Control of R7T7 Nuclear Glass Alteration Kinetics Under Saturation Conditions

MRS Proceedings ◽

10.1557/proc-412-189 ◽

1995 ◽

Vol 412 ◽

Cited By ~ 18

Author(s):

S. Gin

Keyword(s):

Critical Role ◽

Solution Flow Rate ◽

Additional Experiment ◽

Solution Flow ◽

Flow Rates ◽

Dissolved Silica ◽

Glass Dissolution ◽

Geological Repository ◽

Nuclear Waste Glass

AbstractThe hypothesis of French nuclear waste glass disposal in a geological repository implies a comprehensive assessment of all the glass elements liable to participate in controlling the material alteration kinetics. The hypothetical existence of kinetically limiting elements other than silica could account for the observed R7T7 glass behavior in the presence of certain clays, and notably the continued high alteration rates observed even after silica saturation occurs. Flowing experiments with solutions near silica saturation but highly subsaturated with respect to aluminum hydroxide were defined to investigate the possible limiting role of aluminum. Experiments were conducted at different flow rates with the same constant steady-state H4 SiO4 activity for all the tests. The glass dissolution rate was observed to depend on the solution flow rate, indicating that under these conditions the kinetics are not controlled by dissolved silica alone. An additional experiment, in which only the Al(OH)4− activity in solution was allowed to vary, demonstrated the critical role of this element. Several interpretations are discussed.

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Effect of Nutrient Solution Flow Rate on Hydroponic Plant Growth and Root Morphology

Plants ◽

10.3390/plants10091840 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1840 ◽

Cited By ~ 1

Author(s):

Bateer Baiyin ◽

Kotaro Tagawa ◽

Mina Yamada ◽

Xinyan Wang ◽

Satoshi Yamada ◽

...

Keyword(s):

Plant Growth ◽

Root Growth ◽

Surface Area ◽

Flow Rate ◽

Root Morphology ◽

Root Surface ◽

Solution Flow Rate ◽

Root Surface Area ◽

Solution Flow ◽

Flow Rates

Crop production under hydroponic environments has many advantages, yet the effects of solution flow rate on plant growth remain unclear. We conducted a hydroponic cultivation study using different flow rates under light-emitting diode lighting to investigate plant growth, nutrient uptake, and root morphology under different flow rates. Swiss chard plants were grown hydroponically under four nutrient solution flow rates (2 L/min, 4 L/min, 6 L/min, and 8 L/min). After 21 days, harvested plants were analyzed for root and shoot fresh weight, root and shoot dry weight, root morphology, and root cellulose and hemicellulose content. We found that suitable flow rates, acting as a eustress, gave the roots appropriate mechanical stimulation to promote root growth, absorb more nutrients, and increase overall plant growth. Conversely, excess flow rates acted as a distress that caused the roots to become compact and inhibited root surface area and root growth. Excess flow rate thereby resulted in a lower root surface area that translated to reduced nutrient ion absorption and poorer plant growth compared with plans cultured under a suitable flow rate. Our results indicate that regulating flow rate can regulate plant thigmomorphogenesis and nutrient uptake, ultimately affecting hydroponic crop quality.

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Borosilicate Nuclear Waste Glass Alteration Kinetics: Chemical Inhibition and Affinity Control

MRS Proceedings ◽

10.1557/proc-506-63 ◽

1997 ◽

Vol 506 ◽

Cited By ~ 25

Author(s):

T. Advocat ◽

J. L. Chouchan ◽

J. L. Crovisier ◽

C. Guy ◽

V. Daux ◽

...

Keyword(s):

Nuclear Waste ◽

Mathematical Formulation ◽

Order Kinetic ◽

Exact Role ◽

Dissolved Silica ◽

First Order ◽

Nuclear Waste Glass ◽

Chemical Inhibition ◽

Kinetics Of

ABSTRACTThe objective of this work was to develop a more representative mathematical formulation of the alteration kinetics of the borosilicate SON68 glass by combining three approaches: (1) Compare extensive prior experimental static leaching results for SON68 glass with the first-order kinetic law in which silica is the predominant element, (2) Assess the exact role of dissolved silica on the alteration rate under conditions near and far from saturation, by means of dynamic leach tests and, (3) Compare the new data with the general kinetic law for silicates in which the reaction affinity, catalysis and inhibition are the three influencing factors.

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A Kinetic Model of Nuclear Waste Glass Dissolution in Flowing Water Environments

MRS Proceedings ◽

10.1557/proc-44-229 ◽

1984 ◽

Vol 44 ◽

Cited By ~ 2

Author(s):

Aaron Barkatt ◽

Barbara C. Gibson ◽

Marek Brandys

Keyword(s):

Kinetic Model ◽

Nuclear Waste ◽

Flow Rate ◽

Flowing Water ◽

Flow Rates ◽

Glass Dissolution ◽

Nuclear Waste Glass ◽

Simple Kinetic Model ◽

Leachate Composition ◽

Flow Experiments

AbstractA simple kinetic model for the description of the interaction of nuclear waste borosilicate glass with water has been developed. In the case of SRL TDS-131 glass leached in water at 70°C over a broad range of flow rates this model was found useful both in describing the evolution of leachate composition as a function of exposure time at a particular flow rate and in describing the dependence of the steady-state concentrations of the leached elements in solution on flow rate in a series of flow experiments.

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Nature and Effect of the Alteration Layer During Nuclear Waste Glass Dissolution

MRS Proceedings ◽

10.1557/proc-713-jj13.4 ◽

2002 ◽

Vol 713 ◽

Cited By ~ 1

Author(s):

A. Gauthier ◽

P. Le Coustumer ◽

J-H. Thomassin

Keyword(s):

Nuclear Waste ◽

Pure Water ◽

Aqueous Media ◽

Glass Dissolution ◽

Icp Ms ◽

Nuclear Waste Glass ◽

Texture Structure ◽

The Stability ◽

Short Time

ABSTRACTThe goal of this study is to understand the role of the interface developed during R7T7 glass alteration. This glass has been leached in two different aqueous media (pure water, silica rich water and phosphorous rich water). The lixiviation tests have been optimized to assess the role of the alteration layer developed on the surface of the glass. The solution and the solid have been characterized by ICP-MS and TEM/X-EDS respectively. The results put in evidence that a complex alteration layer is formed. Its texture, structure and chemistry are discussed with respect to the evolution of the solution during the tests. The alteration layer is always present on the surface of the glass and is considered to control (at short time) diffusion of the different species through the layer. Further study must be undertaken to assess the evolution and the stability of the interface for longer time periods.

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Fabrication and Characterization of Zinc Oxide-Based Electrospun Nanofibers for Mechanical Energy Harvesting

Journal of Nanotechnology in Engineering and Medicine ◽

10.1115/1.4027447 ◽

2014 ◽

Vol 5 (1) ◽

Cited By ~ 17

Author(s):

Suyitno Suyitno ◽

Agus Purwanto ◽

R. Lullus Lambang G. Hidayat ◽

Imam Sholahudin ◽

Mirza Yusuf ◽

...

Keyword(s):

Zinc Oxide ◽

Fiber Diameter ◽

Mechanical Energy ◽

Electrospun Nanofibers ◽

Solution Flow Rate ◽

Maximum Power Density ◽

Solution Flow ◽

Flow Rates ◽

Fabrication And Characterization

Doped and undoped zinc oxide fibers were fabricated by electrospinning at various solution flow rates of 2, 4, and 6 μl/min followed by sintering at 550 °C. The nanogenerators (NGs) fabricated from the fibers were examined for their performance by applying loads (0.25–1.5 kg) representing fingers taps on the keyboard. A higher solution flow rate resulted in a larger fiber diameter, thus reducing nanogenerator voltage. The maximum power density for undoped zinc oxide-based and doped zinc oxide-based nanogenerators was 17.6 and 51.7 nW/cm2, respectively, under a load of 1.25 kg. Enhancing nanogenerator stability is a topic that should be investigated further.

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Effect of Channel Geometry Variations on the Performance of a Constrained Microscale-Film Ammonia-Water Bubble Absorber

Journal of Heat Transfer ◽

10.1115/1.2970065 ◽

2008 ◽

Vol 130 (11) ◽

Cited By ~ 10

Author(s):

Jeromy Jenks ◽

Vinod Narayanan

Keyword(s):

Weak Solution ◽

Gas Flow ◽

Water Solution ◽

Flow Rate Ratio ◽

Solution Flow Rate ◽

Inlet Temperature ◽

Ammonia Vapor ◽

Solution Flow ◽

Flow Rates ◽

Ammonia Water

An experimental study of the absorption of ammonia vapor in a constrained thin film of ammonia-water solution is presented. A large aspect ratio microchannel with one of its walls formed of a porous material is used to constrain the thickness of the liquid film. Experiments are performed at a pressure of 2.5 bar absolute and 4 bar absolute and at a fixed weak solution inlet temperature. Weak solution flow rates are varied from 10 g/min to 30 g/min (corresponding to the weak solution Reynolds number, Re, from 15 to 45), inlet mass concentrations are varied from 0% to 15%, and gas flow rates are varied between 1 g/min and 3 g/min (corresponding to the vapor Re from 160 to 520). Six geometries, including three smooth-bottom-walled channels of differing depths and three channels with structured bottom walls, are considered. Results indicate that, for identical rates of vapor absorption, the overall heat transfer coefficient of the 400 μm absorber is in most cases significantly larger than that of other absorbers. For the 150 μm and 400 μm absorbers, a trade-off between the high overall heat and mass transfer coefficients is achieved for the highest vapor to solution flow rate ratio.

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The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

Perspectives on Language Learning and Education ◽

10.1044/lle15.2.50 ◽

2008 ◽

Vol 15 (2) ◽

pp. 50-59 ◽

Cited By ~ 1

Author(s):

Amy Philofsky

Keyword(s):

Language Development ◽

Critical Role ◽

Children With Autism ◽

Autism Spectrum ◽

Children With Asd ◽

Prevalence Estimates ◽

Notable Increase ◽

Screening Assessment ◽

Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

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