|
|
Ex-Situ Xrd Characterization Of Electrodes For Electrochemical Power Sources
Klvač, Ondřej
The article describes a theoretical method of a research of graphite electrodes in an electrochemical cell where the problem is with the preferred orientation and a thin layer. As a result, only a reflection (002) is visible. However, there is a possibility to determine crystallographic parame-ters from these peaks because of the effect of a destructive and constructive interference caused by intercalated lithium atoms. At the same time, the work shows that Kapton is not a suitable material for ex-situ cell production, as samples have been destroyed by air humidity. Finally, a circular ex-situ cell was made and tested with the pure sodium. This modification reduces a rate of degradation of the samples.
|
|
|
Design and testing of XRD holder for post-mortem analysis of li-ion battery electrodes performed in an inert atmosphere
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The work describes the design and manufacturing of a test device for post-mortem measurements of electrodes of electrochemical cells using X-ray diffraction spectroscopy. The theoretical part describes the diffractometer Rigaku Miniflex 600, for which the product is intended. At the same time, an overview of solutions in various applications is processed here in the form of a recherche. The practical part documents the current development of a new cell, on which tests were performed. Here is an overview of the influence of gases and insulating materials on the resulting data, especially distortion and attenuation. Subsequently, a new design with improved hermetic insulation and sample displacement error correction is described. The principle of operation of the manufactured cell, including the control unit and software, is elaborated in the form of technical documentation. Finally, the functionality is verified by comparing the diffractograms of the powder standards and the graphite electrodes.
|
|
|
Xrd Characterization Of Graphite For
Electrochemical Power Sources
Klvač, Ondřej
The article describes possibilities for research method of graphene atomic structure as electrochemical power source electrode. At first there is a computation of difractogram maximums and intensities. Next part compares real measurements and conclusions of previous theoretical part. At this point comes determination of lattice parameters. As last part there is an interaction of graphite by lithium ions and discussion of important results.
|
|
|
XRD characterization of electrodes and electrode materials for electrochemical power sources
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The thesis describes available choices of methods for research of electrochemical power source electrode strcture by x-ray diffraction spectroscopy. At first there is a theoretical computation of difractogram. Then there are discussed possibilities of in-situ and ex-situ techniques as background research. Practical part of thesis compares theoretical assumptions to measurements of lithium and sodium cells, including analyze of crystallographic phases and lattice constants. As a conclusion, there are discussed possibilities of subsequent research.
|
|
|
Analýza deformace dřeva s imperfekcí na základě srovnání jednoduchého numerického modelu s optickou metodou DIC
Klvač, Ondřej
This work is devoted to the analysis of wood with imperfection in tension, digital image correlation method and finite element method. It is investigated the comparability of the results of these two methods on the example of behaving of the wood in tension with imperfection. The imperfection could be for example any weakening of the wood structure. It could be natural (knots, cracks and so on). The example of artificial imperfection here is a drilled hole. In this work an experiment with plastic sample in the same manner was also conducted in order to validate the analytical procedure for calculating the stress and practically demonstrate the difference between isotropic and anisotropic material. The work also includes general information from the literature, theoretical assumptions, methodologies, measured results and the comparison of these results each other and with the literature. The result of this work is to evaluate the behavior of wood with a hole in the tension and the comparison of these two methods of measuring deformation. In the end there are the advantages and disadvantages of each method.
|
|
|
Analýza vlivu odklonu vláken v lamelách dřevěného lepeného nosníku na jeho tuhost
Klvač, Ondřej
This thesis deals with the analysis of the influence of deflection of grain in the single slats in the wooden glued beam on its stiffness by the finite element method. It is concerned with the deflection of the grains in single slats and a possible combination of changing these slats in the beam.The ascertainment of overal deformation, stiffness and tension placement in the beam cross- section. The thesis also contains general information from the technical literature regarding the issues of glued beams, manufacture technology, examples of use and a comparison and the measured outcomes of the finite element method. The result of the thesis is to evaluate the deflection laminated beams and determine the optimal arrangement the slats in terms of minimum deflection.
|
guest ::
RSS feed.