scholarly journals The role of oxygen packing in the structural transformations of oxide glasses

2016 ◽  
Vol 72 (a1) ◽  
pp. s150-s150
Author(s):  
Anita Zeidler ◽  
Philip S. Salmon
Keyword(s):  
Structural Transformations ◽  
Oxide Glasses

Mineral transformations

2000 ◽  
Vol 64 (2) ◽  
pp. 155-156 ◽  
Author(s):  
S. A. T. Redfern
Keyword(s):  
European Union ◽  
Chemical Composition ◽  
Structural Transformations ◽  
Atomic Scale ◽  
Special Session ◽  
The European Union ◽  
Mineral Science ◽  
Research Programmes ◽  
Mineral Transformations

One of the major goals of mineral science is attaining an understanding of the atomic-scale mechanisms and dynamics of minerals that control their structural transformations as a function of pressure, temperature or chemical composition in the natural environment. Examples of research programmes that sail under this heading include those devoted to observing and modelling the role of phase transformations on controlling mineral microstructures, ordering, elasticity, transport, premelting and exsolution. The geological relevance and intrinsic importance (as being representative of specific properties or thermodynamic/ kinetic behaviour) of mineral transformations has long been appreciated. It prompted the recent initiation of a network on Mineral Transformations (http://www.esc.cam.ac.uk/mintrans/) under the European Union TMR Programme. In response to this development, a special session on Mineral Transformations was held at the EUG congress in Strasbourg last year.

Phonons in deformable microporous crystalline solids

2019 ◽  
Vol 234 (7-8) ◽  
pp. 513-527 ◽  
Author(s):  
Bogdan Kuchta ◽  
Filip Formalik ◽  
Justyna Rogacka ◽  
Alexander V. Neimark ◽  
Lucyna Firlej
Keyword(s):  
Periodic Structures ◽  
Structural Transformations ◽  
Crystalline Solids ◽  
Predictive Tool ◽  
Crystalline Materials ◽  
Numerical Tools ◽  
Collective Vibrations ◽  
First Time

Abstract Phonons are quantum elastic excitations of crystalline solids. Classically, they correspond to the collective vibrations of atoms in ordered periodic structures. They determine the thermodynamic properties of solids and their stability in the case of structural transformations. Here we review for the first time the existing examples of the phonon analysis of adsorption-induced transformations occurring in microporous crystalline materials. We discuss the role of phonons in determining the mechanism of the deformations. We point out that phonon-based methodology may be used as a predictive tool in characterization of flexible microporous structures; therefore, relevant numerical tools must be developed.

scholarly journals Structural Transformations Versus Hard Particles Motion in the Brass Ingots

2017 ◽  
Vol 62 (4) ◽  
pp. 2461-2467 ◽  
Author(s):  
W. Wołczyński ◽  
A.A. Ivanova ◽  
P. Kwapisiński ◽  
E. Olejnik
Keyword(s):  
Continuous Casting ◽  
Thermal Gradient ◽  
Structural Transformations ◽  
Gradient Field ◽  
Hard Particles ◽  
Columnar Grains ◽  
Solid Liquid ◽  
Equiaxed Grains ◽  
Structural Zones

AbstractA mathematical method for the forecast of the type of structure in the steel static ingot has been recently developed. Currently, the method has been applied to structural zones prediction in the brass ingots obtained by the continuous casting. Both the temperature field and thermal gradient field have been calculated in order to predict mathematically the existence of some structural zones in the solidifying brass ingot. Particularly, the velocity of theliquidusisotherm movement and thermal gradient behavior versus solidification time have been considered. The analysis of the mentioned velocity allows the conclusion that the brass ingots can evince: chilled columnar grains-, (CC), fine columnar grains-, (FC), columnar grains-, (C), equiaxed grains zone, (E), and even the single crystal, (SC), situated axially. The role of the mentioned morphologies is analyzed to decide whether the hard particles existing in the brass ingots can be swallowed or rejected by the solid / liquid (s/l) interface of a given type of the growing grains. It is suggested that the columnar grains push the hard particles to the end of a brass ingot during its continuous casting.

scholarly journals Structural Transformations and Their Precursors

1983 ◽  
Vol 36 (4) ◽  
pp. 553 ◽  
Author(s):  
TR Finlayson
Keyword(s):  
Thermal Expansion ◽  
Electron Diffraction ◽  
Physical Properties ◽  
Elastic Constants ◽  
Direct Evidence ◽  
Indirect Evidence ◽  
Structural Transformations ◽  
X Ray ◽  
Kinetics Of

For a number of materials which exhibit a change of structure on being cooled below a certain temperature Tm, some physical properties display anomalous behaviour at temperatures above Tm. The particular structural transformations in mind have been broadly classified as 'martensitic' and the anomalous physical properties as 'precursive phenomena'. Some debate exists regarding the role of the precursive phenomenon in the kinetics of the structural transformation. The most direct evidence for 'martensite precursors' is obtained from electron diffraction, although various indirect evidence is contained in X-ray, neutron and y-ray diffraction and various physical properties, for example, elastic constants and thermal expansion. In this paper current understanding of 'martensite precursors' is reviewed and examples of data from the A15 structure compounds V 3Si and Nb3Sn,. In-TI and TiNi alloys are discussed.

scholarly journals Structural, Thermal and Optical Properties of Rare Earth Doped Lead-Tellurite Oxide Glasses

2021 ◽  
Vol 81 (2) ◽  
pp. 52-58
Author(s):  
Fong W. L. ◽  
Sharudin Omar Baki ◽  
N. M. Arifin ◽  
Yaakob Mansor ◽  
Ahmad Nazri ◽  
...  
Keyword(s):  
Optical Properties ◽  
Rare Earth ◽  
Energy Gap ◽  
Structural Deformation ◽  
Oxide Glasses ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Erbium Ions ◽  
Glass Transformation

Structural, thermal and optical properties of lead-tellurite oxide glasses consisting TeO2 – PbO – Bi2O3 – Er2O3, synthesized by high temperature melt-quenching-thermal annealing method were investigated in this study. The role of rare-earth element, erbium ion as dopant into the host glass has affected physically, thermally and optically of the glasses. The amorphous nature of the glasses was confirmed by XRD (x-ray diffraction). Thermal exo-endothermic event profiles clarify its glass transformation temperature Tg, crystallization temperature Tx, and melting temperature Tm are exist. Both UV-Vis-NIR optical absorption and Raman spectroscopy have revealed optical energy gap changes due to the structural deformation by the erbium ions. Related obtained glass parameters such as polarizability, refractive indices and metallization criterion were also explained further in this study.

scholarly journals INFORMATION SUPPORT FOR SCIENTISTS OF SCIENTIFIC CENTERS OF AGRICULTURAL PROFILE OF SIBERIA (1971–2019)

2020 ◽  
pp. 68-73
Author(s):  
T. N. Melnikova ◽  
T. M. Garke ◽  
E. A. Kretova
Keyword(s):  
Structural Transformations ◽  
Information Resources ◽  
Information Space ◽  
Information Support ◽  
Research Institutes ◽  
Modern Period ◽  
The Status

The system of information support of agrarian science of Siberia, created by the Siberian scientific agricultural library, based on its information resources and intercommunications with agricultural libraries of the region, is analyzed. The results of the study of organizational and structural transformations in the management and information support for scientists in the modern period and the analysis of the status of libraries of research institutes are presented. The role of SibSAL as an interlink in maintenance of the united information space of agrarian science of Siberia is shown.

scholarly journals The Role of Cations of the Precipitant in the Interaction of Protein Molecules in the Lysozyme Oligomers in Crystallization Solutions

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1534
Author(s):  
Yuliya V. Kordonskaya ◽  
Vladimir I. Timofeev ◽  
Yulia A. Dyakova ◽  
Margarita A. Marchenkova ◽  
Yury V. Pisarevsky ◽  
...  
Keyword(s):  
Protein Crystallization ◽  
Structural Transformations ◽  
Atomic Mass ◽  
Crystal Formation ◽  
Noticeable Effect ◽  
Protein Molecules ◽  
The Stability ◽  
The Moment ◽  
Dynamics Method

At the moment, the main opinion is that protein crystallization depends mainly on the the precipitant anions, therefore, there have been only few works devoted to the problem of the influence of its cations. Using the molecular dynamics method, we investigated the stability, changes in the compactness and structural transformations of lysozyme dimers and octamers in solutions with different precipitants (LiCl, NaCl, KCl and CuCl2) in order to study the contribution of cations during crystal formation in more detail. As a result, we found that cations have a rather noticeable effect on the behavior of oligomers: the higher the atomic mass of the cation, the greater the changes in the dimers structures during its dynamics and, according to the data of SAXS experiments, the lower the concentration of dimers. However, for octamers, this dependence is more complicated.

Sign in / Sign up

Export Citation Format

Share Document