scholarly journals On the Variability of Critical Size for Homogeneous Nucleation in a Solid-State Diffusional Transformation

2021 ◽  
pp. 126491
Author(s):  
R.M. Raghavendra ◽  
Pooja Rani ◽  
Anandh Subramaniam
Keyword(s):  
Solid State ◽  
Homogeneous Nucleation ◽  
Critical Size ◽  
Diffusional Transformation

Nucleation Barrier for the Precipitation in Nanosized Al-4wt%Cu Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 3463-3466
Author(s):  
Shan Qing Xu ◽  
Zheng Hong Guo ◽  
T.Y. Hsu
Keyword(s):  
Grain Size ◽  
Homogeneous Nucleation ◽  
Critical Size ◽  
Parent Phase ◽  
The Other ◽  
Nucleation Event ◽  
Initial Concentration ◽  
Cu Alloy ◽  
Nucleation Barrier ◽  
Other Hand

The possibility of Al2Cu( q) precipitation in nanosized Al-4wt%Cu alloy is predicted based on the theory of homogeneous nucleation. The result indicates that the initial concentration of Cu in parent phase has little influence on the nucleation event when the grain size is larger than a critical size. On the other hand, when the grain size is smaller than the critical size, the formation of a stable Al2Cu nucleus will be prohibited completely due to the insufficient initial concentration of Cu.

scholarly journals Imaging the Homogeneous Nucleation During the Melting of Superheated Colloidal Crystals

Science ◽  
2012 ◽  
Vol 338 (6103) ◽  
pp. 87-90 ◽  
Author(s):  
Ziren Wang ◽  
Feng Wang ◽  
Yi Peng ◽  
Zhongyu Zheng ◽  
Yilong Han
Keyword(s):  
Phase Transitions ◽  
Homogeneous Nucleation ◽  
Critical Size ◽  
Colloidal Crystals ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Nucleation Process ◽  
Particle Exchange ◽  
Superheat Limit ◽  
Shape And Size

The nucleation process is crucial to many phase transitions, but its kinetics are difficult to predict and measure. We superheated and melted the interior of thermal-sensitive colloidal crystals and investigated by means of video microscopy the homogeneous melting at single-particle resolution. The observed nucleation precursor was local particle-exchange loops surrounded by particles with large displacement amplitudes rather than any defects. The critical size, incubation time, and shape and size evolutions of the nucleus were measured. They deviate from the classical nucleation theory under strong superheating, mainly because of the coalescence of nuclei. The superheat limit agrees with the measured Born and Lindemann instabilities.

The spontaneous nucleation of supercooled water

1952 ◽  
Vol 215 (1120) ◽  
pp. 65-66 ◽  
Keyword(s):  
Activation Energy ◽  
Homogeneous Nucleation ◽  
Critical Size ◽  
Freezing Point ◽  
Pure Water ◽  
Supercooled Water ◽  
Absolute Temperature ◽  
Specific Surface Energy ◽  
Spontaneous Nucleation ◽  
Self Diffusion

A number of experimenters have reported on the possibility of supercooling small droplets of pure water ( r < 10 μ ) to about – 40° C before freezing occurs. As foreign nuclei are excluded it seems that aggregates of the ice phase must be formed by chance associations of the molecules in the supercooled water (i. e. homogeneous nucleation). An expression for rate of production of nuclei of critical size, J cm -3 s -1 , has been given by Turnbull & Fisher (1949), and in the case of ice, may be written (Mason 1952) log J = 32.84 + log T - U /2.303 kT – 760 σ 3 /( T 0 – T ) 2 T ' where U is the activation energy for self-diffusion of a molecule in the liquid, σ the specific surface energy of the crystal-liquid interface, T the absolute temperature, and T 0 (= 273° K) the thermodynamic freezing-point.

scholarly journals Thermodynamics of homogeneous nucleation of ice particles in the polar summer mesosphere

2009 ◽  
Vol 9 (3) ◽  
pp. 965-971 ◽  
Author(s):  
A. Y. Zasetsky ◽  
S. V. Petelina ◽  
I. M. Svishchev
Keyword(s):  
Water Vapor ◽  
Homogeneous Nucleation ◽  
Water Clusters ◽  
Critical Size ◽  
Summer Temperature ◽  
Nano Particles ◽  
Vapor Density ◽  
Water Ice ◽  
Formation Pathway ◽  
Hexagonal Ice

Abstract. We present the hypothesis of homogeneous nucleation of ice nano-particles in the polar summer mesosphere. The nucleation of condensed phase is traced back to the first step on the formation pathway, which is assumed to be the transition of water vapor to amorphous cluster. Amorphous clusters then freeze into water ice, likely metastable cubic ice, when they reach the critical size. The estimates based on the equilibrium thermodynamics give the critical size (radius) of amorphous water clusters as about 1.0 nm. The same estimates for the final transition step, that is the transformation of cubic to hexagonal ice, give the critical size of about 15 nm at typical upper mesospheric conditions during the polar summer (temperature T=150 K, water vapor density ρvapor=109 cm−3).

scholarly journals Computational investigation of chalcogenide spinel conductors for all-solid-state Mg batteries

2020 ◽  
Vol 56 (13) ◽  
pp. 1952-1955 ◽  
Author(s):  
Julius Koettgen ◽  
Christopher J. Bartel ◽  
Gerbrand Ceder
Keyword(s):  
Solid State ◽  
Spinel Structure ◽  
Critical Size ◽  
Computational Investigation ◽  
Chalcogenide Spinel

Lanthanoid cations enable fast Mg2+ mobility in spinel chalcogenides but destabilize the spinel structure beyond a critical size.

scholarly journals Thermodynamics of homogeneous nucleation of ice particles in the polar summer mesosphere

2008 ◽  
Vol 8 (4) ◽  
pp. 14497-14517 ◽  
Author(s):  
A. Y. Zasetsky ◽  
S. V. Petelina ◽  
I. M. Svishchev
Keyword(s):  
Water Vapor ◽  
Homogeneous Nucleation ◽  
Water Clusters ◽  
Critical Size ◽  
Summer Temperature ◽  
Nano Particles ◽  
Vapor Density ◽  
Water Ice ◽  
Formation Pathway ◽  
Hexagonal Ice

Abstract. We present the hypothesis of homogeneous nucleation of ice nano-particles in the polar summer mesosphere. The nucleation of condensed phase is traced back to the first step on the formation pathway, which is assumed to be the transition of water vapor to amorphous cluster. Amorphous clusters then freeze into water ice, likely metastable cubic ice, when they reach the critical size. The estimates based on the equilibrium thermodynamics give the critical size (radius) of amorphous water clusters as about 1.0 nm. The same estimates for the final transition step, that is the transformation of cubic to hexagonal ice, give the critical size of about 15 nm at typical upper mesospheric conditions during the polar summer (temperature T=150 K, water vapor density ρvapor=109 cm−3).

Recollections of early solid state physics

1980 ◽  
Vol 371 (1744) ◽  
pp. 28-38 ◽  
Keyword(s):  
State Physics ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Solid State ◽  
Particle Physics ◽  
Critical Size ◽  
Mathematical Physics ◽  
British Government ◽  
Solid State Physics ◽  
Nuclear Bomb

Peierls, Sir Rudolf Ernst. Born Berlin 1907. Studied at Berlin, Munich and Leipzig. From 1932 held research positions in Manchester and Cambridge. Was Professor of mathematical physics in Birmingham and Oxford. Knighted 1968. Author of many papers applying quantum mechanics to problems in solid state and in particle physics', author of Quantum theory of solids, 1955. Author with 0. R. Frisch in 1940 of ‘ Confidential memorandum to British Government on possibility and critical size of nuclear bomb'.

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