Seminář Ústavu teoretické fyziky

podzim 2002


Proběhlé semináře:

12. listopadu 2002
Nové (i starší) experimenty v CERNu
RNDr. Jiří Dolejší, Csc.
ÚČJF MFF UK
19. listopadu 2002
seminář se nekoná
26. listopadu 2002
Stále záhadná hvězda Beta Lyrae
Doc. RNDr. Petr Harmanec, DrSc.
AÚ MFF UK
3. prosince 2002
seminář se nekoná
10. prosince 2002
Žeň astronomických objevů za rok 2001
Dr. J. Grygar, CSc.
FÚ AV ČR
17. prosince 2002
Non-Hermitean Quantum Mechanics
Prof. Nimrod Moiseyev
Technion Haifa Israel
(seminář v angličtině)
7. ledna 2003
Particle Dynamics in Granular Drainage
Martin Z. Bazant
Dep. of Mathematics, MIT

Granular drainage is a very familiar phenomenon --- the slow flow of sand in an hourglass, corn in a silo... or fuel in a pebble-bed nuclear reactor (our motivation here) --- and yet it presents fundamental theoretical mysteries and experimental challenges. In engineering, the mean flow is commonly described by a ``kinematic'' continuum model, in which the downward velocity satisfies a diffusion equation (with the vertical distance playing the role of time). Litwiniszyn (1963) and Mullins (1972) originally derived this model by assuming that particles move downward as tiny voids make directed random walks upward from the container opening. Taken literally, however, (as has recently been done) this picture predicts mixing rates which are orders of magnitude to too large. Thus we are led to ask: What is the statistical dynamics of particles, consistent with the observed macroscopic flow? In this talk, we discuss particle-tracking experiments using a high-speed digital video camera and a new mathematical model, which suggest that the answer lies in subtle correlations between particle motions.

10. ledna 2003
Seminář mimořádně v pátek ve 14 hod.
Ledvinka, počítace, černé diry
Tomáš Ledvinka
ÚTF MFF UK

Další ročníky:


© 2. ledna 2003; Pavel Krtouš <krtous@mbox.troja.mff.cuni.cz>
© 6. října 2016; vygenerováno pomocí aplikace seminar, verze 2.04 (2003-09-02); správce <Pavel.Krtous@mff.cuni.cz>