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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vývoj algoritmu pro automatickou charakterizaci vzorku na základě dat získaných spektroskopií laserem indukovaného plazmatu (LIBS) / 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 January 2018 (has links)
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.
2

Srovnání přístupů kvantitativní analýzy v spektroskopii laserem buzeného plazmatu / Comparison of quantification strategies in Laser-Induced Breakdown Spectroscopy

Hošek, Martin January 2018 (has links)
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.
3

Optimalizace svařovacích parametrů při laserovém svařování s přídavným studeným drátem / Optimization of welding parameters during laser welding with additional cold wire

Venc, Jan January 2021 (has links)
This diploma thesis deals with the optimization of process parameters of welding a drainage channel using a laser beam with an additional cold wire. This channel is made of austenitic Cr Ni stainless steel X5CrNi 18-10 (1.4301, ČSN 17 240) with a sheet thickness 1,5 mm. Mechanical properties of samples were checked by using transverse tensile test. Subsequently, the samples were macroscopically inspected focusing on dimensions of the weld and the presence of weld defects. Finally, the structure of the weld metal and fundamental material was evaluated by using microscopic control. Based on evaluation tests, the optimal welding parameters were recommended.
4

Úprava laserového svařovacího pracoviště pro svařování materiálů uvolňující nadměrné množství zplodin / Modification of a laser welding system for welding materials releasing excessive amounts of fumes

Kohout, Jaroslav January 2021 (has links)
The thesis deals with the implementation of a suction system for laser welding. The specific product is grate used for outdoor drainage. The original GMAW production technology is to be replaced by a laser. During the welding of S235JR steel, a significant development of exhaust gases was observed, which subsequently made the actual process impossible. Practical experiments were performed and evaluated using tensile testing and metallographic cut. Based on the results, the optimal position of the suction nozzle and welding parameters were recommended. The obtained values were re-verified by experiment. Furthermore, a suitable extraction device was proposed and an economic evaluation was performed.
5

Trendy vývoje LASERové technologie / Trends of development LASER technology

Zlesák, Jakub January 2008 (has links)
The basic acquaintance with laser technology principles. The consideration and evaluation of this technology present state in engineering. The possibilities of applying new knowledge and discoveries in this field for using in engineering. The estimation of laser technology development within further 5 years and consideration of this technology economical demands.
6

Srovnání svarů vytvořených CO2 laserem a vláknovým laserem / Compare weld from CO2 laser and fiber laser

Leidorf, Michal January 2011 (has links)
The project compares the technology of welding of CO2 laser and fiber laser in terms of engineering study, the welds will be made by same welding conditions on two materials (S235JRG2 a X5CrNi 18-10), by using different protective gases (Helium and Argon). In the terms of literal background research both the technologies and questions of laser welding are described. The geometry of welds is carried out in the experimental part. The final results of the experiment are concluded at the end of the diploma thesis.
7

Nekonvenční technologie laserového řezání / Unconventional Technology of Laser Cutting

Indra, Jaroslav January 2011 (has links)
The thesis deals with the technology of laser cutting. The beginning is concerned with a general description of laser technology and laser division into basic groups. Next part refers to possible industrial use of laser beam, especially for cutting. Other chapters deal with the components suitable for the manufacture of this technology, technical preparation of production and the proposal to increase manufacturing flexibility when changing products. The last part is devoted to technical and economic evaluation.
8

Automatizace pracoviště pro svařování laserem / Automation of a workplace for laser welding

Elger, Jiří January 2013 (has links)
The goal of this diploma thesis on the topic of „Automation of workplaces for laser welding“ is the design of a robotic manipulation device for a four position laser welder which has been designed for a real project for automotive parts company. The introduction part of this work analyses the assignment and describes the current state of the workplace, describes each work cycle operation and customer requirements at the workplace. The work then deals with solving individual key nodes at the workplace, including introducing this robot and end effector design. The conclusion of this work explains safety solutions at the workplace, and financial and technical evaluation.
9

Způsoby korekce a standardizace signálu v laserové spektroskopii / Approaches to signal correction and standardization in laser spectroscopy

Schiffer, Štěpán January 2018 (has links)
The subject of this diploma thesis is the study of a sample position influence on results of an experiment in laser spectroscopy. The aim is to design an appropriate way for standardization of signal obtained at different conditions with the respect to its applicability for stand-off analysis. In the theoretical part of the diploma thesis there are the basics of LIBS method described together with the issues of stand-off experiment and both, basic and advanced approches for the processing and correction of obtained spectra. Also the experiment is designed here, which is used for the analysis of the sample inclination and distance influence on the detected signal. The choice of appropriate ways for the signal correction follows and their applicability and efficiency is then experimentally tested.
10

Vizualizace spektroskopických dat pomocí metody analýzy hlavních komponent / Visualization of spectroscopic data using Principal Component Analysis

Šrenk, David January 2019 (has links)
This diploma thesis deals with using laser-induced breakdown plasma spectroscopy for determining the elemental structure of unknown samples. It was necessary to design an appropriate method to qualify material by laser-induced emission spectrum. Pretreatment of data and using a variety of chemometrics methods had to be done in order to qualify the structure of elements. We achieved a required solution by projecting the data to a new PCA space, creating clusters and computing the Euclidean distance between each cluster. The experiment in the practical part was set to detect an interface of two elements. We created a data file simulating the ablation on the interface. This data set was gradually processed applying a mathematical-chemical-physical view. Several data procedures have been compiled: approximation by Lorenz, Gauss and Voigt function and also a pretreatment method such as the detection of outliers, standardization by several procedures and subsequent use of principal components analysis. A summarization of processes for input data is fully described in the thesis.

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