monazite, spinels, and a Zr-Si-Fe-Ti phase. These phases readily incorporated radionuclide and toxic metals into their crystal structures, while corrosion tests have demonstrated that glass-crystal composites can be up to 300-fold more durable than simulated high-level nuclear waste glasses, such as SRL 202U.

Wronkiewicz, D.J.; Wolf, S.F.; DiSanto, T.S.

1995-12-31

92

Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy  

SciTech Connect

(100-x) mol % B{sub 2}O{sub 3} x mol %Me{sub 2}O (Me=Li,Na,K) glasses, exposed to {gamma}-{sup 60}Co irradiation to produce paramagnetic states, were characterized by W-band (95 GHz) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x=16 and x=25 at which the 'boron oxide' anomaly occurs. The high resolution of nuclear frequencies allowed resolving the {sup 7}Li and {sup 11}B ENDOR lines. In the samples with x=16 and x=20 glasses, {sup 11}B hyperfine couplings of 16, 24, and 36 MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x=25 samples showed hyperfine couplings of 15 MHz for the tetraborate and 36 MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting.

Kordas, George [Sol Gel Laboratory for Glass and Ceramics, Institute of Materials Science, NCSR 'Demokritos', 15310 Aghia Paraskevi Attikis (Greece); Goldfarb, Daniella [Department of Chemical Engineering, Weizmann Institute of Science, 76100 Rehovot (Israel)

2008-10-21

93

Specific outcomes of the research on the radiation stability of the French nuclear glass towards alpha decay accumulation  

NASA Astrophysics Data System (ADS)

This paper presents an overview of the main results of the French research on the long-term behavior of SON68 nuclear glass towards alpha decay accumulation. The effect of the radiation damage induced by alpha decay and also helium build-up were investigated by examining glass specimens, doped with a short-lived actinide 244Cm, irradiated by light and heavy ions. Additionally, atomistic simulations by molecular dynamics have provided further information on the atomic-scale effects of the macroscopic phenomena observed. These studies have shown that some macroscopic properties vary with the accumulation of alpha decay, but then stabilize after integrated doses of the order of 4 × 1018 ? g-1. For example, the glass density diminishes by about 0.6%, its Young's modulus by about 15%, and its hardness by about 30%, while its fracture toughness increases by around 50%. The SEM and TEM characterization showed that the glass is still homogeneous. No phase separation, crystallization or bubbles formation was noticed up to an alpha decay dose corresponding to several thousand years of disposal of nuclear glass canister. Moreover the initial alteration rate of the glass is not significantly affected by the glass damage induced by alpha decays or heavy ions irradiations. The comparison of the macroscopic evolutions of the Cm doped glass with those obtained for glasses irradiated with light or heavy ions (from either experimental and molecular dynamic studies) suggests that the macroscopic evolutions are induced by the nuclear interactions induced by the recoil nuclei of alpha decay. The analysis of the behavior of the glass structure subjected to ballistic effects with various spectroscopic studies, together with the results of atomistic modeling by molecular dynamics, have identified some slight changes in the local order around some cations. Moreover a modification of the medium-range order has also been demonstrated through changes in the bond angles between network formers and broadening of the ring size distributions, indicating increasing disorder of the glass structure. This structural evolution induced by alpha decays would be driven by the reconstruction of the glass disorganized by displacement cascades of the recoil nuclei, freezing a glass structure with a higher fictive temperature. This "ballistic disordering (BD) fast quenching" event induces a new glassy state characterized by a higher enthalpy state. Accumulation of ? decays induce similar phenomena of "BD-fast quenching", increasing the fraction of the sample volume characterized by a "high enthalpy state". At dose around 4 × 1018 ? g-1 the entire sample volume has been affected by "BD-fast quenching" events at least once, which explain the stabilization of the evolutions of glass structure and properties. Helium behavior was also studied by measuring the helium solubility constants and diffusion coefficients. Helium atoms are incorporated into the glass free volume with a solubility constant that varies less than 10% around a value of about 1011 at cm-3 Pa-1 and a density of solubility sites accessible for helium around 2 × 1021 sites cm-3 which is larger than helium production in a glass package. Helium diffusion experiments performed on infused and Cm doped SON68 glasses indicate that helium migration is controlled by a classical thermally activated diffusion process, whose activation energy (e.g. 0.6 ± 0.03 eV) is not affected by an alpha decay dose of around 1019 ? g-1. Helium implantation studies suggest that helium trapping could exist in nanometer size bubbles. SEM and TEM analysis performed on a Cm doped glass damaged by an alpha decay dose of around 1019 ? g-1, showed a homogeneous glass without crystallization, phase separation or bubbles with a spatial resolution limit of 10 nm. Bubbles of significant size seem very unlikely to form at room temperatures. But, the ability to form helium bubbles of nanometer size, at temperature below the glass vitreous transition temperature cannot be excluded. However, al

Peuget, S.; Delaye, J.-M.; Jégou, C.

2014-01-01

94

Crystallization in simulated glasses from Hanford high-level nuclear waste composition range.  

National Technical Information Service (NTIS)

Glass crystallization was investigated as part of a property-composition relationship study of Hanford waste glasses. Non-radioactive glass samples were heated in a gradient furnace over a wide range of temperatures. The liquidus temperature was measured,...

D. S. Kim P. Hrma D. E. Smith M. J. Schweiger

1993-01-01

95

Radiation effects in moist-air systems and the influence of radiolytic product formation on nuclear waste glass corrosion  

SciTech Connect

Ionizing radiation may affect the performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water to produce a variety of radiolytic products. Tests were conducted to examine the effects of radiolysis under high gas/liquid ratios. Results indicate that nitrate is the predominant radiolytic product produced following both gamma and alpha radiation exposure, with lesser amounts of nitrite and carboxylic acids. The formation of nitrogen acids during exposure to long-lived, alpha-particle-emitting transuranic elements indicates that these acids may play a role in influencing nuclear waste form reactions in a long-term unsaturated disposal scenario. Experiments were also conducted with samples that simulate the composition of Savannah River Plant nuclear waste glasses. Radiolytic product formation in batch tests (340 m{sup {minus}1}, 90 C) resulted in a small increase in the release rates of many glass components, such as alkali and alkaline earth elements, although silicon and uranium release rates were slightly reduced indicating an overall beneficial effect of radiation on waste form stability. The radiolytic acids increased the rate of ion exchange between the glass and the thin film of condensate, resulting in accelerated corrosion rates for the glass. The paragenetic sequence of alteration phases formed on both the irradiated and nonirradiated glass samples reacted in the vapor hydration tests matches closely with those developed during volcanic glass alteration in naturally occurring saline-alkaline lake systems. This correspondence suggests that the high temperatures used in these tests have not changed the underlying glass reaction mechanism relate to that which controls glass reactions under ambient surficial conditions.

Wronkiewicz, D.J.; Bates, J.K.; Buck, E.C.; Hoh, J.C.; Emery, J.W. [Argonne National Lab., IL (United States). Chemical Technology Div.; Wang, L.M. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Geology

1997-07-01

96

Heat Transfer in Waste Glass Melts - Measurement and Implications for Nuclear Waste Vitrification  

NASA Astrophysics Data System (ADS)

Thermal properties of waste glass melts, such as high temperature density and thermal conductivity, are relevant to heat transfer processes in nuclear waste vitrification. Experimental measurement techniques were developed and applied to four nuclear waste glasses representative of those currently projected for treatment of Hanford HLW and LAW streams to study heat flow mechanisms in nuclear waste vitrification. Density measurement results by Archimedes' method indicated that densities of the melts investigated varied considerably with composition and temperature. Thermal diffusivities of waste melts were determined at nominal melter operating temperatures using a temperature-wave technique. Thermal conductivities were obtained by combining diffusivity data with the experimentally-acquired densities of the melts and their known heat capacities. The experimental results display quite large positive dependences of conductivities on temperature for some samples and much weaker positive temperature dependences for others. More importantly, there is observed a big change in the slopes of the conductivities versus temperature as temperature is increased for two of the melts, but not for the other two. This behavior was interpreted in terms of the changing contributions of radiation and conduction with temperature and composition dependence of the absorption coefficient. Based on the obtained thermal conductivities, a simple model for a waste glass melter was set up, which was used to analyze the relative contributions of conduction and radiation individually and collectively to the overall heat flow and to investigate factors and conditions that influence the radiation contribution to heat flow. The modeling results showed that unlike the case at lower temperatures, the radiant energy flow through waste melts could be predominant compared with conduction at temperature of about 900 °C or higher. However, heat flow due to radiation was roughly equal to that from conduction as temperatures below about 700 °C. Moreover, the effect was reduced for higher absorption coefficient samples. Modeling further demonstrated that geometry exerts a significant influence on the radiation contribution to heat transfer. Room temperature radiation absorption coefficients of the same samples were determined using FTIR, which were compared with those estimated by modeling.

Wang, Chuan

97

Dynamics of asymmetric binary glass formers. I. A dielectric and nuclear magnetic resonance spectroscopy study  

NASA Astrophysics Data System (ADS)

Dielectric spectroscopy as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) in the full concentration (cTPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: Tg1(cTPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower Tg2(cTPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?2-process), the other (?1-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?1-fraction of TPP decreases until above some temperature Tc only a single ?2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the ?2-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?2-relaxation resembles a secondary process. Yet, 31P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high cTPP the super-Arrhenius temperature dependence of ?2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.

Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A.

2014-01-01

98

Multinuclear and multi-dimensional nuclear magnetic resonance investigation of silver iodide-silver phosphate fast ion conducting glasses  

Microsoft Academic Search

The results of a multi-nuclear nuclear magnetic resonance (NMR) study of (AgI)x(Ag2O)y(P2O5)1 ? x ? y glasses are reported. Using the two-dimensional variable-angle correlation spectroscopy experiment, the isotropic and anisotropic chemical shift interactions of phosphorus were determined as a function of silver iodide and silver oxide composition. From these measurements we determine the average conformation of the phosphate groups. In

K. K. Olsen; J. W. Zwanziger

1995-01-01

99

Dynamics of asymmetric binary glass formers. II. Results from nuclear magnetic resonance spectroscopy.  

PubMed

Various (2)H and (31)P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d3 (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (?1-process), the second reorienting isotropically (?2-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP ?2-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional (31)P NMR spectra prove exchange within the broadly distributed ?2-process. As demonstrated by (2)H NMR, the PS matrix reflects the faster ?2-process of TPP by performing a spatially highly hindered motion on the same timescale. PMID:24606366

Bock, D; Kahlau, R; Pötzschner, B; Körber, T; Wagner, E; Rössler, E A

2014-03-01

100

An evaluation of glass-crystal composites for the disposal of nuclear and hazardous waste materials  

SciTech Connect

Waste forms made of a glass-crystal composite (GCC) are being evaluated at Argonne National Laboratory for their potential use in the disposal of low-level nuclear and hazardous waste materials. This waste form is being developed within the framework strategy of DOE`s minimum Additive Waste Stabilization (MAWS) Program. The MAWS protocol involves the blending of multiple waste streams to achieve an optimal feed composition, which eliminates the need to use large amounts of additives to produce an acceptable waste form. The GCCs have a particularly useful utility in their ability to incorporate waste streams with high metal contents, including those that contain large amounts of scrap metals, and in their potential for sequestering radionuclide and hazardous constituents in corrosion-resistant mineral phases. This paper reports the results from tests conducted with simulated feeds representative of potential DOE and industry waste streams. Topics addressed include the partitioning of various radioactive and hazardous constituents between the glass and crystalline portions of the waste form, the development of secondary phases on the altered sample surfaces during corrosion testing, and the fate of waste components during corrosion testing, as indicated by elements released to solution and microanalysis of the reacted solid samples.

Wronkiewicz, D.J.; DiSanto, T.; Wolf, S.F.; Buck, E.C.; Dietz, N.L. [Argonne National Lab., IL (United States); Feng, X. [Pacific Northwest Lab., Richland, WA (United States)

1995-03-01

101

Raman and X-ray absorption spectroscopic studies of hydrothermally altered alkali-borosilicate nuclear waste glass  

NASA Astrophysics Data System (ADS)

Raman spectroscopy and X-ray absorption spectroscopy (XAS) are used to characterize structural changes that took place in hydrothermally altered (Na,K)-alumina-borosilicate glasses with different Na/K ratios, formulated as part of a durability study to investigate the behavior of glasses for nuclear waste storage. The hydrothermal experiments, or vapor hydration tests (VHT), were performed on each glass for 3 and 20 days at 200 °C to accelerate and approximate long-term alteration processes that may occur in a nuclear waste repository. Results found for both glasses and their VHT altered counterparts show little, if any, structural influence from the different starting Na/K ratios. X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Raman spectroscopy indicate that the altered samples are mostly amorphous with small amounts of analcime-like and leucite-like crystals within 200 ?m of the sample surface and contain up to 9.7 wt.% water or OH. The Raman data are nearly identical for the amorphous portions of all altered VHT samples investigated, and indicate that two glass structural changes took place during alteration: one, partial depolymerization of the alumina-borosilicate network, and two, introduction of water or OH. Al and Si XAS data indicate tetrahedral AlO 4 and SiO 4 environments in the original glasses as well as in the altered samples. Small energy shifts of the Si K-edge also show that the altered VHT samples have less polymerized networks than the original glass. Na XAS data indicate expanded Na environments in the VHT samples with longer Na-O distances and more nearest-neighbor oxygen atoms, compared with the original glasses, which may be due to hydrous species introduced into the expanding Na-sites.

McKeown, David A.; Buechele, Andrew C.; Viragh, Carol; Pegg, Ian L.

2010-04-01

102

Effect of Composition and Radiation on the Hertzian Indentation Behavior of Nuclear Waste Glasses (77-MeV alpha Particles).  

National Technical Information Service (NTIS)

The Hertzian indentation technique has been used to determine the fracture toughness, K/sub Ic/ of two borosilicate glasses developed to contain high-level nuclear waste. For the product VG 98/12, adding selected groups of fission products leaves K/sub Ic...

H. Matzke L. Kahl J. L. Routbort J. Saidl

1983-01-01

103

Comprehensive data base of high-level nuclear waste glasses: September 1987 status report: Volume 2, Additional appendices  

SciTech Connect

The Materials Characterization Center (MCC) is assembling a comprehensive data base (CDB) of experimental data collected for high-level nuclear waste package components. The status of the CDB is summarized in Volume I of this report. Volume II contains appendices that present data from the data base and an evaluation of glass durability models applied to the data base.

Kindle, C.H.; Kreiter, M.R.

1987-12-01

104

Measurement of the nuclear electromagnetic cascade development in glass at energies above 200 GeV  

NASA Technical Reports Server (NTRS)

The longitudinal development of nuclear-electromagnetic cascades with energies greater than 200 GeV was measured in a low-Z (glass) absorber. This was done in the course of operating an ionization spectrometer at mountain altitude in an experiment to study the properties of gamma rays emitted from individual interactions at energies around 10,000 GeV. The ionization produced by a cascade is sampled by 20 sheets of plastic scintillator spaced uniformly in depth every 2.2 radiation lengths. Adjacent pairs of scintillators are viewed by photomultipliers which measure the mean ionization produced by an individual cascade in 10 layers each 1.1 interaction length (4.4 radiation lengths) thick. The longitudinal development of the cascades was measured for about 250 cascades having energies ranging from 200 GeV to 2500 GeV. The observations are compared with the predictions of calculations made for this specific spectrometer using a three-dimensional Monte Carlo model of the nuclear-electromagnetic cascade.

Gillespie, C. R.; Huggett, R. W.; Humphreys, D. R.; Jones, W. V.; Levit, L. B.

1971-01-01

105

Nuclear reaction microanalysis and electron microanalysis of light elements in minerals and glasses  

NASA Astrophysics Data System (ADS)

Electron microprobe analysis (EMA) and nuclear microanalysis (NMA) have been used to determine light elements ( Z ? 30) in minerals and glasses. Optimum NMA reaction conditions for the detection of various elements are presented and detection limits are estimated for both micro- and macrobeams. A comparison is made between results of EMA and NMA analyses for several elements. Peculiarities of both methods are emphasized. While EMA is convenient in fast routine measurement for most elements in the periodic table above Na, with analytical sensitivities ranging from 100 to 1000 wt. ppm, NMA in charged-particle or prompt gamma-ray nuclear reaction analysis (NRA) mode allows the analysis of all the isotopes between 1H and 19F (except 4He and 20Ne), with a sensitivity often better than 50 ppm. In addition, proton-induced gamma-ray emission (PIGE) enables the determination of heavier elements (from Na to Zn) with relatively good performances. Furthermore, depth profiling and local isotopic ratio measurements constitute some new interesting applications for NMA.

Courel, P.; Trocellier, P.; Mosbah, M.; Toulhoat, N.; Gosset, J.; Massiot, P.; Piccot, D.

1991-03-01

106

Cerium, uranium, and plutonium behavior in glass-bonded sodalite, a ceramic nuclear waste form.  

SciTech Connect

Glass-bonded sodalite is being developed as a ceramic waste form (CWF) to immobilize radioactive fission products, actinides, and salt residues from electrometallurgical treatment of spent nuclear reactor fuel. The CWF consists of about 75 mass % sodalite, 25 mass % glass, and small amounts of other phases. This paper presents some results and interpretation of physical measurements to characterize the CWF structure, and dissolution tests to measure the release of matrix components and radionuclides from the waste form. Tests have been carried out with specimens of the CWF that contain rare earths at concentrations similar to those expected in the waste form. Parallel tests have been carried out on specimens that have uranium or plutonium as well as the rare earths at concentrations similar to those expected in the waste forms; in these specimens UCl{sub 3} forms UO{sub 2} and PuCl{sub 3} forms PuO{sub 2}. The normalized releases of rare earths in dissolution tests were found to be much lower than those of matrix elements (B, Si, Al, Na). When there is no uranium in the CWF, the release of cerium is two to ten times lower than the release of the other rare earths. The low release of cerium may be due to its tetravalent state in uranium-free CWF. However, when there is uranium in the CWF, the release of cerium is similar to that of the other rare earths. This trivalent behavior of cerium is attributed to charge transfer or covalent interactions among cerium, uranium, and oxygen in (U,Ce)O{sub 2}.

Lewis, M. A.; Lexa, D.; Morss, L. R.; Richmann, M. K.

1999-09-03

107

Quantitative fluid inclusion gas analysis of airburst, nuclear, impact and fulgurite glasses  

Microsoft Academic Search

We present quantitative fluid inclusion gas analysis on a suite of violently-formed glasses. We used the incremental crush mass spectrometry method (Norman & Blamey, 2001) to analyze eight pieces of Libyan Desert Glass (LDG). As potential analogues we also analyzed trinitite, three impact crater glasses, and three fulgurites. The 'clear' LDG has the lowest CO content and O\\/Ar ratios are

John Parnell; Horton E. Newsom; Nigel J. F. Blamey; Mark Bruce Elrick Boslough

2010-01-01

108

INCORPORATION OF MONO SODIUM TITANATE AND CRYSTALLINE SILICOTITANATE FEEDS IN HIGH LEVEL NUCLEAR WASTE GLASS  

SciTech Connect

Four series of glass compositions were selected, fabricated, and characterized as part of a study to determine the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. All of the glasses studied were considerably more durable than the benchmark Environmental Assessment (EA) glass. The measured Product Consistency Test (PCT) responses were compared with the predicted values from the current DWPF durability model. One of the KT01-series and two of the KT03-series glasses had measured PCT responses that were outside the lower bound of the durability model. All of the KT04 glasses had durabilities that were predictable regardless of heat treatment or compositional view. In general, the measured viscosity values of the KT01, KT03, and KT04-series glasses are well predicted by the current DWPF viscosity model. The results of liquidus temperature (T{sub L}) measurements for the KT01-series glasses were mixed with regard to the predictability of the T{sub L} for each glass. All of the measured T{sub L} values were higher than the model predicted values, although most fell within the 95% confidence intervals. Overall, the results of this study show a reasonable ability to incorporate the anticipated SCIX streams into DWPF-type glass compositions with TiO{sub 2} concentrations of 4-5 wt % in glass.

Fox, K.; Johnson, F.; Edwards, T.

2010-11-23

109

Simultaneous nuclear reaction analyses of boron and phosphorus in thin borophosphosilicate glass films using /(?,p) reactions  

NASA Astrophysics Data System (ADS)

A method combining (?,p) nuclear reaction analysis (NRA) and ellipsometry has been developed for measuring the boron and phosphorus content of borophosphosilicate glass (BPSG) used for interlevel dielectrics in integrated circuits. Yields from the 31P(?,p 0) 34S ( Q=0.63 MeV) and 10B(?,p 0) 13C ( Q=4.06 MeV) reactions are coupled with ellipsometry thickness measurements to determine the average atomic percent of B and P in the film. We have determined that 6.0 MeV incident ?'s with a detector angle of 135° and about 100 ?m of Mylar range foil are optimum for our system. The yield for the 10B(?,p 0) 13C reaction is quite constant in our energy range of interest (˜5.8-6 MeV) but the yield for the 31P(?,p 0) 34S is not. Consequently, a simple conversion from "standard" BPSG reference samples (independently quantified by ICP mass spectrometry) is adequate to calculate a film's %B content. The %P calculation is more complex, involving a three-dimensional fit of the P yield data and measured film thickness to the film %P content. This fit is based upon yield data from a matrix of standard film samples. The technique is sensitive to 0.1% with an accuracy of ±3-±10% depending on the sample. This measurement method is now used routinely at Sandia National Laboratories in support of our fabrication process lines.

Walsh, D. S.; Doyle, B. L.

2000-03-01

110

Resarch investigation on dense scintillation glass for use in total absorption nuclear cascade detectors  

NASA Technical Reports Server (NTRS)

Three approaches to the development of a high density scintillation glass were investigated: They include the increase of density of glass systems containing cerium - the only systems which were known to show scintillation, the testing of a novel silicate glass system containing significant concentrations of silver produced by ion exchange and never tested previously, and the hot pressing of a diphasic compact of low density scintillation glass with high density passive glass. In first two cases, while ultraviolet excited fluorescence was maintained in the glasses showing high density, scintillation response to high energy particles was not retained in the case of the cerium containing glasses or developed in the case of the silver containing glasses. In the case of the compacts, the extremely long path length caused by the multiple internal reflections which occur in such a body resulted in attenuation even with glasses of high specific transmission. It is not clear why the scintillation efficiency is not maintained in the higher density cerium containing glasses.

Hensler, J. R.

1973-01-01

111

Nuclear magnetic resonance study of ultraslow diffusion in electrolytes and glass-forming liquids  

NASA Astrophysics Data System (ADS)

We have studied ultraslow diffusion in liquids with nuclear magnetic resonance (NMR). In particular, we applied magnetic field gradients in the fringe fields of NMR magnets, from 42 to 216 T/m, and resolved diffusivities as low as 10-10 cm2/s. To recover from the slice-selection signal-to-noise limitation imposed by the gradient, we implemented a fast frequency jumping acquisition mode. We also pursued an opposite "hole-burning" limit and chose small excitation slices, down to one micron in thickness, whose time evolution provided a diffusion measurement. We have investigated the effect of "phase noise." In an unstable magnetic field, a signal-averaged NMR experiment will suffer an artificial decoherence. We have calculated and measured this effect in harmonic instabilities, and employed two methods to suppress it: polar averaging and inductive shielding. In high field resistive magnet experiments at the National High Magnetic Field Laboratory, we demonstrated an significant extension of the effective NMR coherence time through inductive shielding. We studied a macrocyclic lithium electrolyte, consisting of a salt (LiMPSA) combined with a cation-encapsulating macrocycle ([2.2.2] cryptand). Through a combination of 7Li, 19F, and 1H NMR experiments, we measured the diffusivities of all three components of this system, with the striking result that all three were equal. The ideal conductivity predicted from these diffusivities was compared to the measured conductivity. The discrepancy between the two quantified the system's ion pairing, which compared well with molecular dynamics simulations. All of this work suggested a carrier-dominated model for the lithium transport. We also studied transport in the small-molecule glass-forming liquids glycerol and propylene carbonate. We measured the diffusivity in both cases by dephasing methods, and complemented this data with "hole-burning" measurements. We observed a dynamical crossover in the diffusivity of glycerol, but found no evidence of dynamical heterogeneity through comparison with viscosity data. The opposite was true in the case of propylene carbonate. This behavior is consistent with the different fragilities of the glass-formers, and suggests a gradual variation of the fragility parameter might enhance understanding of these two effects.

Sigmund, Eric Edward

112

Application of the GRAAL model to leaching experiments with SON68 nuclear glass in initially pure water  

NASA Astrophysics Data System (ADS)

Based on a review of the current state of knowledge concerning the aqueous alteration of SON68 nuclear glass we have proposed a mechanistic model, GRAAL (Glass Reactivity with Allowance for the Alteration Layer) [P. Frugier, S. Gin, Y. Minet, T. Chave, B. Bonin, N. Godon, J.E. Lartigue, P. Jollivet, A. Ayral, L. De Windt, G. Santarini, J. Nucl. Mater. 380 (2008) 8]. This article describes how the GRAAL model hypotheses are solved using a calculation code coupling chemistry and transport. The geochemical solution of this model combines three major phenomena: chemical equilibria in solution, water and ion transport by convection or diffusion, and element diffusion through the passivating reactive interphase. The model results are compared with experimental data for SON68 glass leached in initially pure water both in a closed system and in renewed media. The comparison shows the model very satisfactorily accounts for variations in the pH and the element concentrations in solution as a function of time, the glass surface area in contact with solution, and the solution renewal rate. This success is due to the fact that the diffusion of elements through the alteration gel is taken into account in the model. This mechanism cannot be disregarded under most experimental conditions — if only to predict the solution pH — and must therefore be an integral part of the geochemical model.

Frugier, P.; Chave, T.; Gin, S.; Lartigue, J.-E.

2009-08-01

113

Use of depleted uranium silicate glass to minimize release of radionuclides from spent nuclear fuel waste packages  

SciTech Connect

A Depleted Uranium Silicate Container Backfill System (DUSCOBS) is proposed that would use small, isotopically-depleted uranium silicate glass beads as a backfill material inside repository waste packages containing spent nuclear fuel (SNF). The uranium silicate glass beads would fill the void space inside the package including the coolant channels inside SNF assemblies. Based on preliminary analysis, the following benefits have been identified. DUSCOBS improves repository waste package performance by three mechanisms. First, it reduces the radionuclide releases from SNF when water enters the waste package by creating a local uranium silicate saturated groundwater environment that suppresses (a) the dissolution and/or transformation of uranium dioxide fuel pellets and, hence, (b) the release of radionuclides incorporated into the SNF pellets. Second, the potential for long-term nuclear criticality is reduced by isotopic exchange of enriched uranium in SNF with the depleted uranium (DU) in the glass. Third, the backfill reduces radiation interactions between SNF and the local environment (package and local geology) and thus reduces generation of hydrogen, acids, and other chemicals that degrade the waste package system. Finally, DUSCOBS provides a potential method to dispose of significant quantities of excess DU from uranium enrichment plants at potential economic savings. DUSCOBS is a new concept. Consequently, the concept has not been optimized or demonstrated in laboratory experiments.

Forsberg, C.W.

1996-01-20

114

A review of literature pertaining to the leaching and sorption of radionuclides associated with nuclear explosive melt glasses  

SciTech Connect

For the purposes of groundwater characterization, environmental remediation and health risk assessment, the mechanism and rate by which radionuclides bound within nuclear device melt glass are manifest in Nevada Test Site groundwaters must be known. Exchange between radionuclides and groundwater is dominated by the kinetics of leaching and the resultant sorption of derivative nuclides by minerals along the flow-path. In this context, a survey of the report literature has been conducted to review work related to these subjects. This report provides a representative, although not exhaustive, summary of the literature; because of the specialized nature of nuclear melt glass, emphasis was given to the report literature available from Lawrence Livermore and Los Alamos National Laboratories, the Department of Energy and its predecessor agencies and pertinent contractors. Where data is corroborated in journal literature, those references are also included. Before the risk to ground waters is estimated with any accuracy, recommendations for continued future work integrate systematic characterization of melt glass with leaching studies of these heterogeneous matrices.

Smith, D.K.

1993-05-01

115

Annual progress report to Battelle Pacific Northwest National Laboratories on prediction of phase separation of simulated nuclear waste glasses  

SciTech Connect

The objective of this research is to predict the immiscibility boundaries of multi-component borosilicate glasses, on which many nuclear waste glass compositions are based. The method used is similar to the prediction method of immiscibility boundaries of multi-component silicate glass systems successfully made earlier and is based upon the superposition of immiscibility boundaries of simple systems using an appropriate parameter. This method is possible because many immiscibility boundaries have similar shapes and can be scaled by a parameter. In the alkali and alkaline earth binary silicate systems, for example, the critical temperature and compositions were scaled using the Debye-Hueckel theory. In the present study on borosilicate systems, first, immiscibility boundaries of various binary alkali and alkaline borate glass systems (e.g. BaO-B{sub 2}O{sub 3}) were examined and their critical temperatures were evaluated in terms of Debye-Hueckel theory. The mixing effects of two alkali and alkaline-earth borate systems on the critical temperature were also explored. Next immiscibility boundaries of ternary borosilicate glasses (e.g. Na{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, K{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, Rb{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, and Cs{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}) were examined. Their mixing effects are currently under investigation.

Sung, Y.M.; Tomozawa, M.

1996-02-01

116

Fluorescent microscopic determination of proteins in human serum with the self-ordered ring of nuclear fast red formed on the solid support of glass slides  

Microsoft Academic Search

A self-ordered ring (SOR) technique based on the assembly of fluorescent molecules on the solid support of glass slides is presented for the detection of trace amount of proteins by using fluorescence microscope. At pH 6.62 and with the aid of poly(vinyl alcohol)-124 (PVA-124), a droplet of nuclear fast red (NFR) solution can form a fluorescent SOR on hydrophobic glass

Yu Chun Chen; Cheng Zhi Huang

2003-01-01

117

On the cooperative nature of the ?-process in neat and binary glasses: A dielectric and nuclear magnetic resonance spectroscopy study  

NASA Astrophysics Data System (ADS)

By means of dielectric as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) the component dynamics of the binary glass tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) is selectively investigated for concentrations distributed over the full range. We study the secondary (?-) relaxation below Tg, which is found in all investigated samples containing TPP, but not in neat polystyrene. The dielectric spectrum of the ?-process is described by an asymmetric distribution of activation energies, essentially not changing in the entire concentration regime; its most probable value is E/k ? 24 Tg. Persistence of the ?-process is confirmed by 31P NMR Hahn-echo and spin-lattice relaxation experiments on TPP, which identify the nature of the ?-process as being highly spatially hindered as found for other (neat) glasses studied previously, or re-investigated within this work. The corresponding 2H NMR experiments on PS-d3 confirm the absence of a ?-process in neat PS-d3, but reveal a clear signature of a ?-process in the mixture, i.e., polystyrene monomers perform essentially the same type of secondary relaxation as the TPP molecules. Yet, there are indications that some fractions of PS-d3 as well as TPP molecules become immobilized in the mixture in contrast to the case of neat glasses. We conclude that in a binary glass the ?-process introduced by one component induces a highly similar motion in the second component, and this may be taken as an indication of its cooperative nature.

Bock, D.; Kahlau, R.; Micko, B.; Pötzschner, B.; Schneider, G. J.; Rössler, E. A.

2013-08-01

118

On the cooperative nature of the ?-process in neat and binary glasses: a dielectric and nuclear magnetic resonance spectroscopy study.  

PubMed

By means of dielectric as well as (2)H and (31)P nuclear magnetic resonance spectroscopy (NMR) the component dynamics of the binary glass tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) is selectively investigated for concentrations distributed over the full range. We study the secondary (?-) relaxation below T(g), which is found in all investigated samples containing TPP, but not in neat polystyrene. The dielectric spectrum of the ?-process is described by an asymmetric distribution of activation energies, essentially not changing in the entire concentration regime; its most probable value is E/k ? 24 T(g). Persistence of the ?-process is confirmed by (31)P NMR Hahn-echo and spin-lattice relaxation experiments on TPP, which identify the nature of the ?-process as being highly spatially hindered as found for other (neat) glasses studied previously, or re-investigated within this work. The corresponding (2)H NMR experiments on PS-d3 confirm the absence of a ?-process in neat PS-d3, but reveal a clear signature of a ?-process in the mixture, i.e., polystyrene monomers perform essentially the same type of secondary relaxation as the TPP molecules. Yet, there are indications that some fractions of PS-d3 as well as TPP molecules become immobilized in the mixture in contrast to the case of neat glasses. We conclude that in a binary glass the ?-process introduced by one component induces a highly similar motion in the second component, and this may be taken as an indication of its cooperative nature. PMID:23947872

Bock, D; Kahlau, R; Micko, B; Pötzschner, B; Schneider, G J; Rössler, E A

2013-08-14

119

Deuteron NMR (Nuclear Magnetic Resonance) in relation to the glass transition in polymers  

NASA Technical Reports Server (NTRS)

H-2NMR is introduced as a tool for investigating slow molecular motion in the glass transition region of amorphous polymers. In particular, we compare H-2 spin alignment echo spectra of chain deuterated polystyrene with model calculations for restricted rotational Brownian motion. Molecular motion in the polyztyrene-toluene system has been investigated by analyzing H-2NMR of partially deuterated polystyrene and toluene, respectively. The diluent mobility in the mixed glass has been decomposed into solid and liquid components where the respective average correlation times differ by more than 5 decades.

Roessler, E.; Sillescu, H.; Spiess, H. W.; Wallwitz, R.

1983-01-01

120

Behaviour of silicon released during alteration of nuclear waste glass in compacted clay  

Microsoft Academic Search

Long term integrated in situ experiments are performed in the HADES underground research facility (Mol, Belgium) in order to study the coupled reactivity between the different components of an underground repository for vitrified high level radioactive waste (HLW): glass, compacted clay, and stainless steel containers, at 90 °C and under gamma irradiation. Studies pertaining to the behaviour of silicon, a major

C. Pozo; O. Bildstein; J. Raynal; M. Jullien; E. Valcke

2007-01-01

121

Nuclear Magnetic Resonance in Thallium Borate Glasses. I. The Thallium-205 Chemical Shift.  

National Technical Information Service (NTIS)

Chemical shift measurements on 205Tl in thallium borate glasses at temperatures up to and above the softening temperature (300C) indicate that the interactions of Tl(I) with oxygen atoms in the borate network are predominantly ionic. There is relatively l...

R. K. Momii N. H. Nachtrieb

1968-01-01

122

Crystallization in simulated glasses from Hanford high-level nuclear waste composition range  

SciTech Connect

Glass crystallization was investigated as part of a property-composition relationship study of Hanford waste glasses. Non-radioactive glass samples were heated in a gradient furnace over a wide range of temperatures. The liquidus temperature was measured, and primary crystalline phases were determined using optical microscopy and Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM/EDS). Samples have also been heat treated according to a simulated canister centerline cooling curve. The crystalline phases in these samples have been identified by optical microscopy, SEM/EDS, and X-ray diffraction (XRD). Major components of the borosilicate glasses that were melted at approximately 1150{degrees}C were SiO{sub 2}, B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O, CaO, MgO, Fe{sub 2}O{sub 3}, Al{sub 2}O{sub 3}, ZrO{sub 2}, and ``Others`` (sum of minor components). The major crystalline phases identified in this study were zircon, nepheline, calcium silicate, lithium silicate, and a range of solid solutions from clinopyroxenes, orthopyroxenes, olivines, and spiners.

Kim, Dong-Sang; Hrma, P.; Smith, D.E.; Schweiger, M.J.

1993-04-01

123

Role of Metal Ion Solubility in Leaching of Nuclear Waste Glasses.  

National Technical Information Service (NTIS)

From the results of a variety of experiments it can be concluded that reaction of the matrix is the fundamental process that occurs in the leaching of PNL 76-68 glass. This reaction has two aspects. Without solubility restrictions, congruent leaching beha...

B. Grambow

1982-01-01

124

ANNUAL REPORT. IRON PHOSPHATE GLASSES: AN ALTERNATIVE FOR VITRIFYING CERTAIN NUCLEAR WASTES  

EPA Science Inventory

The two multifaceted objectives of this research project are to (1) investigate the feasibility of vitrifying 2 or 3 high priority wastes, as identified by the Tank Focus Area group, using iron phosphate glasses (i.e., determine chemical durability as a function of waste loading,...

125

New functionality of chalcogenide glasses for radiation sensing of nuclear wastes.  

PubMed

Data about gamma radiation induced effects in Ge40Se60 chalcogenide thin films and radiation induced silver diffusion within these are presented. Blanket films and devices were created to study the structural changes, diffusion products, and device performance. Raman spectroscopy, X-ray diffraction, current vs. voltage (I-V) and impedance measurements expound the behavior of Ge40Se60 glass and silver diffusion within this glass under radiation. Raman study shows that there is a decrease in the area ratio between edge shared and corner shared structural units revealing structural reorganization occurring in the glasses as a result of gamma radiation. X-ray diffraction studies revealed that with sufficiently radiation dose it is also possible to create Ag2Se in selenium-depleted systems. Oxidation of the Ge enriched chalcogenide backbone is confirmed through the electrical performance of the sensing elements based on these films. Combination of these structural and diffusion products influences the device performance. The I-V behavior is characterized by increase in current and then stabilization as a function of radiation dose. Additionally, device modeling is also presented using Silvaco software and analytical methods to shed light on the device behavior. This type of sensor design and material characterizations facilitate in improving the radiation sensing capabilities of silver containing chalcogenide glass thin films. PMID:24332317

Ailavajhala, M S; Gonzalez-Velo, Y; Poweleit, C D; Barnaby, H J; Kozicki, M N; Butt, D P; Mitkova, M

2014-03-30

126

Kinetics of surface-layer formation on simulated nuclear waste glass  

SciTech Connect

Waste glass immersed in water at high temperatures and pressures rapidly develops a surface layer. The growth of this layer was followed semiquantitatively using an optical interference technique. Growth rates were measured as a function of temperature and pressure in distilled water and 1% NaCl solution. Pressures of 25 to 85 x 10/sup 5/ Pa had no measurable effect at 200/sup 0/C on glass immersed in water. At a pressure of 25 x 10/sup 5/ Pa the growth rate increased with temperature in both water and salt solution. The rates were described in terms of activation energies (83.4 kJ/mol for water and 53.0 for salt solution) with approximately equal rates in both solutions at 240/sup 0/C. The rates of growth were linear in all cases. The surface layer began to exhibit cracks when its thickness exceeded approx. = 2.5 ..mu..m and it eventually spalled.

Pickering, S.

1980-09-01

127

Development and testing of matrices for the encapsulation of glass and ceramic nuclear waste forms.  

SciTech Connect

This report details the results of research on the matrix encapsulation of high level wastes at PML over the past few years. The demonstrations and tests described were designed to illustrate how the waste materials are effected when encapsulated in an inert matrix. Candidate materials evaluated for potential use as matrices for encapslation of pelletized ceramics or glass marbles were categorized into four groups: metals, glasses, ceramics, and graphite. Two processing techniques, casting and hot pressing, were investigated as the most promising methods of formation or densification of the matrices. The major results reported deal with the development aspects. However, chemical durability tests (leach tests) of the matrix materials themselves and matrix-waste form composites are also reported. Matrix waste forms can provide a low porosity, waste-free barrier resulting in increased leach protection, higher impact strength and improved thermal conductivity compared to unencapsulated glass or ceramic waste materials. Glass marbles encapsulated in a lead matrix offer the most significant improvement in waste form stability of all combinations evaluated. This form represents a readily demonstrable process that provides high thermal conductivity, mechanical shock resistance, radiation shielding and increased chemical durability through both a chemical passivation mechanism and as a physical barrier. Other durable matrix waste forms evaluated, applicable primarily to ceramic pellets, involved hot-pressed titanium or TiO/sub 2/ materials. In the processing of these forms, near 100% dense matrices were obtained. The matrix materials had excellent compatibility with the waste materials and superior potential chemical durability. Cracking of the hot-pressed ceramic matrix forms, in general, prevented the realization of their optimum properties.

Wald, J.W.; Brite, D.W.; Gurwell, W.E.; Buckwalter, C.Q.; Bunnell, L.R.; Gray, W.J.; Blair, H.T.; Rusin, J.M.

1982-02-01

128

Properties of Plutonium-Containing Colloids Released from Glass-Bonded Sodalite Nuclear Waste Form  

SciTech Connect

In glass-bonded sodalite, which is the ceramic waste form (CWF) to immobilize radioactive electrorefiner salt from spent metallic reactor fuel, uranium and plutonium are found as 20-50 nm (U,Pu)O{sub 2} particles encapsulated in glass near glass-sodalite phase boundaries. In order to determine whether the (U,Pu)O{sub 2} affects the durability of the CWF, and to determine release behavior of uranium and plutonium during CWF corrosion, tests were conducted to measure the release of matrix and radioactive elements from crushed CWF samples into water and the properties of released plutonium. Released colloids have been characterized by sequential filtration of test solutions followed by elemental analysis, dynamic light scattering, transmission electron microscopy (TEM), and X-ray absorption spectroscopy. This paper reports the composition, size, and agglomeration of these colloids. Significant amounts of colloidal, amorphous aluminosilicates and smaller amounts of colloidal crystalline (U,Pu)O{sub 2} were identified in test solutions. The normalized releases of uranium and plutonium were significantly less than the normalized releases of matrix elements.

Morss, L.R.; Mertz, C.J.; Kropf, A.J.; Holly, J.L.

2004-10-11

129

Numerical simulation of high-level radioactive nuclear waste glass production  

SciTech Connect

Vitrification of radioactive waste has become an international approach for converting highly radioactive wastes into a durable solid prior to placing them in a permanent disposal repository. The technology for the process is not new. The conversion melter is a direct descendant of all electric melters used for manufacturing of some commercial glass types. Therefore, the vitrification process of radioactive wastes inherits typical problems of all electric furnaces and creates some other specific problems such as noble metal sedimentation. The noble metals and nickel sulfides in the melter are heavier than molten glass and have a low solubility. In a reducing condition, these metals amalgamate and tend to settle on the melter floor. The metal deposit resulting from this settling has a potential to short circuit the melter. The objective of this paper is to identify the typical problems that have been encountered in the waste melter operations and to address how these problems can be tackled using state-of-the-art numerical simulation techniques. It is believed that the large amount of pilot-scale melter experience throughout the world, combined with the knowledge gained from state-of-the-art computer modeling techniques would give assurance that the existing and future radioactive wastes can be effectively converted into a durable glass material and safely placed in a permanent repository.

Choi, I.G. (Westinghouse Savannah River Co., Aiken, SC (United States)); Ungan, A. (Purdue Univ., Indianapolis, IN (United States). Dept. of Mechanical Engineering)

1991-01-01

130

Numerical simulation of high-level radioactive nuclear waste glass production  

SciTech Connect

Vitrification of radioactive waste has become an international approach for converting highly radioactive wastes into a durable solid prior to placing them in a permanent disposal repository. The technology for the process is not new. The conversion melter is a direct descendant of all electric melters used for manufacturing of some commercial glass types. Therefore, the vitrification process of radioactive wastes inherits typical problems of all electric furnaces and creates some other specific problems such as noble metal sedimentation. The noble metals and nickel sulfides in the melter are heavier than molten glass and have a low solubility. In a reducing condition, these metals amalgamate and tend to settle on the melter floor. The metal deposit resulting from this settling has a potential to short circuit the melter. The objective of this paper is to identify the typical problems that have been encountered in the waste melter operations and to address how these problems can be tackled using state-of-the-art numerical simulation techniques. It is believed that the large amount of pilot-scale melter experience throughout the world, combined with the knowledge gained from state-of-the-art computer modeling techniques would give assurance that the existing and future radioactive wastes can be effectively converted into a durable glass material and safely placed in a permanent repository.

Choi, I.G. [Westinghouse Savannah River Co., Aiken, SC (United States); Ungan, A. [Purdue Univ., Indianapolis, IN (United States). Dept. of Mechanical Engineering

1991-12-31

131

Effect of Alumina Source on the Rate of Melting Demonstrated with Nuclear Waste Glass Batch  

SciTech Connect

The melting behaviors of three glass batches formulated to vitrify high-level waste were compared. These batches, otherwise identical, differed in the alumina source: one was prepared with corundum (Al2O3), another with gibbsite [Al(OH)3], and the other with boehmite [AlO(OH)]. Batch samples, in the form of loose batches or pressed pellets, were heated at 5°C/min up to 1200°C. The expansion of pellets was monitored photographically. Quenched samples of batches, heated in crucibles, were thin-sectioned, investigated with optical microscopy, and analyzed with X-ray diffraction to quantify crystalline phases. Finally, batch-to-glass conversion was investigated with thermal analysis. Corundum was still present in one batch up to 900°C whereas gibbsite and boehmite dissolved below 500°C. In the batch with corundum, quartz, the source of silica, dissolved marginally earlier than in the batches with gibbsite and boehmite. Unlike the batch with corundum that exhibited considerable foaming, the batches with gibbsite and boehmite did not produce primary foam and made a more homogeneous glass. The occurrence of primary foam in the batch with corundum is a likely cause of a low rate of melting within the cold cap of a large-scale electric melter.

Pierce, David A.; Hrma, Pavel R.; Marcial, Jose; Riley, Brian J.; Schweiger, Michael J.

2012-03-30

132

Quantitative fluid inclusion gas analysis of airburst, nuclear, impact and fulgurite glasses.  

SciTech Connect

We present quantitative fluid inclusion gas analysis on a suite of violently-formed glasses. We used the incremental crush mass spectrometry method (Norman & Blamey, 2001) to analyze eight pieces of Libyan Desert Glass (LDG). As potential analogues we also analyzed trinitite, three impact crater glasses, and three fulgurites. The 'clear' LDG has the lowest CO{sub 2} content and O{sub 2}/Ar ratios are two orders of magnitude lower than atmospheric. The 'foamy' glass samples have heterogeneous CO{sub 2} contents and O{sub 2}/Ar ratios. N{sub 2}/Ar ratios are similar to atmospheric (83.6). H{sub 2} and He are elevated but it is difficult to confirm whether they are of terrestrial or meteoritic origin. Combustion cannot account for oxygen depletion that matches the amount of CO{sub 2} produced. An alternative mechanism is required that removes oxygen without producing CO{sub 2}. Trinitite has exceedingly high CO{sub 2} which we attribute to carbonate breakdown of the caliche at ground zero. The O{sub 2}/Ar ratio for trinitite is lower than atmospheric but higher than all LDG samples. N{sub 2}/Ar ratios closely match atmospheric. Samples from Lonar, Henbury and Aouelloul impact craters have atmospheric N{sub 2}/Ar ratios. O{sub 2}/Ar ratios at Lonar and Henbury are 9.5 to 9.9 whereas the O{sub 2}/Ar ratio is 0.1 for the Aouelloul sample. In most fulgurites the N{sub 2}/Ar ratio is higher than atmospheric, possibly due to interference from CO. Oxygen ranges from 1.3 to 19.3%. Gas signatures of LDG inclusions neither match those from the craters, trinitite nor fulgurites. It is difficult to explain both the observed depletion of oxygen in the LDG and a CO{sub 2} level that is lower than it would be if the CO{sub 2} were simply a product of hydrocarbon combustion in air. One possible mechanism for oxygen depletion is that as air turbulently mixed with a hot jet of vaporized asteroid from an airburst and expanded, the atmospheric oxygen reacted with the metal vapor to form metal oxides that condensed. This observation is compatible with the model of Boslough & Crawford (2008) who suggest that an airburst incinerates organic materials over a large area, melting surface materials that then quench to form glass. Bubbles would contain a mixture of pre-existing atmosphere with combustion products from organic material and products of the reaction between vaporized cosmic materials (including metals) and terrestrial surface and atmosphere.

Parnell, John (University of Aberdeen, Aberdeen, UK); Newsom, Horton E. (University of New Mexico, Albuquerque, NM); Blamey, Nigel J. F. (New Mexico Tech, Socorro, NM); Boslough, Mark Bruce Elrick

2010-10-01

133

Chemical decomposition of high-level nuclear waste storage/disposal glasses under irradiation. 1997 annual progress report  

SciTech Connect

'The objective of this research is to use the sensitive technique of electron spin resonance (ESR) to look for evidence of radiation-induced chemical decomposition of vitreous forms contemplated for immobilization of plutonium and/or high-level nuclear wastes, to interpret this evidence in terms of existing knowledge of glass structure, and to recommend certain materials for further study by other techniques, particularly electron microscopy and measurements of gas evolution by high-vacuum mass spectroscopy. Previous ESR studies had demonstrated that an effect of y rays on a simple binary potassium silicate glass was to induce superoxide (O{sub 2}{sup -}) and ozonide (O{sub 3}{sup -}) as relatively stable product of long-term irradiation Accordingly, some of the first experiments performed as a part of the present effort involved repeating this work. A glass of composition 44 K{sub 2}O: 56 SiO{sub 2} was prepared from reagent grade K{sub 2}CO3 and SiO{sub 2} powders melted in a Pt crucible in air at 1,200 C for 1.5 hr. A sample irradiated to a dose of 1 MGy (1 MGy = 10{sup 8} rad) indeed yielded the same ESR results as before. To test the notion that the complex oxygen ions detected may be harbingers of radiation-induced phase separation or bubble formation, a small-angle neutron scattering (SANS) experiment was performed. SANS is theoretically capable of detecting voids or bubbles as small as 10 \\305 in diameter. A preliminary experiment was carried out with the collaboration of Dr. John Barker (NIST). The SANS spectra for the irradiated and unirradiated samples were indistiguishable. A relatively high incoherent background (probably due to the presence of protons) may obscure scattering from small gas bubbles and therefore decrease the effective resolution of this technique. No further SANS experiments are planned at this time.'

Griscom, D.L.; Merzbacher, C.I.

1997-01-01

134

Development of a device for helium thermal diffusion investigations by IBA in self-irradiated nuclear glass  

NASA Astrophysics Data System (ADS)

To minimize the amount of nuclear waste issuing from the nuclear power plants, the solution adopted in France consists in the reprocessing of spent fuel to isolate long lived and high level radioactive waste (minor actinides and fission products). They are incorporated into a glassy matrix in order to be placed in dedicated long-term disposal repository. The confinement of the radioelements depends strongly on the integrity of the glassy matrix which could be damaged by the radiations and the generation of helium produced by ?-decays of the minor actinides. In the past few years, several studies were conducted in order to understand the behaviour of helium, especially its thermal diffusion into the glassy matrix [1-3]. However none were conducted on self-irradiated samples and a validation on radioactive glasses and in the temperature range of the repository conditions is still needed. For this purpose, a specific setup was developed on the analysis chamber of the nuclear microprobe dedicated to radioactive samples in Saclay [4]. The temperature of the sample is controlled during all the experiment, in the range from 143 to 323 K; 3He ions are implanted at low temperature. Helium profiles are measured at low temperature using the 3He(d,p)4He reaction, as-implanted and after several stages of annealing. We will present the developed setup and show the preliminary results of the measurements made on non-active samples.

Raepsaet, C.; Peuget, S.; Khodja, H.; Gutierrez, G.; Hoarau, J.; Sauvage, T.

2014-07-01

135

Direct conversion of surplus fissile materials, spent nuclear fuel, and other materials to high-level-waste glass  

SciTech Connect

With the end of the cold war the United States, Russia, and other countries have excess plutonium and other materials from the reductions in inventories of nuclear weapons. The United States Academy of Sciences (NAS) has recommended that these surplus fissile materials (SFMs) be processed so they are no more accessible than plutonium in spent nuclear fuel (SNF). This spent fuel standard, if adopted worldwide, would prevent rapid recovery of SFMs for the manufacture of nuclear weapons. The NAS recommended investigation of three sets of options for disposition of SFMs while meeting the spent fuel standard: (1) incorporate SFMs with highly radioactive materials and dispose of as waste, (2) partly burn the SFMs in reactors with conversion of the SFMs to SNF for disposal, and (3) dispose of the SFMs in deep boreholes. The US Government is investigating these options for SFM disposition. A new method for the disposition of SFMs is described herein: the simultaneous conversion of SFMs, SNF, and other highly radioactive materials into high-level-waste (HLW) glass. The SFMs include plutonium, neptinium, americium, and {sup 233}U. The primary SFM is plutonium. The preferred SNF is degraded SNF, which may require processing before it can be accepted by a geological repository for disposal.

Forsberg, C.W.; Elam, K.R.

1995-01-31

136

6Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses; Journal of Non-Crystalline Solids.  

National Technical Information Service (NTIS)

(sup 6)Li and (sup 7)Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi(sub 2)O (1-x)P(sub 2)O(sub 5) glasses, where 0.05 = ...

T. M. Alam T. J. Boyle R. K. Brow S. Conzone

1999-01-01

137

Raman, Brillouin, and nuclear magnetic resonance spectroscopic studies on shocked borosilicate glass  

NASA Astrophysics Data System (ADS)

Using Brillouin and Raman scattering and NMR techniques, we have investigated the elastic and structural properties of four post-shocked specimens of borosilicate glass, recovered from peak pressures of 19.8, 31.3, 40.3, and 49.1 GPa. The Raman spectra of shock-wave compressed borosilicate glass for peak pressures of 19.8 and 31.3 GPa show two new peaks at 606 cm-1 and near 1600 cm-1, while a peak at ~923 cm-1 disappears in these glasses following shock-loading. The mode at 606 cm-1 is correlated with four-membered rings, composed of one BO4 and three SiO4 tetrahedra (a reedmergneritelike configuration). Modes near ~1600 cm-1 are of uncertain origin, while that at 923 cm-1 may associated with silica tetrahedra with two nonbridging oxygens, although standard models of this type of glass suggest that total nonbridging oxygen contents should be low. The Raman spectra for the shocked samples at 40.3 and 49.1 GPa are similar to that of the unshocked sample, suggesting that much of the irreversible density and structural changes are recoverable following adiabatic decompression and thermal relaxation. This reversibility for the highest pressure shocked samples is in accord with the Brillouin results, which show an increase in the product of sound velocity and index of refraction at pressures up to 20 GPa. The Raman band initially at 450 cm-1, which corresponds to the bending vibration mode of the Si-O-Si, Si-O-B (with primarily six-membered rings in the network) reaches a maximum frequency of 470 cm-1 and narrowing at a peak shock pressure of 31.3 GPa, and then also decreases to its initial values for samples shocked at 40.3 and 49.1 GPa. This shift toward higher frequency under shock-wave compression indicates the average Si-O-Si, Si-O-B angles decrease with pressure. The narrowing of this band suggests a narrower distribution of Si-O-Si angles in the shocked samples for peak pressures of 19.8 and 31.3 GPa. 11B NMR spectra for all four shocked glasses are similar, and indicate ratios of BO3 to BO4 that are not greatly changed from the starting material. However, changes in peak shapes suggest significant changes in the connectivity of the B and Si components of the network, with more silicon neighbors surrounding BO4 tetrahedra in the shocked glasses, and a modest increase in the number of nonring related BO3 groups following shock-loading. Thus, the irreversible effects of shock-loading appear to be to generate smaller rings of tetrahedra (hence decreasing the average T-O-T bond angle), and to increase the average number of neighbors of Si around boron tetrahedra.

Manghnani, Murli H.; Hushur, Anwar; Sekine, Toshimori; Wu, Jingshi; Stebbins, Jonathan F.; Williams, Quentin

2011-06-01

138

Solubility Limits of Metal Ions and Mechanism of Leaching Nuclear-Waste Glasses.  

National Technical Information Service (NTIS)

A number of studies have qualitatively considered solubility limits to be important in the leaching of nuclear waste forms with respect to reaction layer formation and the prediction of long-term behavior under accidental conditions in a repository. These...

B. Grambow

1982-01-01

139

Biological effect of Acidithiobacillus thiooxidans on some potentially toxic elements during alteration of SON 68 nuclear glass  

NASA Astrophysics Data System (ADS)

Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH, with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25degC. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, trace and ultra-trace elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials are found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium as tracer, showed that the progressive formation of a biofilm on the surface of glass has a protective effect against its alteration. Uranium and rare earth elements (REE) are efficiently trapped in the biogenic compartment of the system (exopolysaccharides + bacterial cells). Besides, the ratio biotic/abiotic concentrations of REE and U in the leachant decreases with increasing time which seems to indicate a good capacity of EPS for long term trapping of potentially toxic elements. Aouad G., Crovisier J.-L., Damidot D., Stille P., Hutchens E., Mutterer J., Meyer J.-M., and Geoffroy V. A. (2008) Interactions between municipal solid waste incinerator bottom ash and bacteria (Pseudomonas aeruginosa). Science of The Total Environment 393((2-3)), 385-393.

Bachelet, M.; Crovisier, J. L.; Stille, P.; Vuilleumier, S.; Geoffroy, V.

2009-04-01

140

Noble metal behavior during melting of simulated high-level nuclear waste glass feeds  

SciTech Connect

Noble metals and their oxides can settle in waste glass melters and cause electrical shorting. Simulated waste feeds from Hanford, Savannah River, and Germany were heat treated for 1 hour in a gradient furnace at temperatures ranging from approximately 600{degrees}C--1000{degrees}C and examined by electron microscopy to determine shapes, sizes, and distribution of noble metal particles as a function of temperature. Individual noble metal particles and agglomerates of rhodium (Rh), ruthenium (RuO{sub 2}), and palladium (Pd), as well as their alloys, were seen. the majority of particles and agglomerates were generally less than 10 microns; however, large agglomerations (up to 1 mm) were found in the German feed. Detailed particle distribution and characterization was performed for a Hanford waste to provide input to computer modeling of particle settling in the melter.

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

1993-04-01

141

Pr3+-doped fluoro-oxide lithium glass as scintillator for nuclear fusion diagnostics.  

PubMed

Experimental results are presented on the neutron scintillating properties of a custom-designed Pr3+ (praseodymium)-doped lithium (Li) glass. Luminescence was observed at 278 nm wavelength, originating from the 5d-4f transition. Time-resolved measurements yielded about 20 ns decay times for ultraviolet and x-ray excitation while much faster decay times of about 6 ns were observed for alpha particle and neutron excitation. Actual time-of-flight data in laser fusion experiments at the GEKKO XII facility of the Institute of Laser Engineering, Osaka University reveal that it can clearly discriminate fusion neutrons from the much stronger x-rays signals. This material can promise improved accuracy in future scattered neutron diagnostics. PMID:19947728

Arikawa, Yasunobu; Yamanoi, Kohei; Nakazato, Tomoharu; Estacio, Elmer Surat; Shimizu, Toshihiko; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Azechi, Hiroshi; Murata, Takahiro; Fujino, Shigeru; Yoshida, Hideki; Kamada, Kei; Usuki, Yoshiyuki; Suyama, Toshihisa; Yoshikawa, Akira; Sato, Nakahiro; Kan, Hirofumi

2009-11-01

142

Pr{sup 3+}-doped fluoro-oxide lithium glass as scintillator for nuclear fusion diagnostics  

SciTech Connect

Experimental results are presented on the neutron scintillating properties of a custom-designed Pr3+(praseodymium)-doped lithium (Li) glass. Luminescence was observed at 278 nm wavelength, originating from the 5d-4f transition. Time-resolved measurements yielded about 20 ns decay times for ultraviolet and x-ray excitation while much faster decay times of about 6 ns were observed for alpha particle and neutron excitation. Actual time-of-flight data in laser fusion experiments at the GEKKO XII facility of the Institute of Laser Engineering, Osaka University reveal that it can clearly discriminate fusion neutrons from the much stronger x-rays signals. This material can promise improved accuracy in future scattered neutron diagnostics.

Arikawa, Yasunobu; Yamanoi, Kohei; Nakazato, Tomoharu; Estacio, Elmer Surat; Shimizu, Toshihiko; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Murata, Takahiro [Department of Chemistry, School of Science, Tokai University, Kawayou, Minamiaso, Aso, Kumamoto 869-1404 (Japan); Fujino, Shigeru [Department of Materials Process Engineering, Graduate School of Engineering, Kyushu University, 744 Nishikyo Motooka, Fukuoka 819-0395 (Japan); Yoshida, Hideki [Ceramic Research Center of Nagasaki, Hiekoba, Hasami, Higashisonogi, Nagasaki 859-3726 (Japan); Kamada, Kei; Usuki, Yoshiyuki [Furukawa Co., Ltd., Kannondai, Tsukuba, Ibaraki 1-25-13 (Japan); Suyama, Toshihisa [Tokuyama Corporation Shibuya, 3-3-1, Shibuya, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoyou, Sendai, Miyagi 980-8577 (Japan); Sato, Nakahiro; Kan, Hirofumi [Central Research Laboratory, Hamamatsu Photonics K. K., 5000 Hiraguchi, Hamakitaku, Hamamatsu, Shizuoka 434-8601 (Japan)

2009-11-15

143

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

SciTech Connect

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

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

2012-08-13

144

Rare-earth doped glass scintillators effective to spent nuclear fuels through photocatalyst  

Microsoft Academic Search

New rare-earth doped scintillators were grown to change radioactive energies of spent nuclear fuels exhausted out of atomic power plants to UV-light, followed by making absorb into photocatalyst soaked in water to get yield hydrogen gas available to fuel cells and oxygen gas for medical usages. This project requires that the scintillating light should exist in the absorption edge 380nm

K. Kawano; H. Tasaki; B.-C. Hong; T. Ishitsuka

2008-01-01

145

Nuclear spin lattice relaxation and conductivity studies of the non-Arrhenius conductivity behavior in lithium fast ion conducting sulfide glasses  

NASA Astrophysics Data System (ADS)

Homogeneous xB2O3 + (1-x)B 2S3 glasses were prepared between 0 ? x ? 0.80. Raman, IR, and 11B NMR spectroscopies show that the boron oxide structures of B2O3, especially the six-membered rings, quickly diminish with increasing sulfide content, whereas the corresponding sulfide structures in B2S3 remain relatively intense as oxide content is increased. Differential scanning calorimetry (DSC) and density measurements show that physical properties of these boron oxysulfide glasses heavily favor the B2S3 properties regardless of the amount of B2O3 added to the system. It is hypothesized that the stability of the thioboroxol ring group relative to that of the BS 3/2 trigonal group is a possible source of this behavior. The formation of mixed boron oxysulfide structures of composition BSzO3-z where 0 < z < 3 is proposed. Structural studies of the ternary xLi2S + (1-x)[0.5 B2S3 + 0.5 GeS2] glasses using IR, Raman, and 11B NMR show that these glasses do not have equal sharing of the lithium atoms between GeS2 and B2S3. The IR spectra indicates that the B2S3 glass network are under-doped in comparison to corresponding compositions in the xLi 2S + (1-x)B2S3 binary system. Additionally, the Raman spectra show that the GeS2 glass network is over-modified. 11Boron static NMR gives evidence that ˜80% of the boron atoms are in tetrahedral coordinated. A super macro tetrahedron is proposed as one of the structures in these glasses in which some of them may contain boron sites substituted by germanium atoms at lower Li2S content. Nuclear Spin Lattice Relaxation and ionic conductivity measurements of Li doped Li2S + GeS2 + B2S3 glasses were performed to investigate the ion hopping dynamics and the non-Arrhenius conductivity behavior that has been observed in some fast ion conducting glasses. A distribution of activation energies model was used to fit the NSLR results and conductivity results. Comparisons are made to previously studied binary lithium thio-germanate and binary lithium thio-borate glasses to help yield information about the conduction mechanisms in these new glasses. An ion trapping model is used in conjunction with the distribution of activation energies model to describe the non-Arrhenius behavior observed in the dc conductivity.

Meyer, Benjamin Michael

146

Physics and Chemistry of the Transition of Glass to Authigenic Minerals: State of Nevada, Agency for Nuclear Projects/Nuclear Waste Project Office.  

National Technical Information Service (NTIS)

The paper provides a basic review of the topic of volcanic-glass hydration and the diagenetic formation of authigenic minerals from the hydrated-glass products. The Yucca Mountain Draft Environmental Assessment (DEA) of December 1984 indicates that: most ...

M. E. Morgenstein

1984-01-01

147

Quasicrystalline Approach to Prediting the Spinel-Nepheline Liquidus: Application to Nuclear Waste Glass Processing  

SciTech Connect

The crystal-melt equilibria in complex fifteen component melts are modeled based on quasicrystalline concepts. A pseudobinary phase diagram between acmite (which melts incongruently to a transition metal ferrite spinel) and nepheline is defined. The pseudobinary lies within the Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3}-Na{sub 2}O-SiO{sub 2} quaternary system that defines the crystallization of basalt glass melts. The pseudobinary provides the partitioning of species between the melt and the primary liquidus phases. The medium range order of the melt and the melt-crystal exchange equilibria are defined based on a constrained mathematical treatment that considers the crystallochemical coordination of the elemental species in acmite and nepheline. The liquidus phases that form are shown to be governed by the melt polymerization and the octahedral site preference energies. This quasicrystalline liquidus model has been used to prevent unwanted crystallization in the world's largest high level waste (HLW) melter for the past three years while allowing >10 wt% higher waste loadings to be processed.

Jantzen, Carol

2005-10-10

148

Nuclear Spin Lattice Relaxation and Conductivity Studies of the Non-Arrhenius Conductivity Behavior in Lithium Fast Ion Conducting Sulfide Glasses  

SciTech Connect

As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages of ethanol in gasoline. Consumers are increasingly demanding that energy sources be more powerful, more durable, and, ultimately, more cost efficient. Fast Ionic Conducting (FIC) glasses are a material that offers great potential for the development of new batteries and/or fuel cells to help inspire the energy density of battery power supplies. This dissertation probes the mechanisms by which ions conduct in these glasses. A variety of different experimental techniques give a better understanding of the interesting materials science taking place within these systems. This dissertation discusses Nuclear Magnetic Resonance (NMR) techniques performed on FIC glasses over the past few years. These NMR results have been complimented with other measurement techniques, primarily impedance spectroscopy, to develop models that describe the mechanisms by which ionic conduction takes place and the dependence of the ion dynamics on the local structure of the glass. The aim of these measurements was to probe the cause of a non-Arrhenius behavior of the conductivity which has been seen at high temperatures in the silver thio-borosilicate glasses. One aspect that will be addressed is if this behavior is unique to silver containing fast ion conducting glasses. more specifically, this study will determine if a non-Arrhenius correlation time, {tau}, can be observed in the Nuclear Spin Lattice Relaxation (NSLR) measurements. If so, then can this behavior be modeled with a new single distribution of activation energies (DAE) to calculate the corresponding conductivity and relaxation rates as a function of temperature and frequency?

Benjamin Michael Meyer

2003-05-31

149

Thermal Conductivity of Glasses Induced by Nuclear Quadrupole Interaction at Ultra Low Temperatures  

NASA Astrophysics Data System (ADS)

It is investigated how nuclear degrees of freedom of tunneling system (TS) inherent in amorphous solids influence its acoustic properties. It was shown in our previous papers that below 10 mK nuclear quadrupole interaction breaks down the coherent tunneling. This phenomenon results in appearance of the quasi-gap in the distribution function for the tunneling amplitude splitting. The quasi-gap is responsible for the plateau in the temperature dependence of the real part of a dielectric permittivity or speed of sound. In this paper we are interested in ultrasonic absorption and thermal conductivity which are intimately connected. We demonstrate that there exists a temperature interval in a millikelvin region where the sound absorption behavior changes drastically from the behavior predicted by the standard tunneling model (STM). In particular, the sound absorption increases approximately by an order of magnitude. Since in the millikelvin region the heat transport is due to acoustic phonons, the thermal conductivity also should demonstrate a strong increase as compared to standard tunneling model. The application of a strong magnetic field is known to restore the coherent tunneling and the standard distribution for the tunneling splitting amplitude. Thus, one can expect that in a strong magnetic field the thermal conductivity should drop in the temperature interval where the coherent tunneling was initially destroyed.

Polishchuk, I. Y.; Burin, A. L.

2011-03-01

150

Micro-fluidics and integrated optics glass sensor for in-line micro-probing of nuclear samples  

SciTech Connect

We study the miniaturisation of Thermal Lens Spectrometry (TLS) towards Lab-on-chip integration in order to reduce the volume of fluid assays in nuclear process control. TLS is of great interest in this context since it combines the advantages of optical detection methods with an inherent suitability for small-scale samples. After validating the experimental principle in a classical thermal lens crossed-beam setup, we show the integration of a Young-interferometer with a microcapillary on a glass substrate, reducing the necessary sample size to 400 nl. The interferometer translates the photo-thermally induced refractive index change in the fluid to a phase shift of the fringe pattern, which can then be detected by a camera. Measurements of Co(II) in ethanol yield a detection limit of c = 5 x 10{sup -4} M for the crossed-beam setup and c = 6x10{sup -3} M for the integrated sensor. At an interaction length of 10 {mu}m, it detects a minimum absorbance of AU = 6 x 10{sup -5} in a probed volume of 10 pl. (authors)

Schimpf, A. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France); Canto, F. [Commissariat a l'Energie Atomique CEA de Marcoule, DEN - DRCP - SEAA - LAMM, BP17171, 30207 Bagnols sur Ceze Cedex (France); Bucci, D. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France); Magnaldo, A.; Couston, L. [Commissariat a l'Energie Atomique CEA de Marcoule, DEN - DRCP - SEAA - LAMM, BP17171, 30207 Bagnols sur Ceze Cedex (France); Broquin, J. E. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France)

2011-07-01

151

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

SciTech Connect

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.

Kruger, A.A.

1995-07-01

152

A 25-year laboratory experiment on French SON68 nuclear glass leached in a granitic environment - First investigations  

NASA Astrophysics Data System (ADS)

We have investigated a 25.75-year old leaching experiment to improve our understanding of the mechanisms controlling glass dissolution in geological disposal conditions. A SON68 glass block was leached in slowly renewed synthetic groundwater (at 90 °C, 100 bar) in contact with some pieces of granite and Ni-Cr-Mo alloy as environmental storage materials. One hundred and sixty-three samplings were carried out over the entire duration of the experiment and were used to calculate the mean thickness of the altered glass (28 (±9) ?m) and the glass dissolution rate. After few months, the rate remained very constant at 6 × 10 -3 g m -2 d -1 which is about 20 times higher than the residual rate measured in a batch reactor at the same temperature. At the end of the experiment, mainly SEM analyses were performed on the entire glass block. Surprisingly, the glass alteration layer has neither a homogeneous thickness, nor a homogeneous morphology. The location of the sampling valve (at half height of the glass block) seems to divide the glass block into two parts. In the upper half (above the sampling valve), the general morphology of the alteration layer consists in a relatively simple and uniform gel and some secondary phases which are rare-earth phosphates. The mean measured thickness of this alteration layer is 6.7 (±0.3) ?m. However, in the lower half of the glass block, the gel is globally larger and frequently contains rounded shapes which are rare-earth phosphates. This section is edged by secondary phases bearing Mg, Na, Zn and Ni. The mean measured thickness is 81.3 (±1.1) ?m in the lower half. In this experiment, the flow rate which leads to the hydrodynamic transport of the soluble species must be a key factor for the local glass alteration process. We have also shown that this unexpected behavior is likely due to heterogeneities of the chemistry of the solution. This conclusion is supported by the behavior of Mg. This element, supplied by the inlet solution, precipitates with Si and forms clay minerals and therefore weakens the passivating properties of the gel. Mg-rich clay minerals are only observed in the lower half of the glass block. Further investigations are necessary to better understand the coupling between the hydrodynamics and chemistry in this experiment. However, based on this study, we can conclude that glass in disposal should be very sensitive to the water renewal near the glass surface.

Guittonneau, C.; Gin, S.; Godon, N.; Mestre, J. P.; Dugne, O.; Allegri, P.

2011-01-01

153

Radiation effects in moist-air systems and the influence of radiolytic product formation on nuclear waste glass corrosion.  

National Technical Information Service (NTIS)

Ionizing radiation may affect the performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water to produce a variety of radiolytic products. Tests were conducted to examine the effects of radiolysis under hig...

D. J. Wronkiewicz E. C. Buck J. C. Hoh J. K. Bates J. W. Emery

1997-01-01

154

Secondary phase formation and the microstructural evolution of surface layers during vapor phase alteration of the French SON 68 nuclear waste glass at 200{degrees}C  

SciTech Connect

The SON 68 inactive {open_quotes}R7T7{close_quotes} composition is the French reference glass for the LWR nuclear waste glass. Vapor phase alteration was used to accelerate the reaction progress of glass corrosion and to develop the characteristic suite of secondary, alteration phases. Extensive solid-state characterization (AEM/SEM/HRTEM) was completed on six inactive R7T7 waste glasses which were altered in the presence of saturated water vapor (200{degrees}C) for 91, 241, 908, 1000, 1013, and 1021 days. The AEM samples were examined in cross-section (lattice-fringe imaging, micro-diffraction, and quantitative thin-film EDS analysis). The glass monoliths were invariably covered with a thin altered rind. The layer became thicker with time: 0.5 {mu}m for 22 days; 4 {mu}m for 91 days; 6 {mu}m for 241 days; 10 {mu}m for 908 days; 26 {mu}m for 1013 days; and <35 {mu}m for 1021 days. The composite alteration layer of the SON 68 samples is at least four time less thick than that of the SRL 131 glass composition. Six distinctive zones, based on phase chemistry and microstructure, were distinguished within the well-developed surface layers. Numerous crystalline phases such as analcime, tobermorite, apatite, and weeksite were identified on the surfaces of the reacted glasses as precipitates. Two crystalline phases, Ag{sub 2}TeO{sub 3} and (Ca,Sr)Mo{sub 3}O{sub 9}(OH){sub 2}, were found within the inner zones of surface layers, and they must have nucleated in situ, indicating that Ag, Te, Sr, and Mo can be retained within the surface layer. The majority of the surface layer volume is composed of two morphologically and chemically different structures: one consists of well-crystallized fibrous smectite aggregates occurring along with cavities, the A-domain; and the other consists of poorly-crystallized regions containing needle-like smectite (montmorillonite) crystallites, a silica-rich amorphous matrix, and possibly ZrO{sub 2} particles, the B-domain.

Gong, W.L.; Ewing, R.C.; Wang, L.M. [Univ. of New Mexico, Albuquerque, NM (United States)] [and others

1995-12-31

155

Application of EQ3/6 to modeling of nuclear waste glass behavior in a tuff repository  

SciTech Connect

Modeling of glass degradation based on sound geochemical principles appears to be possible with revisions to EQ3/6. Realistic source terms for several repository scenarios may be generated with such a model. One scenario which appears very likely and which is also amenable to modeling using EQ3/6 is that in which an intact but perforated canister holds water in contact with waste glass. The water overflows continuously or periodically, allowing radionuclides to come in contact with repository rock. This isolated-type scenario will be the first realistic modeling effort because it limits complex interactions between rock and glass. However, EQ3/6 modeling should be possible even for very complicated scenarios if sufficient experimental data are available on rates and thermodynamics. This will be the limiting factor in progress toward modeling the complete system.

Aines, R.D.

1986-05-01

156

DEVELOPMENT OF GLASS COMPOSITIONS TO IMMOBILIZE ALKALI, ALKALINE EARTH, LANTHANIDE AND TRANSITION METAL FISSION PRODUCTS FROM NUCLEAR FUEL REPROCESSING  

SciTech Connect

The Advanced Fuel Cycle Initiative (AFCI) waste management strategy revolves around specific treatment of individual or groups of separated waste streams. A goal for the separations processes is to efficiently manage the waste to be dispositioned as high level radioactive waste. The Advanced Fuel Cycle Initiative (AFCI) baseline technology for immobilization of the lanthanide (Ln) and transition metal fission product (TM) wastes is vitrification into a borosilicate glass. A current interest is to evaluate the feasibility of vitrifying combined waste streams to most cost effectively immobilize the wastes resulting from aqueous fuel reprocessing. Studies showed that high waste loadings are achievable for the Ln only (Option 1) stream. Waste loadings in excess of 60 wt % (on a calcined oxide basis) were demonstrated via a lanthanide borosilicate (LaBS) glass. The resulting glasses had excellent relative durability as determined by the Product Consistency Test (PCT). For a combined Ln and TM waste stream glass (Option 2), noble metal solubility was found to limit waste loading. However, the measured PCT normalized elemental releases for this glass were at least an order of magnitude below that of Environmental Assessment (EA) glass. Current efforts to evaluate the feasibility of vitrifying combined Ln, TM, alkali (Cs is the primary radionuclide of concern) and alkaline earth (Sr is the primary radionuclide of concern) wastes (Option 3) have shown that these approaches are feasible. However, waste loading limitations with respect to heat load (Cs/Sr loading), molybdenum solubility and/or noble metal solubility will likely be realized and must be considered in determining the cost effectiveness of these approaches.

Marra, J.; Billings, A.

2009-06-24

157

DEVELOPMENT OF GLASS COMPOSITIONS TO IMMOBILIZE ALKALI, ALKALINE EARTH, LANTHANIDE AND TRANSITION METAL FISSION PRODUCTS FROM NUCLEAR FUEL REPROCESSING  

SciTech Connect

The Advanced Fuel Cycle Initiative (AFCI) waste management strategy revolves around specific treatment of individual or groups of separated waste streams. A goal for the separations processes is to efficiently manage the waste to be dispositioned as high level radioactive waste. The Advanced Fuel Cycle Initiative (AFCI) baseline technology for immobilization of the lanthanide (Ln) and transition metal fission product (TM) wastes is vitrification into a borosilicate glass. A current interest is to evaluate the feasibility of vitrifying combined waste streams to most cost effectively immobilize the wastes resulting from aqueous fuel reprocessing. Studies showed that high waste loadings are achievable for the Ln only (Option 1) stream. Waste loadings in excess of 60 wt % (on a calcined oxide basis) were demonstrated via a lanthanide borosilicate (LaBS) glass. The resulting glasses had excellent relative durability as determined by the Product Consistency Test (PCT). For a combined Ln and TM waste stream glass (Option 2), noble metal solubility was found to limit waste loading. However, the measured PCT normalized elemental releases for this glass were at least an order of magnitude below that of Environmental Assessment (EA) glass. Current efforts to evaluate the feasibility of vitrifying combined Ln, TM, alkali (Cs is the primary radionuclide of concern) and alkaline earth (Sr is the primary radionuclide of concern) wastes (Option 3) have shown that these approaches are feasible. However, waste loading limitations with respect to heat load (Cs/Sr loading), molybdenum solubility and/or noble metal solubility will likely be realized and must be considered in determining the cost effectiveness of these approaches.

Marra, James C.; Billings, Amanda Y.; Crum, Jarrod V.; Ryan, Joseph V.; Vienna, John D.

2010-02-26

158

Experimental Hydration Studies of Natural and Synthetic Glasses.  

National Technical Information Service (NTIS)

The results of a series of hydration experiments on natural glasses (Hawaiian basalt, obsidian) and the nuclear waste glass WV-44 done to examine laboratory methods of accelerating reaction processes are summarized. The glasses were reacted in hydrotherma...

J. K. Bates T. A. Abrajano W. L. Ebert J. J. Mazer T. J. Gerding

1988-01-01

159

Direct conversion of surplus fissile materials, spent nuclear fuel, and other materials to high-level-waste glass  

Microsoft Academic Search

With the end of the cold war the United States, Russia, and other countries have excess plutonium and other materials from the reductions in inventories of nuclear weapons. The United States Academy of Sciences (NAS) has recommended that these surplus fissile materials (SFMs) be processed so they are no more accessible than plutonium in spent nuclear fuel (SNF). This spent

C. W. Forsberg; K. R. Elam

1995-01-01

160

Does fully radioactive glass behave differently than simulated waste glass  

SciTech Connect

There has been interest in the comparison of the leach behavior between fully radioactive and simulated nuclear waste glasses, to assess the differences in reaction mechanism, type, and sequence of secondary phases, and the relative durability among the two types of glasses. The results from these comparisons will provide confidence in the use of the large amount of the data generated in the studies of simulated nuclear waste glass for the modeling of performance of radioactive glasses. Most of the previous comparison studies have been performed at a low to intermediate ratio of glass surface area to solution volume and for time periods of less than one year. These studies have generally concluded there is a little difference in leach behavior between the two glass types. This study reinvestigates that conclusion by utilizing an extensive test matrix, with SA/V ranging between 340 to 20,000 m[sup 1] on three waste glass compositions, for time periods planned up to eight years. The early results are consistent with other studies, in that the leach behavior of simulated waste glasses is similar to that of fully radioactive glasses. However, the longer-term tests at higher SA/V suggest that the leach behavior of the two types of glass diverges, under certain conditions. The longer-term comparison of the leach behavior is discussed.

Feng, X.; Bates, J.K.; Bradley, C.R.; Buck, E.C.

1992-01-01

161

Does fully radioactive glass behave differently than simulated waste glass?  

SciTech Connect

There has been interest in the comparison of the leach behavior between fully radioactive and simulated nuclear waste glasses, to assess the differences in reaction mechanism, type, and sequence of secondary phases, and the relative durability among the two types of glasses. The results from these comparisons will provide confidence in the use of the large amount of the data generated in the studies of simulated nuclear waste glass for the modeling of performance of radioactive glasses. Most of the previous comparison studies have been performed at a low to intermediate ratio of glass surface area to solution volume and for time periods of less than one year. These studies have generally concluded there is a little difference in leach behavior between the two glass types. This study reinvestigates that conclusion by utilizing an extensive test matrix, with SA/V ranging between 340 to 20,000 m{sup 1} on three waste glass compositions, for time periods planned up to eight years. The early results are consistent with other studies, in that the leach behavior of simulated waste glasses is similar to that of fully radioactive glasses. However, the longer-term tests at higher SA/V suggest that the leach behavior of the two types of glass diverges, under certain conditions. The longer-term comparison of the leach behavior is discussed.

Feng, X.; Bates, J.K.; Bradley, C.R.; Buck, E.C.

1992-12-31

162

Development of continuous liquid-fed laboratory-scale mini-melter for nuclear waste glass development  

SciTech Connect

A small, continuous liquid-fed mini-melter (LFMM) has been developed at Pacific Northwest Laboratory (PNL) to aid in waste glass feed slurry development. The LFMM offers several advantages over testing in large-scale melters. The LFMM requires little lead time in preparing for a test run, and the labor and material requirements are low. Real-time melting behavior of liquid feed slurries can be investigated, and feed rates can be estimated for larger-scale melters. The glass produced is representative of that produced by a larger-scale melter, as well as representative of the processing operation itself. Glass produced by the LFMM may subsequently be analyzed for metallic and other secondary phase formation. In contrast to larger-scale melters, the LFMM may be easily and inexpensively installed in a hot cell because of its relatively small size and simple configuration, enabling testing of radioactive feeds. A total of six LFMM experimental runs were performed. Feeds were obtained which corresponded to PNL melter runs performed in larger PNL developmental joule-heated research melters. These nonradioactive liquid-fed ceramic melters are known as the High-Bay Ceramic Melter (HBCM), the Experimental Ceramic Melter (ECM), and the Pilot-Scale Ceramic Melter (PSCM). Preliminary results obtained with the limited testing are promising. Feeds processed in the LFMM exhibited behavior closely resembling that observed in the large-scale melters. Feed rate correlations between the LFMM and ECM, HBCM, and PSCM were developed to estimate a range of expected feed rates for the large-scale melters from LFMM data. More developmental work with LFMM testing needs to be completed. Further testing will eliminate bias and establish the LFMM's true correlation to, and representation of, large-scale melters.

Reimus, M.A.H.; Marschman, S.C.; Graff, G.L.

1987-02-01

163

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

National Technical Information Service (NTIS)

This report discusses a methodology for increasing the efficiency and decreasing the cost of vitrifying nuclear waste by optimizing waste-glass formulation. This methodology involves collecting and generating a property-composition database (for glass pro...

D. Kim J. Vienna P. Hrma

2002-01-01

164

Biodegradation of the french reference nuclear glass SON 68 by Acidithiobacillus thiooxidans : protective effect of the biofilm,U and REE retention  

NASA Astrophysics Data System (ADS)

Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 ?m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25°C. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, traces and ultra-traces elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 ?m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials can be found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium, molybdenum and caesium as tracers, showed that the biofilm has a protective effect against glass alteration. U and REE are efficiently trapped in the biogenic compartment of the system (exopolysaccharides (EPS) + bacterial cells). Biofilm analysis are in progress to determine whether these elements are in bacterial cells or in the EPS. . Aouad G., Crovisier J.-L., Damidot D., Stille P., Hutchens E., Mutterer J., Meyer J.-M., and Geoffroy V. A. (2008) Interactions between municipal solid waste incinerator bottom ash and bacteria (Pseudomonas aeruginosa). Science of The Total Environment 393(2-3), 385-393.

Bachelet, M.; Crovisier, J.; Stille, P.; Boutin, R.; Vuilleumier, S.; Geoffroy, V.

2008-12-01

165

Chalcogenide Glasses,  

National Technical Information Service (NTIS)

Although there are some significant exceptions, most important glass-forming systems contain elements from the sixth, or chalcogenide, column of the periodic table (oxygen, sulfur, selenium, or tellurium). The glasses which contain oxygen are typically in...

P. C. Taylor

1987-01-01

166

Glass corrosion in natural environments  

NASA Technical Reports Server (NTRS)

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 carried out on these glasses in order to characterize their magnetic properties. Results of these studies are described.

Thorpe, Arthur N.; Barkatt, Aaron

1992-01-01

167

Glass Artworks  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

168

Simultaneous Nuclear Reaction Analysis of Boron and Phosphorus in Thin Borophosphosilicate Glass Films Using (A,P) Reactions  

SciTech Connect

A method combining ({alpha},p) NRA and ellipsometry has been developed for measuring the Boron and Phosphorus content of borophosphosilicate glass (BPSG) used for interlevel dielectrics in integrated circuits. Yields from the {sup 31}P({alpha},p{sub 0}){sup 34}S (Q = 0.63 MeV) and {sup 10}B({alpha},p{sub 0}) {sup 13}C (Q = 4.06 MeV) reactions are coupled with ellipsometry thickness measurements to calculate the average atomic percent of B and P in the film. Due to the relatively low Q value of the {sup 31}P({alpha},p{sub 0}){sup 34}S reaction and the thickness range of the glass films ({le} 1.2 micrometers) they analyze, fairly high energy alpha particles, and Mylar range foils on the detector are required. Alpha energy, detector angle and range foil thickness were determined by reaction yields and the need to separate the yield peaks of interest from competing ({alpha},p) reactions and backscattered alphas. They have determined that 6.0 MeV incident alphas with a detector angle of 135{degree} and about 100 micrometers of Mylar range foil are optimum for the system. The yield for the {sup 10}B({alpha},p{sub 0}) {sup 13}C reaction is quite constant in the energy range of interest ({approximately} 5.8 to 6 MeV) but the yield for the {sup 31}P({alpha},p{sub 0}){sup 34}S is not. Consequently, a simple conversion from standard BPSG reference samples (independently quantified by ICP mass spectrometry) is adequate to calculate a film's %B content. The %P calculation is more complex, involving a three-dimensional fit of the P yield data and measured film thickness to the film %P content. This fit is based upon yield data from a matrix of standard film samples. The technique is sensitive to 0.1% with an accuracy of {+-}3 to {+-}10% depending on the sample. This measurement method is used routinely at Sandia National Laboratories in support of their fabrication process lines.

Walsh, D.S.; Doyle, B.L.

1999-06-22

169

Glass research  

NASA Technical Reports Server (NTRS)

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.

Weinberg, M. C.

1985-01-01

170

glass ceramic  

NASA Astrophysics Data System (ADS)

Glass sample with a composition of Li1.3Nb0.3Fe1.7(PO4)3, prepared by a conventional melt-quenching method, was heat treated to obtain glass ceramics of NASICON type. Glass transition ( T g) and crystallization ( T c) temperatures of as-quenched glass sample were determined by differential thermal analysis (DTA). X-ray diffraction (XRD) patterns also confirmed the formation of glass sample. After heat treatment above T c, precipitation of crystalline particles with NASICON-type structure was confirmed by XRD. Valency and local structure of Fe atoms were investigated by Mössbauer spectroscopy at room temperature. DC-conductivity and impedance measurements of the glass ceramics proved the increased electrical conduction caused by heat treatment.

Hassaan, M. Y.; Salem, S. M.; Moustafa, M. G.; Kubuki, S.; Matsuda, K.; Nishida, T.

2014-04-01

171

Glass Electrolytes.  

National Technical Information Service (NTIS)

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 exp 0 C) and is stable in the cell environment. Experiments in this program are focussed on glasses in the quaternary sy...

1984-01-01

172

Metallic glasses.  

PubMed

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. PMID:17770105

Greer, A L

1995-03-31

173

Rainbow Glasses  

NSDL National Science Digital Library

In this activity, learners explore light, color and rainbows by making their own rainbow glasses. Learners glue "rainbow optics paper" onto the glasses cutout, add decorations and attach pipe cleaner earpieces. Learners name the different colors they observe and notice that the colors always appear in the same order. This activity guide includes open-ended questions to help learners explore these topics further.

Omsi

2004-01-01

174

Frosty Glasses  

NSDL National Science Digital Library

In this activity, learners explore why frost forms. They create their own frost using a solution of ice water and salt in a glass. The salt allows the temperature of the water to drop below the normal freezing point, so that water vapor in the air turns directly into solid ice on the surface of the glass.

Cosi

2009-01-01

175

Optical properties and structure of Pr3+-doped Al(PO3)3-LiF glasses as scattered neutron scintillator for nuclear fusion diagnostics  

NASA Astrophysics Data System (ADS)

Scattered neutron diagnostics is an indispensable tool for both inertial confinement and magnetic confinement fusion research. For this purpose, a fast-response neutron scintillator with a high cross section for scattered neutrons is strongly required. Recently, based on our material design strategy, we have successfully developed the fast response time Pr3+-doped 20Al(PO3)3-80LiF glass scintillator for scattered neutron originated from inertial confinement fusion. The matrix glass 20Al(PO3)3-80LiF shows good glass forming ability, chemical durability and transparency in the deep ultraviolet region. The purpose of this work is to investigate the glass structure of 20Al(PO3)3-80LiF glasses using Raman spectroscopy and to discuss the relationship between physical and scintillation properties and glass structure.

Murata, T.; Fujino, S.; Yoshida, H.; Arikawa, Y.; Nakazato, T.; Shimizu, T.; Sarukura, N.; Nakai, M.; Norimatsu, T.; Azechi, H.; Kamada, K.; Usuki, Y.; Suyama, T.; Yoshikawa, A.; Sato, N.; Kan, H.

2011-10-01

176

Glass-An Environmental Protector  

SciTech Connect

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.

MARRA, JAMES

2004-11-01

177

Comparison of mechanical properties of glass-bonded sodalite and borosilicate glass high-level waste forms.  

National Technical Information Service (NTIS)

Argonne National Laboratory has developed a glass-bonded sodalite waste form to immobilize the salt waste stream from electrometallurgical treatment of spent nuclear fuel. The waste form consists of 75 vol.% crystalline sodalite and 25 vol.% glass. Microi...

T. O'Holleran T. DiSanto S. Johnson K. Goff

2000-01-01

178

The leaching behavior of borate waste glass SL1  

Microsoft Academic Search

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak.

Jiawei Sheng; Shanggeng Luo; Baolong Tang

1999-01-01

179

Failure analysis of the lithium battery: A study of the header deposit on the cell top and diffusion within the electrode glass seal using nuclear microanalysis and FFTIR spectroscopy  

NASA Technical Reports Server (NTRS)

The Solid Rocket Booster Range Safety System (SRBRSS) uses a lithium/poly-carbon monofluoride primary battery as a source of electrical power. After cell fabrication and activation, some battery cells have shown self discharge. One possible source of this cell discharge has been suggested to be the formation and growth of a conducting crystallized chemical compound across the glass bead insulator, electrically shorting the glass bead to the casing. This laboratory has begun an analysis of this compound, the glass seal holding the cathode into place, and the cell electrolyte, using Fast Fourier Transform Infrared (FFTIR) Analysis, Rutherford Backscattering Spectroscopy (RBS), and Nuclear Reaction Microanalysis. Preliminary measurements have confirmed the existence of lithium, nitrogen, fluorine, and oxygen on a reddish-brown deposit covering parts of the glass seal holding the positive electrode in place. Cells using Li metal electrodes, have many advantages over conventional primary batteries. One principal disadvantage of using Li batteries on a commercial basis would be the environmental impact of the fluorocarbon material. Another would be the relatively high expense of (CF)n.

Hassan, Razi A.

1991-01-01

180

Optical Glass.  

National Technical Information Service (NTIS)

The patent describes an optical glass which contains SiO2, B2O3, GA2O3, NA2O, LI2O. A noncrystallizing glass with shortened partial dispersion in the blue portion of the spectrum is produced by using (in wt %): SiO2--30-60; B2O3--less than 12; GA2O3--30-4...

G. T. Petrovskii

1967-01-01

181

Edible Glass  

NSDL National Science Digital Library

In this activity, learners discover the principles of edible glass by making a supersaturated sugar solution. The goal of this activity is to provide an interesting experiment which learners of many different levels can perform. The write-up for this activity provides explanatory information that presents the experiment from several different perspectives. This activity includes an introduction to common sugars, as well as some discussion of temperature and thermometry, basic thermodynamics, and the experimental procedure to make the candy glass.

Pomeroy, Josh

2012-01-01

182

Plutonium dioxide dissolution in glass  

SciTech Connect

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

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

1996-09-01

183

Nuclear  

NSDL National Science Digital Library

What part does nuclear energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to the uranium atom as an energy source. Here students read about the history of nuclear energy, how energy is derived from uranium, and benefits of nuclear energy. Information is also provided about limitations, particularly disposal problems and radioactivity, and geographical considerations of nuclear power in the United States. Thought-provoking questions afford students chances to reflect on what they've read about the uses of nuclear power. Articles and information on new nuclear plant design and nuclear accidents are available from a sidebar. Five energy-related PBS NewsHour links are provided. A web link to the U.S. Nuclear Regulatory Commission is included. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

184

Nuclear magnetic resonance spectroscopic investigations of phase biaxiality in the nematic glass of a shape-persistent V-shaped mesogen.  

PubMed

Deuterium and carbon-13 NMR spectroscopy were used to study both the high temperature uniaxial nematic and the low temperature biaxial nematic glass of a shape-persistent V-shaped mesogen. It was found that biaxial ordering determined in the domains of the latter has symmetry lower than D(2h) and is compatible with C(2h) symmetry or lower. In particular, elements of the ordering matrix including biaxial phase order parameters were determined from (2)H NMR at two temperatures, one just below the glass transition, and the other deep inside the biaxial glass, which allowed for the characterization of the dominant molecular motions at these temperatures. (13)C NMR magic angle spinning sideband patterns, collected both in the high temperature nematic phase and in the nematic glass, clearly show the difference between them in terms of the phase symmetry. PMID:21054053

Figueirinhas, João L; Feio, Gabriel; Cruz, Carlos; Lehmann, Matthias; Köhn, Christiane; Dong, Ronald Y

2010-11-01

185

DURABLE GLASS FOR THOUSANDS OF YEARS  

SciTech Connect

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.

Jantzen, C.

2009-12-04

186

Durability of Silicate Glasses: An Historical Approach  

SciTech Connect

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.

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

2007-01-02

187

Inorganic glasses, glass-forming liquids and amorphizing solids  

NASA Astrophysics Data System (ADS)

We take familiar inorganic oxide glasses and non-oxide glasses and the liquids from which they derive to review the current understanding of their atomic structure, ranging from the local environments of individual atoms to the long-range order which can cover many interatomic distances. The structural characteristics of important glasses and melts, like silicates, borates, alumino-silicates, halides and chalcogenides, are drawn from the results of recent spectroscopy and scattering experiments. The techniques include Nuclear Magnetic Resonance (NMR) and X-ray Absorption Fine Structure (XAFS), Neutron Scattering (NS) and Small- and Wide-angle X-ray Scattering measurements (SAXS/WAXS), and are often combined with computer simulation experiments in order to obtain detailed images of structure and diffusion in the glassy as well as in the molten state. We then review the current understanding of relaxation in glasses, liquids and polyamorphic states. This includes phenomenological models and theories of relaxation in different dynamical regimes, spectroscopic studies of atomic-scale mechanisms of viscous flow in inorganic glass-formers and the signatures of relaxational behaviour embedded in the low-frequency vibrational dynamics of glasses including the Boson peak and the Two-Level Systems (TLS) that control conformational transformation. We conclude this review by extending concepts of the dynamics of the glass transition from the supercooled liquid in order to understand the solid-state amorphization of crystals under temperature and pressure and to determine the thermodynamic limits of the crystalline and glassy state.

Greaves, G. N.; Sen, S.

2007-01-01

188

Glass Ceramic Formulation Data Package  

SciTech Connect

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 waste form.

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

2012-06-17

189

Engineering Glass Passivation Layers Model Results  

Microsoft Academic Search

The immobilization of radioactive waste into glass waste forms is a baseline process of nuclear waste management not only in the United States, but worldwide. The rate of radionuclide release from these glasses is a critical measure of the quality of the waste form. Over long-term tests and using extrapolations of ancient analogues, it has been shown that well designed

Daniel C. Skorski; Joseph V. Ryan; Denis M. Strachan; William C. Lepry

2011-01-01

190

Effect of different glasses in glass bonded zeolite.  

National Technical Information Service (NTIS)

A mineral waste form has been developed for chloride waste salt generated during the pyrochemical treatment of spent nuclear fuel. The waste form consists of salt-occluded zeolite powders bound within a glass matrix. The zeolite contains the salt and immo...

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

1995-01-01

191

Metallic glasses  

SciTech Connect

The novel internal structures of metallic glasses lead to exceptional strength, corrosion resistance, and ease of magnetization. Combined with low manufacturing costs, these properties make glassy ribbons attractive for many applications. These materials also have scientific fascination because their compositions, structures, and properties have unexpected features.

Gilman, J.J.

1980-05-23

192

Pinhole Glasses  

ERIC Educational Resources Information Center

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…

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

2008-01-01

193

Topography of borosilicate glass reacting interface under aqueous corrosion  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations were performed to calculate the structure of a Na-borosilicate glass. The topography of an initial flat surface of this glass caused by the instantaneous release of atoms weakly bonded to the silicate network was studied, giving the minimum roughness of the surface. The resulting profiles were compared to experimental data obtained by atom probe tomography on a complex nuclear glass, after having verified that simulations are valid for the complex glass. As experimental profiles are much thicker, these comparisons support the concept that interdiffusion is a key mechanism controlling the long-term corrosion rate of nuclear glasses.

Delaye, J. M.; Kerrache, A.; Gin, S.

2013-11-01

194

Current status of the GLASS code  

SciTech Connect

This paper summarizes the current status of the Generalized Lattice Analysis SubSystem (GLASS) computer code and its supporting cross section libraries. GLASS was developed at the Savannah River Site (SRS) in the early 1970's. The GLASS code has been instrumental in supporting safe Heavy Water Reactor (HWR) operations and predicting material production at SRS for more than 20 years. The Department of Energy Office of New Production Reactors (ONPR) program has chosen to use the GLASS code for the design of the HWR option of the New Production Reactor (NPR). A substantial body of validation calculations have been performed and additional validation calculations will be performed to qualify the new GLASS multigroup cross section libraries derived from the ENDF/B-5 and 6 nuclear data files. Several improvements to the code are in progress. Many other improvements are planned to bring GLASS up to modern physics and compute technology.

Hootman, H.E. (Westinghouse Savannah River Co., Aiken, SC (United States)); Honeck, H.C. (Computer Application Technology, Inc., Aiken, SC (United States))

1991-01-01

195

Current status of the GLASS code  

SciTech Connect

This paper summarizes the current status of the Generalized Lattice Analysis SubSystem (GLASS) computer code and its supporting cross section libraries. GLASS was developed at the Savannah River Site (SRS) in the early 1970`s. The GLASS code has been instrumental in supporting safe Heavy Water Reactor (HWR) operations and predicting material production at SRS for more than 20 years. The Department of Energy Office of New Production Reactors (ONPR) program has chosen to use the GLASS code for the design of the HWR option of the New Production Reactor (NPR). A substantial body of validation calculations have been performed and additional validation calculations will be performed to qualify the new GLASS multigroup cross section libraries derived from the ENDF/B-5 and 6 nuclear data files. Several improvements to the code are in progress. Many other improvements are planned to bring GLASS up to modern physics and compute technology.

Hootman, H.E. [Westinghouse Savannah River Co., Aiken, SC (United States); Honeck, H.C. [Computer Application Technology, Inc., Aiken, SC (United States)

1991-12-31

196

Holograms writing on glass  

NASA Astrophysics Data System (ADS)

Holographic gratings recorded in photoresist, are used by common techniques of lithography, for writing on glass. We present a study of the technique used to erode the glass using hydrofluoric acid and copy the holographic element on the glass. We observe that holograms written in glass are very strong and durable. The behavior of the dispersion caused by the glass erosion also is studied.

Olivares-Pérez, Arturo; Fuentes-Tapia, Israel; Toxqui-López, Santa

2014-02-01

197

Borosilicate glass alteration driven by magnesium carbonates  

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

198

Combining two types of molecular dynamics for rapid computation of high-energy displacement cascades. II. Application of the method to a 70-keV cascade in a simplified nuclear glass  

NASA Astrophysics Data System (ADS)

A combined molecular dynamics method is proposed to accelerate the computation of displacement cascades in nuclear glass arising from recoil nuclei in the 70-100 keV energy range. The method combines two types of molecular dynamics calculations: classical MD with standard empirical potentials and a simplified form with the potentials reduced to their short-range component to estimate the morphology of a displacement cascade. With this method we were able to reconstitute the behavior of a simplified oxide glass impacted by a 70-keV projectile. Compared with the results obtained by classical molecular dynamics, mechanisms observed at lower energies (temporary depolymerization followed by progressive structure recovery) are correctly reproduced at 70 keV; the number of atom displacements and the intermediate depolymerization peak intensity remain linear at energies ranging from 0 to 70 keV. The large volume of the 70-keV cascade allowed us to demonstrate that structure recovery was not homogeneous: the coolest regions were less annealed than the hottest regions. The residual depolymerization was more intense in regions struck by lower-energy projectiles—i.e., at the end of the cascade. Local thermal agitation in the hottest regions rapidly diminished as it propagated, and the neighboring regions were largely unaffected. Thermal agitation in the hottest regions thus had little effect on the recovery of regions impacted by low-energy projectiles.

Delaye, J.-M.; Ghaleb, D.

2005-06-01

199

Strength of inorganic glass  

SciTech Connect

This book presents information on the following topics: a look at the history of glass strength; atomistic theory of fracture; surface chemistry in relation to the strength and fracture of silicate glasses; high-speed photographic investigations of the dynamic localized loading of some oxide glasses; a correction for measurements of contact area using Newton's rings; envionmentally enhanced crack growth; fatigue in glass; behavior of flaws in fused silica fibers; fracture toughness of chalcogenide glasses and glass-ceramics; fracture analysis of glass surfaces; and fracture mechanics parameters for glasses - a compilation and correlation.

Kurkjian, C.R.

1985-01-01

200

Analytical electron microscopy study of surface layers formed on the french SON68 nuclear waste glass during vapor hydration at 200{degree}C.  

SciTech Connect

Extensive solid-state characterization (AEM/SEM/HRTEM) was completed on six SON68 (inactive R7T7) waste glasses which were altered in the presence of saturated water vapor (200{sup o}C) for 22, 91, 241, 908, 1000, 1013, and 1021 days. The samples were examined by AEM in cross-section (lattice-fringe imaging, micro-diffraction, and quantitative thin-film EDS analysis). The glass monoliths were invariably covered by a thin altered rind, and the surface layer thickness increased with increasing time of reaction, ranging from 0.5 to 30 {mu}m in thickness. Six distinctive zones, based on phase chemistry and microstructure, were distinguished within the well-developed surface layers. Numerous crystalline phases such as analcime, gyrolite, tobermorite, apatite, and weeksite were identified on the surfaces of the reacted glasses as precipitates. The majority of the surface layer volume was composed of two basic structures that are morphologically and chemically distinct: The A-domain consisted of well-crystallized fibrous smectite aggregates; and the B-domain consisted of poorly-crystallized regions containing smectite, possibly montmorillonite, crystallites and a ZrO{sub 2}-rich amorphous silica matrix. The retention of the rare-earth elements, Mo, and Zr mostly occurred within the B-domain; while transition metal elements, such as Zn, Cr, Ni, Mn, and Fe, were retained in the A-domain. The element partitioning among A-domains and B-domains and recrystallization of the earlier-formed B-domains into the A-domain smectites were the basic processes which have controlled the chemical and structural evolution of the surface layer. The mechanism of surface layer formation during vapor hydration are discussed based on these cross-sectional AEM results.

Gong, W. L.; Wang, L. M.; Ewing, R. C.; Vernaz, E.; Bates, J. K.; Ebert, W. L.; Chemical Engineering; Univ. of New Mexico; CEA-VALRHO

1998-04-01

201

Analytical electron microscopy study of surface layers formed on the French SON68 nuclear waste glass during vapor hydration at 200°C  

NASA Astrophysics Data System (ADS)

Extensive solid-state characterization (AEM/SEM/HRTEM) was completed on six SON68 (inactive R7T7) waste glasses which were altered in the presence of saturated water vapor (200°C) for 22, 91, 241, 908, 1000, 1013, and 1021 days. The samples were examined by AEM in cross-section (lattice-fringe imaging, micro-diffraction, and quantitative thin-film EDS analysis). The glass monoliths were invariably covered by a thin altered rind, and the surface layer thickness increased with increasing time of reaction, ranging from 0.5 to 30 ?m in thickness. Six distinctive zones, based on phase chemistry and microstructure, were distinguished within the well-developed surface layers. Numerous crystalline phases such as analcime, gyrolite, tobermorite, apatite, and weeksite were identified on the surfaces of the reacted glasses as precipitates. The majority of the surface layer volume was composed of two basic structures that are morphologically and chemically distinct: The A-domain consisted of well-crystallized fibrous smectite aggregates; and the B-domain consisted of poorly-crystallized regions containing smectite, possibly montmorillonite, crystallites and a ZrO 2-rich amorphous silica matrix. The retention of the rare-earth elements, Mo, and Zr mostly occurred within the B-domain; while transition metal elements, such as Zn, Cr, Ni, Mn, and Fe, were retained in the A-domain. The element partitioning among A-domains and B-domains and recrystallization of the earlier-formed B-domains into the A-domain smectites were the basic processes which have controlled the chemical and structural evolution of the surface layer. The mechanism of surface layer formation during vapor hydration are discussed based on these cross-sectional AEM results.

Gong, W. L.; Wang, L. M.; Ewing, R. C.; Vernaz, E.; Bates, J. K.; Ebert, W. L.

1998-04-01

202

Glass melter off-gas system pluggages: Cause, significance, and remediation.  

National Technical Information Service (NTIS)

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. Experimental glass melters, used to develop the vitrification process, have occasionally experienced problems with pluggage of the...

C. M. Jantzen

1991-01-01

203

Optical Absorption, ESR and Termoluminescence (TL) in Copper-Doped Lithium Borate Glasses.  

National Technical Information Service (NTIS)

Boron oxide plays a significant role in numerous glasses of high technological importance, such as nuclear wastes management, electronics, low density fibrous silica insulation used in space vehicles, and radiation dosimetry. Lithium borate glasses were p...

E. F. Chinaglia M. L. F. Nascimento M. Matsuoka S. Watanabe

1999-01-01

204

Gaseous Sulfate Solubility in Glass: Experimental Method  

SciTech Connect

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.

Bliss, Mary

2013-11-30

205

Alteration of glasses by micro-organisms  

NASA Astrophysics Data System (ADS)

Micro-organisms are suspected to play a basic part in materials alteration. Obviously, they will be present in nuclear waste repositories, either introduced by technological activity or laid by fluids circulation. Their metabolism may induce chemical modifications to the surrounding media and then affect the durability of storage materials. Biodegradation of glasses is studied in the Pierre Süe Laboratory. In the frame of a collaboration with microbiologists interested in stained glasses alteration, leaching experiments with various species of bacteria and fungi are carried out. Ion beam analysis techniques are performed to quantify surface modification of glasses and elemental incorporation in micro-organisms. Analyses of the solutions will lead to a complete assessment of elemental exchanges between glass sample, culture media and micro-organisms. In this paper, preliminary results on characterisation of glasses and micro-organisms and the first results of leaching experiments are presented.

Gallien, Jean-Paul; Gouget, Barbara; Carrot, Francine; Orial, Geneviève; Brunet, Anne

2001-07-01

206

Electron Spin Resonance Study of Fe3+ and Mn2+ Ions in 17-Year-Old Nuclear-Waste-Glass Simulants Containing PuO2 with Different Degrees of 238Pu Substitution  

SciTech Connect

Three samples of a model nuclear waste glass, DRG-P1, P2, and P3, were prepared at PNNL in 1982 with identical chemical compositions but were respectively batched with 0.0, 0.1, and 0.9 wt% of 238PuO2 (half life 87.8 years) partially replacing the 1.0 wt% 239PuO2 present in DRG-P1. In 1999, samples of these glasses were sent to the Naval Research Laboratory for electron spin resonance (ESR) measurements. No radiation-induced point defects were observed. Profound alpha decay-induced changes in the ESR spectra of the batched iron-group ions were found. The spectra recorded for DRG-P1 were shown by absolute spin counts to have ESR intensities equivalent to ~85% of the sum of the batched 8.28 mole% Fe3+ and 2.79 mole% Mn2+, assuming all of those ions to behave as paramagnetic S=5/2 states at room temperature. Separate experiments and calculations ruled out the possibility of precipitated magnetite-like precipitates comprising even so much as 0.01% of the total iron. A relatively weak ESR spectral feature observed at g=4.3 is the known signature of dilute Fe3+ in glasses. However, the strongest ESR signal was found to be characterized by a first-derivative zero crossing at g=2.06 and a peak-to-peak derivative linewidth of ~150 mT, which is virtually invariant in shape with both measurement temperature and alpha-decay dose. It was discovered that these broad line shapes could be accurately simulated as weighted sums of Lorentzian shape functions of differing widths but having the same g value. The absence of any measurable anisotropy in the broad line, coupled with the temperature invariance of its width, imply the existence of extremely strong exchange interactions within clusters of Fe3+, Fe2+, Mn2+, and Ni2+ ions characterized by extremely short-range magnetic order. The result is a speromagnetic system rather than exhibiting a distinct Néel temperature. The most evident ESR effect of 17 years of 238Pu decay is the (irreversible) lowering of the intensity of the "broad line" in rough proportion to the amount of 238Pu in the sample, with concomitant increases in the amplitude of the g=4.3 feature. It was additionally observed that cooling these glasses to successively lower temperatures gives rise to reversible lowering of the broad-line intensity and increasing of the strength of the g=4.3 feature when compared with theoretical expectation for non-interacting paramagnets. The truly remarkable observation that the broad lines could be simulated as weighted sums of pure Lorentzian functions of differing widths fortuitously opened the way for high precision measurements of the ESR intensities of experimental spectra that are far broader than the magnetic field range of the available laboratory electromagnets. The areas under the simulated absorption curves fitted to the experimental spectra in the manner described provided an empirical measure of the degrees to which the present model nuclear waste glasses had been affected by alpha-decay self irradiation. Specifically, the broad-line ESR integrated-intensity data as a function of 238Pu alphadecay dose (proportional to the 238Pu doping level in these fixed-time experiments) proved to be accurately fitted by a simple saturating exponential function asymptotic to zero for infinite-time self irradiation. This result promises a precise means of extrapolating thousands of years into the future the process of "super-vitrification" that results from the creation and rapid quenching of thermal spikes due to alpha decay in glasses immobilizing 239Pu and other actinide elements. In addition, because the ESR spectra of several very different candidate high-level nuclear waste (HLW) glass compositions containing even higher amounts of Fe2O3 are also shown here to be decomposable into sums of pure Lorentzians, the analytical method we describe should be applicable to these and many other HLW glasses containing both iron-group oxides and radionuclides.

Griscom, David L.; Weber, William J.

2011-03-01

207

Glass Compositions Having Fluorescence Properties.  

National Technical Information Service (NTIS)

The patent application concerns glasses such as borate glass, phosphate glass, calibo glass and germanate glass containing predetermined quantities of certain components adapted to result in the emission of radiation in the desired spectral range, and at ...

R. Reisfeld Y. Eckstein L. Boehm

1976-01-01

208

Chemical Principles Revisited: The Chemistry of Glass.  

ERIC Educational Resources Information Center

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)

Kolb, Doris; Kolb, Kenneth E.

1979-01-01

209

Repairing cracked glass  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

210

Ultraviolet Faraday Rotator Glass.  

National Technical Information Service (NTIS)

A Faraday rotator glass composition based on a fluoride glass, phosphate glass, fluorophosphate glass or a mixture there of is dope with a lanthanide in concentration sufficient to provide a Verdet constant above at least 2870 deg/Tesla-meter (1 MIN/CM-Oe...

J. L. Dexter D. G. Cooper D. H. Blackburn

1993-01-01

211

Physical properties of barium borate glasses determined over a wide range of compositions  

Microsoft Academic Search

Barium borate glasses are reported over an extended glass-forming range from R=0.2 (16.7 mol% BaO) to R=2.0 (66.7 mol% BaO), where R is the molar ratio of barium oxide to boron oxide. The density, Tg (glass transition temperature), Tx (glass recrystallization temperature), and optical cutoffs were determined. These data were compared with structural models for the glasses based on nuclear

Shalini Kapoor; Henry Bola George; Ashlea Betzen; Mario Affatigato; Steve Feller

2000-01-01

212

Comparison of mechanical properties of glass-bonded sodalite and borosilicate glass high-level waste forms  

SciTech Connect

Argonne National Laboratory has developed a glass-bonded sodalite waste form to immobilize the salt waste stream from electrometallurgical treatment of spent nuclear fuel. The waste form consists of 75 vol.% crystalline sodalite and 25 vol.% glass. Microindentation fracture toughness measurements were performed on this material and borosilicate glass from the Defense Waste Processing Facility using a Vickers indenter. Palmqvist cracking was confined for the glass-bonded sodalite waste form, while median-radial cracking occurred in the borosilicate glass. The elastic modulus was measured by an acoustic technique. Fracture toughness, microhardness, and elastic modulus values are reported for both waste forms.

O'Holleran, T. P.; DiSanto, T.; Johnson, S. G.; Goff, K. M.

2000-05-09

213

DEVELOPMENT OF GLASS MATRICES FOR HLW RADIOACTIVE WASTES  

SciTech Connect

Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either borosilicate glass or phosphate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt waste plus glass forming frit additives and cast. A second reason that glass has become widely used for HLW is that the short range order (SRO) and medium range order (MRO) found in glass atomistically bonds the radionuclides and governs the melt properties such as viscosity, resistivity, sulphate solubility. The molecular structure of glass controls contaminant/radionuclide release by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to waste variability. Nuclear waste glasses melt between 1050-1150 C which minimizes the volatility of radioactive components such as Tc{sup 99}, Cs{sup 137}, and I{sup 129}. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models based on the molecular structure of glass have been mechanistically derived and have been demonstrated to be accurate enough to control the world's largest HLW Joule heated ceramic melter in the US since 1996 at 95% confidence.

Jantzen, C.

2010-03-18

214

Picture Wall (Glass Structures)  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

215

Reaction cured glass and glass coatings  

NASA Technical Reports Server (NTRS)

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).

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

1978-01-01

216

Laboratory work in support of West Valley glass development  

SciTech Connect

Over the past six years, Pacific Northwest Laboratory (PNL) has conducted several studies in support of waste glass composition development and testing of glass compositions suitable for immobilizing the nuclear wastes stored at West Valley, New York. As a result of pilot-scale testing conducted by PNL, the glass composition was changed from that originally recommended in response to changes in the waste stream, and several processing-related problems were discovered. These problems were solved, or sufficiently addressed to determine their likely effect on the glass melting operations to be conducted at West Valley. This report describes the development of the waste glass composition, WV-205, and discusses solutions to processing problems such as foaming and insoluble sludges, as well as other issues such as effects of feed variations on processing of the resulting glass. An evaluation of the WV-205 glass from a repository perspective is included in the appendix to this report.

Bunnell, L.R.

1988-05-01

217

Investigation of lead-iron-phosphate glass for SRP waste  

SciTech Connect

Development of a host solid for immobilizing nuclear waste has focused on various vitreous wasteforms. Recently, lead-iron-phosphate (LIP) glasses have been proposed for solidifying all types of high-level liquid waste (HLLW). Investigation of this glass for vitrifying Savannah River Plant (SRP) waste demonstrated that the phosphate glass is incompatible with current borosilicate glass processing. Although the durability of the LIP glasses in deionized water was comparable to current borosilicate waste glass formulations, many of the defense waste constituents have low solubility in the phosphate melt, producing a nonhomogeneous or nonvitreous product. Although the LIP glass has a low melt-temperature, it is highly corrosive, which prevents the use of current melter materials such as Inconel and alumina, and requires more exotic materials of construction such as platinum.

Jantzen, C M

1986-01-01

218

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

219

Role of structure in ion movement of glasses  

SciTech Connect

Three kinds of experiments were performed: modified random network model and ion movement; role of melt structure in ion transport in glassy state; and ion movement in fluorozirconate glass (breakdown of correspondence between electrical and nuclear spin relaxation). A comment is offered on dielectric loss peak in glasses. 11 refs, 1 fig. (DLC)

Jain, H.

1992-11-03

220

Foam Glass Insulation from Waste Glass.  

National Technical Information Service (NTIS)

Waste glass has proven to be effective for the production of foam glass insulation both in the bulk or rigid board form and pellet form. Problems inherent with the use of water, carbon black and calcium carbonate as the foaming agents, have been identifie...

W. G. Oakseson J. G. Lee S. K. Goyal T. Robson I. B. Cutler

1977-01-01

221

Magnetic Resonance Studies of the Structure of Glasses.  

National Technical Information Service (NTIS)

Nuclear magnetic resonance techniques have been used to study atomic arrangements and chemical bonds in glasses. The principal results are as follows: (1) NMR distinguishes between BO3 and BO4, configurations; quantitative measures of each configuration i...

P. J. Bray

1970-01-01

222

WASTE GLASS MELTER PROCESS MONITORING WITH MILLIMETER WAVES  

EPA Science Inventory

Millimeter-wave technologies can provide novel and reliable online monitoring capability for many important parameters inside nuclear waste glass melters, including temperature, emissivity, density, and viscosity. The physical and analytical basis for millimeter-wave monitoring o...

223

Hydrogen-Impregnated Glass Covers for Hardened Solar Cells.  

National Technical Information Service (NTIS)

The report summarizes the entire development program conducted by Tem-Pres Research/Carborundum which experimentally demonstrated that hydrogen impregnation will significantly reduce darkening of solar cell glass covers under solar, nuclear, and van Allen...

S. P. Faile W. R. Harding

1970-01-01

224

Glass tube splitting tool  

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

225

Radiation effects in silicate glasses: A review  

SciTech Connect

The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as immobilization of high level nuclear wastes and fiber optics. Radiation may change the properties of these glasses by altering their electronic and atomic configurations. Electronic defects may cause absorption centers that limit their optical uses and also cause microscopic phase changes and dilatations. Atomic dislocations induced in the already disordered structure of the glasses may affect their use where heavy radiations such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may be caused. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions.

Bibler, N.E. [Du Pont de Nemours (E.I.) and Co., Aiken, SC (United States). Savannah River Lab.; Howitt, D.G. [California Univ., Davis, CA (United States). Dept. of Mechanical Engineering

1988-12-31

226

Radiation effects in silicate glasses: A review  

SciTech Connect

The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as immobilization of high level nuclear wastes and fiber optics. Radiation may change the properties of these glasses by altering their electronic and atomic configurations. Electronic defects may cause absorption centers that limit their optical uses and also cause microscopic phase changes and dilatations. Atomic dislocations induced in the already disordered structure of the glasses may affect their use where heavy radiations such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may be caused. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions.

Bibler, N.E. (Du Pont de Nemours (E.I.) and Co., Aiken, SC (United States). Savannah River Lab.); Howitt, D.G. (California Univ., Davis, CA (United States). Dept. of Mechanical Engineering)

1988-01-01

227

Silicon Oxycarbide Glasses  

Microsoft Academic Search

The first attempts to introduce carbon into glass date back to 1951. But up until recently, the use of carbon or carbide raw materials, and the oxidation, volatilization and decomposition that accompany high temperature melting, have limited the synthesis of true silicon oxycarbide glasses. Here, the term silicon-oxycarbide refers specifically to a carbon-containing silicate glass wherein oxygen and carbon atoms

Carlo G. Pantano; Anant K. Singh; Hanxi Zhang

1999-01-01

228

Spin-glass dynamics  

Microsoft Academic Search

Spin glasses are magnetic systems with conflicting and random interactions between the individual spins. The dynamics of spin glasses, as of structural glasses, reflect their complexity. Both in experimental and numerical work the relaxation below the freezing temperature depends strongly on the annealing conditions (aging) and, above the freezing point, relaxation in equilibrium is slow and non-exponential. In this Forum,

I. A. Campbell; J. Hammann; H. Kawamura; R. H. McKenzie; P. Nordblad; R. Orbach; H. Takayama

1998-01-01

229

COMBINED RETENTION OF MOLYBDENUM AND SULFUR IN SIMULATED HIGH LEVEL WASTE GLASS  

Microsoft Academic Search

This study was undertaken to investigate the effect of elevated sulfate and molybdenum concentrations in nuclear waste glasses. A matrix of 24 glasses was developed and the glasses were tested for acceptability based on visual observations, canister centerline-cooled heat treatments, and chemical composition analysis. Results from the chemical analysis of the rinse water from each sample were used to confirm

Fox

2009-01-01

230

Optical properties of glass  

SciTech Connect

The author deals in depth with reflection, refraction, absorption, scatter, polarization, birefringence, and interference (the effects of the interaction of radiation with glass). The most significant optical phenomena have been approached from the points of view of theory, measurement, and the dependence of optical phenomena on the chemical composition, temperature, thermal history, etc. Attention is also given to the classification of glasses according to their optical properties, and chapters have been included on colour generation in glasses, modification of the optical properties of glasses by the application of coating, and glasses exhibiting special optical properties.

Fanderlick, I.

1983-01-01

231

Radiation coloration resistant glass  

DOEpatents

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.

Tomozawa, Minoru (Troy, NY); Watson, E. Bruce (Troy, NY); Acocella, John (Troy, NY)

1986-01-01

232

Correlation of nuclear criticality safety computer codes with plutonium benchmark experiments and derivation of subcritical limits. [MGBS, TGAN, KEFF, HRXN, GLASS, ANISN, SPBL, and KENO  

SciTech Connect

A compilation of benchmark critical experiments was made for essentially one-dimensional systems containing plutonium. The systems consist of spheres, series of experiments with cylinders and cuboids that permit extrapolation to infinite cylinders and slabs, and large cylinders for which separability of the neutron flux into a product of spatial components is a good approximation. Data from the experiments were placed in a form readily usable as computer code input. Aqueous solutions of Pu(NO/sub 3/)/sub 4/ are treated as solutions of PuO/sub 2/ in nitric acid. The apparent molal volume of PuO/sub 2/ as a function of plutonium concentration was derived from analyses of solution density data and was incorporated in the Savannah River Laboratory computer codes along with density tables for nitric acid. The biases of three methods of calculation were established by correlation with the benchmark experiments. The oldest method involves two-group diffusion theory and has been used extensively at the Savannah River Laboratory. The other two involve S/sub n/ transport theory with, in one method, Hansen-Roach cross sections and, in the other, cross sections derived from ENDF/B-IV. Subcritical limits were calculated by all three methods. Significant differences were found among the results and between the results and limits currently in the American National Standard for Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactor (ANSI N16.1), which were calculated by yet another method, despite the normalization of all four methods to the same experimental data. The differences were studied, and a set of subcritical limits was proposed to supplement and in some cases to replace those in the ANSI Standard, which is currently being reviewed.

Clark, H.K.

1981-10-01

233

Design and Operation of a 100 Kg/H Electric Melter for Nuclear-Waste Vitrification.  

National Technical Information Service (NTIS)

The proposed use of ceramic-lined, electric-heated glass melters for the vitrification of nuclear wastes requires careful adaptation of commercial glass furnace practices. The vitrification of simulated nuclear waste calcines was studied in a ceramic-line...

R. D. Dierks

1980-01-01

234

High-level waste glass compendium; what it tells us concerning the durability of borosilicate waste glass  

SciTech Connect

Facilities for vitrification of high-level nuclear waste in the United States are scheduled for startup in the next few years. It is, therefore, appropriate to examine the current scientific basis for understanding the corrosion of high-level waste borosilicate glass for the range of service conditions to which the glass products from these facilities may be exposed. To this end, a document has been prepared which compiles worldwide information on borosilicate waste glass corrosion. Based on the content of this document, the acceptability of canistered waste glass for geological disposal is addressed. Waste glass corrosion in a geologic repository may be due to groundwater and/or water vapor contact. The important processes that determine the glass corrosion kinetics under these conditions are discussed based on experimental evidence from laboratory testing. Testing data together with understanding of the long-term corrosion kinetics are used to estimate radionuclide release rates. These rates are discussed in terms of regulatory performance standards.

Cunnane, J.C. [Argonne National Lab., IL (United States); Allison, J. [USDOE, Washington, DC (United States)

1993-12-31

235

Neutron Detection using Lithium Glass Scintillator  

NASA Astrophysics Data System (ADS)

We have developed a neutron detector using a thin sheet of lithium-6 glass scintillator. Lithium-6 has a high capture cross-section for neutrons, giving high neutron detection efficiency. One of the difficulties of neutron detection is discriminating between neutron and gamma radiation. We have measured the gamma sensitivity of our detector to be one in 10,000. For nuclear non-proliferation applications, radioactive sources may be shielded. Unlike most neutron detectors, lithium glass detectors are more efficient at detecting neutrons if the source is shielded. We are testing different configurations to optimize the detector's neutron capture efficiency.

Wallace, Adam; Rees, Lawrence; Czirr, Bart

2011-10-01

236

Scintillating Fluorohafnate Glasses  

Microsoft Academic Search

Data are presented on the roentgenoluminescence and gamma-radiation resistance of Ce3+-doped fluorohafnate glasses prepared under different redox conditions and containing different additions. The glasses are shown to contain several types of luminescence centers and radiation-induced color centers, whose concentrations are governed by the preparation conditions and the nature of the dopants. The radiation resistance and light output of the glasses

S. Kh. Batygov; M. N. Brekhovskikh; N. N. Vinogradova; L. N. Dmitruk; L. V. Moiseeva; V. A. Fedorov

2002-01-01

237

Containerless processing of glass  

NASA Technical Reports Server (NTRS)

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.

Happe, R. A.

1981-01-01

238

Helium diffusion in curium-doped borosilicate waste glass  

NASA Astrophysics Data System (ADS)

The isothermal release of helium from 244Cm-doped borosilicate glass has been studied as a function of time at different annealing temperatures. Helium measurements were performed using a micro gas chromatograph coupled to a furnace installed in a hot cell at ATALANTE nuclear research facility. Plane-parallel glass samples were prepared from glass discs that had been stored for 5.1 years at room temperature, accumulating around 10 19 alpha decays per gram of glass, a level that will be reached in current nuclear glass packages several thousand years after disposal. The experimental helium release data were simulated using a 3D numerical model to determine the helium diffusion coefficients. The extracted diffusion coefficients follow the Arrhenius law with an activation energy of 0.61 ± 0.03 eV and a pre-exponential factor of (5.7 ± 1.6) × 10 -3 cm 2 s -1. The results were compared with literature data on damaged and undamaged glasses to assess the effect of glass damage on helium release. The helium release results are consistent with a thermal diffusion mechanism involving only one population of helium atoms. The helium diffusion coefficients were unaffected by the glass alpha damage.

Fares, T.; Peuget, S.; Bouty, O.; Deschanels, X.; Magnin, M.; Jégou, C.

2011-09-01

239

Rare Earth Phosphate Glass and Glass-Ceramic Proton Conductors  

SciTech Connect

The structure and conductivity of cerium and lanthanum phosphate glasses and glass-ceramics were investigated. The effects of varying the metal to phosphate ratio in the glasses, doping LaP3O9 glasses with Ce, and recrystallization of CeP3O9 glasses, on the glasses' microstructure and total conductivity were investigated using XRD, SEM, and AC impedance techniques. Strong increases in conductivity occurred when the glasses were recrystallized: the conductivity of a cerium metaphosphate glass increased conductivity after recrystallization from 10-7.5 S/cm to 10-6 S/cm at 400oC.

De Jonghe, Lutgard C.; Ray, Hannah L.; Wang, Ruigang

2008-12-03

240

Digitization of stained glass  

Microsoft Academic Search

Digital photography was applied to the capture of images of the stained glass windows in the historic parish church in Fairford, Gloucestershire, England. Because of their size, the windows had to be photographed in 45 separate sections in order to capture all the detail present in the painting on the glass. The digital images of each section, approximately 3000 by

Lindsay W. MacDonald

1997-01-01

241

Fluoride Glass Compositions.  

National Technical Information Service (NTIS)

This invention relates to Fluoride-based glasses that exhibit a high degree of transparency throughout the near ultraviolet visible and mid infrared portions of the spectrum. The glasses are composed of MgF2 and ZnF2 as essential compositional ingredients...

O. El-Bayoumi

1983-01-01

242

Supercooled Liquids and Glasses  

Microsoft Academic Search

Selected aspects of recent progress in the study of supercooled liquids and glasses are presented in this review. As an introduction for nonspecialists, several basic features of the dynamics and thermodynamics of supercooled liquids and glasses are described. Among these are nonexponential relaxation functions, non-Arrhenius temperature dependences, and the Kauzmann temperature. Various theoretical models which attempt to explain these basic

M. D. Ediger; C. A. Angell; Sidney R. Nagel

1996-01-01

243

Surface Conductive Glass.  

ERIC Educational Resources Information Center

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)

Tanaka, John; Suib, Steven L.

1984-01-01

244

Stained Glass Glue  

NSDL National Science Digital Library

In this activity on page 6 of the PDF, learners use glue instead of glass to create artwork that can be hung in a window. Discover how the chemicals in various materials mix together to make a colorful, translucent "stained glass" creation.

Society, American C.

2001-01-01

245

Structural analysis and thermal behavior of diopside-fluorapatite-wollastonite-based glasses and glass-ceramics.  

PubMed

Glass-ceramics in the diopside (CaMgSi2O6)-fluorapatite (Ca5(PO4)3F)-wollastonite (CaSiO3) system are potential candidates for restorative dental and bone implant materials. The present study describes the influence of varying SiO2/CaO and CaF2/P2O5 molar ratio on the structure and thermal behavior of glass compositions in the CaO-MgO-SiO2-P2O5-Na2O-CaF2 system. The structural features and properties of the glasses were investigated by nuclear magnetic resonance (NMR), infrared spectroscopy, density measurements and dilatometry. Sintering and crystallization behavior of the glass powders were studied by hot-stage microscopy and differential thermal analysis, respectively. The microstructure and crystalline phase assemblage in the sintered glass powder compacts were studied under non-isothermal heating conditions at 825 °C. X-ray diffraction studies combined with the Rietveld-reference intensity ratio (R.I.R) method were employed to quantify the amount of amorphous and crystalline phases in the glass-ceramics, while scanning electron microscopy was used to shed some light on the microstructure of resultant glass-ceramics. An increase in CaO/SiO2 ratio degraded the sinterability of the glass powder compacts, resulting in the formation of akermanite as the major crystalline phase. On the other hand, an increase in P2O5/CaF2 ratio improved the sintering behavior of the glass-ceramics, while varying the amount of crystalline phases, i.e. diopside, fluorapatite and wollastonite. PMID:20561991

Kansal, Ishu; Tulyaganov, Dilshat U; Goel, Ashutosh; Pascual, Maria J; Ferreira, José M F

2010-11-01

246

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 [micro]m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. (Kyoto Univ., Osaka (Japan)); Luo, S.; Tang, B. (China Inst. of Atomic Energy, Beijing (China))

1999-01-01

247

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 {micro}m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. [Kyoto Univ., Osaka (Japan)] [Kyoto Univ., Osaka (Japan); Luo, S.; Tang, B. [China Inst. of Atomic Energy, Beijing (China)] [China Inst. of Atomic Energy, Beijing (China)

1999-11-01

248

40 CFR Requirements - Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission...  

Code of Federal Regulations, 2010 CFR

...Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations and the...Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63...Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations and...

2010-07-01

249

PbO-free glasses for low temperature packaging  

SciTech Connect

Zinc polyphosphate glasses were examined as potential candidates for low temperature sealing applications. Glass-formation and properties were determined for the ZnO-P{sub 2}O{sub 5}, ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} and ZnO-SnO-P{sub 2}O{sub 5} systems, and information about the short-range structures of these glasses was obtained by Raman and solid state nuclear magnetic resonance spectroscopies. In general, the most durable polyphosphate glasses have structures based on relatively short pyrophosphate chain lengths (i.e., 2 P-tetrahedra). Modified phosphate compositions are given, including compositions used to seal float glass substrates at temperatures as low as 500{degrees}C.

Brow, R.K.; Bencoe, D.N.; Tallant, D.R. [and others

1997-10-01

250

CCMR: Study of Mixed Glass Former Phenomena in Glasses  

NSDL National Science Digital Library

Water concentration in varying compositions of sodium borosilicate glass was studied by Fourier Transform Infrared Spectroscopy. This is to further explore the Mixed Glass Former Effect (MGFE) in glasses with two or more network formers. Previous data shows that the water concentration increases with time.1 Thick and thin sample analysis was carried out on the glass to validate this data.

Clark, Braeden

2009-08-15

251

Assessment of water/glass interactions in waste glass melter operation  

SciTech Connect

A study was made to assess the possibility of a vapor explosion in a liquid-fed glass melter and during off-standard conditions for other vitrification processes. The glass melter considered is one designed for the vitrification of high-level nuclear wastes and is comprised of a ceramic-lined cavity with electrodes for joule heating and processing equipment required to add feed and withdraw glass. Vapor explosions needed to be considered because experience in other industrial processes has shown that violent interactions can occur if a hot liquid is mixed with a cooler, vaporizable liquid. Available experimental evidence and theoretical analyses indicate that destructive glass/water interactions are low probability events, if they are possible at all. Under standard conditions, aspects of liquid-fed melter operation which work against explosive interactions include: (1) the aqueous feed is near its boiling point; (2) the feed contains high concentrations of suspended particles; (3) molten glass has high viscosity (greater than 20 poise); and (4) the glass solidifies before film boiling can collapse. While it was concluded that vapor explosions are not expected in a liquid-fed melter, available information does not allow them to be ruled out altogether. Several precautionary measures which are easily incorporated into melter operation procedures were identified and additional experiments were recommended.

Postma, A.K.; Chapman, C.C.; Buelt, J.L.

1980-04-01

252

Glass Ceiling Commission  

NSDL National Science Digital Library

Existing from 1991-1996, the Glass Ceiling Commission was a federally funded commission which considered the "invisible, artificial barriers that prevent qualified individuals from advancing within their organization and reaching full potential." While the term "Glass Ceiling" originally referred to women, it was expanded to also include minorities. The Catherwood Library at the School of Industrial and Labor Relations at Cornell University has electronically archived the reports and findings of the commission, as well as a host of papers written on the Glass Ceiling Commission. The Commission summaries, reports, and findings are annotated, as are the accompanying papers.

Commission., United S.

253

Residual stresses in glasses.  

PubMed

The history dependence of glasses formed from flow-melted steady states by a sudden cessation of the shear rate ?[over ?] is studied in colloidal suspensions, by molecular dynamics simulations and by mode-coupling theory. In an ideal glass, stresses relax only partially, leaving behind a finite persistent residual stress. For intermediate times, relaxation curves scale as a function of ?[over ?]t, even though no flow is present. The macroscopic stress evolution is connected to a length scale of residual liquefaction displayed by microscopic mean-squared displacements. The theory describes this history dependence of glasses sharing the same thermodynamic state variables but differing static properties. PMID:23745896

Ballauff, M; Brader, J M; Egelhaaf, S U; Fuchs, M; Horbach, J; Koumakis, N; Krüger, M; Laurati, M; Mutch, K J; Petekidis, G; Siebenbürger, M; Voigtmann, Th; Zausch, J

2013-05-24

254

Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses.  

SciTech Connect

A glass-bonded sodalite ceramic waste form is being developed for the long-term immobilization of salt wastes that are generated during spent nuclear fuel conditioning activities. A durable waste form is prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. A mechanistic description of the corrosion processes is being developed to support qualification of the CWF for disposal. The initial set of characterization tests included two standard tests that have been used extensively to study the corrosion behavior of high level waste (HLW) glasses: the Material Characterization Center-1 (MCC-1) Test and the Product Consistency Test (PCT). Direct comparison of the results of tests with the reference CWF and HLW glasses indicate that the corrosion behaviors of the CWF and HLW glasses are very similar.

Ebert, W. L.; Lewis, M. A.

1999-05-06

255

The ion beam analysis of laser-irradiated borosilicate glass  

NASA Astrophysics Data System (ADS)

The chemical effects of carbon dioxide laser irradiation on some borosilicate glasses have been investigated. Specimens of Tempax and BK7 glass were analysed before and after laser irradiation and were found to have undergone subtle changes in chemical composition. These were thought to have been caused by surface heating. This paper describes the application of Rutherford backscattering spectrometry and nuclear reaction analysis using the 11B(p,?) 8Be and 16O(d,p) 17O reactions to the study of these glasses.

Lane, D. W.

1992-02-01

256

Reference commercial high-level waste glass and canister definition.  

SciTech Connect

This report presents technical data and performance characteristics of a high-level waste glass and canister intended for use in the design of a complete waste encapsulation package suitable for disposal in a geologic repository. The borosilicate glass contained in the stainless steel canister represents the probable type of high-level waste product that will be produced in a commercial nuclear-fuel reprocessing plant. Development history is summarized for high-level liquid waste compositions, waste glass composition and characteristics, and canister design. The decay histories of the fission products and actinides (plus daughters) calculated by the ORIGEN-II code are presented.

Slate, S.C.; Ross, W.A.; Partain, W.L.

1981-09-01

257

40 CFR Requirements - Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission...  

Code of Federal Regulations, 2010 CFR

... Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations Requirements Compliance...Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission...

2010-07-01

258

Bioactive glass in tissue engineering  

Microsoft Academic Search

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.

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

2011-01-01

259

Photoelectric Effect from Borosilicate Glass  

Microsoft Academic Search

Values of the photoelectric quantum efficiency of glass for different wavelengths have been determined and data have been obtained on the status of electrons placed on glass surfaces. One of the borosilicate glasses commonly used in discharge tube manufacture and soda glass were studied in vacuum with 2537 A photons from a quartz Heraeus mercury arc and with light from

Vijay Kumar Rohatgi

1957-01-01

260

Thick Film Glasses.  

National Technical Information Service (NTIS)

The technicA1 literature was reviewed in order to characterize the thermal expansion, viscosity, surface tension and wetting behavior as functions of composition for glasses of present or potential use in thick film formulations. The applicability of the ...

R. W. Vest

1978-01-01

261

Glass formation in microgravity  

NASA Technical Reports Server (NTRS)

An account is given of containerless glass-forming experiments conducted aboard the Space Shuttle in 1985, using a single-axis acoustic levitator furnace apparatus. An attempt was made to obtain quantitative evidence for the suppression of heterogeneous nucleation/crystallization in containerless melts under microgravity conditions, as well as to study melt homogenization in the absence of gravity-driven convection and assess the feasibility of laser fusion target glass microsphere preparation with a microgravity apparatus of the present type. A ternary calcia-gallia-silica glass thus obtained indicated a 2-3-fold increase in glass-formation tendency for this material composition in microgravity, by comparison with 1g.

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

1987-01-01

262

THE COLOR GLASS CONDENSATE.  

SciTech Connect

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.

MCLERRAN,L.

2001-08-26

263

CCMR: Water in Glass  

NSDL National Science Digital Library

Water uptake for various compositions of the model glass (Fe2O3)0.01(B2O3)0.048(Na2O)0.142(SiO2)0.8x(Al2O3)0.8(1âx) under fixed annealing conditions was studied via FTIR. Glasses of this formulation were found to take up water at both 300 and 380 °C. The time dependence of their water uptake entails that the governing kinetics are determined by the diffusion of water molecules in the glass network. The experimental approach used was validated by confirming previous water concentration results regarding glasses of the composition (Na2O)0.2[(BO1.5)x(SiO2)1âx]0.8.

Harrell, Stuart

2010-08-15

264

Ultrastable nanostructured polymer glasses.  

PubMed

Owing to the kinetic nature of the glass transition, the ability to significantly alter the properties of amorphous solids by the typical routes to the vitreous state is restricted. For instance, an order of magnitude change in the cooling rate merely modifies the value of the glass transition temperature (T(g)) by a few degrees. Here we show that matrix-assisted pulsed laser evaporation (MAPLE) can be used to form ultrastable and nanostructured glassy polymer films which, relative to the standard poly(methyl methacrylate) glass formed on cooling at standard rates, are 40% less dense, have a 40 K higher T(g), and exhibit a two orders of magnitude enhancement in kinetic stability at high temperatures. The unique set of properties of MAPLE-deposited glasses may make them attractive in technologies where weight and stability are central design issues. PMID:22306770

Guo, Yunlong; Morozov, Anatoli; Schneider, Dirk; Chung, Jae Woo; Zhang, Chuan; Waldmann, Maike; Yao, Nan; Fytas, George; Arnold, Craig B; Priestley, Rodney D

2012-04-01

265

Super ionic conductive glass  

DOEpatents

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.

Susman, Sherman (Park Forest, IL); Volin, Kenneth J. (Fort Collins, CO)

1984-01-01

266

Seeing Glass Contractors Clearly.  

ERIC Educational Resources Information Center

Offers seven tips for finding and working with an effective glass contractor. For example, schools should consider the company's reputation and longevity of service, and whether it has in-house engineering capabilities. (EV)

Deliberato, Jerry

2003-01-01

267

Laser Phosphate Glasses.  

National Technical Information Service (NTIS)

This book gives a detailed description of the physical properties of effective new laser materials - phosphate glasses doped with rare-earth ions, and demonstrates the possibilities and prospects for their use in various types of lasers. Data are presente...

M. E. Zhabotinskii N. E. Alekseev V. B. Kravchenko V. P. Gapontsev Y. P. Rudnitskii

1983-01-01

268

Whisker reinforced glass ceramic  

SciTech Connect

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.

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

1996-06-03

269

Glasses and Contact Lenses  

MedlinePLUS

... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ... trouble, it's often a refractive problem. Glasses or contact lenses work so well because they can correct ...

270

Low Melting Glasses.  

National Technical Information Service (NTIS)

The methods of preparation of glasses containing zinc, lead, tellurium, thallium, molybdenum, vanadium, borates, phosphates, chalcogenides, oxychalcogenides, and other elements and compounds are reviewed and their structure discussed. The properties given...

N. M. Pavlushin

1974-01-01

271

Baseline LAW Glass Formulation Testing  

SciTech Connect

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.

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

2013-06-13

272

Fluoride glass compositions  

SciTech Connect

This invention relates to Fluoride-based glasses that exhibit a high degree of transparency throughout the near ultraviolet visible and mid infrared portions of the spectrum. The glasses are composed of MgF2 and ZnF2 as essential compositional ingredients together with at least two other metallic fluorides from the group of YbF3, ThF4, PbF2, A1F3 and MnF2.

El-Bayoumi, O.

1983-08-09

273

Metallic glass composition  

DOEpatents

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.

Kroeger, Donald M. (Knoxville, TN) [Knoxville, TN; Koch, Carl C. (Raleigh, NC) [Raleigh, NC

1986-01-01

274

Glasses formed by hypervelocity impact  

NASA Technical Reports Server (NTRS)

This paper presents description, classification, and geological setting of impact glasses, which are formed as a result of meteorite impacts with the planetary surface, and discusses the impact-glass formation process in the context of cratering mechanics. Impact glasses can be classified as belonging to two major groups: (1) mineral glasses, which are identical in composition to a mineral, and (2) rock glasses, which have the composition of a rock or a mixture of various rocks. Rock glasses may be (1) melt ejecta, (2) parts of a coherent melt layer inside the crater cavity, or (3) dikes or veins. The composition of rock glasses at a particular crater can be matched by that of the target. In nonporous rocks, the formation of rock glasses requires peak pressures in excess of 60-80 GPa, while mineral glasses are formed in the pressure range of about 25 to 55 GPa; in porous rocks, interstitial glass forms at pressures as low as 5 GPa.

Stoeffler, D.

1984-01-01

275

Towards ultrastrong glasses.  

PubMed

The development of new glassy materials is key for addressing major global challenges in energy, medicine, and advanced communications systems. For example, thin, flexible, and large-area glass substrates will play an enabling role in the development of flexible displays, roll-to-roll processing of solar cells, next-generation touch-screen devices, and encapsulation of organic semiconductors. The main drawback of glass and its limitation for these applications is its brittle fracture behavior, especially in the presence of surface flaws, which can significantly reduce the practical strength of a glass product. Hence, the design of new ultrastrong glassy materials and strengthening techniques is of crucial importance. The main issues regarding glass strength are discussed, with an emphasis on the underlying microscopic mechanisms that are responsible for mechanical properties. The relationship among elastic properties and fracture behavior is also addressed, focusing on both oxide and metallic glasses. From a theoretical perspective, atomistic modeling of mechanical properties of glassy materials is considered. The topological origin of these properties is also discussed, including its relation to structural and chemical heterogeneities. Finally, comments are given on several toughening strategies for increasing the damage resistance of glass products. PMID:22103001

Wondraczek, Lothar; Mauro, John C; Eckert, Jürgen; Kühn, Uta; Horbach, Jürgen; Deubener, Joachim; Rouxel, Tanguy

2011-10-18

276

Perspective: The glass transition  

NASA Astrophysics Data System (ADS)

We provide here a brief perspective on the glass transition field. It is an assessment, written from the point of view of theory, of where the field is and where it seems to be heading. We first give an overview of the main phenomenological characteristics, or ``stylised facts,'' of the glass transition problem, i.e., the central observations that a theory of the physics of glass formation should aim to explain in a unified manner. We describe recent developments, with a particular focus on real space properties, including dynamical heterogeneity and facilitation, the search for underlying spatial or structural correlations, and the relation between the thermal glass transition and athermal jamming. We then discuss briefly how competing theories of the glass transition have adapted and evolved to account for such real space issues. We consider in detail two conceptual and methodological approaches put forward recently, that aim to access the fundamental critical phenomenon underlying the glass transition, be it thermodynamic or dynamic in origin, by means of biasing of ensembles, of configurations in the thermodynamic case, or of trajectories in the dynamic case. We end with a short outlook.

Biroli, Giulio; Garrahan, Juan P.

2013-03-01

277

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

278

Containerless synthesis of interesting glasses  

NASA Technical Reports Server (NTRS)

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.

Weinberg, Michael C.

1990-01-01

279

Competitive formation of glasses and glass-matrix composites  

SciTech Connect

By systematically investigating the effect of chemical composition on the competitive formation of glasses in various systems, we attempt to address two long-standing scientific puzzles upon metallic glasses, i.e., (i) which composition is the best for forming glasses and glass-matrix composites and (ii) what determines the easy glass-forming composition range in a given alloy system. Our findings have led to the construction of a qualitative microstructure selection map, which is useful for guiding the design of bulkier metallic glasses and glass-matrix composites. In addition, our analysis demonstrates that the classical kinetic treatment of glass formation is insufficient; to analyze glass formation properly, it is necessary to go beyond simple assumptions of single polymorphic solidification during crystallization.

Lu, Zhao Ping [ORNL; Ma, D. [University of Wisconsin, Madison; Liu, Chain T [ORNL; Chang, Y. Austin [University of Wisconsin, Madison

2007-01-01

280

DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION  

SciTech Connect

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 that the test apparatus had to be disassembled to dislodge the plugs created in the system.

Adamson, D; Bradley Pickenheim, B

2008-11-24

281

Glass microsphere lubrication  

NASA Technical Reports Server (NTRS)

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 manufacturing of the microspheres, while sorting entails deciphering the good microspheres from the bad ones. Each process is discussed in detail.

Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

1991-01-01

282

Jet penetration in glass  

SciTech Connect

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.

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

1991-05-01

283

Modifier coordination and phosphate glass networks  

SciTech Connect

The addition of up to approximately 16 mole% Cs{sub 2}O to vitreous P{sub 2}O{sub 5} reduces the glass transition temperature (T{sub g}) by 150 K, whereas further additions up to 50 mole% produce little additional change in T{sub g}. {sup 31}P magic angle spinning nuclear magnetic resonance spectra indicate that the phosphate network is progressively dipolymerized over the entire range of compositions. The property trend is explained by a transition in the Cs{sup +} coordination environment, from isolated Cs-polyhedra below {approximately}16 mole% Cs{sub 2}O to a corner-sharing Cs-polyhedral sub-structure in the glasses with greater Cs{sub 2}O contents. This modifier transition does not occur in Al-phosphate glasses. {sup 27}Al MAS NMR spectra indicate that the average Al coordination number decreases with increasing Al{sub 2}O{sub 3} content to avoid the formation of Al-O-Al bonds in these binary phosphate glasses.

Brow, R.; Click, C.A.; Alam, T.M.

1999-11-30

284

Effect of Gamma Irradiation on Alkali Borate Glasses by EPR Spectroscopy  

NASA Astrophysics Data System (ADS)

Alkali borate glasses interesting application in safe nuclear fuel disposal were investigated under gamma irradiation. Glasses with different composition were prepared by conventional melt quench technique. In order to explore the defects created in the glass structure due to gamma irradiation, the EPR spectrum has been taken before and after high dose rate. The results revealed that the signal of involved paramagnetic species after irradiation shown slow time decay. Annealing procedure was performed to recover radiation damage.

Catallo, N.; Baccaro, S.; Colacicchi, S.; Gualtieri, G.; Ferrara, G.; Sharma, G.

2010-04-01

285

Extent of intermixing among framework units in silicate glasses and melts  

NASA Astrophysics Data System (ADS)

One aspect of the inherent disorder in silicate glasses and melts is the intermixing among framework units, which has important implications to the macroscopic properties of silicate magmas. We present experimental evidence of extensive mixing of these framework units in silicate glasses including aluminosilicate and borosilicate glasses from oxygen-17 nuclear magnetic resonance (NMR), which shows remarkable similarity to predictions from ab initio molecular orbital calculations. We quantify the extent of framework disorder by introducing the degree of interdispersion ( P) ranging from complete phase separation to random distribution for borosilicate glasses and the degree of Al avoidance ( Q) for aluminosilicate glasses. Boron-11 triple quantum magic angle spinning NMR results show that the fraction of the boroxol ring group increases with increasing boron content in binary borosilicate glasses, affecting the corresponding configurational enthalpy. We demonstrate that a more complete description of the macroscopic thermodynamic properties of silicate glasses can be successfully derived from detailed information on the degree of framework disorder.

Lee, S. K.; Stebbins, J. F.

2002-01-01

286

Recycling of waste glasses into partially crystallized glass foams  

Microsoft Academic Search

Waste soda-lime glass, alone or mixed with wastes from the manufacturing of glass fibers, was successfully converted into\\u000a partially crystallized glass foams by a particularly simple and economic processing, consisting of a direct heating of glass\\u000a powders at temperatures from 900 to 1050 °C. The foaming operated by the oxidation of SiC, inserted as powder additive, was\\u000a found to depend on

Enrico Bernardo; Giovanni Scarinci; Paolo Bertuzzi; Piero Ercole; Ludovico Ramon

2010-01-01

287

Laser zone texturing on glass and glass-ceramic substrates  

Microsoft Academic Search

A RF driven CO2 laser is used to create laser bumps on glass and glass-ceramic substrates. The resulting bump height is found to be a function of laser parameters such as pulse width, spot size, and pulse energy. Composition, structure and chemical strengthening of the substrates also affect the laser bump topography. Laser bumps on glass-ceramic, non-strengthened glass, or strengthened

David Kuo; Stan D. Vierk; O. Rauch; Don Polensky

1997-01-01

288

Transient nucleation in glasses  

NASA Technical Reports Server (NTRS)

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.

Kelton, K. F.

1991-01-01

289

Glass as the First Barrier for Long-Term Storage of Highly Active Radioactive Wastes.  

National Technical Information Service (NTIS)

The glasses selected for this use are of siliceous composition, and ought to have adequate properties of nuclear, chemical and thermal stability. After a period of artificial storage at the surface to allow cooling, the glass blocks are normally buried in...

F. Laude

1977-01-01

290

Role of structure in ion movement of glasses. Progress report, January 5, 1992--November 1, 1992  

SciTech Connect

Three kinds of experiments were performed: modified random network model and ion movement; role of melt structure in ion transport in glassy state; and ion movement in fluorozirconate glass (breakdown of correspondence between electrical and nuclear spin relaxation). A comment is offered on dielectric loss peak in glasses. 11 refs, 1 fig. (DLC)

Jain, H.

1992-11-03

291

Glass matrix composites from coal flyash and waste glass  

Microsoft Academic Search

Glass matrix composites have been fabricated from waste materials by means of powder technology. Flyash from coal power stations and waste glass, residue of float glass production, were used. Commercial alumina platelets were employed as the reinforcing component. For flyash contents up to 20% by weight nearly fully dense compacts could be fabricated by using relatively low sintering temperatures (650°C).

Aldo R. Boccaccini; Michael Bücker; Jörg Bossert; Konstantin Marszalek

1997-01-01

292

Glass ceramic toughened with tetragonal zirconia  

DOEpatents

A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nuclearing agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200 to 1700/sup 0/C and is then heat-treated at a temperature within the range of 800 to 1200/sup 0/C in order to precipitate tetragonal ZrO/sub 2/. The composition, as well as the length and temperature of the heat treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.

Keefer, K.D.

1984-02-10

293

Effects of gamma Radiation on Groundwater Chemistry and Glass Reaction in a Saturated Tuff Environment.  

National Technical Information Service (NTIS)

The Nevada Nuclear Waste Storage Investigations project has completed a series of experiments that provide insight into groundwater chemistry and glass waste form performance in the presence of a gamma radiation field at 90 sup 0 C. Results from experimen...

W. L. Ebert J. K. Bates T. J. Gerding R. A. Van Konynenburg

1986-01-01

294

Fabrication and Characterization of MCC Approved Testing Material - ATM-1 Glass.  

National Technical Information Service (NTIS)

The Materials Characterization Center Approved Testing Material ATM-1 is a borosilicate glass that incorporates nonradioactive constituents and uranium to represent high-level waste (HLW) resulting from the reprocessing of commercial nuclear reactor fuel....

J. W. Wald

1985-01-01

295

Borate Glasses, Crystals and Melts.  

National Technical Information Service (NTIS)

The Final Proceedings for Borate, Glasses, Crystals and Melts, 22 July 1996 - 25 July 1996. This is an interdisciplinary conference. Topics include glass forming systems, triborate systems, structural studies, modeling and computer simulation, super-ionic...

1997-01-01

296

Characterizing glass frits for slurries  

NASA Technical Reports Server (NTRS)

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.

Nakano, H. N.

1979-01-01

297

Containerless processing of fluoride glass  

NASA Technical Reports Server (NTRS)

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.

Doremus, Robert H.

1990-01-01

298

Glass ceramic development for the combined fission products streams  

SciTech Connect

After immobilization, nuclear waste is stored for minimally hundreds of years. In waste-forms {beta}, {gamma}-radiation are main causes for damage. The objectives is to test radiation stability of PNNL synthesized glass-ceramics. Monitoring was done looking for changes in the microstructure or phase composition. These are designed for immobilization of: lanthanides, alkaline metals, alkaline arths, transition metals, high molybdenum content - 6.94%, and multi-phase glass-ceramic. The conclusion on aqueous stability is the PNNL glass ceramics - glass phase erodes but crystalline phases don't and it's more resistant to corrosion than vitrified waste. Leachability tests in accordance with standards will be performed and the results will be compared to XRD.

Kossoy-simakov, Anna-eden [Los Alamos National Laboratory; Tang, Ming [Los Alamos National Laboratory; Valdez, James A [Los Alamos National Laboratory; Usov, Igor O [Los Alamos National Laboratory; Sickafus, Kurt E [Los Alamos National Laboratory; Crum, Jarrod [PNNL; Turo, Laura [PNNL; Riley, Brian [PNNL

2011-01-18

299

Glass-ionomer dental restorative: part I: a structural study.  

PubMed

A structural study of glass-ionomer cement (GIC) dental restoratives has been completed. Transmission electron microscopy, selected area electron diffraction, and X-ray diffraction studies indicate domain-like microstructure in a new experimental material, whereas a featureless amorphous gel-like microstructure exists in the conventional GIC. Nuclear magnetic resonance studies were also conducted. The new experimental GIC contains domains of (i) bonelike material (apatite), (ii) mesoporous material and (iii) other framework structures (aluminium phosphate in the high cristobalite structure), with its setting chemistry a restructuring of the aluminosilicate glass around the template of poly(acrylic acid). Conventional glass-ionomer cement may set by a similar but slower process. Leaching properties of glass-ionomer cements are also explained. PMID:15348734

Milne, K A; Calos, N J; O'Donnell, J H; Kennard, C H; Vega, S; Marks, D

1997-06-01

300

Attenuation of Glass Dissolution in the Presence of Natural Additives  

NASA Technical Reports Server (NTRS)

The study described here explored the dissolution kinetics of glasses in aqueous environments in systems which included a variety of natural crystalline solids in addition to the glass itself and the aqueous phase. The results demonstrated the possibility of a dramatic decrease in the rate of dissolution of silicate glass in the presence of certain varieties of olivine-based materials. This decrease in dissolution rate was shown to be due to the fact that these additives consist mostly of Mg-based material but also contain minor amounts of Al and Ca. The combined presence of Mg with these minor species affected the corrosion rate of the glass as a whole, including its most soluble components such as boron. The study has potentially important implications to the durability of glasses exposed to natural environments. The results may be relevant to the use of active backfill materials in burial sites for nuclear waste glasses as well as to better understanding of the environmental degradation of natural and ancient glasses.

Sang, Jing C.; Barkatt, Aaron; OKeefe, John A.

1993-01-01

301

Antagonist effects of calcium on borosilicate glass alteration  

NASA Astrophysics Data System (ADS)

Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon-calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass-cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C-S-H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon-calcium interactions on glass durability and open the way for a better understanding of glass-cement mixing in civil engineering applications as well as in nuclear waste storage.

Mercado-Depierre, S.; Angeli, F.; Frizon, F.; Gin, S.

2013-10-01

302

Gradient index in borate glasses  

NASA Astrophysics Data System (ADS)

A number of aluminum-borate glasses has been developed for producing gradient index glasses by exchanging. Both positive and negative axial gradient were fabricated in the glasses by exchange of Li+ for Na+ and Na+ for Li+, respectively. Index change to 0.03 and gradient index Abble number larger than +100 were achieved. The diffusion coefficients of Na+ and Li+ in borate glasses were calculated by fitting the profiles of refractive index to complimentary error function.

Sun, Yunan; Kindred, Douglas S.; Moore, Duncan T.

1994-08-01

303

Glass and ceramics. [lunar resources  

NASA Technical Reports Server (NTRS)

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.

Haskin, Larry A.

1992-01-01

304

Making Highly Pure Glass Rods  

NASA Technical Reports Server (NTRS)

Proposed quasi-containerless method for making glass rods or fibers minimizes contact between processing equipment and product. Method allows greater range of product sizes and shapes than achieved in experiments on containerless processing. Molten zone established in polycrystalline rod. Furnace sections separated, and glass rod solidifies between them. Clamp supports solid glass as it grows in length. Pulling clamp rapidly away from melt draws glass fiber. Fiber diameter controlled by adjustment of pulling rate.

Naumann, R. J.

1986-01-01

305

Enthalpy of diaplectic labradorite glass  

Microsoft Academic Search

Enthalpies of solution in molten 2PbO·B2O3 at ~988 K have been measured for diaplectic labradorite glass from the Manicouagan impact crater and a fused glass formed from the same material. The enthalpies of solution of the diaplectic and fusion-formed glasses are 4,347 and 2,023 cal mol-1, respectively. The more endothermic enthalpy of solution of the diaplectic glass indicates a greater

K. L. Geisinger; A. Navrotsky; J. Arndt

1986-01-01

306

Glass-matrix biocomposites.  

PubMed

CaO-SiO(2) base glass-matrix/Ti particle biocomposite coatings on Ti6Al4V substrates have been prepared by means of Vacuum Plasma Spray. The base glass is considered bioactive, because, when soaked in a fluid that simulates the inorganic ion concentration of human plasma (SBF), it develops a bonelike apatite layer on its surface. The aim of this research activity was to toughen this brittle bioactive material and to broaden its biomedical applications. Pure titanium was chosen as toughening phase because of its well-known biocompatibility, and Ti6Al4V alloy as substrate because of both its biocompatibility and its mechanical reliability. At first the composites were prepared as bulk materials, by means of a simple sintering process. Then, by ball-milling the sintered composite, the as-obtained "composite powders" were sprayed by Vacuum Plasma Spray (VPS) on the substrate. By means of Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC), the characteristic temperatures of the base glasses were determined. The thermal properties of mixtures of glass powders and different vol% Ti particles were studied by means of DTA, DSC, hot-stage microscopy, and dilatometry, with the aim of optimizing the sintering conditions. Both the bulk and the coated samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), compositional analysis (EDS), Vickers indentations, and leaching tests after soaking in a simulated body fluid (SBF). PMID:10898882

Verné, E; Brovarone, C V; Milanese, D

2000-01-01

307

Laser damage in glasses  

Microsoft Academic Search

Results are described which suggest that a laser beam focused inside a sample of glass produces a superheated liquid, and that the resulting internal pressure can only be released by internal fracturing, and, in some cases, also by fragmentation of the sample. The evidence is that the Brillouin scattered energy, demonstrated by Chiao, Townes, and Stoicheff is necessary, but not

D W Harper

1965-01-01

308

Light Bends Glass  

NSDL National Science Digital Library

This site, from Physical Review Focus, describes a recent experiment to find out how the momentum of a photon changes when it passes from a glass fiber into air. The article describes the 100-year-old controversy on this question and explains the results of this experiment. Links are provided for more information.

2009-02-26

309

Glass Static Fatigue.  

National Technical Information Service (NTIS)

Phase separation in the sodium borosilicate system was studied, as well as reasons for immiscibility in silicate. Models for the alkali ion peak and a higher temperature peak in the internal friction in alkali silicate glasses were developed. Models for s...

R. H. Doremus

1971-01-01

310

What Glass Ceiling?  

ERIC Educational Resources Information Center

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)

Lynch, Michael; Post, Katherine

1996-01-01

311

Stained-Glass Pastels  

ERIC Educational Resources Information Center

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…

Laird, Shirley

2009-01-01

312

Work with magnifying glasses  

Microsoft Academic Search

At workplaces with optical aids workers complain more often from visual and musculoskeletal disorders compared to those working in offices. These complaints concern more often workers using magnifying glasses than those using stereo-microscopes. Bad working-postures at workplaces with loupes and the worse optical quality of todays loupes are two causes. In addition, the measured magnification was less than the theoretical

HELMUT KRUEGER; PETER CONRADY; JÖRN ZüLCH

1989-01-01

313

Nonsilica glasses for holey fibers  

Microsoft Academic Search

The authors of this paper investigated the thermal properties and optical properties of typical nonsilica glasses, including viscosity, surface tension, thermal conductivity, transmission, linear and nonlinear refractive index, and fiber attenuation in order to judge the feasibility of using nonsilica glasses as the background material of holey fibers (HFs). Novel techniques were presented to fabricate the nonsilica glass microstructured fiber

Xian Feng; Arshad K. Mairaj; Daniel W. Hewak; Tanya M. Monro

2005-01-01

314

Containerless Processing of Advanced Glasses  

NASA Technical Reports Server (NTRS)

Report describes investigation of containerless processing of glass, conducted in preparation of gravity-free processing experiments on board Space Shuttle. 105 candidate glass materials screened. Large number of oxide proportions studied and ternary phase diagram of glass formation developed as result.

Happe, R.; Kim, K.

1984-01-01

315

New Cerium Activated Scintillating Glasses  

Microsoft Academic Search

The synthesis of cerium activated scintillating glasses is being continued, and two new types have been developed. One of these, a magnesium aluminum borate, is similar to the alkali borate glasses reported previously and was made in an effort to provide a scintillating glass with the highest possible boron content in which a reasonable pulse height could be retained. Its

Robert J. Ginther

1960-01-01

316

Method for manufacturing glass frit  

Microsoft Academic Search

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

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

1977-01-01

317

Glass for Solid State Devices  

NASA Technical Reports Server (NTRS)

Glass film has low intrinsic compressive stress for isolating active layers of magnetic-bubble and other solid-state devices. Solid-state device structure incorporates low-stress glasses as barrier and spacer layers. Glass layers mechanically isolate substrate, conductor, and nickel/iron layers.

Bailey, R. F.

1982-01-01

318

Heliostat glass survey and evaluation  

Microsoft Academic Search

The glass characterization and specification task included a comprehensive survey of both foreign and domestic sources of low distortion, low iron, .125 nominal flat glass for use in heliostat applications. PNL attempted to determine the availability of production lines, estimate industry interest, lead times, and costs for producing glass for second surface heliostat mirrors for the Barstow pilot plant and

M. A. Lind; J. M. Russin

1978-01-01

319

Water's second glass transition  

PubMed Central

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.

Amann-Winkel, Katrin; Gainaru, Catalin; Handle, Philip H.; Seidl, Markus; Nelson, Helge; Bohmer, Roland

2013-01-01

320

Enhanced diffusion processes during heavy-ion irradiation of glasses  

SciTech Connect

Alkali silicate glasses have been irradiated by using Ar ions at energy of and above 200 keV. The target temperature was varied in the range between liquid nitrogen temperature and 200/sup 0/C. The observed modifications in alkali depth distribution, determined by nuclear techniques, have been analyzed on the basis of phenomenological models. 12 refs., 3 figs.

Arnold, G.W.; Battaglin, G.; Della Mea, G.; De Marchi, G.; Mazzoldi, P.; Miotello, A.

1987-01-01

321

THE DEVELOPMENT OF RADIOACTIVE GLASS SURROGATES FOR FALLOUT DEBRIS  

SciTech Connect

The production of glass that emulates fallout is desired for the nuclear forensics community for training and measurement exercises. The composition of nuclear fallout is complex varying isotopic compositions . As the gaseous cloud traverses from hotter to cooler regions of the atmosphere, the processes of condensation and nucleation entrain environmental materials, vaporized nuclear materials and fission products. The elemental and isotopic composition of the fission products is altered due to chemical fractionation (i.e. the fission product composition that would be expected from fission of the original nuclear material is altered by differences in condensation rates of the elements); the fallout may be enriched or depleted in volatile or refractory fission products. This work describes preliminary results to synthesize, irradiate and fractionate the fission product content of irradiated particulate glass using a thermal distillation two hours after irradiation. The glass was synthesized using a solution-based polymerization of tetraethyl orthosilicate. Uranium was incorporated into the glass particulate at trace concentrations during polymerization. The particulate was subjected to a short thermal neutron irradiation then heated to 1273 K approximately 2 hours after the end of irradiation. Fission products of 133, 134, 135I, 132, 134Te, 135Xe, 138Cs and 91, 92Sr were observed to be distilled from the particulate. The results of these preliminary studies are discussed.

Martha R. Finck; Leigh R. Martin; Russel R. Lewis; Kevin P. Carney; Christopher A. McGrath

2014-01-01

322

NMR excitation and relaxation in a ``single domain'' spin glass  

Microsoft Academic Search

Zero field NMR measurements of the spin lattice relaxation time T1 on copper satellite nuclei in a frozen CuMn ``single domain'' spin glass show that the longitudinal nuclear magnetization recovery is not purely exponential. Three possible causes for the observed nonexponentiality have been considered: The distribution of enhancement factors, the differences in neighbourhood experienced by the satellite nuclei and a

E. Tönsing; H. Jung; C. Tempelmann; H. Brömer

1991-01-01

323

Solubility Effects in Waste Glass-Demineralized Water Systems.  

National Technical Information Service (NTIS)

A study was carried out to determine the solubility limits of various elements found in waste glasses in demineralized water as a function of temperature. The work was sponsored by the Office of Nuclear Waste Isolation under contract to the Department of ...

H. T. Fullam

1981-01-01

324

Local and Medium Range Order Around Fission Products in Inactive Waste Glasses: Implication for Glass Structure and Stability  

NASA Astrophysics Data System (ADS)

Borosilicate glasses are used to store high level nuclear waste in France (R7T7 glass). The structure of the glass around elements such as fission products controls important parameters as the homogeneity of the glass and/or the melted glass rheology. Data on the local and medium range order structure of these glasses could help improving the resistance toward leaching and/or irradiation, in relation with surface or geological storage of these vitrified wastes. Due to the complex composition of these glasses (up to 30 oxides), chemically selective methods are required to understand the environment of elements. X-ray Absorption Spectroscopy (XAS) is, from this point of view, a powerful tool as it provides a direct access to the investigation of the structure around specific cations in this multicomponent amorphous material, to specify their role in the glass durability. We will present different XAS studies (synchrotrons in LURE and ESRF, France) on the inactive amorphous analog for the R7T7 glass (the SON 68 glass). This report will illustrate the potentialities of this approach through the determination of the environment around fission products such as Zr, Zn and Mo. XAS shows the peculiarity of the sites occupied by these glass components of technological interest. Coordination numbers are shown to be systematically smaller than in crystalline compounds with close composition. Below the definition of the sites occupied by the chemical elements, XAS allows to detect some degree of medium range order which gives insight on the bonding of the site to the poymeric borosilicate network and allow to link precisely experimental data to theoretical calculations. Eventually, XAS is used to study the interaction between noble metals (Pd and Ru) and the glassy matrix. These elements are at the origin of small precipitates that induce changes in the melt vicosity. They occur as a result of the non-insertion of these elements in the glassy matrix. To accurate and precise structural interpretations, a direct comparison with MD calculations on simplified nuclear glass comprising 5 oxides, is performed.

Galoisy, L.; Calas, G.; Ghaleb, D.; Morin, G.

2002-12-01

325

Shedding Synchrotron Light on a Puzzle of Glasses  

ScienceCinema

Vibrational dynamics of glasses remains a point of controversial discussions. In particular, the density of vibrational states (DOS) reveals an excess of states above the Debye model called "boson peak." Despite the fact that this universal feature for all glasses has been known for more than 35 years, the nature of the boson peak is still not understood. The application of nuclear inelastic scattering via synchrotron radiation perhaps provides a clearer, more consistent picture of the subject. The distinguishing features of nuclear inelastic scattering relative to, e.g., neutron inelastic scattering, are ideal momentum integration and exact scaling of the DOS in absolute units. This allows for reliable comparison to data from other techniques such as Brillouin light scattering. Another strong point is ideal isotope selectivity: the DOS is measured for a single isotope with a specific low-energy nuclear transition. This allows for special "design" of an experiment to study, for instance, the dynamics of only center-of-mass motions. Recently, we have investigated the transformation of the DOS as a function of several key parameters such as temperature, cooling rate, and density. In all cases the transformation of the DOS is sufficiently well described by a transformation of the continuous medium, in particular, by changes of the macroscopic density and the sound velocity. These results suggest a collective sound-like nature of vibrational dynamics in glasses and cast doubts on microscopic models of glass dynamics. Further insight can be obtained in combined studies of glass with nuclear inelastic and inelastic neutron scattering. Applying two techniques, we have measured the energy dependence of the characteristic correlation length of atomic motions. The data do not reveal localization of atomic vibrations at the energy of the boson peak. Once again, the results suggest that special features of glass dynamics are related to extended motions and not to local models.

326

Influence of La2O3 Additions on Chemical Durability and Dielectric Properties of Boroaluminosilicate Glasses  

NASA Astrophysics Data System (ADS)

Boroaluminosilicate glasses containing La2O3 were prepared by the normal quenching method. The glass transition temperatures (Tg) were measured by differential scanning calorimetry (DSC). The structural role of RO was investigated by nuclear magnetic resonance (NMR). Chemical durability was evaluated by weight losses of glass samples after immersion in HC1 solution. High resolution scanning electron microscopy (HR-SEM) was used to examine the surface micrographs of corroded glass samples. The dielectric constant and tangent loss were measured in the frequency range 10-106 Hz. The results revealed that chemical durability and dielectric properties increased with increasing La2O3 content.

Zhang, X. H.; Yue, Y. L.; Wu, H. T.

2012-12-01

327

Fluoride glass: Crystallization, surface tension  

NASA Technical Reports Server (NTRS)

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.

Doremus, R. H.

1988-01-01

328

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

SciTech Connect

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

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

1986-09-01

329

Digitization of stained glass  

NASA Astrophysics Data System (ADS)

Digital photography was applied to the capture of images of the stained glass windows in the historic parish church in Fairford, Gloucestershire, England. Because of their size, the windows had to be photographed in 45 separate sections in order to capture all the detail present in the painting on the glass. The digital images of each section, approximately 3000 by 2300 pixels, were then mosaiced together in order to construct the very high resolution image needed for the complete window. A special backlight panel was constructed for the purpose, and techniques developed for minimizing the effects of reflected light and for calibrating the color of the images. Improvements in the technology for mounting and positioning the camera were identified as the most significant factors currently preventing the widespread adoption of this technology for virtual heritage applications.

MacDonald, Lindsay W.

1997-04-01

330

Outgassing of Glass  

Microsoft Academic Search

The gas evolved from glass at temperatures below the softening point, which is of interest in bake-out problems, is primarily water. The water evolved from unit surface at constant temperature above 300°C is linear with respect to the square root of the time of bake-out. The intercept of the linear plot, which can be altered by different surface treatments, is

B. Johnson Todd

1955-01-01

331

CCMR: Water in Glass  

NSDL National Science Digital Library

Water uptake for various compositions of the model glass (CaO·Al2O3)x (2 SiO2)1-x under fixed annealing conditions was studied via FTIR. The water saturation concentration increased with time for certain sample sets, suggesting slow equilibration of the surface with the annealing atmosphere, while the water diffusion coefficient exhibited no appreciable time dependence. The saturation concentration and diffusion coefficient were not found to vary significantly with composition.

Uspal, William

2005-08-17

332

Athermal photofluidization of glasses  

NASA Astrophysics Data System (ADS)

Azobenzene and its derivatives are among the most important organic photonic materials, with their photo-induced trans-cis isomerization leading to applications ranging from holographic data storage and photoalignment to photoactuation and nanorobotics. A key element and enduring mystery in the photophysics of azobenzenes, central to all such applications, is athermal photofluidization: illumination that produces only a sub-Kelvin increase in average temperature can reduce, by many orders of magnitude, the viscosity of an organic glassy host at temperatures more than 100?K below its thermal glass transition. Here we analyse the relaxation dynamics of a dense monolayer glass of azobenzene-based molecules to obtain a measurement of the transient local effective temperature at which a photo-isomerizing molecule attacks its orientationally confining barriers. This high temperature (Tloc~800?K) leads directly to photofluidization, as each absorbed photon generates an event in which a local glass transition temperature is exceeded, enabling collective confining barriers to be attacked with near 100% quantum efficiency.

Fang, G. J.; Maclennan, J. E.; Yi, Y.; Glaser, M. A.; Farrow, M.; Korblova, E.; Walba, D. M.; Furtak, T. E.; Clark, N. A.

2013-02-01

333

NMR and conductivity studies of the mixed glass former effect in lithium borophosphate glasses.  

PubMed

Alkali ion charge transport has been studied in a series of mixed glass former lithium borophosphate glasses of composition 0.33Li(2)O + 0.67[xB(2)O(3) + (1 - x)P(2)O(5)]. The entire concentration range, 0.0 ? x ? 1.0, from pure glassy Li(2)P(4)O(11) to pure glassy Li(2)B(4)O(7) has been examined while keeping the molar fraction of Li(2)O constant. Electrical conductivity measurements and nuclear magnetic resonance techniques such as spin relaxometry, line shape analysis, and stimulated-echo spectroscopy were used to examine the temperature and frequency dependence of the Li(+) ion motion over wide ranges of time scale and temperature. By accurately determining motional time scales and activation energies over the entire composition range the ion dynamics and the charge transport are found to be fastest if the borate and the phosphate fractions are similar. The nonlinear variation of the charge conduction, the most notable feature of the mixed glass former effect, is discussed in terms of the composition dependence of network former units which determine the local glass structure. PMID:23020343

Storek, Michael; Böhmer, Roland; Martin, Steve W; Larink, Dirk; Eckert, Hellmut

2012-09-28

334

NMR and conductivity studies of the mixed glass former effect in lithium borophosphate glasses  

NASA Astrophysics Data System (ADS)

Alkali ion charge transport has been studied in a series of mixed glass former lithium borophosphate glasses of composition 0.33Li2O + 0.67[xB2O3 + (1 - x)P2O5]. The entire concentration range, 0.0 <= x <= 1.0, from pure glassy Li2P4O11 to pure glassy Li2B4O7 has been examined while keeping the molar fraction of Li2O constant. Electrical conductivity measurements and nuclear magnetic resonance techniques such as spin relaxometry, line shape analysis, and stimulated-echo spectroscopy were used to examine the temperature and frequency dependence of the Li+ ion motion over wide ranges of time scale and temperature. By accurately determining motional time scales and activation energies over the entire composition range the ion dynamics and the charge transport are found to be fastest if the borate and the phosphate fractions are similar. The nonlinear variation of the charge conduction, the most notable feature of the mixed glass former effect, is discussed in terms of the composition dependence of network former units which determine the local glass structure.

Storek, Michael; Böhmer, Roland; Martin, Steve W.; Larink, Dirk; Eckert, Hellmut

2012-09-01

335

Cluster-assembled metallic glasses  

PubMed Central

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.

2013-01-01

336

Enthalpy of diaplectic labradorite glass  

NASA Astrophysics Data System (ADS)

Enthalpies of solution in molten 2PbO·B2O3 at ˜988 K have been measured for diaplectic labradorite glass from the Manicouagan impact crater and a fused glass formed from the same material. The enthalpies of solution of the diaplectic and fusion-formed glasses are 4,347 and 2,023 cal mol-1, respectively. The more endothermic enthalpy of solution of the diaplectic glass indicates a greater relative energetic stability of about 2.3 kcal mol-1. The data are consistent with Diemann and Arndt's (1984) structural model that suggests the diaplectic glass is more ordered than fusion-formed glass and with the presence of crystallites. Comparison of data to enthalpies of solution of crystalline labradorite (Carpenter et al. 1985) indicates a maximum percentage of crystalline relics of ˜15 18%, also consistent with Diemann and Arndt's (1984) estimate of <17%. Thus the diaplectic glass is intermediate in thermochemical properties between normal glass and crystal (much closer to glass) and does not represent any state more unstable than normal fusion-formed glass.

Geisinger, K. L.; Navrotsky, A.; Arndt, J.

1986-11-01

337

Bioactive glass in tissue engineering.  

PubMed

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

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

2011-06-01

338

Bioactive glass in tissue engineering  

PubMed Central

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.

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

2011-01-01

339

Inorganic glasses, glass-forming liquids and amorphizing solids  

Microsoft Academic Search

We take familiar inorganic oxide glasses and non-oxide glasses and the liquids from which they derive to review the current understanding of their atomic structure, ranging from the local environments of individual atoms to the long-range order which can cover many interatomic distances. The structural characteristics of important glasses and melts, like silicates, borates, alumino-silicates, halides and chalcogenides, are drawn

G. N. Greaves; S. Sen

2007-01-01

340

Structures and optical properties of tellurite glasses and glass ceramics  

Microsoft Academic Search

The structures and optical properties of (K2O)15(Nb 2O5)15(TeO2)70 glass and glass ceramic have been studied in order to understand the second harmonic generation observed from the glass ceramic. We have used 93Nb NMR, Raman spectroscopy, differential scanning calorimetry, small angle x-ray scattering, transmission electron microscopy, and powder x-ray and neutron scattering. We find that there is a microstructure consistent with

Robert Theodore Hart Jr.

2004-01-01

341

Glass fibre versus non-glass fibre splinting bandages.  

PubMed

We have assessed the current range of synthetic splinting bandages, comparing glass with non-glass fabrics and plaster-of-Paris. Physical and mechanical tests have been carried out and the opinions of patients, volunteers and orthopaedic staff were recorded. Modern bandages have some better properties than standard plaster bandage but do not conform as well, are more expensive and potentially more hazardous. However, non-glass bandages are lighter, less brittle, more radiolucent and less hazardous than glass fibre bandages and are preferred by both patients and applicators. PMID:1572703

Wytch, R; Ross, N; Wardlaw, D

1992-01-01

342

Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.  

PubMed

We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed. PMID:24709542

Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

2014-07-01

343

Containing nuclear waste via chemical polymerization  

SciTech Connect

Disclosed is a method of immobilizing nuclear waste in glass. A composition is prepared of 60 to 100% of a hydrolyzed glassforming silicon compound and up to about 40% of a glass-forming aluminum compound. About 1 to about 50% liquid nuclear waste and up to about 10% solid nuclear waste is mixed into the composition. The composition is heated at about 200 to about 500/sup 0/C to drive off water and organics, with the result vitreous product totally containing the nuclear waste. Finally, this product can be sintered at about 800 to about 900/sup 0/C to reduce porosity, or warm pressed into block form.

Harrison, D.E.; Pope, J.M.; Wood, S.

1983-03-22

344

Atomic dynamics of tin nanoparticles embedded into porous glass  

SciTech Connect

The method of resonant nuclear inelastic absorption of synchrotron radiation has been used to study the phonon spectrum for tin nanoparticles (with a natural isotope mixture) embedded into a porous glassy (silica) matrix with an average pore diameter of 7 nm in comparison to the analogous spectrum of bulk tin enriched with {sup 119}Sn isotope. Differences between the spectra have been observed, which are related to both the dimensional effects and specific structural features of the porous glass-tin nanocomposite. Peculiarities in the dynamics of tin atoms embedded into nanopores of glass are interpreted in terms of a qualitative model of the nanocomposite structure.

Parshin, P. P.; Zemlyanov, M. G., E-mail: zeml@isssph.kiae.ru; Panova, G. Kh.; Shikov, A. A. [Russian Research Centre Kurchatov Institute (Russian Federation); Kumzerov, Yu. A.; Naberezhnov, A. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Sergueev, I.; Crichton, W. [European Synchrotron Radiation Facility (France); Chumakov, A. I. [Russian Research Centre Kurchatov Institute (Russian Federation); Rueffer, R. [European Synchrotron Radiation Facility (France)

2012-03-15

345

Fracture mechanics of cellular glass  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

346

Micromachining of glass inertial sensors  

Microsoft Academic Search

We demonstrate the feasibility of a powder blasting micro-erosion process for the micromachining of accelerometer devices in glass. Using high-speed abrasive microparticles and a metal contact mask, we structure millimeter-size cantilever beams from simple glass slides. By metalizing one side of the glass substrate, we demonstrate both capacitive and piezoresistive\\/strain gauge detection of the vibrating cantilever mass and measure the

Eric Belloy; Abdeljalil Sayah; Martin A. M. Gijs

2002-01-01

347

Electronic structure of metallic glasses  

SciTech Connect

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.

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

348

New glasses with high photosensitivity  

NASA Astrophysics Data System (ADS)

New germanosilicate glasses with high photosensitivity were fabricated and studied. Addition of sodium produced an increase of 6-fold Ge ions and the appearance of a UV absorption band at 285 nm in the as cast glasses. Laser exposure produced bleaching of such band, when present. Further studies are needed to correlate the two phenomena and find out the best composition in terms of photosensitivity. A new tin sodium silicate glass was also fabricated: glass fibers were produced and high temperature stable gratings were obtained by irradiation with a UV laser.

Ferraris, Monica; Milanese, Daniel; Chen, Qiuping; Menke, Yvonne; Monchiero, Elena

2003-11-01

349

Glass corrosion in natural environment  

NASA Technical Reports Server (NTRS)

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.

Thorpe, Arthur N.

1989-01-01

350

The Lévy spin glass transition  

NASA Astrophysics Data System (ADS)

We determine the phase transition in the Lévy spin glass. A regularized model where the coupling constants smaller than some cutoff ? are neglected can be studied by the cavity method for diluted spin glasses. We show how to handle the ??0 limit and determine the de Almeida-Thouless transition temperature in the presence of an external field. Contrary to previous findings, in zero external field we do not find any stable replica-symmetric spin glass phase: the spin glass phase is always a replica-symmetry-broken phase.

Janzen, K.; Engel, A.; Mézard, M.

2010-03-01

351

Water sprints uphill on glass  

NASA Astrophysics Data System (ADS)

As a material, glass has been widely used in traditional fluidic devices and more recently in micro- and nanofluidic devices, and its wetting properties are crucially important in these applications. In this work, by using a high-intensity femtosecond laser structuring technique, we create a unique surface pattern on glass that transfer a regular glass surface to superwicking. As a result, water defies the gravity and sprints vertically uphill along the structured glass surface at an unprecedented velocity of 3.8 cm/sec. Our study shows that the dynamics of this fast self-propelled water flow follows a square root of time dependence.

Vorobyev, A. Y.; Guo, Chunlei

2010-12-01

352

Method for heating a glass sheet  

DOEpatents

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.

Boaz, P.T.

1998-07-21

353

Creep in colloidal glasses.  

PubMed

We investigate the nonlinear response to shear stress of a colloidal hard-sphere glass, identifying several regimes depending on time, sample age, and the magnitude of applied stress. This emphasizes a connection between stress-imposed deformation of soft and hard matter, in particular, colloidal and metallic systems. A generalized Maxwell model rationalizes logarithmic creep for long times and low stresses. We identify diverging time scales approaching a critical yield stress. At intermediate times, strong aging effects are seen, which we link to a stress overshoot seen in stress-strain curves. PMID:23004620

Siebenbürger, M; Ballauff, M; Voigtmann, Th

2012-06-22

354

Low Temperature Sintering of P2O5-Added Cordierite Glass with Borosilicate Glass  

NASA Astrophysics Data System (ADS)

Borosilicate glass was adopted as a sintering aid to improve the sinterability of P2O5-added cordierite glass. The flux effect of borosilicate glass aids the coalescence of cordierite glass particles, which promotes the densification. Crystallization of cordierite glass is the major reaction during the sintering of cordierite glass with borosilicate glass. Besides the advantage of lower sintering temperature, the addition of borosilicate glass lowers the dielectric constant of sintered composites.

Fu, Shen-Li; Chen, Lih-Shan

1993-03-01

355

Low Temperature Sintering of P2O5-Added Cordierite Glass with Lead Borosilicate Glass  

NASA Astrophysics Data System (ADS)

Cordierite was prepared by the sintering of cordierite glass and lead borosilicate glass. With the addition of lead borosilicate glass, P2O5-added cordierite glass can be densified at lower sintering temperature. Owing to the flux effect of lead borosilicate glass, the coalescence of glass particles was aided by the viscous flow of the glass. Besides the advantage of lower temperature sintering, the addition of lead borosilicate glass enhances the formation of ?-cordierite crystalline phase.

Chen, Lih-Shan; Fu, Shen-Li

1992-08-01

356

Friction Between Glass Fiber and Resin in Glass Reinforced Plastics.  

National Technical Information Service (NTIS)

The glass fiber vs plastic friction phenomena and their consequences were measured on laminates of Buna G polyester and a hydrocarbon-based resin reinforced by a commercial twill-weave glass fiber fabric by determining the decay of a torsional vibration i...

G. Pohl

1968-01-01

357

Foam glass insulation from waste glass. Final report  

Microsoft Academic Search

Waste glass has proven to be effective for the production of foam glass insulation both in the bulk or rigid board form and pellet form. Problems inherent with the use of water, carbon black and calcium carbonate as the foaming agents, have been identified and many have been solved by various techniques. Water was found to be best suited for

W. G. Oakseson; J. Lee; S. K. Goyal; T. Robson; I. B. Cutler

1977-01-01

358

Spin glasses and fragile glasses: Statics, dynamics, and complexity  

PubMed Central

In this paper I will briefly review some theoretical results that have been obtained in recent years for spin glasses and fragile glasses. I will concentrate my attention on the predictions coming from the so called broken replica symmetry approach and on their experimental verifications. I will also mention the relevance or these results for other fields, and in general for complex systems.

Parisi, Giorgio

2006-01-01

359

Glass transition and viscosity of simple glasses and liquids  

Microsoft Academic Search

The theoretical understanding of liquids and glasses at an atomistic level lags well behind that of crystalline materials, even though they are important in many fields including biology and the medical sciences. We present a simple microscopic model for the glass transition based on topological fluctuations in the bonding network. The model makes predictions for important parameters of the glassy

Takeshi Egami; S. Joseph Poon; Valentin Levashov; Rachel Aga; James Morris

2006-01-01

360

Sensitization of Nd3(+) laser glass and Faraday rotator glasses  

Microsoft Academic Search

Seven different fluorophosphate glass compositions were doped with cerium and terbium. Initial results indicated that these glasses, as they stood, had only a limited ability to dissolve the rare earth ions. A series of melt modifications was attempted to improve the solubility.

J. D. Myers

1976-01-01

361

Glass Formulation Development for INEEL Sodium-Bearing Waste  

SciTech Connect

For about four decades, radioactive wastes have been collected and calcined from nuclear fuels reprocessing at the Idaho Nuclear Technology and Engineering Center (INTEC), formerly Idaho Chemical Processing Plant (ICPP). Over this time span, secondary radioactive wastes have also been collected and stored as liquid from decontamination, laboratory activities, and fuel-storage activities. These liquid wastes are collectively called sodium-bearing wastes (SBW). About 5.7 million liters of these wastes are temporarily stored in stainless steel tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). Vitrification is being considered as an immobilization step for SBW with a number of treatment and disposal options. A systematic study was undertaken to develop a glass composition to demonstrate direct vitrification of INEEL's SBW. The objectives of this study were to show the feasibility of SBW vitrification, not a development of an optimum formulation. The waste composition is relatively high in sodium, aluminum, and sulfur. A specific composition and glass property restrictions, discussed in Section 2, were used as a basis for the development. Calculations based on first-order expansions of selected glass properties in composition and some general tenets of glass chemistry led to an additive (fit) composition (68.69 mass % SiO{sub 2}, 14.26 mass% B{sub 2}O{sub 3}, 11.31 mass% Fe{sub 2}O{sub 3}, 3.08 mass% TiO{sub 2}, and 2.67 mass % Li{sub 2}O) that meets all property restrictions when melted with 35 mass % of SBW on an oxide basis, The glass was prepared using oxides, carbonates, and boric acid and tested to confirm the acceptability of its properties. Glass was then made using waste simulant at three facilities, and limited testing was performed to test and optimize processing-related properties and confirm results of glass property testing. The measured glass properties are given in Section 4. The viscosity at 1150 C, 5 Pa{center_dot}s, is nearly ideal for waste-glass processing in a standard liquid-fed joule-heated melter. The normalized elemental releases by 7-day PCT are all well below 1 g/m{sup 2}, which is a very conservative set point used in this study. The T{sub L}, ignoring sulfate formation, is less than the 1050 C limit. Based on these observations and the reasonable waste loading of 35 mass 0/0, the SBW glass was a prime candidate for further testing. Sulfate salt segregation was observed in all test melts formed from oxidized carbonate precursors. Melts fabricated using SBW simulants suggest that the sulfate-salt segregation seen in oxide and carbonate melts was much less of a problem. The cause for the difference is likely H{sub 2}SO{sub 4} fuming during the boil-down stage of wet-slurry processing. Additionally, some crucible tests with SBW simulant were conducted at higher temperatures (1250 C), which could increase the volatility of sulfate salts. The fate of sulfate during the melting process is still uncertain and should be the topic of future studies. The properties of the simulant glass confirmed those of the oxide and carbonate glass. Corrosion tests on Inconel 690 electrodes and K-3 refractory blocks conducted at INEEL suggest that the glass is not excessively corrosive. Based on the results of this study, the authors recommend that a glass made of 35% SBW simulant (on a mass oxide and halide basis) and 65% of the additive mix (either filled or raw chemical) be used in demonstrating the direct vitrification of INEEL SBW. It is further recommended that a study be conducted to determine the fate of sulfate during glass processing and the tolerance of the chosen melter technology to sulfate salt segregation and corrosivity of the melt.

J.D. Vienna; M.J. Schweiger; D.E. Smith; H.D. Smith; J.V. Crum; D.K. Peeler; I.A. Reamer; C.A. Musick; R.D. Tillotson

1999-08-03

362

Studies on the effect of Li{sub 2}SO{sub 4} on the structure of lithium borate glasses  

SciTech Connect

Thermal and spectroscopic investigations have been carried out on a number of glasses with a wide range of compositions in the pseudoternary glass system, Li{sub 2}SO{sub 4}-Li{sub 2}O-B{sub 2}O{sub 3}, to understand the role of sulfate ions in modifying the borate glass structure. Both nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic results indicate that four-coordinate boron atoms are retained in the glass structure to a greater extent in sulfate-containing glasses than in pure lithium borate glasses. There seems to be some evidence for the existence of sulfoborate-type units in Raman spectra in the region of 800--960 cm{sup {minus}1}. These conclusions are supported by the observed behavior of glass transition temperatures and molar volumes. The possibility of formation of sulfoborate-type units is discussed from bonding and thermodynamic points of view.

Ganguli, M.; Rao, K.J. [Indian Inst. of Science, Bangalore (India). Solid State and Structural Chemistry Unit] [Indian Inst. of Science, Bangalore (India). Solid State and Structural Chemistry Unit

1999-02-11

363

Thermochemical study of rare earth and nitrogen incorporation in glasses  

NASA Astrophysics Data System (ADS)

Rare earth containing aluminosilicate, borosilicate, aluminate and nitrogen containing aluminosilicate glasses are technically important materials. They have extraordinary physical and chemical properties such as high glass transition temperature, very low electrical conductivity, and excellent chemical stability. These unique properties lead to applications as coatings on metals and ceramics, optical fibers, semiconductors, and nuclear waste containment materials. In addition, such systems contain the most widely used additives for sintering of Si3N4, SiAlON and SiC ceramics for high temperature applications. Thermodynamic properties and the relations among energetics, structure and bonding are essential to controlling processing parameters to synthesize, at lower cost, materials having better properties. Earlier investigations mainly pertained to specific physical properties of rare-earth doped oxide and oxynitride glasses. Work on the thermodynamic stability and materials compatibility has been very sparse. High temperature solution calorimetry in molten oxide solvents is a powerful tool for the thermodynamic study of refractory materials. With implementation and improvement, this technique has been applied to the first measurement of enthalpies of formation of RE-Si-Al-O glasses, REAlO3 glasses, RE-Si-Al-O-N glasses, and Si3N 4 and Ge3N4 with high pressure spinel structure. The first successful synthesis of REAlO3 glasses has been achieved by containerless melting. Their large enthalpies of crystallization confirm that they are reluctant glass formers. For glasses along the 2REAlO3 -3SiO2 join, the strongly negative heats of mixing support the absence of miscibility gaps except possibly at very high silica content. Energetic evidence has been presented for incipient phase-ordered regions in Gd- or Hf-containing sodium alumino-borosilicate glasses for plutonium immobilization. Linear relations between enthalpies of formation of RESiAlON glasses from elements and nitrogen content indicate that within the experimental composition range, sites occupied by nitrogen ions are roughly energetically equivalent in a given substitution series. The energetics of difference rare-earth substitution appears to be dominated by differences in the acid/base character of the cations.

Zhang, Yahong

364

Quinary metallic glass alloys  

DOEpatents

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.

Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

1998-01-01

365

Quinary metallic glass alloys  

DOEpatents

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.

Lin, X.; Johnson, W.L.

1998-04-07

366

Solution of naturally-ocurring glasses in the geological environment  

NASA Technical Reports Server (NTRS)

As part of a study to investigate the feasibility of putting nuclear wastes in glass containers and burying them on land or dumping them in the ocean, the amount of solution experience by naturally occurring glasses from two land sites and thirty-four deep sea sites was studied. The glasses are microtektites from three strewn fields and from the Zhamanshin impact crater. The microtektites range in age from 0.7 to 35 m.y. and have a wide range in composition. The weight percent SiO2, for example, ranges from 44.8 to 81.7. Although several criteria for determining the amount of solution were considered, most of the conclusions are based on two criteria: (1) width of cracks, and (2) elevation of silica rich inclusions above the adjacent microtektite surface. All the measurements were made on scanning electron microscope photomicrographs of the microtektites.

Glass, B. P.

1982-01-01

367

Raman study of Kr ion irradiated sodium aluminoborosilicate glass  

NASA Astrophysics Data System (ADS)

Raman spectroscopy was used to investigate the microstructure evolution of sodium aluminoborosilicate glass after 4 MeV Kr17+ ions irradiation at various fluences from 3.1 × 1011 to 1.8 × 1015 ions/cm2. The Si-O-Si vibration band around 450 cm-1 was slightly shifted to higher Raman shift after irradiation, and stabilized after the nuclear deposited energy reached about 1024 eV/cm3. An increase in the population of 3-membered rings and decrease in the species of 4-membered rings were evidenced in the irradiated samples. These have been correlated to the densification process of glass. Depolymerization of glass network caused by Kr ion irradiation was also observed. These results indicate that the microstructural modifications caused by Kr ion irradiation are the consequence of ballistic effects.

Chen, L.; Wang, T. S.; Yang, K. J.; Peng, H. B.; Zhang, G. F.; Zhang, L. M.; Jiang, H.; Wang, Q.

2013-07-01

368

ConcepTest: Glass-Rock Analogy  

NSDL National Science Digital Library

Glass is made by melting silica-rich sand. The molten glass is then formed into shapes as it cools. Glass making could be seen as an analog for the formation of a. igneous rock b. metamorphic rock c. sedimentary ...

369

Reactions and Bonding Between Glasses and Titanium.  

National Technical Information Service (NTIS)

Hermetic seals between titanium and both silicate and alkaline earth boroaluminate glasses have been made. Mechanical testing of pin-seal configurations indicate that the boroaluminate glass seals are at least 50% stronger than the silicate glass seals. T...

R. K. Brow R. D. Watkins

1987-01-01

370

Silver Valence and Local Environments in Borosilicate and Calcium Aluminoborate Waste Glasses as determined from X-ray Absorption Spectroscopy  

SciTech Connect

Silver K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data were collected and analyzed to characterize silver (Ag) environments in borosilicate and Ca-aluminoborate glass formulations developed as potential candidates for the immobilization of certain nuclear wastes. Silver is found in some nuclear waste streams and must be encapsulated in glass during waste vitrification processes. A related concern deals with phase separation within these glasses and whether colloidal silver would be present in the glass melt, which could present processing issues, or in the waste glass product. Characterization of the silver environments provides useful information for optimizing the silver incorporation ability of such glasses. Data were also gathered on four crystalline standards: Ag-foil, Ag{sub 2}O, argentojarosite (AgFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}), and AgO. XANES data indicate Ag{sup +} as the dominant species in the glasses. XANES and EXAFS data show that the average Ag environment in the Ca-aluminoborate glass is different compared with those in the two borosilicate glasses investigated. EXAFS analyses show that Ag in the borosilicate glasses is coordinated by two oxygens in a similar environment to that in crystalline Ag{sub 2}O, except that the associated Ag-O distances are approximately 0.10 Angstroms longer in the glass. Silver in the Ca-aluminoborate glass may be within one highly disordered site, or possibly, several different sites, where the average Ag-O distance, coordination number, and Debye-Waller factor are larger than those determined for the borosilicate glasses. Despite their relatively high silver contents, there is no evidence from XANES or EXAFS of colloidal silver in the glasses investigated.

McKeown,D.; Gan, H.; Pegg, I.

2005-01-01

371

Basic Research on Oxynitride Glasses.  

National Technical Information Service (NTIS)

Nitrogen has been partially substituted for oxygen in a wide variety of silicate systems to produce oxynitride glasses with improved properties. Nitrogen contents as high as 12 at% have been achieved. The glass-forming regions in the Y-Si-Al-O-N, Mg-Si-Al...

R. E. Loehman

1982-01-01

372

SRNL POROUS WALL GLASS MICROSPHERES  

Microsoft Academic Search

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

G Wicks; L Leung Heung; R Ray Schumacher

2008-01-01

373

Refractory Glass Seals for SOFC  

SciTech Connect

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.

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

2011-07-01

374

Glass Fiber Based Friction Materials  

Microsoft Academic Search

Glass fibers have been considered as a reinforcing agent in friction linings as one component of a potential substitute for asbestos. The mechanical, thermal and frictional properties of six different grades of glass fibers have been evaluated in model phenolic resin based friction materials. The Young's modulus, ultimate tensile strength, flexural strength, flexural modulus, coefficient of thermal expansion and friction

N. Subramaniam; Brijnaresh R. Sinha; Frank D. Blum; Yung-Rwei Chen; L. R. Dharani

1991-01-01

375

Training Guidelines: Glass Furnace Operators.  

ERIC Educational Resources Information Center

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…

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

376

Method of determining glass durability  

DOEpatents

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.

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

1998-12-08

377

Method of determining glass durability  

DOEpatents

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.

Jantzen, Carol Maryanne (Aiken, SC); Pickett, John Butler (Aiken, SC); Brown, Kevin George (Augusta, GA); Edwards, Thomas Barry (Aiken, SC)

1998-01-01

378

Porous Layers at Glass Surfaces  

Microsoft Academic Search

PREVIOUS investigations have shown that porous modifications of the surfaces of glasses may be formed by the action of liquid water1 and water vapour2. I have now studied the formation of porosity in the surface of grains of soda-lime-silica glass in various conditions.

P. A. Sewell

1968-01-01

379

Glass Nanofiber Fabrication and Devices  

NASA Astrophysics Data System (ADS)

We have integrated electric field assisted spinning (electrospinning) of polymeric materials with photolithography for the fabrication of glass nanostructures. We incorporated spin on glass (SOG) dielectric coating with poly-vinyl-pyrrolidone (PVP) and spun this solution over trenches etched in silicon. A calcination eliminated the PVP polymer from these fibers, while cross-linking the SOG, leaving silica glass fibers with diameters as small as 70 nm. We demonstrated the operation of these fibers as nanomechanical oscillators. We also spun heat depolymerizable polycarbonate (HDPC) fibers over silicon trenches. These fibers were coated with glass by chemical vapor deposition or sputtering, followed by thermal elimination of the polymer core. This yielded suspended glass channels of elliptical cross sections, with inner major and minor axes as small as 75 and 50 nm. These nanochannels offer a low background option for doing fluorescence detection, as demonstrated by single molecule detection, using a confocal microscope, of cellulase enzymes in these channels.

Verbridge, Scott; Edel, Joshua

2005-03-01

380

Energetics of glass fragmentation: Experiments on synthetic and natural glasses  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

381

Characterization of projected DWPF glasses heat treated to simulate canister centerline cooling  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). Eventually these canistered waste forms will be sent to a geologic repository for final disposal. In order to assure acceptability by the repository, the Department of Energy has defined requirements which DWPF canistered waste forms must meet. These requirements are the Waste Acceptance Preliminary Specifications (WAPS). The WAPS require DWPF to identify the crystalline phases expected to be present in the final glass product. Knowledge of the thermal history of the borosilicate glass during filling and cooldown of the canister is necessary to determine the amount and type of crystalline phases present in the final glass product. Glass samples of seven projected DWPF compositions were cooled following the same temperature profile as that of glass at the centerline of the full-scale DWPF canister. The glasses were characterized by x-ray diffraction and scanning electron microscopy to identify the crystalline phases present The volume percents of each crystalline phase present were determined by quantitative x-ray diffraction. The Product Consistency Test (PCI) was used to determine the durability of the heat-treated glasses.

Marra, S.L.; Jantzen, C.M.

1992-05-01

382

Characterization of projected DWPF glasses heat treated to simulate canister centerline cooling. Revision 1  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). Eventually these canistered waste forms will be sent to a geologic repository for final disposal. In order to assure acceptability by the repository, the Department of Energy has defined requirements which DWPF canistered waste forms must meet. These requirements are the Waste Acceptance Product Specifications (WAPS). The WAPS require DWPF to identify the crystalline phases expected to be present in the final glass product. Knowledge of the thermal history of the borosilicate glass during filling and cooldown of the canister is necessary to determine the amount and type of crystalline phases present in the final glass product. Glass samples of seven projected DWPF compositions were cooled following the same temperature profile as that of glass at the centerline of the full scale DWPF canister. The glasses were characterized by X-ray diffraction and scanning electron microscopy to identify the crystalline phases present. The volume percents of each crystalline phase present were determined by quantitative x-ray diffraction. The Product Consistency Test (PCT) was used to determine the durability of the heat treated glasses.

Marra, S.L.; Jantzen, C.M.

1993-06-01

383

Containerless glass fiber processing  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

384

Surface flaws in glass  

SciTech Connect

The nature of surface flaws in glass is examined in the light of indentation fracture theory. First, the mechanical response of well-developed indentation cracks to applied stresses is described. A characteristic feature of the predicted response is a stage of precursor growth to a critical failure configuration, due to the stabilizing influence of residual elastic-plastic stresses. This characteristic is confirmed by direct observations of the crack evolution. Then, it is demonstrated from acoustic scattering experiments that machining damage flaws have essentially the same characteristic response, implying that they are true microcracks. Finally, aging experiments on indented, machined and abraded surfaces, in aqueous environments, are described. Strength recovery with aging time is observed in all cases, provided residual stresses remain active during exposure to the environment, and is directly attributable to secondary crack growth effects.

Marshall, D.B.; Lawn, B.R.

1983-05-01

385

Silica glass fiber photorefractometer.  

PubMed

We report a fiber-optic refractive-index sensor that is applicable to a long-distance measurement. The sensor consists of a silica glass fiber bent into a U shape with a bending radius of typically several hundred micrometers. The cladding at the tip of the sensor is stripped off. The sensing mechanism is based on the variation of the output intensity that is induced by radiation loss at the bend, which enables us to measure the refractive index of the outer medium. A fabrication method of fusing the sensor with a CO(2) laser and etching with HF is described. Multipoint measurements of optical-time-domain reflectometry are also described. PMID:20717369

Takeo, T; Hattori, H

1992-01-01

386

Product consistency testing of West Valley Compositional Variation Glasses  

SciTech Connect

Nuclear waste glass produced by the West Valley Demonstration Project (WVDP) must meet the requirements of the Waste Acceptance Preliminary Specification (WAPS) as developed by the US Department of Energy (DOE). To assist WVDP in complying with WAPS, the Materials Characterization Center (MCC) at Pacific Northwest Laboratory (PNL) used the Product Consistency Test (PCT) to evaluate 44 West Valley glasses that had previously been tested in FY 1987 and FY 1988. This report summarizes the results of the PCTs. The glasses tested, which were fabricated as sets of Compositional Variation Glasses for studies performed by the West Valley Support Task (WVST) at PNL during FY 1987 and FY 1988, were doped with Th and U and were variations of West Valley reference glasses. In addition, Approved Reference Material-1 (ARM-1) was used as a test standard (ARM-1 is supplied by the MCC). The PCT was originated at Westinghouse Savannah River Company (WSRC) by C. M. Jantzen and N. R. Bibler (Jantzen and Bibler 1989). The test is a seven-day modified MCC-3 test that uses crushed glass in the size range -100 +200 mesh with deionized water in a Teflon container. There is no agitation during the PCT, and no attempt to include CO{sub 2} from the test environment. Based on B and Li release, the glasses performed about the same as in previous modified MCC-3 testing performed in FY 1987 and FY 1988 (Reimus et al. 1988). The modified MCC-3 tests performed by Reimus et al. were similar to the PCT containers and the exclusion of CO{sub 2} from the tests.

Olson, K.M.; Marschman, S.C.; Piepel, G.F.; Whiting, G.K.

1994-11-01

387

Structure, surface reactivity and physico-chemical degradation of fluoride containing phospho-silicate glasses  

SciTech Connect

We report on the structure, apatite-forming ability and physicochemical degradation of glasses along fluorapatite [FA; Ca5(PO4)3F] - diopside (Di; CaMgSi2O6) join. A series of glasses with varying FA/Di ratio have been synthesised by melt-quenching technique. The amorphous glasses could be obtained only for compositions up to 40 wt.% of FA. The detailed structural analysis of glasses has been made by infra-red spectroscopy (FTIR), Raman spectroscopy and magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR). Silicon was predominantly present as Q2 (Si) species while phosphorus was found in orthophosphate type environment in all the investigated glasses. The apatite forming ability of glasses was investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h – 28 days. An extensive precipitation of calcite (CaCO3) after immersion in SBF was found in all the glasses which considerably masked the formation of hydroxyapatite [HA; Ca5(PO4)3OH] as depicted by X-ray diffraction (XRD) and FTIR. The possible mechanism favouring formation of calcite instead of HA has been explained on the basis of experimental results obtained for structure of glasses, leaching profile of glass powders in SBF solution and pH variation in SBF solution. Further, physico-chemical degradation of glasses has been studied in accordance with ISO 10993-14 “Biological evaluation of medical devices – Part 14: Identification and quantification of degradation products from ceramics” in Tris HCl and citric acid buffer. All the FA containing glasses exhibited a weight gain (instead of weight loss) after immersion in citric acid buffer due to the formation of different crystalline products.

Kansal, Ishu; Goel, Ashutosh; Tulyaganov, Dilshat U.; Santos, Luis F.; Ferreira, Jose M.

2011-03-28

388

The rheology of solid glass  

NASA Astrophysics Data System (ADS)

As the glass transition is approached from the high temperature side, viewed as a liquid, the properties of the ever more viscous supercooled liquid are continuous functions of temperature and pressure. The point at which we decide to classify the fluid as a solid is therefore subjective. This subjective decision does, however, have discontinuous consequences for how we determine the rheological properties of the glass. We apply the recently discovered relaxation theorem to the time independent, nondissipative, nonergodic glassy state to derive an expression for the phase space distribution of an ensemble of glass samples. This distribution is then used to construct a time dependent linear response theory for aged glassy solids. The theory is verified using molecular dynamics simulations of oscillatory shear for a realistic model glass former with excellent agreement being obtained between the response theory calculations and direct nonequilibrium molecular dynamics calculations. Our numerical results confirm that unlike all the fluid states, including supercooled liquids, a solid glass (in common with crystalline states) has a nonzero value for the zero frequency shear modulus. Of all the states of matter, a supercooled fluid approaching the glass transition has the highest value for the limiting zero frequency shear viscosity. Finally, solid glasses like dilute gases and crystals have a positive temperature coefficient for the shear viscosity whereas supercooled and normal liquids have a negative temperature coefficient.

Williams, Stephen R.; Evans, Denis J.

2010-05-01

389

Paradigms for the Glass Transition  

NASA Astrophysics Data System (ADS)

Several paradigms of the glass transition are commonly used to either characterize the behavior of glass-forming materials or as ``targets'' for theoretical outcomes. The purpose of the work and discussion was motivated by a view that some of the paradigms currently used to frame the glass transition event, while potentially useful, may also have limitations that we often do not fully consider. Discussion focuses on isochoric glass formation paths, thermodynamic and dynamic fragilities and how dynamic fragility in many systems (especially polymers, metals, ionic liquids and hydrogen bonding systems) seems to vary primarily with the glass transition temperature, Tg, itself. This leads to the conclusion that such systems have an apparent activation energy that varies as the square of the glass temperature and consequently a fragility index m that varies linearly in Tg. The work concludes with a presentation of evidence that the apparent super Arrhenius divergence of viscosity or relaxation time as temperature decreases towards the Tg is precarious, suggesting that the common expectations of a diverging relaxation time or viscosity as the glass temperature is approached are not met.

McKenna, Gregory

2009-03-01

390

Glass ceramic seals to inconel  

DOEpatents

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.

McCollister, Howard L. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM)

1983-11-08

391

Radiation Effects in Nuclear Waste Materials  

Microsoft Academic Search

Radiation effects from the decay of radionuclides may impact the long-term performance and stability of nuclear waste forms and stabilized nuclear materials. In an effort to address these concerns, the objective of this project was the development of fundamental understanding of radiation effects in glasses and ceramics, particularly on solid-state radiation effects and their influence on aqueous dissolution kinetics. This

William J. Weber; L. Rene Corrales; Jonathan P. Icenhower; Suntharampillai Thevuthasan; B. Peter McGrail; Ramaswami Devanathan; Renee M. Van Ginhoven; Jakyoung Song; Weilin Jiang; Bruce D. Begg; R. B. Birtcher; X. Chen; Steven D. Conradson

2000-01-01

392

Radiation Effects in Nuclear Waste Materials  

SciTech Connect

The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials.

William j. Weber; Lumin Wang; Jonathan Icenhower

2004-07-09

393

Stainless steel/glass ceramic interactions under hot isostatic pressing (HIPing) conditions  

NASA Astrophysics Data System (ADS)

The interactions between stainless steel (SS) and a glass-ceramic designed for immobilisation of the high-level nuclear waste generated at the Idaho chemical processing plant (ICPP) under hot isostatic pressing (HIPing) conditions (100 MPa in argon at 1200 °C) have been studied and subsequently the effect of such interactions on the chemical durability of the glass-ceramic waste form has been examined. The diffusion of Cr from SS (Cr depletion in SS) through the interaction layer and formation of crystalline Cr/Al oxides in glass dominate the overall interaction process. It appears that the depletion of Cr in SS may reduce the potential of SS as a barrier. However, such interactions have no significant impact on the glass-ceramic and the presence of the interaction layer does not seem to have any detrimental effect on the chemical durability of the glass-ceramic as a waste form.

Zhang, Y.; Li, H.; McGlinn, P. J.; Yang, B.; Begg, B. D.

2008-04-01

394

NMR spin-lattice relaxation in the deuterium quadrupolar glass  

Microsoft Academic Search

We present measurements of nuclear spin-lattice relaxation in solid D2 for para concentrations 0.24glass state. A model of para-ortho cross relaxation is presented which allows our D2 data to be compared with previous H2 relaxation data.

Donald Candela; Saps Buchman; W. T. Vetterling; R. V. Pound

1983-01-01

395

Are gel-derived glasses different from ordinary glasses?  

NASA Technical Reports Server (NTRS)

A review is presented of some of the previously reported differences and similarities between comparable gel glasses (and gels) and ordinary glasses. In this regard, considerations are made with respect to such factors as structure, physical and thermal properties, and phase transformation behavior. A variety of silicate glass compositions are used for illustrative purposes. The discussion is roughly divided into two sections: low and high temperature behavior. At low temperatures one anticipates that differences between gel and conventional glasses will exist, but such dissimilarities are not expected to persist to high temperatures. However, experimental evidence is presented which indicates the perpetuation of such differences to very high temperatures. A partial resolution for this anomalous behavior is offered.

Weinberg, M. C.

1986-01-01

396

Proton-conducting glass electrolyte.  

PubMed

A new porous glass electrolyte consisting of heteropolyacids, i.e., phosphotungstic acid (PWA) and phosphomolybdic acid, was investigated and was found to yield a remarkably high proton conductivity of 1.014 S cm(-1) at 30 degrees C and 85% relative humidity. This is the first time such a high proton conductivity value has been reported for a heteropolyacid glass membrane. The glass was applied as the electrolyte for an H(2)/O(2) fuel cell, and a maximum power density of 41.5 mW/cm(2) at 32 degrees C was attained using this new PWA-containing electrode. PMID:18081259

Uma, Thanganathan; Nogami, Masayuki

2008-01-15

397

Recent developments in laser glasses  

SciTech Connect

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.

Weber, M.J.

1983-01-10

398

Settling of Spinel in a High-Level Waste Glass Melter  

Microsoft Academic Search

High-level nuclear waste is being vitrified, i.e., converted to a durable glass that can be stored in a safe repository for hundreds of thousands of years. Waste vitrification is accomplished in reactors called melters to which the waste is charged together with glass-forming additives. The mixture is electrically heated to a temperature as high as 1150?C (or even higher in

Pavel R. Hrma; Pert Schill; Lubomir Nemec

2002-01-01

399

Corrosion of glass-bonded sodalite as a function of pH and temperature  

Microsoft Academic Search

This paper reports the results of corrosion tests with monoliths of sodalite, binder glass, and glass-bonded sodalite, a ceramic waste form (CWF) that is being developed to immobilize radioactive electrorefiner salt used to condition spent sodium-bonded nuclear fuel. These tests were performed with dilute pH-buffered solutions in the pH range of 5-10 at temperatures of 70 and 90 C. The

L. R. Morss; C. Tatko; W. L. Ebert

1999-01-01

400

The precision of product consistency tests conducted with a glass-bonded ceramic waste form  

Microsoft Academic Search

The product consistency test (PCT) that is used for qualification of borosilicate high-level radioactive waste (HLW) glasses for disposal can be used for the same purpose in the qualification of the glass-bonded sodalite ceramic waste form (CWF). The CWF was developed to immobilize radioactive salt wastes generated during the electrometallurgical treatment of spent sodium-bonded nuclear fuels. An interlaboratory study was

W. L Ebert; M. A Lewis; S. G Johnson

2002-01-01

401

Continuous Fibre Reinforced Glass and Glass-Ceramic Matrix Composites  

Microsoft Academic Search

Glass and glass-ceramic matrix composites with continuous fibre reinforcement are considered in this Chapter, covering aspects\\u000a of their fabrication, microstructural characterisation, properties and applications. The great variety of composite systems\\u000a developed during the last 30 years is discussed and their outstanding thermomechanical properties and high technological potential\\u000a are highlighted. These composites constitute a new family of high-temperature capability, lightweight structural

Aldo R. Boccaccini

402

Fabrication and characterization of MCC approved testing material - ATM-12 glass  

SciTech Connect

The Materials Characterization Center (MCC) Approved Testing Material ATM-12 is a borosilicate glass that incorporates elements typical of high-level waste (HLW) resulting from the reprocessing of commercial nuclear reactor fuels. The composition has been adjusted to match that predicted for HLW type 76-68 glass at an age of 300 y. Radioactive constituents contained in this glass include depleted uranium, {sup 99}Tc, {sup 237}Np, {sup 239}Pu, and {sup 241}Am. The glass was produced by the MCC at the Pacific Northwest Laboratory (PNL). ATM-12 glass ws produced from July to November of 1984 at the request of the Nevada Nuclear Waste Site Investigations (NNWSI) Program and is the third in a series of glasses produced for NNWSI. Most of the glass produced was in the form of cast bars; special castings and crushed material were also produced. Three kilograms of ATM-12 glass were produced from a feedstock melted in a nitrogen-atmosphere glove box at 1150{sup 0}C in a platinum crucible, and formed into stress-annealed rectangular bars and the special casting shapes requested by NNWSI. Bars of ATM-12 were nominally 1.9 x 1.9 x 10 cm, with an average mass of 111 g each. Nineteen bars and 37 special castings were made. ATM-12 glass has been provided to the NNWSI Program, in the form of bars, crushed powder and special castings. As of August 1985 approximately 590 g of ATM-12 is available for distribution. Requests for materials or services related to this glass should be directed to the Materials Characterization Center Program Office, PNL.

Wald, J.W.

1985-10-01

403

Glass-glass transition during aging of a colloidal clay.  

PubMed

Colloidal suspensions are characterized by a variety of microscopic interactions, which generate unconventional phase diagrams encompassing fluid, gel and glassy states and offer the possibility to study new phase and/or state transitions. Among these, glass-glass transitions are rare to be found, especially at ambient conditions. Here, through a combination of dilution experiments, X-ray photon correlation spectroscopy, small angle X-ray scattering, rheological measurements and Monte Carlo simulations, we provide evidence of a spontaneous glass-glass transition in a colloidal clay. Two different glassy states are distinguished with evolving waiting time: a first one, dominated by long-range screened Coulombic repulsion (Wigner glass) and a second one, stabilized by orientational attractions (Disconnected House of Cards glass), occurring after a much longer time. These findings may have implications for heterogeneously charged systems out-of-equilibrium and for applications where a fine control of the local order and/or long term stability of the amorphous materials are required. PMID:24887086

Angelini, Roberta; Zaccarelli, Emanuela; de Melo Marques, Flavio Augusto; Sztucki, Michael; Fluerasu, Andrei; Ruocco, Giancarlo; Ruzicka, Barbara

2014-01-01

404

Etude des performances du controle par emission acoustique de tubes en materiaux composites resine-fibre de verre contenant des defauts. (Study of the performances of acoustic emission testing for glass fibre reinforced plastic pipes containing defects).  

National Technical Information Service (NTIS)

Glass fibre reinforced plastic pipes are more and more often used, in nuclear power plants, for building or replacement of water pipings classified 'nuclear safety'. Tests have been performed to evaluate the performances of acoustic emission testing for i...

D. Villard M. C. Vidal

1995-01-01

405

Galactic Hearts of Glass  

NASA Technical Reports Server (NTRS)

[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 crystals in 20 additional galaxies, all belonging to a class called ultraluminous infrared galaxies. These extremely bright and dusty galaxies usually consist of two galaxies in the process of smashing into each other. Astronomers believe massive stars at the hearts of the galaxies are churning out clouds of silicate crystals. This phenomenon may represent a short-lived phase in the evolution of galactic mergers.

2006-01-01

406

Effect of silver concentration on the silver-activated phosphate glass  

Microsoft Academic Search

The effects of silver concentration on the structure and properties of silver-activated phosphate glasses, with the nominal molar compositions xAg2O·(1?x)(30Na2O·10Al2O3·60P2O5) and 0?x?10mol%, were studied. Increasing the Ag2O-content decreases the glass transition temperature (Tg), increases the thermal expansion coefficient (TEC) and increases the glass dissolution rate in water. 31P nuclear magnetic resonance (NMR) and Raman spectroscopies indicate that the addition of

S. M. Hsu; S. W. Yung; R. K. Brow; W. L. Hsu; C. C. Lu; F. B. Wu; S. H. Ching

2010-01-01

407

Stress Corrosion and Static Fatigue of Glass  

Microsoft Academic Search

Stress corrosion cracking of six glasses was studied using fracture mechanics techniques. Crack velocities in water were measured as a function of applied stress intensity factor and temperature, and apparent activation energies for crack mo- tion were obtained. Data were consistent with the universal fatigue curve for static fatigue of glass, which depended on glass composition. Of the glasses tested,

S. M. WIEDERHORN; L. H. BOLZ

1970-01-01

408

Infrared properties of diabase glass and wool  

Microsoft Academic Search

Results from infrared reflectance and collimated transmittance of a diabase glass are presented and compared with data for wool, prepared from the same glass. Using very thin glass slices it proved possible to establish a lower limit to the extinction coefficient k (1200 cm?1)?0.043 where the glass exhibits a low reflectance minimum and the wool transmittance a sharp maximum, related,

Gösta Ljungdahl; Carl G. Ribbing

1989-01-01

409

Dynamics of glass forming ammonia hydrates.  

PubMed

The dielectric relaxation of ammonia-water mixtures was studied for a range of NH3 mole fractions x. For 0.01 ? x < 0.33, the samples can be supercooled relatively easily. In this composition range, the relaxation strength is proportional to x. The dielectric relaxation times display a super-Arrhenius behavior, are independent of the NH3 content in the specified range, and, for T > 250 K, line up smoothly with those of pure water. The relaxation behavior of glass forming ammonia hydrates was also investigated using nuclear magnetic resonance techniques including deuteron relaxometry and stimulated-echo spectroscopy, as well as static field-gradient proton diffusometry. These experiments yielded additional insights into the rotational and translational dynamics of ammonia hydrates. PMID:24020514

Didzoleit, H; Storek, M; Gainaru, C; Geil, B; Böhmer, R

2013-10-10

410

Tailoring Silicon Oxycarbide Glasses for Oxidative Stability  

NASA Technical Reports Server (NTRS)

Blackglas(Trademark) polysiloxane systems produce silicon oxycarbide glasses by pyrolysis in inert atmosphere. The silicon oxycarbides evidence oxidative degradation that limits their lifetime as composite matrices. The present study characterizes bonding rearrangements in the oxycarbide network accompanying increases in pyrolysis temperature. It also addresses the changes in susceptibility to oxidation due to variations in the distribution of Si bonded species obtained under different processing conditions. The study is carried out using Si-29 nuclear magnetic resonance (NMR) spectroscopy and a design of experiments approach to model the oxidation behavior. The NMR results are compared with those obtained by thermogravimetric analysis (TGA). Samples pyrolyzed under inert conditions are compared to those pyrolyzed in reactive ammonia environments.

Hurwitz, F. I.; Meador, M. A. B.

1997-01-01

411

Characterization of electrostatic glass actuators  

NASA Astrophysics Data System (ADS)

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.

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

2003-06-01

412

Taylor impact of glass bars  

NASA Astrophysics Data System (ADS)

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.

Murray, Natalie; Bourne, Neil; Field, John

1997-07-01

413

High Tech Art: Chameleon Glass  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

414

Scintillating glass fiber neutron sensors.  

National Technical Information Service (NTIS)

Cerium-doped lithium-silicate glass fibers have been developed at Pacific Northwest Laboratory (PNL) for use as thermal neutron detectors. By using highly-enriched (sup 6) Li , these fibers efficiently capture thermal neutrons and produce scintillation li...

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

1994-01-01

415

Fast Crystals and Strong Glasses  

SciTech Connect

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."

Weitz, David (Harvard) [Harvard

2009-11-04

416

Fiber glass pulling. [in space  

NASA Technical Reports Server (NTRS)

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

Workman, Gary L.

1987-01-01

417

Rare earth doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Glasses based on TeO2-BaO-MgO-ZnO-Na2O have been made successfully. The Raman scattering and the transmission properties were measured, and the photoluminescence properties of Pr3+ doped tellurite glasses were studied. Tellurite glasses exhibit an IR transmission cut- off beyond approximately 6 micrometers . The maximum-phonon band is at 745 cm-1. The emission from the Pr3+:1G4 yields 3H5 transition is at 1.295 micrometers wavelength with a spectral bandwidth of 30 nm. Pr3+ doped tellurite glasses appear to be a promising candidate for waveguide amplifiers in the 1.3 micrometers telecommunication window.

Man, S. Q.; Liu, H. W.; Pun, Edwin Y.; Chung, Po Sheun

1998-12-01

418

Dispersion of barium gallogermanate glass.  

PubMed

Gallogermanate glasses are the subject of intense study as a result of their unique combination of physical and optical properties, including transmission from 0.4 to beyond 5.0 microm. These glasses can be easily made into large optics with high-index homogeneity for numerous U.S. Department of Defense and commercial visible-IR window applications such as reconnaissance, missile domes, IR countermeasures, avionics, and collision avoidance on automobiles. These applications require a knowledge of the refractive index of glass throughout the region of transmission. Consequently, we have measured the refractive index of BaO-Ga2O3-GeO2 glass from 0.4 to 5.0 microm and calculated the Sellmeier coefficients required for optical device design. PMID:11900015

Zelmon, David E; Bayya, Shyam S; Sanghera, Jasbinder S; Aggarwal, Ishwar D

2002-03-01

419

Ion implantation in silicate glasses  

SciTech Connect

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.

Arnold, G.W.

1993-12-01

420

Inorganic glass ceramic slip rings  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

421

Characterization of the Defense Waste Processing Facility (DWPF) Environmental Assessment (EA) glass Standard Reference Material. Revision 1  

SciTech Connect

Liquid high-level nuclear waste at the Savannah River Site (SRS) will be immobilized by vitrification in borosilicate glass. The glass will be produced and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). Other waste form producers, such as West Valley Nuclear Services (WVNS) and the Hanford Waste Vitrification Project (HWVP), will also immobilize high-level radioactive waste in borosilicate glass. The canistered waste will be stored temporarily at each facility for eventual permanent disposal in a geologic repository. The Department of Energy has defined a set of requirements for the canistered waste forms, the Waste Acceptance Product Specifications (WAPS). The current Waste Acceptance Primary Specification (WAPS) 1.3, the product consistency specification, requires the waste form producers to demonstrate control of the consistency of the final waste form using a crushed glass durability test, the Product Consistency Test (PCI). In order to be acceptable, a waste glass must be more durable during PCT analysis than the waste glass identified in the DWPF Environmental Assessment (EA). In order to supply all the waste form producers with the same standard benchmark glass, 1000 pounds of the EA glass was fabricated. The chemical analyses and characterization of the benchmark EA glass are reported. This material is now available to act as a durability and/or redox Standard Reference Material (SRM) for all waste form producers.

Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Crawford, C.L.; Pickett, M.A.

1993-06-01

422

Driving bubbles out of glass  

NASA Technical Reports Server (NTRS)

Surface tension gradient in melt forces gas bubbles to surface, increasing glass strength and transparency. Conventional chemical and buoyant fining are extremely slow in viscous glasses, but tension gradient method moves 250 um bubbles as rapidly as 30 um/s. Heat required for high temperature part of melt is furnished by stationary electrical or natural-gas heater; induction and laser heating are also possible. Method has many applications in industry processes.

Mattox, D. M.

1981-01-01

423

''S'' glass manufacturing technology transfer  

Microsoft Academic Search

A glass-ceramic to metal sealing technology patented by Sandia National Laboratories, Albuquerque (SNL) was developed by MRC-Mound for use in the manufacture of weapon components. successful implementation attracted increasingly widespread weapons of this technology. ''S-glass'' manufacturing technology was transferred to commercial vendors to ensure that weapons production schedules would be met in the coming years. Such transfer also provided sources

D. A. Buckner; H. L. McCollister

1988-01-01

424

''S'' glass manufacturing technology transfer  

Microsoft Academic Search

A glass-ceramic-to metal sealing technology patented by Sandia National Laboratores, Albuquerque (SNLA) was developed by MRC-Mound for use in the manufacture of weapon components. Successful implementation attracted increasingly widespread weapon use of this technology. ''S-glass'' manufacturing technology was transferred to commercial vendors to ensure that weapons production schedules would be met in the coming years. Such transfer also provided sources

D. A. Buckner; H. L. McCollister

1988-01-01

425

Luminescence of powdered uranium glasses  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

426

Multimegajoule laser design. [Glass lasers  

SciTech Connect

New technologies make multimegajoule glass lasers economically feasible. We have devised new laser architectures using harmonic switchout, target-plane holographic injection, phase conjugation, continuous apodization, and higher amplifier efficiencies. Our plan for building a multimegajoule laser for a recurring cost under $300 million relies on the following manufacturing economies of scale: high-volume glass production, rapid harmonic-crystal growth, capacitor sizing and packing to increase energy capacity, and part standardization.

Manes, K.R.; Ozarski, R.G.; Hagen, W.F.; Holzrichtr, J.F.

1985-08-01

427

Glass melting furnace and process  

Microsoft Academic Search

In Leone International Sales Corp.'s new glass-melting furnace, heat transfer from the burning fuel to the melting glass is substantially increased by precisely adjusting the position of the burners to substantially reduce the excess-air requirement while maintaining an acceptable carbon monoxide level (35 to 50 ppM) in the flue gases, and to maximize flame coverage of the raw batch material

J. D. Nesbitt; D. H. Larson; M. E. Fejer

1974-01-01

428

Perspective: Supercooled liquids and glasses.  

PubMed

Supercooled liquids and glasses are important for current and developing technologies. Here we provide perspective on recent progress in this field. The interpretation of supercooled liquid and glass properties in terms of the potential energy landscape is discussed. We explore the connections between amorphous structure, high frequency motions, molecular motion, structural relaxation, stability against crystallization, and material properties. Recent developments that may lead to new materials or new applications of existing materials are described. PMID:22938210

Ediger, M D; Harrowell, Peter

2012-08-28

429

Laser texturing of doped borosilicate glasses  

NASA Astrophysics Data System (ADS)

We describe a novel process of laser-assisted fabrication of surface structures on doped oxide glasses with heights reaching 10 - 13% of the glass thickness. This effect manifests itself as a swelling of the irradiated portion of the glass, and occurs in a wide range of glass compositions. The extent of such swelling depends on the glass base composition. Doping with Fe, Ti, Co, Ce, and other transition metals allows for adjusting the absorption of the glass and maximizing the feature size. In the case of bumps grown on borosilicate glasses, we observe reversible glass swelling and the bump height can increase or decrease depending on whether the consecutive laser pulse has higher or lower energy compared with the previous one. To understand the hypothetical mechanism, which includes laser heating of glass, glass melting, and directional flow, we explored density, refractive index, fictive temperature, and phase separation dynamics.

Streltsov, Alexander; Dickinson, James; Grzybowski, Richard; Harvey, Daniel; Logunov, Stephan; Ozturk, Alper; Sutherland, James; Potuzak, Marcel

2010-02-01

430

Comparison of Macedon and Darwin glass  

USGS Publications Warehouse

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.

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

1967-01-01

431

Ion transport mechanism in glasses  

NASA Astrophysics Data System (ADS)

In this contribution, we report the non-Arrhenius behaviour (nAB) in the temperature-dependent dc conductivity of silver ion conducting vanadate, alkali ion conducting borate and silicate glasses well below their glass transition temperature. The temperature-dependent dc conductivity shows the strong departure from the Arrhenius behaviour in the studied glasses. In the case of silver ion conducting glasses, the nAB depends strongly on the silver halide content and on the type of the halide anion. From the frequency dependence of the conductivity, we draw conclusions on the origin of the nAB. In contrast to the silver ion conducting glasses, alkali ion conducting borate and silicate glasses show the positive curvature in the Arrhenius plot. These results are the manifestation of local structural changes of the borate and silicate network with temperature, and give rise to different local environments into which the alkali ions hop. Furthermore, the present study provides new insights into the strong link between the dynamics of the alkali ions and different sites associated with it in the glassy materials.

Murugavel, Sevi

2012-06-01

432

BNFL Report Glass Formers Characterization  

SciTech Connect

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.

Schumacher, R.F.

2000-07-27

433

Fabrication of glass microspheres with conducting surfaces  

DOEpatents

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.

Elsholz, W.E.

1982-09-30

434

Glass Membrane For Controlled Diffusion Of Gases  

SciTech Connect

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.

Shelby, James E. (Alfred Station, NY); Kenyon, Brian E. (Pittsburgh, PA)

2001-05-15

435

Structure and surface chemistry of borate and boroaluminate glasses  

NASA Astrophysics Data System (ADS)

The short and intermediate range structure of boroaluminate glasses has been investigated using solid state magic angle spinning nuclear magnetic resonance (MAS NMR). It was found that the aluminum ion may exhibit 4, 5, and 6-fold coordination. It was also shown that the aluminum can adopt the role of both a modifier and network former in the glass backbone. The dependence of the local aluminum structure on composition is discussed. The intermediate range order in barium boroaluminate glasses was directly probed using solid state double resonance NMR experiments. It was found that connections between (AlOsb{4/2})sp- and (BOsb{4/2})sp- units are strongly discouraged. This restriction affects the short range order of the boron atoms in the glass since it places a constraint on the maximum number of possible tetrahedral boron and aluminum-oxide polyhedra in the glass. The surface structure and chemistry in borate and boroaluminate glasses has been investigated. X-ray photoelectron spectroscopy (XPS), low energy ion scattering spectroscopy (ISS) and sp1H->sp{11}B cross polarization (CP) MAS NMR have been used in the surface characterization. O 1s and B 1s chemical shifts in the XPS spectra were described using a modified Sanderson model for the calculation of charge density. A peak corresponding to non-bridging oxygens (NBO) in the borate glasses was identified and used to quantify the NBO density. ISS analyses of the outermost atomic layer of clean vacuum fracture surfaces showed that relaxation of the surface atoms occurs during or shortly after the fracture event. The surface was found to be depleted in modifying cations, in contrast to silicate glasses. This is thought to be due to a conversion of tetrahedral units to trigonal coordination in an effort to reduce surface energy. Melt surfaces and graphite interfaces were found to exhibit chemical deviations from the corresponding fracture surfaces. The chemical shifts in the XPS spectra were consistent with enrichment of trigonally-coordinated boron-oxide units at the melt and interface surfaces. ISS and CP MAS NMR analyses of borate glass surfaces formed at high temperatures also provide direct evidence of structural rearrangement concordant with the geometrical optimization of the planar BOsb3 groups at the surface.

Beall, Douglas Munroe

436

A Cosmic Magnifying Glass  

NASA Technical Reports Server (NTRS)

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.

2000-01-01

437

Nuclear Medicine  

MedlinePLUS

Nuclear Medicine What is nuclear medicine? What are radioactive tracers? What is Single Photon Emission Computed Tomography (SPECT)? What ... funded researchers advancing nuclear medicine? What is nuclear medicine? Nuclear medicine is a medical specialty that uses ...

438

Glass matrix composites from coal flyash and waste glass  

SciTech Connect

Glass matrix composites have been fabricated from waste materials by means of powder technology. Flyash from coal power stations and waste glass, residue of float glass production, were used. Commercial alumina platelets were employed as the reinforcing component. For flyash contents up to 20% by weight nearly fully dense compacts could be fabricated by using relatively low sintering temperatures (650 C). For higher flyash contents the densification was hindered due to the presence of crystalline particles in the as-received flyash, which jeopardized the viscous flow densification mechanism. The addition of alumina platelets resulted in better mechanical properties of the composites than those of the unreinforced matrix, despite a residual porosity present. Young`s modulus, modulus of rupture, hardness and fracture toughness increase with platelet volume fraction. The low brittleness index of the composites suggests that the materials have good machinability. A qualitative analysis of the wear behavior showed that the composite containing 20% by volume platelet addition has a higher wear resistance than the unreinforced matrix. Overall, the results indicate that the materials may compete with conventional glasses and glass-ceramics in technical applications.

Boccaccini, A.R. [Technische Univ. Ilmenau (Germany). Fachgebiet Werkstofftechnik] [Te