Simulation of radiotracer method for diffusion studies using short-lived radioactive nuclear beams

AbstractWe have studied self-diffusion in the bulk metallic glasses Zr46.75Ti8.25Cu7.5Ni10Be27.5 and Zr65Cu17.5Ni10A17.5 by means of the radiotracer method. Diffusion of 63Ni has been investigated as a function of temperature in both alloys and also as a function of hydrostatic pressure in Zr46.75Ti8.25Cu7.5Ni10Be27.5. With the isotope 95Zr diffusion studies of the major component Zr were performed in Zr46.75Ti8.25Cu7.5Ni10Be27.5. The diffusivity of 95Zr is much smaller than that of 63Ni. The temperature dependence of 63Ni self-diffusion into Zr46.75Ti8.25Cu7.5Ni10Be27.5 and into Zr65Cu17.5Ni10A17.5 cannot be described by a single set of Arrhenius parameters, breaks in the Arrhenius curves are observed. We attribute the non-linear Arrhenius behaviour to the transition from the glassy to the supercooled liquid state. For the first time activation volumes of diffusion in a supercooled melt have been determined. From the pressure dependence of 63Ni diffusion in Zr46.75Ti8.25Cu7.5 Ni10Be27.5 we get activation volumes around one mean atomic volume favouring a diffusion mechanism via vacancy-like defects.

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Host element chemical diffusion studies in high-purity Fe-Cr-Al model alloys

Matériaux & Techniques ◽

10.1051/mattech/200391070087 ◽

2003 ◽

Vol 91 (7-8-9) ◽

pp. 87-91

Author(s):

P. Dawah Tankeu ◽

A. Gruzdeva ◽

M. Zapukhlyak ◽

L. Doerrer ◽

K. Goemann ◽

...

Keyword(s):

High Purity ◽

Chemical Diffusion ◽

Diffusion Studies

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Capillary-reservoir diffusion studies in Hg-In alloys utilizing continuous resistivity measurement of composition

10.31274/rtd-180813-4119 ◽

1971 ◽

Author(s):

Robert Hamilton Kaiser

Keyword(s):

Resistivity Measurement ◽

Diffusion Studies

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Characterization of New Ionically Conducting Peo-Based Networks by Diffusion, Elasticity Modulus and Ionic Conductivity Measurements

MRS Proceedings ◽

10.1557/proc-293-123 ◽

1992 ◽

Vol 293 ◽

Cited By ~ 1

Author(s):

Herve Cheradame ◽

F. Desbat ◽

P. Mercier-Niddam ◽

S. Boileau

Keyword(s):

Diffusion Coefficient ◽

Ionic Conductivity ◽

Elasticity Modulus ◽

Sol Gel ◽

Cation Transport ◽

Lithium Cation ◽

Conductivity Measurements ◽

Conducting Materials ◽

Diffusion Studies

AbstractIonically conducting materials containing PEO were prepared from telechelic di(methyl-diethoxy-silane) PEO, synthesized by the hydrosilylation of telechelic diallyl-PEO with methyldiethoxysilane. The network is obtained by the usual sol-gel chemistry. Then, it is filled with LiClO4 by diffusion of the salt and further drying. A comparison is made with the same kind of materials crosslinked using urethane chemistry. Diffusion studies show that the diffusion coefficient of solvent is similar for both types of materials, whilst the ionic conductivity is higher for the networks crosslinked with siloxane bonds. An experiment of diffusion of LiClO4 without solvent showed that this salt has a diffusion coefficient of the order of 2.10-8 cm2.sec-1 at 34°C. The conductivity calculated from this determination is compatible with the mechanism of lithium cation transport by the diffusion of salt molecules. Elasticity modulus measurements show that the salt aggregates are essentially located within the crosslinks at low concentration, but also in the PEO chains for salt concentrations higher than 1 mol/l.

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Evaluation of antipsoriatic activity of gel containing Pongamia pinnata extract on Imiquimod-induced psoriasis

Clinical Phytoscience ◽

10.1186/s40816-021-00256-6 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Kamlesh Wadher ◽

Shital Dabre ◽

Anjali Gaidhane ◽

Sagar Trivedi ◽

Milind Umekar

Keyword(s):

Mouse Model ◽

Pongamia Pinnata ◽

Gelling Agent ◽

Proper Treatment ◽

Phytochemical Screening ◽

Diffusion Studies ◽

In Vitro Diffusion ◽

Gel Formulations ◽

Disease And Disorders

Abstract Background Pongamia pinnata (Fabaceae) is among those categories of plants mentioned in Ayurveda and traditionally known to use in several types of disease and disorders. The objective of the present work was to investigate the anti-psoriatic activity of Pongamia pinnata leaves extracts in Herbal gel formulation. Results Hydroalcoholic leaves extract of Pongamia pinnata was first subjected to phytochemical screening and quantification of phytoconstituents. Herbal gel was prepared containing Pongamia pinnata extracts using Carbopol 934 as gelling agent. The prepared gel formulations were studied for pH, viscosity, Spreadability and in vitro diffusion studies. The imiquimod-induced psoriatic mouse model, showed a prominent anti-psoriatic activity of the extract as evident through index grading. Treatment with extract confirmed a noteworthy reduction in psoriasis in the treated groups as there was a considerable diminution in the thickness and scaling of skin. Conclusions Lack of proper treatment and disadvantages associated with allopathic medicines pave the way to extensive research in natural products with anti-psoriatic activity. The present research scientifically justified the anti-psoriatic activity of the Hydroalcoholic extracts of Pongamia pinnata leaves.

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A Precision Grinding Machine for Diffusion Studies

Review of Scientific Instruments ◽

10.1063/1.1771195 ◽

1954 ◽

Vol 25 (9) ◽

pp. 865-868 ◽

Cited By ~ 33

Author(s):

Harry Letaw ◽

Lawrence M. Slifkin ◽

William M. Portnoy

Keyword(s):

Precision Grinding ◽

Diffusion Studies ◽

Grinding Machine

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Diffusion Studies. I. Diffusion Coefficients in Liquids by a Radiometric Porous-Frit Method1

The Journal of Physical Chemistry ◽

10.1021/j100885a047 ◽

1965 ◽

Vol 69 (1) ◽

pp. 303-309 ◽

Cited By ~ 8

Author(s):

Arthur E. Marcinkowsky ◽

Frederick Nelson ◽

Kurt A. Kraus

Keyword(s):

Diffusion Coefficients ◽

Diffusion Studies

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Non-Stoichiometry and Cation Tracer Diffusion Studies in the Magnetite-UlvÖSpinel Solution, (Fe,Ti)3-δO4

MRS Proceedings ◽

10.1557/proc-369-307 ◽

1994 ◽

Vol 369 ◽

Author(s):

Sanjeev Aggarwal ◽

Rudiger Dieckmann

Keyword(s):

Diffusion Coefficients ◽

Tracer Diffusion ◽

Oxygen Activity ◽

Spinel Solid Solution ◽

Low Oxygen ◽

Cation Diffusion ◽

Deviation From Stoichiometry ◽

Diffusion Studies ◽

Tracer Diffusion Coefficients ◽

Point Defect Structure

AbstractCation diffusion in the spinel solid solution (Fe1-xTix)3-δO4 (0≤ x ≤ 0.3) was investigated at 1200 ºC as a function of oxygen activity, aO2 and cationic composition, x. At different cationic compositions, cation tracer diffusion coefficients, D*Me of Me = Fe and Ti were measured as a function of oxygen activity. Plots of log DMe vs. loga0 show V-shaped curves, indicating that different types of point defects prevail at high anc low oxygen activities. Thermogravimetric experiments were conducted, using a high resolution microbalance, to determine the deviation from stoichiometry in (Fe1-xTix)3-δO4 at 1200 °C. δversus log aO2 curves are S-shaped. An analysis of the oxygen activity dependences of thecation diffusion coefficients and the deviation from stoichiometry with regardto the point defect structure suggests that at high oxygen activities cation vacancies are the predominant defects governing the deviation from stoichiometry and the diffusion ofcations. At low oxygen activities, and at small values of x, cation interstitials determine the deviation from stoichiometry, while they dominate for 0 ≤ x ≤ 0.3 inthe cation diffusion.

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A radiotracer method for the measurement of central nervous system catecholamines in vivo

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y78-085 ◽

1978 ◽

Vol 56 (3) ◽

pp. 535-538 ◽

Cited By ~ 6

Author(s):

S. W. Tang ◽

H. C. Stancer ◽

J. J. Warsh

Keyword(s):

Central Nervous System ◽

Animal Model ◽

Nervous System ◽

Specific Activity ◽

Brain Catecholamines ◽

Radiotracer Method ◽

New Strategy ◽

The Central Nervous System ◽

6 Hydroxydopamine

A new strategy for measurement of brain catecholamines was tested in an animal model. [3H]Norepinephrine was infused intravenously in rabbits to label the peripheral norepinephrine pools. The specific activity of urinary 3-methoxy-4-hydroxymandelic acid was consistently higher than that for 3-methoxy-4-hydroxyphenylglycol (MHPG). Central sympathectomy with 6-hydroxydopamine abolished this difference. Using the formula we propose, it is estimated that 30–50% of urinary MHPG originates from the central nervous system.

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