Investigations on the Role of Surface Layers in HLW Glass Leaching

MRS Proceedings ◽

10.1557/proc-50-203 ◽

1985 ◽

Vol 50 ◽

Cited By ~ 5

Author(s):

R. Conradt ◽

H. Roggendorf ◽

H. Scholze

Keyword(s):

Corrosion Test ◽

Protective Effects ◽

Reaction Products ◽

Surface Layers ◽

Hydrothermal Conditions ◽

Glass Dissolution ◽

Salt Brine ◽

Glass Leaching

AbstractA corrosion test series was performed to clarify the role of reaction product layers on the corrosion of a simulated HLW borosilicate glass in a salt brine under hydrothermal conditions. The layers were unprotective at 200°C. At 120°C, slight protective effects ocurred when the leachant contained dissolved reaction products. The consequence for the long term behaviour between 120 and 200°C is a constant glass dissolution rate.

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The Role of Surface Layers in Glass Leaching Performance

MRS Proceedings ◽

10.1557/proc-212-77 ◽

1990 ◽

Vol 212 ◽

Cited By ~ 9

Author(s):

J. K. Bates ◽

W. L. Ebert ◽

J. J. Mazer ◽

J. P. Bradley ◽

C. R. Bradley ◽

...

Keyword(s):

Surface Layers ◽

Release Process ◽

Long Time ◽

Selective Incorporation ◽

Radionuclide Release ◽

Reaction Processes ◽

Glass Leaching

ABSTRACTThe examination of reacted layers that form as glass reacts can provide insight into reaction mechanisms that control long-term glass reaction, and into processes by which radionuclides are released to solution. Examples are given for the natural glasses obsidian and tektite, and the nuclear waste glasses 131 and 165, where the layers form both in-situ and precipitated from solution, where they are both amorphous and crystal 1ine, where selective incorporation of actinide elements Into stable phases may offer a barrier to release, and where sloughing of the layers from the glass acts as an alternative radionuclide release process to solubility-limited control.Several reaction processes occur simultaneously as glass reacts, and the projection of glass performance to long time periods requires the identification of those processes that dominate the long-term reaction.

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An Essential Role of Polymeric Adhesives in the Reinforcement of Acidified Paper Relics

Polymers ◽

10.3390/polym14010207 ◽

2022 ◽

Vol 14 (1) ◽

pp. 207

Author(s):

Jiaojiao Liu ◽

Huiping Xing ◽

Yajun Zhou ◽

Xiaolian Chao ◽

Yuhu Li ◽

...

Keyword(s):

Essential Role ◽

Polyvinyl Butyral ◽

Scientific Basis ◽

Water Soluble ◽

Wheat Starch ◽

Protective Effects ◽

Ft Ir ◽

Starch Paste

Paper acidification causes paper relics to undergo embrittlement and decay, to form dregs, and even to break upon a single touch; therefore, reinforcement and deacidification treatments are essential steps for paper conservation and to retard the deterioration and prolong the life of objects. Polymeric adhesives play an essential role in reinforcement and deacidification treatments, although it is not well studied. In this work, the effect of polymeric adhesives on the conservation process and their protective effects on acidified paper relics were studied. Firstly, three polymeric adhesives, including wheat starch paste, polyvinyl butyral (PVB), and polyvinyl alcohol (PVA), were selected as research objects. Subsequently, their effects on four popular conservation methods were further discussed, including traditional mounting, hot-melt with silk net, alcohol-soluble cotton mesh, and water-soluble cotton mesh. Additionally, as an example, the reversibility and long-term durability of water-soluble adhesive PVA-217 were assessed. Using a computer measured and controlled folding endurance tester, pendulum tensile strength tester, tear tester, burst tester, FT-IR, video optical contact angle tester, and other instruments, the conservation application of water-soluble adhesives in paper relics was evaluated. This study provides a scientific basis and experimental data for the application of polymeric adhesives in the conservation of paper relics.

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Effects of Rocks and Backfill Materials on Waste Glass Leaching

MRS Proceedings ◽

10.1557/proc-50-247 ◽

1985 ◽

Vol 50 ◽

Cited By ~ 1

Author(s):

K. Ishiguro ◽

N. Sasaki ◽

H. Kashihara ◽

M. Yamamoto

Keyword(s):

Waste Glass ◽

Distilled Water ◽

Leach Rate ◽

Glass Dissolution ◽

Crushed Granite ◽

Backfill Materials ◽

Long Term Experiment ◽

Static Conditions ◽

Glass Leaching

AbstractExtensive studies have been made on the interactions between a waste glass and repository materials under static conditions. One of the PNC reference glasses was leached in the solution prepared from water in contact with crushed granite, tuff, diabase and backfill materials such as bentonite and zeolite. The leachant solutions except for some bentonite solutions reduced the glass leach rate compared with that measured in distilled water. The extent of the reduction was a function of silicon concentration in solution. The bentonite solutions enhanced the glass dissolution rate by a factor of 2 to 3 at low bentonite/water ratios but the effect was found to be less important at high bentonite/water ratios and in the long-term experiment. Addition of granite and zeolite to the bentonite solutions decreased the leach rate below the value measured in distilled water.

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Ameliorative Effects of Nano-Selenium Against Fluoride Stress Induced Hepatocytes Autophagy and Apoptosis in Mice

10.21203/rs.3.rs-44205/v1 ◽

2020 ◽

Author(s):

Yajing Wang ◽

Bingxian Liu ◽

Qingyue Han ◽

Khalid Mehmood ◽

Fazul Nabi ◽

...

Keyword(s):

Caspase 3 ◽

Beclin 1 ◽

Protective Effects ◽

Human Beings ◽

Caspase 9 ◽

Nano Material ◽

Cyt C ◽

Hepatocyte Damage

Abstract Background: Fluorine is widespread in the environment, and the injurious impacts of fluoride underscore its significance for public health. The long-term presence of fluorine in environment could be a risk in hepatotoxicity for both human beings and animals. Important role of selenium in mitigation of heavy metal toxicity via regulating autophagy and apoptosis is well-known. Further, nano-Se is a common artificial nano material, with higher biological activity and lower toxicity. The aim of the current study was to examine whether nano-Se supplementation can reduce the effects of fluoride-induced hepatocytes autophagy and apoptosis. Results: Here, we report that fluoride exposure induces apoptosis and autophagy with nucleus broken, dissolved and disappeared of hepatocyte, contributing to its hepatotoxicity. More importantly, Cyt-C and Beclin-1/Bcl-2 pathways are involved in the regulation of autophagy and apoptosis via targeting Caspase-9, Caspase-3, P53, Bax, LC3, ATG-5, P62 and mTOR expressions. Conclusion: Nano-Se is capable to alleviate fluoride-induced hepatocyte damage, that selenium can be prefer to prevent chronic fluorosis-induced autophagy and apoptosis by regulating Cyt-C and Beclin-1/Bcl-2 signaling pathway. In precisely, NaF-induced the liver injury by activating autophagy and apoptosis, which indicate that fluorine exposure, pose an ecological risk to human beings and animals. Nano-Se has protective effects against fluoride-induced hepatocytes.

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FructationIn Vivo: Detrimental and Protective Effects of Fructose

BioMed Research International ◽

10.1155/2013/343914 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 26

Author(s):

H. M. Semchyshyn

Keyword(s):

Oxidative Stress ◽

Side Effects ◽

Experimental Models ◽

Oxygen Species ◽

Protective Effects ◽

Compelling Evidence ◽

Animal Tissues

There is compelling evidence that long-term intake of excessive fructose can have deleterious side effects in different experimental models. However, the role of fructosein vivoremains controversial, since acute temporary application of fructose is found to protect yeast as well as animal tissues against exogenous oxidative stress. This review suggests the involvement of reactive carbonyl and oxygen species in both the cytotoxic and defensive effects of fructose. Potential mechanisms of the generation of reactive species by fructose in the nonenzymatic reactions, their implication in the detrimental and protective effects of fructose are discussed.

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Monte Carlo Modelling of Glass Dissolution: Comparison with Experiments

MRS Proceedings ◽

10.1557/proc-663-237 ◽

2000 ◽

Vol 663 ◽

Cited By ~ 10

Author(s):

M. Lobanova ◽

L. Maurer ◽

P. Barboux ◽

F. Devreux ◽

Y. Minet

Keyword(s):

Surface Layer ◽

Volume Ratio ◽

Protective Role ◽

Glass Dissolution ◽

Altered Surface ◽

Alkali Oxides ◽

Soluble Species ◽

Glass Leaching ◽

Solution Volume

ABSTRACTOne presents the results of numerical simulations of glass leaching. The glass is modelled as a random mixture of partly and totally soluble species, which represent silica, and boron or alkali oxides, respectively. It is shown that the dissolution rate and the thickness of the altered surface layer are strongly dependent on the glass composition, whereas the equilibrium solubility is not. The dependence of the layer thickness on the glass surface area to solution volume ratio is also emphasized. The protective role of the surface layer is shown to arise from its restructuring after the extraction of the soluble species. The simulation results are compared to an experimental study performed on series of SiO2-B2O3-Na2O glasses.

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Hydrothermal Leaching of R7-T7 Borosilicate Glass

MRS Proceedings ◽

10.1557/proc-176-309 ◽

1989 ◽

Vol 176 ◽

Cited By ~ 8

Author(s):

J. Caurel ◽

E. Vemaz ◽

D. Beaufort

Keyword(s):

Low Temperature ◽

Temperature Dependence ◽

Borosilicate Glass ◽

Type Equation ◽

Amorphous Layer ◽

Bulk Glass ◽

Surface Layers ◽

Glass Dissolution ◽

One Year

ABSTRACTThe results of hydrothermal leach tests are intended to be used to predict long-term low-temperature glass dissolution. It is often assumed that data can be extrapolated to other conditions using an Arrhenius-type equation. Hydrothermal leaching mechanisms and their temperature dependence in R7T7 glass were investigated in static experiments lasting from 7 days to 1 year at 150°C and 250°C. Leachates, surface layers and crystalline products were analyzed by ICP, TEM, SEM, EMP, XRD and cathodoluminescence. Unexpectedly, no actual saturation conditions in solutions were reached after one year leaching at 150°C nor at 250°C. The effect of precipitation of alteration products (a silica-enriched amorphous layer and aluminosilicates [smectite at 150°C, smectite and zeolites at 250°C]) is discussed. However, the formation of large cracks in the bulk glass results in a higher glass reacting surface and a higher dissolution rate at 250°C. Arrhenius calculations cannot be used to extrapolate our hydrothermal data to lower-temperatures.

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Alkali Activated Cementitious Materials: An Overview

MRS Proceedings ◽

10.1557/proc-245-153 ◽

1991 ◽

Vol 245 ◽

Cited By ~ 28

Author(s):

D. M. Roy ◽

M. R. Silsbee

Keyword(s):

Amorphous Materials ◽

Cementitious Materials ◽

Solution Chemistry ◽

Reaction Products ◽

Alumino Silicate ◽

Alkali Activated ◽

Very High

ABSTRACTAlkali-activated cementitious materials have considerable potential, with properties ranging from very high early strength to very high long term strength and low porosity. The role of alkalis in activating industrial by-products such as ground granulated (glassy) blast-furnace slag, ultra-fine silica fume or other by-product silicas, glassy fly ashes, and other amorphous materials is discussed. These by-product materials are activated by alkali additions which break the strong silicon oxygen bonds in the silicate or alumino-silicate network, accompanied by the formation of new reaction products. The role of the different components in multi-component activated cements on the reactivity and the nature of the resultant products is discussed. Characterization of starting materials and reaction products by XRD, SEM (including environmental SEM), chemical, and particle characterization techniques has been made. Additional results include investigation of pore solution chemistry as a function of time. Some inferences for long term durability are discussed.

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