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Enhancement of detection limits in Laser-Induced Breakdown Spectroscopy (LIBS) using nanoparticles
Képeš, Erik ; Prochazka, David (referee) ; Sládková, Lucia (advisor)
This bachelor's thesis describes the options of ehnancing the detection limits of laser-induced breakdown spectroscopy (LIBS). It summarizes different modifications of the classical LIBS apparatus, which are used by methods double-pulsed LIBS (DPLIBS), Townsend effect plasma sectroscopy (TEPS), resonance enhanced LIBS (RELIBS), spark discharge LIBS (SDLIBS), flame-enhanced LIBS (FELIBS), and new ways of sample preparation, such as are used in the method nanoparticle enhanced LIBS (NELIBS). It briefly describes the mechanisms, which are used by each method to reduce the detection limit and it contains an overview of obtained enhancements against the classical method LIBS. It deals with the method nanoparticle enhanced LIBS in more detail and experimentally verifies and studies the effects of nanoparticles of different types and sizes on the emission spectrum of the method LIBS.
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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.
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Optimization of the experimental parameters for laser induced breakdown spectroscopy (LIBS) of selected plant samples
Prochazka, David ; Novotný, Karel (referee) ; Kaiser, Jozef (advisor)
This diploma thesis describes optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples. First part deals with the theoretical method of LIBS and explains the principles and terms. In the next part there is described device which was used for measurements. Main part of diploma thesis describes creation of program for measurement-automation. Main task of program was to solve the connection of autofocus on the sample with the sample automatic movement. Furthermore are described and elaborated specific measurements for optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples.
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Automatic sample tilt compensation for chemical mapping by LIBS
Stříbrná, Klára ; Pořízka, Pavel (referee) ; Prochazka, David (advisor)
This thesis deals with designing an algorithm for slope compensation of a sample examined using the LIBS (Laser-induced breakdown spectroscopy) method. It mainly fucuses on the purpose of elemental mapping. The sample slope noticeably affects the result quality and therefore a demand for a simple and inexpensive solution to this problem appeared that would also be applicable for commercial uses of LIBS.
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Development of abrasion resistant concrete
Procházka, David ; Darebník, Zdeněk (referee) ; Hela, Rudolf (advisor)
The resistance of concrete to abrasion is an important feature particularly for transport and water management structures where the surface is exposed to abrasion. Bachelor thesis deals with individual influences on improvement of abrasion resistance of concrete surface. Furthermore, the search of test methods used for testing abroad. In the practical part, we assess the effect of curing agents on resistance to abrasion, water jet and tensile strength by tear-off test.
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Modification of the focusing part of the table-top setup for Laser Induced Breakdown Spectroscopy (LIBS)
Borovský, Ján ; Prochazka, David (referee) ; Samek, Ota (advisor)
This bacheolor thesis solves functional modifications of the foccusing part of the table-top setup for laser induced breakdown spectroscopy LIBS. Main requirements for modified draft includes increasing view field of the navigation camera, increasing the setup’s aperture and prevention of the camera destruction by radiation of plasma. These requirements were fulfilled in new draft of optical stand including possible solution as enlarging focusing lens, new dielectric mirror and mechanical iris shutter. Some elements of proposed solution will be used in suggestion of Tescan company‘s new interaction chambers for LIBS analysis.
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Fluorine detection by means of Laser-Induced Breakdown Spectroscopy
Jaworková, Magdalena ; Pořízka, Pavel (referee) ; Prochazka, David (advisor)
This work concerns the Laser Induced Break-down Spectroscopy LIBS and it´s usage in detection of fluorine in specimens. This method and the particular methods of measurements suitable for fluorine detection are analysed in theoretical part. The sensitivity of particular methods such as usage of buffer gases (He), change of ambient pressure, usage of double laser pulse (DP–LIBS) or detection of molecular bands are compared in experimental part.
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Effect of magnetic field on laser-induced plasma characteristics
Vrábel, Jakub ; Pořízka, Pavel (referee) ; Prochazka, David (advisor)
This work is based on topic of laser induced breakdown spectroscopy „LIBS“ and its application to chemical analysis of materials. Paper presents a brief theoretical basis of LIBS with focus on effect of magnetic field to plasmas and modeling spectras for calib-ration-free LIBS analysis. Considerable part of work is dedicated to practical demon-stration of modeling spectras, using Matlab and interpretation of experimental results. The final output is automatized method for evaluation of spectras, which could leads to calibration-free LIBS analysis. Also there is an effort to increase sensitivity of method.
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Comparison of quantification strategies in Laser-Induced Breakdown Spectroscopy
Hošek, Martin ; Hrdlička, Aleš (referee) ; Prochazka, David (advisor)
The aim of the submitted work is a comparison of methods of quantitative analysis used in laser-induced breakdown spectroscopy (LIBS). The principles of LIBS method are explained at first, followed by a research of the most often used methods of quantitative analysis. The next part provides their description enabling a better comprehension and an eventual use of the methods in practice. Finally, the chosen methods are used to process data from the real experiment and the results are compared.
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