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Global phylogeography of the deep-sea fishes
Knězů, Tereza ; Musilová, Zuzana (advisor) ; Vukićová, Jasna (referee)
Phylogeography of deep-sea fish remains poorly explored, largely due to the extreme conditions in which these organisms live and limited technological capabilities for researching these species. The aim of this thesis is to summarize the information known about the phylogeography of deep-sea fish, identify factors influencing population distributions, and connect them on a global scale. The distribution of deep-sea fish populations is influenced by physical, topographic, and hydrographic factors. Their connectivity is driven by the migratory abilities of fish and the utilization of marine currents for their dispersion. Migration is divided into vertical and horizontal. The vast majority of deep sea fish undergo some form of migration, at least during ontogenetic development. The most common is diurnal vertical migration, where fish regularly move to shallower depths at night for feeding. Molecular methods, mainly mitochondrial DNA markers, were used for research to determine the phylogenetic tree of species. The results suggest that the topography of the seafloor is rarely a barrier to the flow of genetic information. Furthermore, the results often refute the hypothesis of isolation caused by the distance between populations. They often exhibit a relatively high rate of panmixia. When speciation...
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Morphological adaptations of spores of ectomycorrhizal fungi and their role in dispersal
Jašková, Eliška ; Janošík, Lukáš (advisor) ; Kohout, Petr (referee)
The spore morphology determines the distance and the substrate on which they land. Recent studies show that colonization of a suitable substrate is more important than long-distance dispersal itself. Spore morphology therefore likely reflects specific ecological requirements of a particular species and is shaped by the selective pressure on their effective dispersal. In the case of ectomycorrhizal fungi, on which the work is focused, an important ecological requirement is a substrate where the spore can find a suitable partner for ectomycorrhiza. The beginning of the thesis is dedicated to a brief characterization of ectomycorrhizal fungi. The main part is divided into the summary of current knowledge about the key morphological features of ectomycorrhizal fungi (fruiting body, spore size, spore shape and cell wall ornamentation) and the specific ways how their spores can be dispersed. In the end, I also mention the possibilities of further research in this area.
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Demonstration kit for fiber optic sensing system
Beránek, Karel ; Klíčník, Ondřej (referee) ; Dejdar, Petr (advisor)
This bachelor thesis focuses on the design and implementation of a~demonstration kit for a~fiber optic sensing system. The thesis includes a~theoretical analysis of optical phenomena such as polarization, dispersion, and interference, which are crucial to understanding the principles of fiber optic sensors. The designed sensing system comprises a~Mach-Zehnder interferometer, a~UP-Board development kit, an external 24-bit sound card, and a~touch display. The practical part of the thesis is focused on the construction of the enclosure using 3D printing, the integration of individual components, the design of a~custom application, and the testing of the system. The results of this work contribute to the development of knowledge in the field of fiber optic sensors and can be utilized in both academic and industrial settings.
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Preparation and characterization of epoxy potting resins modified with nanoparticles
Lednický, Jiří ; Polsterová, Helena (referee) ; Chladil, Ladislav (advisor)
This bachelor's thesis focuses on nanocomposites composed of an organic matrix in the form of epoxy resin and TiO2 filler in the anatase crystallographic structure with dimensions in the order of tens of nanometers. The work is aimed at understanding the issue of nanocomposites, summarizing the results of other studies, and especially at the production and characterization of samples with nanoparticles dispersed using a planetary mill. Furthermore, the effect of the used nanoparticles and dispersion in the planetary mill on the dielectric properties of pure epoxy resin was analyzed.
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Laboratory exercises: Dispersion in optical fibers
Bilek, Maroš ; Klíčník, Ondřej (referee) ; Münster, Petr (advisor)
This thesis first addresses the theoretical analysis of optical fiber transmissions with a focus on the dispersions occurring in optical fibers. Chromatic and polarization mode dispersion are described in detail, including their origin, impact on the transmitted signal, and measurement methods. Based on the theoretical analysis of measurement methods, two were selected for application in the practical part of the thesis, specifically for designing measuring setups for laboratory exercises. The designed setups were practically implemented on several types of fibers with different lengths. The measured values corresponded with predicted theoretical values and met the limit values of the tested fibers. The main output of this thesis consists of two laboratory exercises focused on chromatic dispersion and polarization mode dispersion. These laboratory exercise designs include a brief theoretical analysis of the respective dispersion, specify the necessary limit values and characteristics of the dispersions for evaluating correct results, and implement the measurement method setups for both dispersions. Specifically, these are the pulse delay method for chromatic dispersion and the fixed analyzer method for polarization mode dispersion.
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The Influence of the Type of Electrodes on the Biological Impedance Measurement
Prokopyeva, Elena
Electric impedance during meat storage can be affected by various processes: microbial growth, changing of ions mobility, structural changes, etc. Impedance of biological tissues is frequency dependent. The aim of current study is to determine and evaluate the impedance properties of pork meat using two types of electrodes. Measurements were performed during three days in frequency range 100 Hz ÷ 1 MHz.
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Dispersion measurements of optical transmissions.
Motúz, Rastislav ; Urban, František (referee) ; Filka, Miloslav (advisor)
This thesis firstly theoretically describes phenomena which appear in optical fiber transmission. The theoretical part of the thesis deals with linear and non-linear phenomena, and later on proceeds to dispersions with a more significant effect on the optical transmission quality. It puts polarization to the centre of the phenomenon called Polarization mode dispersion (PMD), which is the main object of our interest. It leads to a deep PMD description from the point of view of polarization states, limit values, compensation methods, and methods of measurement. The practical part of this thesis deals with a draft of PMD measurement via Fixed Analyzer method. For the purposes of this measurement, we used the optical spectral analyzer MS9740A. In order to compare measured values, the proposed idea then proceeds to the reference measurement by using a modular platform EXFO FTB--200 in combination with CD/PMD module EXFO FTB-5700. Results of measurements have been evaluated for the limit values defined by the standard. In the last chapter of this thesis, the reference measurements are compared to the Fixed Analyzer method. All the advantages and disadvantages of individual measurement methods are identified at the end of this chapter too.
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The impact of polarization mode dispersion on error-rate of optical fibre link
Dorociak, Petr ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
Master’s thesis engages in the impact of polarization mode dispersion on optical communication system. Polarization mode dispersion is mathematically described by Stoke’s and Jone’s space and ensure the theoretic causes of the rise of polarization mode dispersion that are divided on the external and internal effects. On the basis of these effects grow up a differential group delay (DGD) which makes causes that individual polarization modes have between them a time delay and limitation of maximum bit rate. Then master´s thesis analyses the influence of the polarization mode dispersion on the pulse enlargement and on the modulation signal. In this work, there are described the most applicated optical modulation formats. Polarization mode dispersion has also influence on the bit error rate of optical fibre link and closing of eye diagram too. Eye diagram is used to view the transmission characteristics and diagnoses the channel errors. Eye diagram is connected with the definitions as a bit error rate (BER) and signal-to-noise ratio (SNR) that are explained in this work too. Following the gained experiences it was designed an useful graphic interface to display the effect of the polarization mode dispersion on the transmitted signal. Realization of the graphic interface is created in the program MATLAB. In Matlab-Simulink are created six models according to the kind of modulations with characteristic AWGN (Additive White Gaussian Noise) channel. Program was tested for a typical values. In all calculations it is counted only with the losses that are caused by the polarization mode dispersion. It is not calculated with the losses that are caused by a chromatic dispersion and attenuation. At the end of this work are evaluated all types of modulation formats depending on the polarization mode dispersion, optical fibre length, price and complexity of the realization. Atteined results of my master’s thesis are compared with two foreign articles.
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The audit methology of optical networks
Štěpán, Petr ; Münster, Petr (referee) ; Reichert, Pavel (advisor)
This work deals with summary of optical system audit in the terms of all layer of the reference model ISO/OSI. Introduction of the work focuses on exploring issues of management networks control, the description of ISO/OSI model and explanation of the terms QoS and SLAs. The description of the optical fiber transmission follows after that. The characteristics of the waveguide and optical communication system components with regard to its reliable operation and management are analyzed. Some major types of optical networks are described. Following section contains a description of methods used in the audit, further the methods for measuring physical, connection and network layer of the reference model are discussed more thoroughly. The work also contains a partial analysis of the audit of the physical layer of the selected section of the Brno academic network optical line. Of all these methods for networks control the final audit report for the optical network with selected limits is compiled as a conclusion of the work.
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Modeling of surface waves
Zgabaj, Martin ; Haluza, Miloslav (referee) ; Franců, Jan (advisor)
This bachelor's thesis presents the derivation of basic characteristics of surface waves which includes the dispersion relation, the shape of the wave, the phase velocity, the group velocity and the movement of water particle. Thesis deals with both deep-water waves and shallow-water waves. Derived characteristics are examined in both cases. In the last part of thesis there are specific examples of those two types of waves.
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