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Use of rock mass classifications for rock fall susceptibility analysis in the conditions of the Bohemian Massif
Racek, Jonáš ; Blahůt, Jan (advisor) ; Petružálek, Matěj (referee)
This thesis deals with rock mass classification systems. The aim of the thesis is to describe and compare selected systems and evaluate their possible use in the Bohemian Massif for assessing the stability of the rock slopes in relation to their susceptibility to rock falls. A part of the thesis deals with rock falls and basic mechanical characteristics of a rock mass. Further on, the thesis describes selected classification systems, specifically RQD, RSR, RMR, SMR, Q-system, Q-slope, GSI, RSR-PR and QTS. These systems were then used for evaluation of stability of rock slopes on three geologically different locations of the Bohemian Massif. information from measurement in field and processing of measured data was used for assessing for possible use of each classification system.
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Giant landslides on volcanic islands on the example of the Hawaii archipelago
Kalina, Jan ; Blahůt, Jan (advisor) ; Novotný, Jan (referee)
The bachelor thesis deals with the largest slope movements on Earth - landslides on volcanic islands, with focus on the Hawaii archipelago. It summarizes the knowledge of their classification and evaluates their possible causes with respect to the specifics of the volcanic islands. After introduction, it focuses on a specific area of interest that is the Hawaiian Islands and describes landslides that have occurred during the geological history of these islands. A database of all known the 19 largest landslides is also made, where their location, classification, age and morphometric data such as volume, perimeter, area, length, width and height are recorded. This database will become a part of the database of the giant landslides on volcanic islands on Earth, which is being created at the Institute of Rock Structure and Mechanics of the Czech Academy of Sciences. The database is further explored in the statistical chapter, where the mathematical procedure for calculating the relative runout of the slope movement and the potential energy of the landslide is explained. Additionally, the box plots comparing the selected morphometric parameters are created. For illustrative nature, a map of the giant landslides is also included.
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Study of Electric Properties of Electrochemical Transistors with Ionic Liquids
Blahut, Jan ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor’s thesis is focused on preparation of organic electrochemical transistors and following characterization of electric properties of these systems. Two types of electrode systems were used for preparation – glass substrates with steamed oxide of indium and tin and polylactic acid substrates with admixture of carbon soot. Three methods were tested for creation of PEDOT channel. Materiál printing, spin-coating and manual application. The measurement shows, that voltage applied to gate electrode has no effect switching of transistor. Size and polarity of current between source and drain electrodes has a major influence here.
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Transition metal ion complexes as potential 19F MRI contrast agents
Dobrovolná, Tereza ; Kotek, Jan (advisor) ; Blahut, Jan (referee)
Fluorinated coordination compounds having short nuclear spin relaxation times due to the presence of paramagnetic metal ions close to 19 F nuclei are suitable/potential contrast agents in 19 F MRI. This thesis deals with the preparation of a ligand based on 1,4,7-triazacyclononane (TACN) with pendant arms containing fluorine atoms. The coordination properties to transition metal ions were studied and prepared complexes were characterised. Measured values of longitudinal relaxation times of 19 F NMR signal indicate that the chosen concept is promising for further use in 19 F MRI, especially for the Co(II) complex. Keywords: 19 F MRI, contrast agent, trifluoroethyl phosphinic acid, TACN, paramagnetic ion, relaxation time, effective magnetic moment
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Fluorinated macrocycles for 19F MRI
Šmelko, Andrej ; Hermann, Petr (advisor) ; Blahut, Jan (referee)
19 F MRI contrast agents are relatively new, developing field of medical and chemical sciences. In this Theses, based on previous results in this area, new type of Ni2+ complex with possible 19 F MRI applications was synthesized and characterized by relaxometric measurements.
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Experimental investigation of shear strength of soils from the Dobkovičky landslide area and development of correlations between soil strength and their physical properties
Roháč, Jakub ; Mašín, David (advisor) ; Blahůt, Jan (referee) ; Hrubešová, Eva (referee)
Critical and residual states are key soil conditions relevant to slope stability. Evaluating the available shear strength in relation to these conditions is crucial for reliable stability analyses. The best way to determine the strength parameters is through properly selected laboratory tests of soil mechanics. However, in specific cases, these parameters can be estimated based on other material properties of soils. The work clarifies the applicability of various correlation equations from the literature and proposes new relationships, created from laboratory- determined results of strength and index parameters of soils from the Bohemian Central Mountains. It shows how different equations or different material properties of soils can predict the required value of strength. The work also describes how the residual strength of soils and its estimation can be affected. This is mainly caused by the clay fraction proportion and by the shear rate used in its laboratory determination. The results are applied to a specific geotechnical problem - to estimate the critical state and the residual friction angle of soils from the selected study area of the D8 motorway, which is well known thanks to the stability problems. Last but not least, various errors and misunderstandings are discussed, which are often...
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Dynamics of paramagnetic complexes observed by Nuclear Magnetic Resonance
Blahut, Jan
In this Thesis, structure and dynamics of paramagnetic complexes for medical application are studied by Nuclear Magnetic Resonance (NMR). It focuses mainly on development of contrast agents (CA) for Magnetic Resonance Imaging (MRI) which is one of the most effective radiodiagnostic method nowadays. Most of the MRI CAs contains paramagnetic complexes of d- and f-metal ions. The presence of unpaired electron in proximity of NMR active nuclei has two main effects: paramagnetically induced shift and paramagnetically induced relaxa- tion. Both processes can dramatically change the NMR spectrum and often make it unobservable at all. Nevertheless, in many cases, acquisition of such spectra is possible and sometimes even less time-consuming than observation of diamag- netic molecules. Enhanced T1 relaxation allows faster pulse sequence repetition and increased chemical shift dispersion may lead to resolution of originally over- lapped signals. Moreover, the analysis of paramagnetic effects can provide useful information about the structure and dynamics of the studied system. Theoretical background of these effects is described in the Introduction of the Thesis. In the first part of Discussion in the Thesis, a new class of contrast agents for 19F-MRI based on nickel(II) and cobalt(II/III) ions is introduced...
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Intermolecular Hydrogen Bonds Studied by NMR Spectroscopy
Osifová, Zuzana ; Dračínský, Martin (advisor) ; Blahut, Jan (referee)
N-methylation of nucleic acids is one of the most important epigenetic mechanisms in organisms and viruses and it is observed in connection with physiological or pathological processes in human body. For example, the N- methylation of adenine to give N6 -methyladenine is associated with development of obesity or Alzheimer disease. These systems can be successfully studied by low- temperature NMR spectroscopy because the bond between a purine ring and its substituent has a significant double-bond character and, due to restricted rotation around this bond, two sets of signals are observed in low-temperature NMR spectra. This diploma thesis is focused on research of N-methylated nucleobases' rotamer equilibria and the free-energy changes associated with the hydrogen-bonded base pair formation via simple and straightforward method based on NMR spectroscopy monitoring. We proved that the rotamer equilibria of N-methylated adenine derivatives are dependent on temperature, solvent and bonding partner concentration. We also obtained the geometry of formed intermolecular complexes of N-methylated adenine derivatives with thymine and the free-energy changes associated with their formations via newly developed method based on chemical shift changes dependent on bonding partner concentration. All obtained data...
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Use of rock mass classifications for rock fall susceptibility analysis in the conditions of the Bohemian Massif
Racek, Jonáš ; Blahůt, Jan (advisor) ; Petružálek, Matěj (referee)
This thesis deals with rock mass classification systems. The aim of the thesis is to describe and compare selected systems and evaluate their possible use in the Bohemian Massif for assessing the stability of the rock slopes in relation to their susceptibility to rock falls. A part of the thesis deals with rock falls and basic mechanical characteristics of a rock mass. Further on, the thesis describes selected classification systems, specifically RQD, RSR, RMR, SMR, Q-system, Q-slope, GSI, RSR-PR and QTS. These systems were then used for evaluation of stability of rock slopes on three geologically different locations of the Bohemian Massif. information from measurement in field and processing of measured data was used for assessing for possible use of each classification system.
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