National Repository of Grey Literature 13 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Application of algebraic classification and related methods to problems of higher-dimensional relativity
Tintěra, Tomáš ; Pravda, Vojtěch (advisor) ; Málek, Tomáš (referee) ; Švarc, Robert (referee)
In four-dimensional general relativity, the algebraic classification has played an important role in study of spacetimes, including, but not limited to the search for new solutions to the Einstein equation. In the present work, we study its recent generalization to higher dimensions, based on categorizing Weyl tensor frame components by their transformation properties under boosts. Specifically, we concentrate on its connection to two well-established concepts. Kaluza-Klein reduction can be regarded as a relation between spacetimes of different dimen- sionality. As such, it is desirable to be understood in the context of the higher-dimensional algebraic classification. We study algebraic properties of Weyl tensors related by Kaluza-Klein reduction. Specifically, we concentrate on reduction of vacuum spacetimes by one spatial Killing direction and investigate Weyl-alignment multiplicities of two related null directions that are parallel in a gauge where they are perpendicular to the Maxwell potential. We express rela- tions of various quantities of the related spacetimes, such as Riemann and Weyl tensors, optical matrices and non-geodeticities, revealing some interesting consequences regarding reduction of Kundt spacetimes and of spacetimes admitting a geodetic null direction. Based on this, we...
General Relativity in Higher Dimensions
Málek, Tomáš ; Pravda, Vojtěch (advisor) ; Raeymaekers, Joris (referee) ; Podolský, Jiří (referee)
vii Title: General relativity in higher dimensions Author: Tomáš Málek Institute: Institute of Theoretical Physics Supervisor: Mgr. Vojtěch Pravda, PhD., Institute of Mathematics of the Academy of Sciences of the Czech Republic Abstract: In the first part of this thesis, Kerr-Schild metrics and extended Kerr- Schild metrics are analyzed in the context of higher dimensional general relativ- ity. Employing the higher dimensional generalizations of the Newman-Penrose formalism and the algebraic classification of spacetimes based on the existence and multiplicity of Weyl aligned null directions, we establish various geometri- cal properties of the Kerr-Schild congruences, determine compatible Weyl types and in the expanding case discuss the presence of curvature singularities. We also present known exact solutions admitting these Kerr-Schild forms and con- struct some new ones using the Brinkmann warp product. In the second part, the influence of quantum corrections consisting of quadratic curvature invariants on the Einstein-Hilbert action is considered and exact vacuum solutions of these quadratic gravities are studied in arbitrary dimension. We investigate classes of Einstein spacetimes and spacetimes with a null radiation term in the Ricci tensor satisfying the vacuum field equations of quadratic gravity...
Spirituality and treatment of addictions
Málek, Tomáš ; Junková, Vendula (referee) ; Loneková, Katarína (referee)
Thesis is focused on the relationship between spirituality and treatment of addictions. Short outline is made about main problems involved in treatment centers providing care for addicted people. Problems are seen in paradigma of biological-psychological and social dimensions of human being. Thesis considers Logotherapy (V. Frankl), Focusing (E. Gendlin), Process work (A. Mindell) a Psychedelic therapy (S. Grof) and their attitude toward spiritual dimension of man and specific approach in this dimension and treatment of addictions. Research find out implementation of spiritual dimension into work and facilities providing care for addicted people. Finding says spirituality is integrated only in small number of facilities. All researched facilities are open toward spiritual topics. Key words: Spirituality - Therapy - Addictions - Logotherapy - Focusing - Process-oriented work - Psychedelic Therapy - Holotropic Breathing - Therapeutic community - day care - Aftercare
Determination of the amount of the amorphous phase using x-ray diffraction
Málek, Tomáš ; Daniš, Stanislav (advisor) ; Kužel, Radomír (referee)
Using quantitative analysis based on x-ray diffraction entails complication in the amorphous phase contribution to signal background which may affect results. Often it is impossible to ignore this contribution and thus is appropriately to use some method for separation of the amorphous phase contribution from signal eventually also determine amount of amorphous phase in the sample. Although x-ray diffraction is used for crystalline samples is almost inevitable keep sample clear from amorphous phase which is in all polycrystalline sample in some amount. In this thesis we will effort to determine method or combination of methods which is possible to use for determination of the amount of the amorphous phase that we can use for cleaning results of quantitative analysis from the amorphous phase contribution.
Characteristic of vehicle’s differential
Málek, Tomáš ; Kupčák, Radim (referee) ; Ohnišťová, Petra (advisor)
This bachelor thesis deals with characteristic of various types of differentials in motor vehicles. It represents their functions, various designs and comparisons. It also includes all wheel drive chapter. The main part is the technology of gear production which involves 3D print. There is model of differential, which was created in Solid Works 2016 specifically for this thesis. It is also printed on 3D printer and the printout is compared with a real model of differential.
On type II universal spacetimes
Hervik, S. ; Málek, Tomáš ; Pravda, Vojtěch ; Pravdová, Alena
We briefly summarize our recent results on type II universal metrics of the Lorentzian signature. These metrics simultaneously solve all vacuum field equations of theories of gravity with the Lagrangian being a polynomial curvature invariant constructed from the metric, the Riemann tensor and its covariant derivatives of arbitrary order. It turns out that the results critically depend on the dimensionality of the spacetime. While we discuss examples of type II universal metrics for all composite number dimensions, we have no examples for prime number dimensions. Furthermore, we have proven the non-existence of type II universal spacetimes in five dimensions.
Determination of the amount of the amorphous phase using x-ray diffraction
Málek, Tomáš ; Daniš, Stanislav (advisor) ; Kužel, Radomír (referee)
Using quantitative analysis based on x-ray diffraction entails complication in the amorphous phase contribution to signal background which may affect results. Often it is impossible to ignore this contribution and thus is appropriately to use some method for separation of the amorphous phase contribution from signal eventually also determine amount of amorphous phase in the sample. Although x-ray diffraction is used for crystalline samples is almost inevitable keep sample clear from amorphous phase which is in all polycrystalline sample in some amount. In this thesis we will effort to determine method or combination of methods which is possible to use for determination of the amount of the amorphous phase that we can use for cleaning results of quantitative analysis from the amorphous phase contribution.
General Relativity in Higher Dimensions
Málek, Tomáš ; Pravda, Vojtěch (advisor) ; Raeymaekers, Joris (referee) ; Podolský, Jiří (referee)
vii Title: General relativity in higher dimensions Author: Tomáš Málek Institute: Institute of Theoretical Physics Supervisor: Mgr. Vojtěch Pravda, PhD., Institute of Mathematics of the Academy of Sciences of the Czech Republic Abstract: In the first part of this thesis, Kerr-Schild metrics and extended Kerr- Schild metrics are analyzed in the context of higher dimensional general relativ- ity. Employing the higher dimensional generalizations of the Newman-Penrose formalism and the algebraic classification of spacetimes based on the existence and multiplicity of Weyl aligned null directions, we establish various geometri- cal properties of the Kerr-Schild congruences, determine compatible Weyl types and in the expanding case discuss the presence of curvature singularities. We also present known exact solutions admitting these Kerr-Schild forms and con- struct some new ones using the Brinkmann warp product. In the second part, the influence of quantum corrections consisting of quadratic curvature invariants on the Einstein-Hilbert action is considered and exact vacuum solutions of these quadratic gravities are studied in arbitrary dimension. We investigate classes of Einstein spacetimes and spacetimes with a null radiation term in the Ricci tensor satisfying the vacuum field equations of quadratic gravity...
Spirituality and treatment of addictions
Málek, Tomáš ; Junková, Vendula (referee) ; Loneková, Katarína (referee)
Thesis is focused on the relationship between spirituality and treatment of addictions. Short outline is made about main problems involved in treatment centers providing care for addicted people. Problems are seen in paradigma of biological-psychological and social dimensions of human being. Thesis considers Logotherapy (V. Frankl), Focusing (E. Gendlin), Process work (A. Mindell) a Psychedelic therapy (S. Grof) and their attitude toward spiritual dimension of man and specific approach in this dimension and treatment of addictions. Research find out implementation of spiritual dimension into work and facilities providing care for addicted people. Finding says spirituality is integrated only in small number of facilities. All researched facilities are open toward spiritual topics. Key words: Spirituality - Therapy - Addictions - Logotherapy - Focusing - Process-oriented work - Psychedelic Therapy - Holotropic Breathing - Therapeutic community - day care - Aftercare

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