The Role of Water Diffusion in the Corrosion of the French Nuclear Waste Glass SON 68 under Solution Saturation Conditions

2003 ◽  
Vol 807 ◽  
Author(s):  
Karine Ferrand ◽  
Abdesselam Abdelouas ◽  
Bernd Grambow ◽  
Jean-Louis Crovisier
Keyword(s):  
Inverse Correlation ◽  
Water Diffusion ◽  
Ionic Exchange ◽  
Hydrogen Ions ◽  
Static Tests ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Water Speciation ◽  
Good Agreement

ABSTRACTThe alteration kinetics of the French borosilicate glass SON 68 have been investigated in a dynamic system at 50°C and 90°C under solution saturation conditions. The pH was adjusted to 4.8, 7.2 and 9.8 with addition of chemical buffers or/and by bubbling CO2 in solution. In all experiments, Li and Cs leaching seems to be controlled by a diffusion process. The Li- and Cs-concentrations were used to calculate the sum of ionic exchange and matrix dissolution rates of the glass while Mo-concentrations indicate matrix dissolution. The final leaching rates in saturation condition of Mo were in the order of 10–4–10- g.m-2.d-1 in good agreement with those given in literature for static tests. The glass surface was studied by scanning and transmission electron microscopy (SEM, STEM) for analysis of the corrosion products and by infrared spectroscopy (FTIR) for water speciation and concentration. A good inverse correlation between the water content and the alkali concentrations released from the glass has been obtained. About three hydrogen ions replaced one alkali ion. Modeling of the experimental data using GM 2001 model gives water diffusion coefficients between 10–20 and 10–22 m2.s-1.

Structural evolution in lead substituted Bi–Sr–Ca–Cu–O superconductors

1991 ◽  
Vol 6 (2) ◽  
pp. 278-288 ◽  
Author(s):  
R. Ramesh ◽  
K. Remschnig ◽  
J.M. Tarascon ◽  
S.M. Green
Keyword(s):  
Structural Evolution ◽  
Homogeneous Sample ◽  
X Ray ◽  
Thermodynamics And Kinetics ◽  
Transmission Electron ◽  
Incommensurate Modulation ◽  
Kinetics Of ◽  
Pb Substitution ◽  
Microstructural Homogeneity

The structural evolution and cationic stoichiometry of Bi(Pb)–Sr–Ca–Cu–O superconductors have been studied using transmission electron microscopy and x-ray microanalysis. The nature of the incommensurate modulation changes systematically as increasing amounts of lead are added. X-ray microanalysis studies reveal that lead replaces Bi in the structure. Pb addition improves the microstructural homogeneity leading to the formation of a nearly homogeneous sample consisting of the “2223” phase. Based upon all the experimental results, it is inferred that the role of Pb substitution is related to the thermodynamics and kinetics of the formation of the n = 3 phase.

Kinetics of the Tial3 Formation From Al/Ti Thin Films

1999 ◽  
Vol 563 ◽  
Author(s):  
X. Federspiel ◽  
M. Ignat ◽  
F. Voiron ◽  
H. Fujimoto ◽  
T. Marieb
Keyword(s):  
Integrated Circuits ◽  
Boundary Diffusion ◽  
Microstructural Analysis ◽  
Electrical Measurements ◽  
Nucleation Frequency ◽  
Transmission Electron ◽  
Secondary Ions ◽  
Classical Models ◽  
Kinetics Of

AbstractThe interfacial reactions that may occur from the ageing of integrated circuits during operation will change their properties and produce failures. It is crucial to understand the phenomena that controls these reactions and their kinetics.The object of this work was to establish the role of impurities and grain size on the growth rate of TiAI3 from Al/Ti interfaces. The kinetic study consisted of different annealings followed by electrical measurements. These data were correlated with microstructural analysis and composition evolution from Transmission Electron Microscopy (TEM), Secondary Ions Mass Spectroscopy (SIMS).The kinetic data were fitted using a combination of classical models (parabolic, Avrami, Aronson) and complemented by a simulation, which accounts for the nucleation frequency and the grain boundary diffusion. The growth simulations were compared to microstructures observations using TEM.

White Beam Synchrotron Topographic Studies of the Effects of Localized Stress Fields on the Kinetics of Single Crystal Solid State Reactions.

1988 ◽  
Vol 143 ◽  
Author(s):  
Michael Dudley
Keyword(s):  
Solid State ◽  
Reaction Kinetics ◽  
Local Reaction ◽  
Stress Fields ◽  
Solid State Reactions ◽  
Thermally Induced ◽  
White Beam ◽  
Kinetics Of ◽  
Good Agreement

AbstractWhite Beam Synchrotron Topography has been used to determine the role of localized stress fields in the solid state polymerization of single crystals of the diacetylene PTS. Results indicate that the stress fields due to grown in dislocations can accelerate local reaction kinetics in thermally induced polymerization reactions, although no such effects were previously observable in photolytically or radiolytically induced reactions. Results are analyzed in an analogous fashion to the treatment of the nucleation of solid state phase transformations at dislocations. Good agreement was found between approximate theoretical treatments and experimental observation. The response of the monomer crystal to the inhomogeneous stresses generated as a result of inhomogeneous reaction and the implications regarding local reaction kinetics are discussed in detail.

scholarly journals Nanoscale cluster structure of O2 gas-filled nanobubbles in O2 gas-supersaturated alkaline solution

2021 ◽  
Vol 14 (2) ◽  
pp. 40-40
Author(s):  
Ichiro Otsuka
Keyword(s):  
Biological Effects ◽  
Cluster Structure ◽  
Nmr Studies ◽  
Transmission Electron ◽  
High Dilutions ◽  
Wheat Germination ◽  
Germination Experiments ◽  
Kinetics Of ◽  
Close Parallelism

There exists a close parallelism between gas-filled nanobubble solutions and ultra-high dilutions. Both these solutions contain Brownian nano-sized bubbles. We have studied aggregation kinetics of O2 gas-filled Brownian nanobubbles and their nanoscale cluster structure in 0.1M NaCO3 with NanoSight Particle Tracking Ananlysis (NTA) and transmission electron microscopy (TEM). A number of discrete peaks in a NTA size distribution of O2 nanobubbles in 0.1M NaCO3 eight days later after production are closely related to the existence of stable nanobubble clusters composed of 6-9nm nanobubbles that are inferred from the internal void size observed with TEM. Recent reports on 1HNMR of nanobubble water and its biological effects of wheat germination by Ohshita’s group may correlate with Demangeat`s NMR studies and germination experiments performed by many groups since the first publication by Lily Kolisco in 1923. Demangeat’s has recently published a review on the essential role of succussion that can cause nanobubble formation.

scholarly journals Understanding Surface Interaction and Inclusion Complexes between Piroxicam and Native or Crosslinked β-Cyclodextrins: The Role of Drug Concentration

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2848 ◽  
Author(s):  
Giuseppina Raffaini ◽  
Fabio Ganazzoli
Keyword(s):  
Inclusion Complexes ◽  
Drug Concentration ◽  
A Priori ◽  
Drug Carriers ◽  
Release Process ◽  
Drug Molecules ◽  
Molecular Dynamics Methods ◽  
Kinetics Of ◽  
Good Agreement

Drug concentration plays an important role in the interaction with drug carriers affecting the kinetics of release process and toxicology effects. Cyclodextrins (CDs) can solubilize hydrophobic drugs in water enhancing their bioavailability. In this theoretical study based on molecular mechanics and molecular dynamics methods, the interactions between β-cyclodextrin and piroxicam, an important nonsteroidal anti-inflammatory drug, were investigated. At first, both host–guest complexes with native β-CD in the 1:1 and in 2:1 stoichiometry were considered without assuming any initial a priori inclusion: the resulting inclusion complexes were in good agreement with literature NMR data. The interaction between piroxicam and a β-CD nanosponge (NS) was then modeled at different concentrations. Two inclusion mechanisms were found. Moreover, piroxicam can interact with the external NS surface or with its crosslinkers, also forming one nanopore. At larger concentration, a nucleation process of drug aggregation induced by the first layer of adsorbed piroxicam molecules is observed. The flexibility of crosslinked β-CDs, which may be swollen or quite compact, changing the surface area accessible to drug molecules, and the dimension of the aggregate nucleated on the NS surface are important factors possibly affecting the kinetics of release, which shall be theoretically studied in more detail at specific concentrations.

The Role of Copper in the Precipitation Kinetics of 6000 Series Al Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 169-176 ◽  
Author(s):  
S. Esmaeili ◽  
David J. Lloyd
Keyword(s):  
Isothermal Calorimetry ◽  
Cluster Formation ◽  
Analytical Techniques ◽  
Al Alloys ◽  
Precipitation Kinetics ◽  
Precipitation Behavior ◽  
Transmission Electron ◽  
Precipitate Nucleation ◽  
Kinetics Of

The role of Cu in precipitation behavior of 6000 series aluminum alloys has been investigated by isothermal calorimetry and transmission electron microscopy. The newly developed analytical techniques have been used to evaluate the precipitation kinetics in alloys with or without an initial pre-aging history. It has been found that Cu addition results in increasing the rate of precipitation when artificial aging is applied immediately after solutionizing and quenching. However, Cu has no significant effect on the kinetics of precipitation in alloys with the pre-aging history, while it produces finer microstructures in the pre-aged and then artificially aged alloys. These observations have been explained by the effect of Cu on increasing the rate of precipitate nucleation in 6000 series alloys. It has also been suggested that the effect of Cu on nucleation arises from the role of Cu on the cluster formation during and/or immediately after quenching.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

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