Number of found documents: 15058
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Probability density determination by means of Gibbs entropy probability density
Náprstek, Jiří; Fischer, Cyril
2019 - English
A method of random response investigation of a nonlinear dynam-ical system is discussed. In particular, the solution of the probability density of a single/multi-degree of freedom (SDOF/MDOF) system response is investigated. Multiple stable equilibrium states with possible jumps of the snap-through type among them are considered. The system is Hamiltonian with weak damping excited by a set of non-stationary Gaussian white noises. The solution, which is based on the Gibbs principle of the maximum entropy of probability, can be employed in various branches of engineering. The search for the extreme of the Gibbs entropy functional is formulated as a constrained optimization problem. The secondary constraints follow from the Fokker-Planck equation (FPE) for the system considered or from the system of ordinary di_erential equations for the stochastic moments of the response derived from the relevant FPE Keywords: Fokker-Planck equation; Gibbs entropy functional; maximum entropy; probability density principle Available at various institutes of the ASCR
Probability density determination by means of Gibbs entropy probability density

A method of random response investigation of a nonlinear dynam-ical system is discussed. In particular, the solution of the probability density of a single/multi-degree of freedom (SDOF/MDOF) system ...

Náprstek, Jiří; Fischer, Cyril
Ústav teoretické a aplikované mechaniky, 2019

Laser-generated nanoparticles to change physical properties of solids, liquids and gases
Torrisi, Alfio; Cutroneo, Mariapompea; Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, L.; Vacík, Jiří
2019 - English
Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, energy, wavelength), the irradiation conditions (focal spot, repetition rate, irradiation time) and the medium where the ablation occurs (solid target, water, solution concentration). The nanoparticles can be introduced in solids, liquids or gases to change many physical characteristics. The optical properties of polymers and solutions, the wetting ability of liquids, the electron density of laser-generated plasma, represent some examples that can be controlled by the concentration of metallic nanoparticles (Au, Ag, Ti, Cu). Some bio-medical applications will be presented and discussed. Keywords: bio-medical applications; laser; nanoparticles Available at various institutes of the ASCR
Laser-generated nanoparticles to change physical properties of solids, liquids and gases

Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, ...

Torrisi, Alfio; Cutroneo, Mariapompea; Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, L.; Vacík, Jiří
Ústav jaderné fyziky, 2019

Bolts loading in the stronly stressed rock mass
Waclawik, Petr; Sahendra, Ram; Šňupárek, Richard
2019 - Czech
The trial test of new mining method “Roadway-Pillar” was finished at the underground coal mine – ČSM Mine. The wide ranging monitoring was focused on the load bearing capacity of coal pillars and strata deformation changes induced by the roadway-pillar mining method. The results of monitoring allowed bolts loading and loading characteristics to be described. Further, an attempt is made to understand the rock bolt loading characteristics at different stages of rib dilation using numerical modelling with the available properties of rock mass and reinforcement for the studied site. Elastic and Mohr Coulomb strain-softening constitutive models are considered in FLAC3D to evaluate the performance of the rock bolts. Při zkušebním provozu modifikované metody komora-pilíř s ponechanými stabilními pilíři, nazvané chodba-pilíř byla na Dole ČSM použita svorníková výztuž stropu a boků chodeb (stěn ponechaných pilířů). Zatížení a deformace svorníků byly měřeny v rámci rozsáhlého geotechnického monitoringu [1,2]. Následně bylo použito matematického modelování v softwaru Itasca FLAC3D [3] pro lepší objasnění zatěžovacích charakteristik svorníkové výztuže. Keywords: Roadway-Pillar mining method; ČSM Mine; coal pillars Available in a digital repository NRGL
Bolts loading in the stronly stressed rock mass

The trial test of new mining method “Roadway-Pillar” was finished at the underground coal mine – ČSM Mine. The wide ranging monitoring was focused on the load bearing capacity of coal pillars and ...

Waclawik, Petr; Sahendra, Ram; Šňupárek, Richard
Ústav geoniky, 2019

The scalar-valued score functions of continuous probability distribution
Fabián, Zdeněk
2019 - English
In this report we give theoretical basis of probability theory of continuous random variables based on scalar valued score functions. We maintain consistently the following point of view: It is not the observed value, which is to be used in probabilistic and statistical considerations, but its 'treated form', the value of the scalar-valued score function of distribution of the assumed model. Actually, the opinion that an observed value of random variable should be 'treated' with respect to underlying model is one of main ideas of the inference based on likelihood in classical statistics. However, a vector nature of Fisher score functions of classical statistics does not enable a consistent use of this point of view. Instead, various inference functions are suggested and used in solutions of various statistical problems. Inference function of this report is the scalar-valued score function of distribution. Keywords: Shortcomings of probability theory; Scalar-valued score functions; Characteristics of continous random variables; Parametric estimation; Transformed distributions; Skew-symmetric distributions Available at various institutes of the ASCR
The scalar-valued score functions of continuous probability distribution

In this report we give theoretical basis of probability theory of continuous random variables based on scalar valued score functions. We maintain consistently the following point of view: It is not ...

Fabián, Zdeněk
Ústav informatiky, 2019

Characterization of organic raw and drinking water on Želivka water treatment plant
Pivokonský, Martin; Čermáková, Lenka; Pivokonská, Lenka
2019 - Czech
Natural Organic Matter (NOM) is an important part of surface water. One of the suitable methods of the identification of the composition of NOM is their fractionation based on the principle of sorption of organic matter on ion-exchange resins. Přírodní organické látky (Natural Organic Matter - NOM) jsou významnou součástí povrchových vod. Jednou z vhodných metod identifikace složení NOM je jejich frakcionace založená na principu sorpce organických látek na ionexových pryskyřicích. Keywords: drinking water; water treatment; natural organic matter; fractionation Available at various institutes of the ASCR
Characterization of organic raw and drinking water on Želivka water treatment plant

Natural Organic Matter (NOM) is an important part of surface water. One of the suitable methods of the identification of the composition of NOM is their fractionation based on the principle of ...

Pivokonský, Martin; Čermáková, Lenka; Pivokonská, Lenka
Ústav pro hydrodynamiku, 2019

Laplacian preconditioning of elliptic PDEs: Localization of the eigenvalues of the discretized operator
Gergelits, Tomáš; Mardal, K.-A.; Nielsen, B. F.; Strakoš, Z.
2019 - English
This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of fluorescent particle concentration, see [6, 1, 3, 4, 5]. More precisely, we continue to look for an optimal bleaching pattern used in FRAP (Fluorescence Recovery After Photobleaching), being the initial condition of the Fickian diffusion equation maximizing a sensitivity measure. As follows, we define an optimization problem and we show the special feature (so-called complementarity principle) of the optimal binary-valued initial conditions. Available in digital repository of the ASCR
Laplacian preconditioning of elliptic PDEs: Localization of the eigenvalues of the discretized operator

This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of ...

Gergelits, Tomáš; Mardal, K.-A.; Nielsen, B. F.; Strakoš, Z.
Ústav informatiky, 2019

SNA´19 - Seminar on numerical analysis.
Blaheta, Radim; Starý, Jiří; Sysalová, Dagmar
2019 - English
Seminar on Numerical Analysis 2017 (SNA'17) is a continuation in a series of SNA events held\nin different places in the Czech Republic and organized alternatively by Ostrava and Prague\ninstitutions. The SNA'17 is organized by the Institute of Geonics of the CAS in collaboration with\nVŠB - Technical University of Ostrava and IT4Innovations National Supercomputing Centre.\nConference location is one of the lecture rooms in New Aula of the VŠB-TU Ostrava.\nLet us note that SNA 2016 was reshaped to EMS School in Applied Mathematics (ESSAM)\ndevoted to mathematical modelling, numerical analysis and scientiffc computing. The SNA'17\nis turning back to more traditional winter event.\nIt provides opportunity for meeting and mutual information of the community working in computational\nmathematics and computer science, but an important part of SNA is devoted to the\nWinter School with tutorial lectures focused on selected important topics within the scope of\nnumerical methods and modelling.\nThis year, a part of the Winter School will be the course Parallel Linear Algebra (PLA) organized\nby the European research infrastructure PRACE, particularly by the French PRACE Advanced\nTraining Centre - Maison de la Simulation. Winter school lectures will cover the ongoing topics\nrelated to domain decomposition methods, interval computations and numerical veriffcation. The\nPLA course will provide lectures from the area of direct and iterative parallel solvers, as well as\npractical training with selected programs. Keywords: numerical analysis; mathematical modelling; computer mathematics Fulltext is available at external website.
SNA´19 - Seminar on numerical analysis.

Seminar on Numerical Analysis 2017 (SNA'17) is a continuation in a series of SNA events held\nin different places in the Czech Republic and organized alternatively by Ostrava and Prague\ninstitutions. ...

Blaheta, Radim; Starý, Jiří; Sysalová, Dagmar
Ústav geoniky, 2019

Study of lithium encapsulation in porous membrane using ion and neutron beams
Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
2019 - English
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET polymers was achieved by varying etching temperature and etching time. For determination of the pores' shape, Ion Transmission Spectroscopy technique was employed. In this method, alterations of the energy loss spectra of the transmitted ions reflect alterations in the material density of the porous foils, as well as alterations of their thickness. Simulation code, developed by the team, allowed the tomographic study of the ion track 3D geometry and its evolution during chemical etching. From the doping of porous membranes with lithium-based solution and its analysis by Thermal Neutron Depth Profiling method, the ability of porous PET membranes to encapsulate nano-sized material was also inspected. The study is important for various applications, e.g., for catalysis, active agents, biosensors, etc. Keywords: doping; etching; ion transmission spectroscopy; thermal neutron depth profiling Available at various institutes of the ASCR
Study of lithium encapsulation in porous membrane using ion and neutron beams

Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET ...

Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
Ústav jaderné fyziky, 2019

Large-area scans of paintings with high resolution
Vopálenský, Michal; Kumpová, Ivana
2019 - Czech
The aim of the measurement was to obtain the radiographs from historical paintings from the Faculty of Restoration of the University Pardubice. Due to the dimensions of the paintings (up to 90 x 110 cm) it was necessary to develop a suitable measurement procedure for successive scanning of the paintings in the TORATOM device. The resulting data are important for the planning of the restoration processes of the paintings and can help to discover otherwise invisible details, like underpaintings etc. Cílem měření bylo získat radiografická data z historických maleb, zapůjčených Fakultou restaurování Univerzity Pardubice. Vzhledem k rozměru obrazů (až 90 × 110 cm) bylo třeba vytvořit vhodnou měřicí proceduru pro postupné skenování pláten v zařízení TORATOM. Výsledná data mají význam pro plánování restaurátorských prací na obrazech a mohou pomoci odhalit jinak neviditelné detaily v malbách, např. podmalby apod. Keywords: large-area X-ray scanning; radiography of fine-art objects; restoration of paintings Available at various institutes of the ASCR
Large-area scans of paintings with high resolution

The aim of the measurement was to obtain the radiographs from historical paintings from the Faculty of Restoration of the University Pardubice. Due to the dimensions of the paintings (up to 90 x 110 ...

Vopálenský, Michal; Kumpová, Ivana
Ústav teoretické a aplikované mechaniky, 2019

Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)
Bejšovec, Václav; Cannavó, Antonino; Ceccio, Giovanni; Hnatowicz, Vladimír; Horák, Pavel; Lavrentiev, Vasyl; Macková, Anna; Tomandl, Ivo; Torrisi, Alfio; Vacík, Jiří
2019 - English
Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of specialized techniques-deposition methods for preparation/modification of the materials and analytical tools for proper understanding of their properties. A thoroughly equipped research centers become the requirement for the advance and development not only in nano-sized field. The Center of Accelerators and Nuclear Analytical Methods (CANAM) in the Nuclear Physics Institute (NPI) comprises a unique set of techniques for the synthesis or modification of nanostructured materials and systems, and their characterization using ion beam, neutron beam and microscopy imaging techniques. The methods are used for investigation of a broad range of nano-sized materials and structures based on metal oxides, nitrides, carbides, carbon-based materials (polymers, fullerenes, graphenes, etc.) and nano-laminate composites (MAX phases). These materials can be prepared at NPI using ion beam sputtering, physical vapor deposition and molecular beam epitaxy. Based on the deposition method and parameters, the samples can be tuned to possess specific properties, e.g., composition, thickness (nm-μm), surface roughness, optical and electrical properties, etc. Various nuclear analytical methods are applied for the sample characterization. RBS, RBS-channeling, PIXE, PIGE, micro-beam analyses and Transmission Spectroscopy are accomplished at the Tandetron 4130MC accelerator, and additionally the Neutron Depth Profiling (NDP) and Prompt Gamma Neutron Activation (PGNA) analyses are performed at an external neutron beam from the LVR-15 research reactor. The multimode AFM facility provides further surface related information, magnetic/electrical properties with nano-metric precision, nano-indentation, etc. Keywords: AFM; ion beam analysis; LEIF Available at various institutes of the ASCR
Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)

Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of ...

Bejšovec, Václav; Cannavó, Antonino; Ceccio, Giovanni; Hnatowicz, Vladimír; Horák, Pavel; Lavrentiev, Vasyl; Macková, Anna; Tomandl, Ivo; Torrisi, Alfio; Vacík, Jiří
Ústav jaderné fyziky, 2019

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