Seminar for
RELATIVITY THEORY AND COSMOLOGICAL MODELS

 

PROGRAM

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Plan rada Seminara za teoriju relativnosti i kosmološke modele za APRIL 2022.

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SREDA, 06.04.2022. u 11:00, Online
Miloš Arsenijević, Filozofski fakultet Univerziteta u Beogradu
NEKOLIKO ZAGONETNIH PITANjA O VREMENU
Umesto direktnog odgovora na pitanje ŠTA JE VREME? biće analizirana različita pitanja koja su, od stare Grčke do danas, s njim u vezi razmatrana u filozofiji, fizici i matematici, a koja se tiču njegovog ontološkog statusa, strukture, topologije, metrike, toka, smera, indeterminizma i odnosa prema unutarsvetskoj beskonačnosti.

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SREDA, 13.04.2022. u 11:00, Online
Katica R. (Stevanović) Hedrih, Matematički institut SANU
MATRICES OF METRIC TENSIONS OF THE TANGENT SPACE:
Once again on matrices of metric tensons of the tangent space of a kinetic point position vector in various orthogonal curvilinear systems and their changes with time
The content of the lecture is based on the results of lecturer, published in 2021 in a review paper in the journal The European Physical Journal Special Topics, as well as on new unpublished results achieved in the pandemic 2021. In the first part of the lecture, the lecturer points out the contributions, two heads of the Department of Mechanics of MI SASA, to academician Tatomir P. Andjeliċ (1903-1993) and Professor Danilo P. Raškoviċ (1910-19085) in the inclusion and promotion of tensors and tensor calculus in university teaching at the faculties of natural-mathematical sciences and faculties of mechanical engineering sciences un area of mathematics and mechanics in Yugoslavia, as well as the education of numerous generations of the students of mechanics and mathematics in that field. This part is based on two biobibiographies of these scientists, written and published by this lecturer in the SASA Edition "Life and work of Serbian scientists". The cooperation of Serbian scientists with the Japanese society Tensor, as well as the recently pass a way academician Radu Miron (1927-2922) from Romania, will be briefly pointed out. The next part of the lecture talks about the base vectors of the tangent space of the kinetic point position vector in different orthogonal curvilinear coordinate systems, as well as the angular velocities and extensions of the base vectors of the kinetic point tangent space during its movement. The lecturer will then present the matrices of metric tensors in different orthogonal curvilinear coordinate systems, as well as the matrices of the first derivatives of these metric tensors. The lecturer designed and constructed an orthogonal coordinate system of curvilinear coordinates for rotating surfaces for the purpose of studying rolling, without sliding, of a heavy, homogeneous and isotropic ball on rotating coordinate surfaces of different shapes. In addition in the lecture, the last part will present nonlinear differential equations of rolling, non-slip, heavy homogeneous and isotropic balls on rotating, mutually both sides retaining, coordinate surfaces (sphere, cone, torus, general case of rotating surface). The existence of a cyclic integral and a cyclic coordinate in all these cases is pointed out. He also formulated a number of theorems based on scientific results, which are the content of this lecture.
The lecture is dedicated to the memory of two heads of the Department of Mechanics of MI SASA, academician Tatomir P. Andjeliċ (1903-1993) and Professor Danilo P. Raškoviċ (1910-19085).

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SREDA, 27.04.2022. u 11:00, Online
Nenad Švrakić, Institut za fiziku u Beogradu
POPUNJAVANJA, PAKOVANJA I AGREGACIJE U DVE DIMENZIJE
Dinamika i statistika depozicije konačnih objekata za pokrivanje ravni je značajan teorijski probem koji ima primene u nano-tehnologiji, makromolekularnoj hemiji, medicini, itd. U ovom predavanju, focus će biti na slučajnoj depoziciji hiper-elipsi različitog parametra deformacije, i njihovih kombinacija, uključujući i konkavne slučajeve. Osnovne veličine od interesa su granična zagušenja (jamming limit) i dinamika prilaza ovom limitu. Pojedini od ovih problema mogu analitički da se reše, dok drugi zahtevaju numerički prilaz. Na kraju ćemo nabrojati još nerešene, otvorene probleme pakovanja i agregacije.

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Predavanja su namenjena sirokom krugu slusalaca, ukljucujuci studente redovnih i doktorskih studija. Seminar će se održavati po najavi: sredom u 11:00^h, sala 301f Matematikog instituta SANU, III sprat, Knez Mihailova 36.

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