KEYNOTES/ INVITED TALKS

Opening Lecture:
“Diffusion at Short Circuits. State of the Art”

Professor D.Sc. B.S. Bokstein
Department of Physical Chemistry,
Institute of Steel and Alloys,
Moscow, Russia

DSL-2009 Honorary Chairman

 

Abstract

Evidence for solid-state diffusion ( the second half of 19th century).
The first measurements of solid state diffusion ( W.Roberts-Austin(1896) – 1922).
The first tracer experiments to determine the solid-state diffusion (G.von Hevesy,1913 – 1923).
The first evidence of accelerated diffusion in polycrystalline materials (1924 – 1935).
Autoradiographic studies of grain boundary diffusion (50th of 20th century).
The first quantitative experimental and theoretical studies  of the “short circuiting” diffusion (beginning from 1949, D. Turnbull and R. Hoffman – General Electric Research Lab.): radiotracer serial sectioning method, Fisher’s model (1951)for grain boundary diffusion, exact solutions and developments of Fisher’s model (1954 – 1963).
The progress in the experimental methods for determination of grain boundary diffusion data and results of measurements for different metallic systems ( up to date).
The measurements of grain boundary diffusion parameters in B and C regimes.
The measurements of diffusivities along migrating grain boundaries, dislocation pipes, low-angle grain boundaries, phase boundaries, triple junctions of grains.
Diffusion in thin films. Effect of gradient energy and stress.
Grain boundary diffusion and grain boundary segregation. Nonlinear segregation effects.
Structural effects of grain boundary diffusion. Diffusion in bicrystals. Diffusion in nanocrystals.
Grain boundary wetting and grooving.
Computer simulation of grain boundary diffusion
Mechanisms of grain boundary diffusion

Conclusion: where and why are we going?

 

Plenary Lecture:
“Selected Analyses and Observations in Multicomponent Diffusion”

Professor M.A. Dayananda
Purdue University,
West Lafayette, Indiana - 47907,
USA

 

Abstract

Selected isothermal diffusion studies in ternary and quaternary systems are reviewed in order to present analytical and experimental approaches adopted for the determination of interdiffusion fluxes of components, interdiffusion coefficients, diffusional interactions among components, and internal consistency in the experimental data.

Several interesting phenomena and observations including uphill diffusion, zero-flux planes and flux reversals, flux reversals at interfaces,nonplanar interfaces, demixing of phases, uncommon diffusion paths, and diffusion structure evolution are illustrated with selected single phase and multiphase diffusion couples in Cu-based and Fe-based ternary systems.

The main challenges involved in the experimental determination of interdiffusion data from multicomponent diffusion couples and in the applications of such data are also addressed

Plenary Lecture:
“Single and Two-Phase Flow Heat Transfer in Micropipes”

Professor G.P. Celata
ENEA, Energy Department, Institute of Thermal-Fluid,
Dynamics,
Rome, Italy

 

Abstract

Partly because of the technological challenge, partly because of stark necessity, there has been an increasing movement towards a miniaturization of appliances in the last decade. In all technical fields solutions are sought that encumber as little as possible without compromising on performance: in medical diagnostics, environmental sample analysis, military defence, consumer electronics, biomedical appliances, chemical reactors and heat management a constant research for quicker response times and portable devices has driven the field of microtechnology to impressive levels. In many applications it has been found that many small active components are more productive than few large ones, which is also in keeping with the growing trend towards modular design.

Proper understanding of microscale transport phenomena is therefore fundamental for the designer of microfluidic devices. For this reason, many studies have been conducted to analyse the behaviour of convective flow through microchannels, both in single-phase and in two-phase flow. A first glance of the literature, especially for single-phase flow, leads to the conclusion that up to now we have had an agglomeration of disparate conclusions. In many cases the experimental data in microchannels disagree with the conventional theory and empirical correlations, but they also appear to be inconsistent with one another. The present lecture is an attempt to critically analyse the available results for liquid single-phase and flow boiling heat transfer, trying to provide some sort of base note in the melisma of published data.



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