National Repository of Grey Literature 23 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Design of Monitoring Tower for targetry and laser focusing
Virostková, Kristína ; Kaiser, Jozef (referee) ; Knoflíček, Radek (advisor)
The final thesis was created in cooperation with the Institute of Physics of the Czech Academy of Sciences and European Laser Centre ELI Beamlines. It focuses on design of monitoring device for laser target observation in a high-performance laser particle accelerator. Details of scanning and positioning system designated for operation in UHV environment are presented in this thesis. Design changes were performed in scanning system in order to achieve more effective scanning. Positioning system, consisting of precise linear and rotary motors, is newly designed device with high precision positioning under 1 µm in direction of each axis. The purpose of monitoring device is to improve overall scanning precision, shorten targeting process, and increase user comfort.
Increase of robustness of communication architecture for remote spectroscopy
Cebo, Patrik ; Klus, Jakub (referee) ; Kaiser, Jozef (advisor)
This thesis deals with the design of new communication architecture of a device for remote laser spectroscopy. The conceptual model is based on the analysis of the state of the art systems for remote laser spectroscopy. Moreover, the advantages and disadvantages of custom electric buses and its failures in deployment are discussed within this thesis. The result of the work includes the design of new communication architecture supported by Ethernet standards. The next part of the thesis focuses on the customized stepper motor controller composition, which will resolve the theoretical findings arising from the analysis.
Development of an Algorithm for Automatic Characterization of a Sample Based on the Data Received by Means of the Laser Induced Breakdown Spectroscopy (LIBS).
Klus, Jakub ; Černohorský,, Tomáš (referee) ; Veis,, Pavel (referee) ; Kaiser, Jozef (advisor)
Submitted work concerns with the theoretical and practical requirements for an automatic characterization of samples by means of Laser-Induced Breakdown Spectroscopy (LIBS). Theoretical aspects of laser-matter interaction, plasma expansion, and plasma emission are described theoretically within this work. The description of the plasma emission is enhanced with the spectral detection systems and statistical properties of the plasma. The principle of the automatic characterization is based on the multivariate data analysis theoretical background, which presents recent trend and fundamental approach for automatic spectra analysis in LIBS. Theoretical knowledge is manifested in six applications, which are presented as a comment to published manuscripts. These publications push the frontiers of automatic spectra processing in LIBS.
Growth performance of common-sized planting stock and saplings after plantation on forest sites
Kaiser, Josef ; Kuneš, Ivan (advisor) ; Tužinský, Marek (referee)
The clear-cut area which is afforested in the Czech Republic is around 20 th. hectares large annually. In the last decades, we have observed frequent periods of the spring and late summer drought, which significantly negatively influence survival of the reglarly used transplants (RUT) however. Thus, it is necessary to search methods, which can decrease such losses. One possiblity how to solve this problém is to used containered transplants, the second one is the use of the plant material (PM) of bigger size (semi-large-sized=SLSPS and large-sized planted stock=LSPS). These larger plants are more resistant to unsuitable influences of environment than the RUT. The advantage of SLSPS and LSPS is also shorter time of necessary care to plants and lower costs to secure plants in comparison to RUT. Above mentioned facts were taken into consideration in creation of instructions for my bachelor thesis. The goal was to estimate the parameters of mortality and growth of selected various PM, moreover on sites heavily influenced by human activities. As model trees were selected: oak (Quercus robur) and lime (Tilia cordata). PM was generally bare-rooted (RUT, SLSPS and LSPS) and planting was done by mechanize equipment (into bored holes) at study sites Truba (Kostelec nad Černými lesy) and Hůrka (Planá nad Lužnicí). The first part of experiment was established at Truba on area of former forest nursery and cosisted of lime RUT and LSPS, the second one was established at site Hůrka in area of former sand querry, where RUT, and oak and lime SLSPS and LSPS were used. No one site was moved during experiments. The measurement on Truba was repeated on spring and on autumn 2012-15 and in 2015 on Hůrka. The height of PM was evaluated by using scale lath, the thickness of stem was measured above ground by using digital scale. Subsequently, data were evaluated in Excel and statistically tested by Kruskal-Wallis test. The results indicate, that mortality of RUT at Truba is 5 times larger than that of LSPS. The similar result was obtained also at Hůrka, the mortality of lime RUT was twice larger than in case of LSPS however. The lowest mortality was observed surprisely on SLSPS. The comparison of the oak RUT and LSPS indicated no any differences in mortality. The mortality of oak PM was generally significantly lover than lime PM one. Statistical tests also indicated, that the size of study sets of PM was too low for optimal scientific evaluation of selected parameters. The obtained results also indicate, that important factor, which influences mortality must be (apart from type of the PM) also additional, non-defined factors of environment up to now.
Detection of Braking Tracks using Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Induced Fluorescence Spectroscopy (LIBS + LIFS)
Prochazka, David ; Vémola, Aleš (referee) ; Pína,, Ladislav (referee) ; Kaiser, Jozef (advisor)
The aim of this work is to investigate the potential of Laser-Induced Breakdown Spectroscopy (LIBS) for identification of visually unrecognizable braking tracks. Identification of these tracks is based on different chemical composition of tire tread in comparison to road surface. The investigation was divided in several sequential steps – selection of suitable chemical element and its spectral line for break tracks identification; determination of the limits of detection and threshold intensity respectively for the selected chemical element; verification of LIBS ability to detect braking tracks on a real braking track. This testing braking track was prepared by exactly defined and described conditions. The detection was performed in two ways – laboratory analysis of tire treads particles collected via adhesive tape and in situ analysis via mobile apparatus. Results of both measurements showed that LIBS is able to detect visually unrecognizable braking tracks. Concepts of the devices capable of routine braking tracks identification for both possibilities were introduced.
Using Laser-Induced Breakdown Spectroscopy (LIBS) for Material Analysis
Pořízka, Pavel ; Hrdlička, Aleš (referee) ; Pína,, Ladislav (referee) ; Kaiser, Jozef (advisor)
Tato doktorská práce je zaměřena na vývoj algoritmu ke zpracování dat naměřených zařízením pro spektrometrii laserem indukovaného plazmatu (angl. LIBS). Zařízení LIBS s tímto algoritmem by mělo být následně schopno provést třídění vzorků a kvantitativní analýzu analytu in-situ a v reálném čase. Celá experimentální část této práce byla provedena ve Spolkovém institutu pro materiálový výzku a testování (něm. BAM) v Berlíně, SRN, kde byl sestaven elementární LIBS systém. Souběžně s experimentílní prací byl vytvořen přehled literárních zdrojů s cílem podat ucelený pohled na problematiku chemometrických metod používaných k analýze LIBS měření. Použití chemometrických metod pro analýzu dat získaných pomocí LIBS měření je obecně doporučováno především tehdy, jsou-li analyzovány vzorky s komplexní matricí. Vývoj algoritmu byl zaměřen na kvantitativní analýzu a třídění vyvřelých hornin na základě měření pomocí LIBS aparatury. Sada vzorků naměřených použitím metody LIBS sestávala z certifikovaných referenčních materiálů a vzorků hornin shromážděných přímo na nalezištích mědi v Íránu. Vzorky z Íránu byly následně na místě roztříděny zkušeným geologem a množství mědi v daných vzorcích bylo změřeno na Univerzitě v Clausthalu, SRN. Výsledné kalibrační křivky byly silně nelineární, přestože byly sestaveny i z měření referenčních vzorků. Kalibrační křivku bylo možné rozložit na několik dílčích tak, že závislost intenzity měděné čáry na množství mědi se nacházela v jiném trendu pro jednotlivé druhy hornin. Rozdělení kalibrační křivky je zpravidla přisuzováno tzv. matričnímu jevu, který silně ovlivňuje měření metodou LIBS. Jinými slovy, pokud určujeme množství analytu ve vzorcích s různou matricí, je výsledná kalibrační křivka sestavená pouze z jedné proměnné (intenzity zvolené spektrální čáry analytu) nepřesná. Navíc, normalizace takto vytvořených kalibračních křivek k intenzitě spektrální čáry matrčního prvku nevedla k výraznému zlepšení linearity. Je obecně nemožné vybrat spektrální čáru jednoho matričního prvku pokud jsou analyzovány prvky s komplexním složením matric. Chemometrické metody, jmenovitě regrese hlavních komponent (angl. PCR) a regrese metodou nejmenších čtverců (angl. PLSR), byly použity v multivariační kvantitatvní analýze, tj. za použití více proměnných/spektrálních čar analytu a matričních prvků. Je potřeba brát v potaz, že PCR a PLSR mohou vyvážit matriční jev pouze do určité míry. Dále byly vzorky úspěšně roztříděny pomocí analýzy hlavních komponent (angl. PCA) a Kohonenových map na základě složení matričních prvků (v anglické literatuře se objevuje termín ‚spectral fingerprint‘) Na základě teorie a experimentálních měření byl navržen algoritmus pro spolehlivé třídění a kvantifikaci neznámých vzorků. Tato studie by měla přispět ke zpracování dat naměřených in-situ přístrojem pro dálkovou LIBS analýzu. Tento přístroj je v současnosti vyvíjen v Brně na Vysokém učení technickém. Toto zařízení bude nenahraditelné při kvantifikaci a klasifikaci vzorků pouze tehdy, pokud bude použito zároveň s chemometrickými metodami a knihovnami dat. Pro tyto účely byla již naměřena a testována část knihoven dat v zaměření na aplikaci metody LIBS do těžebního průmyslu.
Remote Laser Induced Breakdown Spectroscopy (LIBS)
Novotný, Jan ; Zemánek, Pavel (referee) ; Pína,, Ladislav (referee) ; Kaiser, Jozef (advisor)
The dissertation thesis deals with the development of the Laser-Induced Breakdown Spectroscopy (LIBS) setup in the modification for the mobile remote material analysis (so called rLIBS). The experimental device is developed at the Institute of Physical Engineering, Faculty of Mechanical Engineering (FME), Brno University of Technology (BUT). Such a modification is possible due to the core principles of LIBS technique, i.e. using a laser for a sample excitation and plasma radiation for spectral analysis. The thesis is focused on the variation called Stand-Off LIBS with the target analyte in the distance of 6 meters. In this case the laser pulse and the plasma radiation are transmitted through the local environment (usually the air) and the direct device-to-sample visibility is expected. The motivation for this development is to avoid traditional processes of sample collection, preparation and transport that are time-consuming, expensive and sometimes even hard to realize. Stand-Off LIBS allows bringing all the LIBS technique benefits from the laboratory to the field, where fast, in-situ analysis can be carried out. The first part of the thesis focuses on the history and principles of the Atomic Emission Spectroscopy (AES), as it is the main principle of LIBS technique. The second part describes the history, theory, instrumentation and applications of LIBS as a modern analytical tool. This part also introduces the remote mobile modification – rLIBS, as well as the current state of knowledge and the state of the development in LIBS laboratories worldwide. The third part describes the individual stages of the rLIBS development at the Institute of Physical Engineering, FME BUT. This chapter details the focusing optics design, building of the collection optics, design and construction of the detection unit, motorized stage and mobile track. This section contains also the results of the test spectroscopy measurements and movement ability measurements.
Diagnostics of Ti:Sa laser pulses for plasma generation
Weiss, Jiří ; Samek, Ota (referee) ; Kaiser, Jozef (advisor)
This diploma thesis is focused on investigation of temporal characteristics of laser pulses generated by oscillator with Ti:Sapphire active laser medium. In terms of properties of laserinduced plasmas the beam quality is crucial, in particular laser pulse contrast ratio. A new prototype of third order autocorrelator was designed. Pulse contrast ratio measurement is based on sum frequency generation between pulse of fundamental wavelength and its frequency doubled replica. Dynamic range of presented autocorrelator is estimated to be up to 8×10^12 which is more than currently available commercial devices can offer.
Optimizing measurement procedure of the optical radiation scattered by solid surface performed by the scattermeter
Klus, Jakub ; Kaiser, Jozef (referee) ; Ohlídal, Miloslav (advisor)
Tato práce se zabývá optimalizací procedury měření optického záření rozptýleného pevnými tělesy prováděného pomocí scatterometru. V práci je popsáno několik metod použitelných k nalezení souboru pozic nepřekrývajících se kruhových detektorů na povrchu polokoule (i koule). Výsledky práce jsou aplikovány na samotný meřicí přístroj a je ukázána shoda experimentálních výsledku získaných před i po optimalizaci. Výhodu nového uspořádání lze nalézt především v převedení dřívejšího způsobu měření na soubor nezávislých měření, což má význam pro matematické zpracování výsledků.
Optimisation of experimental parameters for double-pulse LIBS
Roščák, Michal ; Novotný, Karel (referee) ; Kaiser, Jozef (advisor)
Diploma thesis presents the description of laser induced breakdown spectroscopy (LIBS) analytical method. The possibility to decrease LIBS detection limits using double pulse LIBS (DP-LIBS) is also detailed. Properties of laser induced plasma (LIP) are discussed. Thesis describes the optimisation process of DP-LIBS setup at laser spectroscopy laboratory of Faculty of Mechanical Engineering, Brno University of Technology. Optimisation was carried out for detection of chrome in steel with respect to detection limits and ablation crater size. Optimised DP-LIBS setup is appropriate for mapping chrome distribution in steel samples.

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See also: similar author names
1 Kaiser, Jaroslav
1 Kaiser, Josef
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