National Repository of Grey Literature 61 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Magnetic fabric of detrital sediments as a record of depositional processes and tectonic deformation
Hladíková, Karolína ; Martínek, Karel (advisor) ; Kadlec, Jaroslav (referee)
Fabric of sedimentary rocks can be studied by the analysis of magnetic properties, especially by magnetic anisotropy. Anisotropy of magnetic susceptibility (AMS) is a relatively easy and quick method capable to recognize the rock fabric (primary or secondary). The results of AMS are strongly dependent on magnetic properties of rock- forming minerals and their preferred orientation. The preferred orientation of grains develops by sedimentation, post-depositional diagenetic processes and eventually by tectonic deformation, which can totally overprint the primary structure in some cases. I applied AMS to study the magnetic fabric of fine-grained lacustrine sedimentary rocks from 9 different beds of Vrchlabí section, situated in the northern part of the Krkonoše Piedmont Basin. Paramagnetic minerals dominate the magnetic susceptibility, with possible small amount of ferromagnetic phases of some iron oxides. Most of the samples are laminated mudstones and they have depositional magnetic fabric carried by flat grains of clay minerals deposited horizontally from suspension. Carbonate bed shows signs of inverse magnetic fabric, which is in accordance to magnetocrystalline anisotropy of calcite. Magnetic fabric of early tectonic overprint, probably present in some black shale and siltstone beds, may be...
Structural Properties of Ultralight Concrete and its Optimal Application in Structures
Kadlec, Jaroslav ; Bílek,, Vlastimil (referee) ; Adámek, Jiří (referee) ; Terzijski, Ivailo (advisor)
This doctoral thesis deals with design of three variants of ultra lightweight concrete (ULC) and their mechanical properties. The ULC usually has the dry density of 900-1200 kg/m3 and it is possible to use it for load bearing structures. Low density of ULC is achieved by replacing heavy aggregate for lightweight aggregate. The lightweight aggregate is known under the trade name Liapor in the Czech Republic. To achieve density below 1000 kg/m3, an aeration of the paste has to be done. An exchange of heavy aggregate for lightweight aggregate results in a very fragile behavior of ULC. A great attention is paid to bond strength between concrete and reinforcing steel in the thesis. In addition to the standard test of bond strength testing by pull-out, a modified pull-out test is designed, which includes the effect of minimum reinforcement cover. The mentioned test more precisely simulates a real behaviour of the structure exposed to bending moment. The doctoral thesis tries to point out on different parameters between measured data and the applicable standard for the design of load-bearing structures.
Application of environmental magnetic techniques in Quaternary sediment study
Žatecká, Michaela ; Kadlec, Jaroslav (advisor) ; Kletetschka, Günther (referee)
5 ABSTRACT: The Bachelor Thesis presents basic principles of the environmental magnetic methods and their applications in paleoenvironmental reconstructions from Quaternary sedimentary archives. Description of mineral and rock magnetic principles follows after an introductory sketch of historical development of the environmental magnetic topic. Next part of the thesis is focused on explanation of basic principles of the environmental magnetic methods and application magnetic history of the sedimentary rocks: namely different kinds of magnetic susceptibility, anisotropy of magnetic susceptibility, remanent magnetization and hysteretic parameters of the sediments. Application of the environmental magnetic methods enables interpretation of depositional and/or post- depositional history (e.g., directions of wind or water currents transporting clastic sediments) or intensity of geochemical weathering (connected with pedogenesis) which is directly controlled by climatic conditions and their changes. Examples of application of the environmental magnetic methods in paleoenvironmental research of the deep ocean, lacustrine and eolian natural archives are described in the final part of the thesis. Key words: environmental magnetism, paleoenvironmental reconstruction, sedimentary archives, Quaternary
Reinforced concrete load bearing structure of administration building
Pražan, Jiří ; Kadlec, Jaroslav (referee) ; Girgle, František (advisor)
This bachelor thesis deals with the static solution of the loadbearing reinforced concrete structure of the administrative three-storey building. Specifically, the most loaded inner column on the ground floor and the point-supported, two way, reinforced concrete floor slab above the ground floor with a circumferential shear beam are solved. The structure is designed and checked for the ultimate limit state according to standard ČSN EN 1992-1-1 ed2, including the Z1 amendment from May 2016.
Magnetic fabric of loess and paleosols on selected localities in South Moravia
Obersteinová, Tereza ; Kadlec, Jaroslav (advisor) ; Chadima, Martin (referee)
Pleistocene loess-palaeosol sequences provide a unique proxy-record enabling detailed reconstruction of Quaternary palaeoenvironments. Environmental magnetic methods are often used to read the natural archives. The loess-palaeosol sequences exposed in two sections located in southern Moravia and a sequence from central Bohemia were studied in a frame of this Diploma Thesis. Variations of bulk magnetic susceptibility, measured in the sediments, show similar pattern as in the Chinese loess-palaeosol bodies - i.e. palaeosols reveal higher magnetic susceptibility in comparison with loess due to magnetic enhancement. The magnetic enhancement is driven by weathering during pedogenic processes related to the formation of ultra-fine magnetite particles. The magnetite content is controlling the sediment magnetic behavior. The magnetic enhancement rate indicates more intense pedogenic processes in the Moravia in comparison with Bohemia. Magnetic fabric in studied loess, represented by space orientation of anisotropy of magnetic susceptibility ellipsoid, indicates dominating glacial wind palaeocurrents across the southern Moravia blowing from W or SW, respectively. The magnetic fabric in the central Bohemian sequence has revealed a dominant control of running water and re-deposition of the loess material...
Quaternary climate and origin of eolian deposits
Obersteinová, Tereza ; Kadlec, Jaroslav (advisor) ; Martínek, Karel (referee)
The Quaternary climatic conditions have controlled the origin of eolian deposits. The loess/paleosol sequences represent a valuable natural archives used for understanding of Quaternary climate and stratigraphy. Loess deposits cover about 10% of the continent areas. We can compare a proxy-record from these sediments, often from distant areas, to get knowledge of global significance. The applied mineral magnetic analyses enable understand the paleoenvironmental signal preserved in the loess/paleosol sequences and compare it with a proxy-record obtained from deep ocean sediments

National Repository of Grey Literature : 61 records found   1 - 10nextend  jump to record:
See also: similar author names
15 KADLEC, Jan
20 KADLEC, Jaroslav
5 KADLEC, Josef
14 Kadlec, Jakub
15 Kadlec, Jan
40 Kadlec, Jiří
2 Kadlec, Jiří,
5 Kadlec, Josef
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