Prohlížení Acta Polytechnica dle názvu

Zobrazují se záznamy 707-726 z 880

    • Simulation of laser drilling of Inconel X-750 and Ti-5Al-2.5Sn sheets using COMSOL 

      Autor: Hanon, Muammel M.; Taha, Ziad A.; Zsidai, László
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2021)
      This study aims to investigate the simulation of laser drilling processes on Inconel X-750 and Ti-5Al-2.5Sn sheets. To this end, COMSOL Multiphysics 5.2 software was employed to carry out the virtual experiments. A JK 701 ...

    • SIMULATION OF LOW-GRADE COAL COMBUSTION IN REAL CHAMBERS OF ENERGY OBJECTS 

      Autor: Askarova , Aliya; Bolegenova , Saltanat; Bolegenova , Symbat; Beketayeva , Meruyert; Maximov , Valeriy; Nugymanova , Aizhan; Šafařík , Pavel
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)
      The aim of the work is to create new computer technologies for 3D modelling of heat and mass transfer processes in high-temperature physicochemically reacting environments that will allow to determine the aerodynamics of ...

    • SIMULATION OF RADIATIVE HEAT FLUX DISTRIBUTION UNDER AN INFRARED HEAT EMITTER 

      Autor: Loufek , Jan; Královcová , Jiřina
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2015)
      The article deals with a heat radiation model used for heat flux calculation of an infrared heater. In general, we consider a system consisting of a set of objects, whereas a single object could stand for a heater, a ...

    • SIMULATION OF SURFACE HEATING FOR ARBITRARY SHAPE’S MOVING BODIES/SOURCES BY USING R-FUNCTIONS 

      Autor: Plankovskyy , Sergiy; Shypul , Olga; Tsegelnyk , Yevgen; Tryfonov , Oleg; Golovin , Ivan
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2016)
      The purpose of this article is to propose an efficient algorithm for determining the place of an action of a heat source with a given motion law for a body of an arbitrary shape using methods of analytical geometry. The ...

    • SIMULTANEOUS FITS IN ISIS ON THE EXAMPLE OF GRO J1008–57 

      Autor: Kühnel , M.; Müller , S.; Kreykenbohm , I. Kreykenbohm; Schwarm , F.-W.; Grossberger , C.; Dauser , B. T.; Nowak , M. A.; Pottschmidt , K.; Ferrigno , C.; Rothschild , R. E.; Klochkov , D.; Staubert , R.; Wilms , J.
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2015)
      Parallel computing and steadily increasing computation speed have led to a new tool for analyzing multiple datasets and datatypes: fitting several datasets simultaneously.  With this technique, physically connected parameters ...

    • SIZE ANALYSIS OF SOLID PARTICLES AT THE EXPERIMENTAL DEVICE FOR MULTI-STAGE BIOMASS COMBUSTION 

      Autor: Hrnčířová , Michaela; Špiláček , Michal; Pospíšil , Jiří
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      This paper presents the results of an analysis of ash content particles produced in biomass combustion at an experimental device. The main parts of the device are: the water heater, the gasifying chamber, the air preheater, ...

    • SOLAR ABSORBER WITH A STRUCTURED SURFACE – A WAY TO INCREASE EFFICIENCY 

      Autor: Mrňa , Libor; Řiháček , Jan; Šarbort , Martin; Horník , Petr
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)
      The basic idea of a solar absorber’s thermal gain increase is the keyhole effect utilization during which the radiation is absorbed by multiple reflections on cavity walls. The lattice of pyramidal or conical cavities on ...

    • SPECIFIC EMISSIONS FROM BIOMASS COMBUSTION 

      Autor: Skopec , Pavel; Hrdlička , Jan; Kaválek , Michal
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      This paper deals with determining the specific emissions from the combustion of two kinds of biomass fuels in a small-scale boiler. The tested fuels were pellets made of wood and pellets made of rape plant straw. In order ...

    • SPECIFIC FEATURES OF THE OXYFUEL COMBUSTION CONDITIONS IN A BUBBLING FLUIDIZED BED 

      Autor: Skopec, Pavel; Hrdlička, Jan
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2016)
      Oxyfuel combustion is a promising approach for capturing CO2 from power plants. This technology produces a flue gas with a high concentration of CO2. Our paper presents a verification of the oxyfuel combustion conditions ...

    • Spectral Analysis of Schrödinger Operators with Unusual Semiclassical Behavior 

      Autor: Exner , Pavel; Barseghyan , Diana
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)
      In this paper we discuss several examples of Schrödinger operators describing a particle confined to a region with thin cusp-shaped ‘channels’, given either by a potential or by a Dirichlet boundary; we focus on cases when ...

    • Spectral Singularities do not Correspond to Bound States in the Continuum 

      Autor: Mostafazadeh , Ali
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)
      We show that, contrary to a claim made in arXiv:1011.0645, the von Neumann-Winger bound states that lie in the continuum of the scattering states are fundamentally different from Naimark’s spectral singularities.

    • STABILITY OF BOSE-EINSTEIN CONDENSATES IN A PT-SYMMETRIC DOUBLE-δ POTENTIAL CLOSE TO BRANCH POINTS 

      Autor: Löhle, Andreas; Cartarius, Holger; Haag, Daniel; Dast, Dennis; Main, Jörg; Wunner, Günter Wunner
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      A Bose-Einstein condensate trapped in a double-well potential, where atoms are incoupled to one side and extracted from the other, can in the mean-field limit be described by the nonlinear Gross-Pitaevskii equation (GPE) ...

    • STABILITY OF SYNTHESIZED SILVER NANOPARTICLES IN CITRATE AND MIXED GELATIN/CITRATE SOLUTION 

      Autor: Kavuličová , Jana; Mražíková , Anna; Velgosová , Oksana; Ivánová , Dana; Kubovčíková , Martina
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2018)
      The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPs)synthesized by a chemical reduction ...

    • STABILIZATION TIME AS AN IMPORTANT PARAMETER AFTER DENSIFICATION OF SOLID BIOFUELS 

      Autor: Križan , Peter; Matúš , Miloš; Beniak , Juraj; Kováčová , Monika
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      The aim of this paper is to present some preliminary results from experimental research on the densification process of solid high-grade biofuels. The findings presented in this paper contribute to an investigation of the ...

    • STATIC TESTS OF UNCONVENTIONAL PROPULSION UNITS FOR ULTRALIGHT AIRPLANES 

      Autor: Helmich , Martin
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      This paper presents static tests of a new unconventional propulsion unit for small aviation airplanes. Our laboratory stand – a fan drive demonstrator – enables us to compare various design options. We performed experiments ...

    • Stationary and Dynamical Solutions of the Gross-Pitaevskii Equation for a Bose-Einstein Condensate in a PT symmetric Double Well 

      Autor: Cartarius , Holger; Dast , Dennis; Haag , Daniel; Wunner , Günter; Eichler , Rüdiger; Main , Jorg
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)
      We investigate the Gross-Pitaevskii equation for a Bose-Einstein condensate in a PT symmetric double-well potential by means of the time-dependent variational principle and numerically exact solutions. A one-dimensional ...

    • Stationary solutions of incompressible viscous flow in a wall-driven semi-circular cavity 

      Autor: Erturk, Ercan
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2021)
      Stationary numerical solutions of incompressible viscous flow inside a wall-driven semicircular cavity are presented. After a conformal mapping of the geometry, using a body-fitted mesh, the Navier-Stokes equations are ...

    • STATISTICAL PROPERTIES OF GRB AFTERGLOW PARAMETERS AS EVIDENCE OF COSMOLOGICAL EVOLUTION OF THEIR HOST GALAXIES 

      Autor: Beskin , Gregory; Oganesyan , Gor; Greco , Giuseppe; Karpov , Sergey
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2014)
      The results of a study of 43 peaked R-band light curves of optical counterparts of gamma-ray bursts with known redshifts are presented. The parameters of optical transients were calculated in the comoving frame, and then ...

    • Stator current signal crossing for fault diagnosis of self-excited induction generators 

      Autor: Belynda, Fares; Abdelli, Radia; Bouzida, Ahcene
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)
      This paper presents a novel method for modelling and diagnosis of electrical and mechanical faults in fixed-Speed Self-Excited Induction Generators (SEIGs) operating in autonomous mode in a small-scale wind energy system. ...

    • Status and Perspectives of the Mini-MegaTORTORA Wide-field Monitoring System with High Temporal Resolution 

      Autor: Karpov , Sergey; Beskin , Grigory; Bondar , Sergey; Perkov , Alexey; Ivanov , Evgeny; Guarnieri , Adriano; Bartolini , Corrado; Greco , Giuseppe; Shearer , Andy; Sasyuk , Vyacheslav
      (České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)
      Here we briefly summarize our long-term experience of constructing and operating wide-field monitoring cameras with sub-second temporal resolution to look for optical components of GRBs, fast-moving satellites and meteors. ...