THE CC1 PROJECT – SYSTEM FOR PRIVATE CLOUD COMPUTING

The main features of the Cloud Computing system developed at IFJ PAN are described. The project is financed from the structural resources provided by the European Commission and the Polish Ministry of Science and Higher Education (Innovative Economy, National Cohesion Strategy). The system delivers a solution for carrying out computer calculations on a Private Cloud computing infrastructure. It consists of an intuitive Web based user interface, a module for the users and resources administration and the standard EC2 interface implementation. Thanks to the distributed character of the system it allows for the integration of a geographically distant federation of computer clusters within a uniform user environment

Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2 x 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2 x 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of $\approx$ 0.170 ns for 15 cm axial field-of-view (AFOV) and $\approx$ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.Comment: To be published in Phys. Med. Biol. (26 pages, 17 figures

Resonance production in p+p, p+A and A+A collisions measured with HADES

The knowledge of baryonic resonance properties and production cross sections plays an important role for the extraction and understanding of medium modifications of mesons in hot and/or dense nuclear matter. We present and discuss systematics on dielectron and strangeness production obtained with HADES on p+p, p+A and A+A collisions in the few GeV energy regime with respect to these resonances

New data on the differential cross section of the dp-elastic scattering at 2.5 GeV obtained with HADES detector

New results on the differential cross section in deuteron-proton elastic scattering are obtained at the deuteron kinetic energy of 2.5 GeV with the HADES spectrometer. The angular range of 69°-125° in the center of mass system is covered. The obtained results are compared with the relativistic multiple scattering model calculation using the CD-Bonn deuteron wave function. The data at fixed scattering angles in the c.m. are in qualitative agreement with the constituent counting rules prediction

Finite element analysis of dental restorations under thermal loading

Termiczno-mechaniczna analiza MES umożliwia określenie poziomu naprężeń spowodowanych obciążeniami termicznymi w zębach zdrowych oraz poddanych leczeniu. W artykule dokonano sprzężonej analizy termiczno-mechanicznej symulującej rozkład naprężeń w zębach, spowodowanych przyjmowaniem zimnych i gorących posiłków. Obciążenia termiczne przyłożone były do powierzchni korony zęba i spowodowały powstawanie naprężeń szczególnie w rejonie powierzchni rozdziału ząb-wypełnienie. Obszary o podwyższonej wartości naprężeń zostały zidentyfikowane i określony zostało ich kliniczne znaczenie z uwzględnieniem uszkodzenia wypełnienia i powstania mikroprzecieku.Thermo-mechanical finite element analyses in 3-D models are described for determination of the stress levels due to thermal loads in a healthy and restored tooth. Transient thermal analysis simulating the ingestion of cold and hot drinks was performed to determine the temperature distribution in the models of the teeth, followed by linear elastic stress analyses. The thermal loads were applied on the crown part surfaces. Maximum stresses were verified in resin restoration under thermal loads. Thermal loading showed higher tensile stress values occurred especially at the restoration–dentin interface. Regions of high tensile stress were detected and their possible clinical significance with respect to restoration damage and microleakage were discussed

Analysis of stress level in hard dental tissues using finite element method

W pracy przedstawiono możliwość wykorzystania metody elementów skończonych do analizy stanu naprężenia w twardych tkankach zębów, odbudowanych wypełnieniem stomatologicznym klasy I, poddanych działaniu obciążenia mechanicznego. Badania prowadzono na modelu geometrycznym odwzorowującym rzeczywistą geometrię zęba przedtrzonowego, uzyskaną z wykorzystaniem techniki mikrotomografie rentgenowskiej oraz oprogramowania CAD. Analizie poddano rozkłady naprężenia zredukowanego wyznaczonego wg hipotezy Hubera-Misesa-Hencky'ego (H-M-H) w twardych tkankach zęba, jak również podjęto próbę oceny stopnia wytężenia warstwy adhezyjnej na granicy wypełnienie kompozytowe-tkanka biologiczna. Zastosowanie symulacji numerycznych (Abaqus) umożliwia dokonanie realnej oceny stopnia wytężenia tkanek zęba, co pozwala na ocenę ryzyka niepowodzenia leczenia stomatologicznego i pomaga w opracowaniu racjonalnych metod zapobiegania uszkodzeniom zębów na skutek działania obciążeń mechanicznych.This paper presents the possibility of applying the finite element method for the analysis of stress level in hard dental tissues, restored with class I dental filling and exposed to mechanical load. The studies were made on a geometrical model imitating the real geometry of a premolar tooth obtained using the X-ray microtomography technique and CAD software. The distributions of reduced stress defined in accordance with the Huber-Mises-Hencky (H-M-H) hypothesis in hard dental tissues were analysed, and assessment of the degree of strength of the adhesive layer at the border of the composite filling and biological tissue was attempted. The application of numerical simulations (Abaqus) enables real assessment of the tooth tissue strength, which allows assessing the risk of unsuccessful dental treatment, and helps to prepare rational methods of preventing tooth damage resulting from mechanical load

Dynamic performance analysis of electric controlled pm-excited synchronous machine for electric vehicles

This paper presents a machine topology, by which the field weakening is enabled with a simple stator fixed DC-coil used in modern drives for electro-mobiles. To control the field in the range from zero up to maximal values, which offers wide speed variations, this coil has to be fed by a simple DC-chopper. In this paper present mathematical models describing the machine with additional winding for permanent magnets flux control