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Search Results: 1 - 10 of 19 matches for " Violina Iordanova "
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Freeway ramp metering control made easy and efficient
Hassane Abouaissa,Michel Fliess,Violina Iordanova,Cédric Join
Mathematics , 2012,
Abstract: "Model-free" control and the related "intelligent" proportional-integral (PI) controllers are successfully applied to freeway ramp metering control. Implementing moreover the corresponding control strategy is straightforward. Numerical simulations on the other hand need the identification of quite complex quantities like the free flow sp\^eed and the critical density. This is achieved thanks to new estimation techniques where the differentiation of noisy signals plays a key r\^ole. Several excellent computer simulations are provided and analyzed.
Strangeness and bulk freeze-out properties at RHIC
Aneta Iordanova
Physics , 2007, DOI: 10.1088/0954-3899/35/4/044008
Abstract: Identified charged kaon, pion, and proton spectra and ratios from sqrt(s_NN) = 200 and 62.4 GeV Cu+Cu collisions are studied with a hydro-motivated blast-wave and a statistical model framework in order to explore the strangeness production at RHIC and characterize the bulk freeze-out properties of the created system. The spectra are measured at mid-rapidity |y|<0.1 over the transverse momentum range of 0.25 < p_T < 1.2 GeV/c with particle identification derived from the ionization energy loss in the STAR Time Projection Chamber. The multi-dimensional systematic study of pi(+/-), K(+/-), p and pbar production in Cu+Cu, Au+Au, d+Au and p+p collisions is used to discuss the energy, system size and inferred energy density dependence of freeze-out parameters and strangeness production. The new data from Cu+Cu collisions bridge the gap between the smaller d+Au and larger Au+Au systems, allowing a detailed study of the onset of strangeness equilibration at RHIC.
Heavy-Ion Physics with CMS
Aneta Iordanova
Physics , 2008,
Abstract: This article presents a brief overview of the CMS experiment capabilities to study the hot and dense matter created in relativistic heavy-ion collisions. The CERN Large Hadron Collider will provide collisions of Pb nuclei at 5.5 TeV per nucleon. The CMS heavy ion group has developed a plethora of physics analyses addressing many important aspects of heavy-ion physics in preparation for a competitive and successful program.
Particle Production at RHIC
Aneta Iordanova,for the STAR collaboration
Physics , 2008,
Abstract: Identified hadron spectra and ratios provide a unique tool to study the bulk particle production in heavy-ion collisions and explore the QCD phase diagram. In these proceedings we present the analysis of charged pion, kaon and (anti)proton distributions from sqrt(s_NN)=200 and 62.4 GeV Cu+Cu collisions, collected by the STAR experiment. New measurements extend the systematic studies of bulk properties, addressing the energy and the system size dependence of freeze-out parameters at RHIC. The available centrality selection of Cu+Cu data bridge the gap between the smaller d+Au and larger Au+Au systems, allowing a detailed study of baryon relative to meson and strangeness production as function of system size.
Fast synthesis of the polycrystalline materials on the base of Zn 3 V2 MoO11 and Zn 2.5 VMoO8
Maya Markova-Velichkova,Reni Iordanova
Processing and Application of Ceramics , 2009,
Abstract: In our study we applied two different techniques for the preparation of Zn3V2MoO11 and Zn2.5VMoO8 polycrystalline materials - melt quenching method (up-bottom) and mechanochemical synthesis (bottom- up). These compounds belong to the family of materials with general formula M2.5VMoO8 (M=Zn, Mg, Mn, Co). They are potential candidates as catalysts in processes of selective oxidation of hydrocarbons. Until now, these two compounds were obtained by conventional solid state reaction. Using infrared spectroscopy and X-ray diffraction we proved that the melt quenching technique is a quite appropriate method for the synthesis of bulk Zn3V2-MoO11 phase. Mechanochemical activation is more appropriated for the preparation of nonosized Zn2.5VMoO8 powder. It was established that the melt quenching technique and mechanochemical activation are faster in comparison with conventional ceramic methods for the given synthesis.
System size dependence of freeze-out properties at RHIC
A. Iordanova,O. Barannikova,R. S. Hollis,for the STAR Collaboration
Physics , 2007, DOI: 10.1142/S0218301307007027
Abstract: The STAR experiment at RHIC has measured identified pi(+/-), K(+/-) and p(pbar) spectra and ratios from sqrt(s_NN) = 62.4 and 200 GeV Cu+Cu collisions. The new Cu+Cu results are studied with hydro-motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of this system. Along with measurements from Au+Au and p+p collisions, the obtained freeze-out parameters are discussed as a function of collision energy, system size, centrality and inferred energy density. This multi-dimensional systematic study reveals the importance of the collision geometry and furthers our understanding of the QCD phases.
Participant-like scaling behavior of multiplicity and charged hadron spectra in relativistic heavy ion collisions
R. S. Hollis,A. Iordanova,D. J. Hofman
Physics , 2011,
Abstract: We present a method for parameterizing the charged particle multiplicity and charged hadron spectra from heavy ion data with a simple, Glauber-inspired, model. The basis of this model is derived from the observation of leading hadrons in $pp$ collisions and the number of interactions calculated by a Glauber model. Singly hit and multiply hit nucleons are treated as different sub-components of the same collision. With this scheme, for fixed sub-component yields, we find that the multiplicity and charged hadron spectra can be reproduced, without the need for large suppression at high-p$_T$. Suppression is still observed, in the low- to intermediate-p$_T$ region, but this is confined to suppression of surface emission partons. At high-p$_T$, the suppression disappears entirely, leaving only a possible Cronin-type enhancement. The suppression observed in 200GeV collisions is found to be the same for 62.4GeV data.
Engineered Mitochondrial Ferritin as a Magnetic Resonance Imaging Reporter in Mouse Olfactory Epithelium
Bistra Iordanova, T. Kevin Hitchens, Clinton S. Robison, Eric T. Ahrens
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072720
Abstract: We report the design of a MRI reporter gene with applications to non-invasive molecular imaging. We modified mitochondrial ferritin to localize to the cell cytoplasm. We confirmed the efficient cellular processing of this engineered protein and demonstrated high iron loading in mammalian cells. The reporter’s intracellular localization appears as distinct clusters that deliver robust MRI contrast. We used this new reporter to image in vivo and ex vivo the gene expression in native olfactory sensory neurons in the mouse epithelium. This robust MRI reporter can facilitate the study of the molecular mechanisms of olfaction and to monitor intranasal gene therapy delivery, as well as a wide range of cell tracking and gene expression studies in living subjects.
A Proposal for the Muon Piston Calorimeter Extension (MPC-EX) to the PHENIX Experiment at RHIC
S. Campbell,R. Hollis,A. Iordanova,E. Kistenev,X. Jiang,Y. Kwon,J. Lajoie,J. Perry,R. Seto,A. Sukhanov,A. Timilsina,for the PHENIX Collaboration
Physics , 2013,
Abstract: The PHENIX MPC-EX detector is a Si-W preshower extension to the existing PHENIX Muon Piston Calorimeters (MPC). The MPC-EX will consist of eight layers of alternating W absorber and Si mini-pad sensors and will be installed in time for RHIC Run-15. Covering a large pseudorapidity range, 3.1 < eta < 3.8, the MPC-EX and MPC access high-x partons in the projectile nucleon (and low-x partons in the target nucleon) in p+A and transversely polarized proton-proton collisions at 200 GeV. With the addition of the MPC-EX, the neutral pion reconstruction range extends to energies > 80 GeV, a factor of four improvement over current capabilities. Not only will the MPC-EX strengthen PHENIX's existing forward neutral pion and jet measurements, it also provides the necessary neutral pion rejection to make a prompt photon measurement feasible in both p+A and p+p collisions. With this neutral pion rejection, prompt (direct + fragmentation) photon yields at high p_T, p_T > 3 GeV, can be statistically extracted using a double ratio method. In p+A collisions direct photons at forward rapidities are optimally sensitive to the gluon distribution because, unlike pions, direct photons are only produced by processes that are directly sensitive to the gluon distribution at leading order. A measurement of the forward prompt photon R_pA will cleanly access and greatly expand our understanding of the gluon nuclear parton distribution functions and provide important information about the initial state in heavy ion collisions. In transversely polarized p+p collisions the MPC-EX will make possible a measurement of the prompt photon single spin asymmetry A_N, and will help elucidate the correlation of valence partons in the proton with the proton spin.
The Importance of Correlations and Fluctuations on the Initial Source Eccentricity in High-Energy Nucleus-Nucleus Collisions
B. Alver,B. B. Back,M. D. Baker,M. Ballintijn,D. S. Barton,R. R. Betts,R. Bindel,W. Busza,V. Chetluru,E. García,T. Gburek,J. Hamblen,U. Heinz,D. J. Hofman,R. S. Hollis,A. Iordanova,W. Li,C. Loizides,S. Manly,A. C. Mignerey,R. Nouicer,A. Olszewski,C. Reed,C. Roland,G. Roland,J. Sagerer,P. Steinberg,G. S. F. Stephans,M. B. Tonjes,A. Trzupek,G. J. van Nieuwenhuizen,S. S. Vaurynovich,R. Verdier,G. I. Veres,P. Walters,E. Wenger,B. Wosiek,K. Wo?niak,B. Wys\louch
Physics , 2007, DOI: 10.1103/PhysRevC.77.014906
Abstract: In this paper, we investigate various ways of defining the initial source eccentricity using the Monte Carlo Glauber (MCG) approach. In particular, we examine the participant eccentricity, which quantifies the eccentricity of the initial source shape by the major axes of the ellipse formed by the interaction points of the participating nucleons. We show that reasonable variation of the density parameters in the Glauber calculation, as well as variations in how matter production is modeled, do not significantly modify the already established behavior of the participant eccentricity as a function of collision centrality. Focusing on event-by-event fluctuations and correlations of the distributions of participating nucleons we demonstrate that, depending on the achieved event-plane resolution, fluctuations in the elliptic flow magnitude $v_2$ lead to most measurements being sensitive to the root-mean-square, rather than the mean of the $v_2$ distribution. Neglecting correlations among participants, we derive analytical expressions for the participant eccentricity cumulants as a function of the number of participating nucleons, $\Npart$,keeping non-negligible contributions up to $\ordof{1/\Npart^3}$. We find that the derived expressions yield the same results as obtained from mixed-event MCG calculations which remove the correlations stemming from the nuclear collision process. Most importantly, we conclude from the comparison with MCG calculations that the fourth order participant eccentricity cumulant does not approach the spatial anisotropy obtained assuming a smooth nuclear matter distribution. In particular, for the Cu+Cu system, these quantities deviate from each other by almost a factor of two over a wide range in centrality.
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