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fisica.uc.pt

 
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café com física - ciclo de palestras
palestras de 2012
palestras informais abertas a todos (sala conf. 14:00h ::0.0)

Janeiro

10jan
Edite Figueiras, CI
"Desenvolvimento de fluxómetros laser Doppler para medição da microcirculação"

17jan
Orlando Oliveira, CFC
"Quarks, Gluões, QCD e Confinamento"

24jan
José António Paixão, CEMDRX
"O Prémio Nobel da Química 2011"

26jan
Angels Ramos, Universidade de Barcelona
"eta ' N and eta' nucleus interactions"

Abstract
----------
I will present a study of the eta^prime N interaction, within a chiral unitary approach which includes pi N, eta N and related pseudoscalar meson-baryon coupled channels [1]. The model also incorporates the coupling to vector meson-baryon states and a new term in the Lagrangian, allowed by the symmetries of QCD, which couples baryons to the singlet meson of SU(3). Adjusting the unknown singlet strength to the eta^prime N scattering length, predictions for the elastic and inelastic eta^prime N cross sections at low energies are obtained. I will next discuss a calculation of the eta^prime-nucleus optical potential and the corresponding formation cross section of eta^prime bound states from (pi^+,p) reactions on nuclei [2]. Varying the eta^prime N singlet strength within the uncertainties of the experimental constraints, the spectra of light and medium nuclei show clear structures associated to eta^prime-nuclear bound states and to threshold enhancements in the unbound region. Finally, I will also comment on some preliminary results of the eta^prime nuclear transparency ratio, obtained from eta^prime photoproduction reactions from different nuclei by the CBELSA/TAPS Collaboration [3], establishing an inelastic eta^prime N cross section of 7-11 mb, and a corresponding width of the eta^prime meson at normal nuclear matter density of 15-30 MeV, for an average eta^prime momentum of 1 GeV/c.


31jan
Jaime Silva, UM e CFC
"Multi-scale modelling of smart materials"


fevereiro

7fev
João Moreira, CFC
"Rapidity dependent reaction plane in ultra-relativistic heavy ion collisions: torqued fireballs"

14fev
José Guilherme Vilhena d'Orey, Universidad Autónoma de Madrid
First principles study of nano-scale materials: quantum dots and nanowires.


28fev
Nicolas Lori, IBILI/FMUC
"Quantum Darwinism"


Março

6mar
Rita Costa Pereira, CI.
"Instrumentação Baseada em ATCA Dedicada aos Diagnósticos de Espectroscopia
Digital de Radiação Gama no JET"

abstract:
A apresentação tem como tema um sistema de aquisição e processamento de dados em tempo real, baseado no barramento ATCA e no protocolo de comunicação PCI Express, para espectroscopia de radiação gama. O sistema desenvolvido foi concebido e implementado com o objectivo de processar e armazenar, sem perda de informação durante plasmas nucleares de longa duração, todos os valores de energia dos eventos resultantes da radiação gama gerada na experiência, com uma taxa de ocorrência que pode atingir os 5 M pulsos/s. O sistema foi desenvolvido como parte do projecto de melhoramento dos diagnósticos de radiação gama do tokamak JET e engloba dois sistemas distintos: (i) espectroscopia de raios gama, para determinar espectros em energia; e (ii) câmaras de raios gama, inserida no monitor de perfis de neutrões para localizar a emissão de raios gama. A insuficiente resolução energética, temporal e espacial dos sistemas de aquisição de dados dos actuais diagnósticos de radiação gama no JET, motivou o desenvolviment

13mar
Heinrich Krobath, CFMC, Lisboa
"Nanoscale membrane shape fluctuations and their consequences for receptor
(un-)binding processes in cell adhesion"



27mar2012
Joaquim Candeias, Lusocreen
"Novo motor de combustão interna. Uma revolução na engenharia?"

Abstract:
Aumentar o rendimento dos motores actuais de combustão interna tem sido um desafio permanente da engenharia. Em Fevereiro passado, o Arq. Joaquim Candeias, inventor do Lusocreen, o primeiro e, até agora, único ecrã de projecção do mundo capaz de funcionar sob a luz directa do Sol, patenteado em Portugal e galardoado com a Medalha de Ouro no Salão de Invenções em Genebra, em 1997, submeteu um pedido de patente para um novo modelo de motor de combustão interna.
Ao contrário do que acontece nos motores actuais, onde toda a força obtida pela combustão é aplicada contra o eixo do motor, neste novo engenho conseguiu-se que a combustão ocorra no momento do máximo torque conferindo-lhe um rendimento superior ao obtido com os motores actualmente em uso independentemente do ciclo termodinâmico utilizado.
Neste seminário, depois de uma breve apresentação do orador e da empresa Lusoscreen, irá ser feita uma revisão dos princípios de funcionamento e limitações dos actuais motores de combustão interna seguida de uma descrição detalhada do funcionamento do novo engenho, terminando com a apresentação de um modelo.
A possibilidade de uma discussão com vista à compreensão dos fundamentos teóricos e ao cálculo do rendimento do novo motor, proporcionadas pelo intercâmbio com a comunidade cientifico-académica serão muito valorizadas pelo orador. http://www.lusoscreen.com/motorAbril


Abril

10abr2012
Paulo Silva, CFC
"O princípio da acção mínima em Mecânica Clássica"

17abr2012 Eef van Beveren, CFC
A partícula E38


Maio

2mai2012
Anne L´Huillie, Universidade de Angers
"workshop on the C language."

Abstract:
No specific backgrounds in C are required: the workshop will explain the C language from its basics. The items will be the following (more or less, depending on time):
* variables and arithmetic expressions
* control flow (loops and decisions (if and switch))
* functions
* pointers and arrays
* program structure
No practical lessons will be given; only concepts and applications on exercises.
2 de maio 15h00-17h30; 3 de maio 10h00-12h30


22mai2012
Fabrizio Grill, CFC

"The structure of neutron star Inner Crust"

abstract
In this talk I analyze how the structure of the inner crust is influenced by the approach used in the calculations, the pairing correlations and the parametrization of the nuclear interaction. The inner-crust matter, formed by nuclear clusters immersed in a superfluid neutron gas and ultra-relativistic electrons, is treated in the Wigner-Seitz approximation and the properties of the Wigner-Seitz cells, are obtained from the energy minimization at beta equilibrium. In the first work the properties of the baryonic matter are calculated performing Skyrme-Hartree-Fock-Bogoliubov (HFB) calculations.
We find that the most important effect of pairing is to smooth the dependence of Hartree-Fock (HF) energy on proton number. In the second work the inner crust structure is calculated using a relativistic mean field density dependent Thomas-Fermi approach (TF) and five different parameterizations of the nuclear interaction. We have found that this approach, which neglects the shell effects for both neutrons and protons, is less accurate than the HFB in the low-density regions, where the nucleus strongly influences the cell properties. Anyway we have also found that in the high-density regions, when the free neutron gas becomes more important than the nucleus, the accuracy of the TF approximation can be higher than that of the HFB approach. Moreover, with the TF approach it is possible to study the spherical, the cylindrical and the plane symmetries, making available the droplet, the rod and the slab cell shapes: so we have performed our study also in the pasta phase region and determined the cell structure until the transition with the core. Thus we have found that the dependence of the cell structure on the nuclear interaction, which is weak at low density, gets stronger in the pasta phase region and furthermore it turns out to be very important in the determination of the shape transition densities.

29mai2012
Domenico Logoteta, CFC
"A chiral model approach to quark matter nucleation in neutron stars"

abstract
The nucleation process of quark matter in both cold and hot dense hadronic matter is investigated using a chiral approach to describe the quark phase. We use the Nambu-Jona-Lasinio and the
Chromo Dielectric models to describe the deconfined phase and the non-linear Walecka model for the hadronic one. The effect of hyperons on the transition phase between hadronic and quark matter
is studied. The consequences of the nucleation process for neutron star physics are outlined.


Junho

12jun2012
Filipe Veloso (LIP)
"Search for FCNC top quark decays with the ATLAS detector"

Abstract:
A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of sqrt(s)=7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb-1, were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t->Zq FCNC (q=u,c) channel, and the other through the Standard Model dominant mode t->Wb. Only the decays of the Z boson to charged leptons and leptonic W-boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the t->Zq branching ratio of BR(t->Zq)<0.73% is set at the 95% confidence level.


Julho

3jul2012
Patrick Le Dû, LIP
"Applications outside high-energy physics: technology transfer from physics to
medical applications"


Outubro

2out2012
Guillermo Vilanova Cacoya
"Isogeometric analysis of a tumor angiogenic model"


11out2012
Dave Charlton, da Universidade de Birmingham e do CERN, vice-coordenador da experiência ATLAS,
"Higgs: To be or not to be!"

16out2012
Andrea Trombettoni, (SISSA)
"Quantum simulations with ultracold atoms: an example"

Abstract:
In this talk I will first provide an introduction to the active
field of research of quantum simulations with ultracold atoms. In
the second part I will focus on the specific example of superfluid
fermions in optical lattices, discussing anisotropic Ginzburg-Landau
and Lawrence-Doniach models. The coefficients of the anisotropic
Ginzburg-Landau and the mass tensor are studied as a function of
anisotropy, filling and interaction, showing that near the unitary
limit the effective anisotropy of the masses is significantly
reduced. The anisotropy parameter is shown to vary in realistic
setups in a wide range of values. We also derive the
Lawrence-Doniach model - often used to describe the 2D-3D
dimensional crossover in layered superconductors - for a layered
ultracold Fermi gas, obtaining a relation between the interlayer
Josephson couplings and the Ginzburg-Landau masses.

23out2012
Leo Stodolski, Director Emeritus do Max-Planck-Institut fuer Physik, Werner Heisenberg Institut
"In the Search for Dark Matter"

Abstract:
Why do we believe that most of the matter of the Universe is hidden?
Clear traces of the presence of this Dark Matter. The candidates and its models.
The gigantic effort that is being applied on a closer search for this Matter, at the Earth level and from the Outer Space. The present status of this search.
What are the consequences of its existence at the different scales, from particle physics to cosmology?
Which role it has played in the formation of our Universe and how it will influence its destiny?


Novembro

6nov2012
João Carvalho, Departamento de Física da UC
"Liposomes for targeted cancer multi-therapy and imaging"

Abstract:
Cancer was the second cause of death in the developed world in the
20th century and, if the trend doesn't change, it will the the major
cause of death in the 21st century. The fast development of genomics
is able to produce clues about the genetic defects behind this group
of diseases. But many other research avenues are being pursued in
tumor diagnosis and therapy. One of them is the use of multifunctional
liposomes, targeting tumor cells and delivering drugs and/or
radioisotopes for internal micro radio and/or chemotherapy, with
imaging capabilities. The University of Coimbra is involved in this
research and some recent results will be presented and discussed,
followed by some proposals of new developments.


27nov2012
Rui Silva, LIP
"XIPE space telescope proposal"

Abstract:
By measuring the polarization angle and the degree of polarization of celestial emissions, it will be possible to increase the number of observational parameters, thereby allowing better discrimination between various models characterizing the same object. Polarimetric observations can provide important information about geometries, magnetic fields, composition and emission mechanisms in a wide variety of gamma-ray sources, e.g. Pulsars, Solar Flares, Active Galactic Nuclei, Galactic Black Holes or Gamma-Ray Bursts.
So far, no dedicated gamma-ray polarimeters have ever been launched into space. X-ray Imaging Polarimetry Explorer mission proposal to Small Mission Opportunity of ESA's Science Programme, for a launch in 2017, is one of the few missions that would be able to perform high energy polarimetric observations. Our group has been developing this kind of instruments for more than a decade, optimizing focal plane instrumentation both by Monte Carlo simulations and by prototype testing.
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