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Characterization of magnetic nanostructures by magnetic force microscopy
Staňo, Michal ; Vetushka,, Aliaksei (referee) ; Urbánek, Michal (advisor)
The thesis deals with magnetic force microscopy of soft magnetic nanostructures, mainly NiFe nanowires and thin-film elements such as discs. The thesis covers almost all aspects related to this technique - i.e. from preparation of magnetic probes and magnetic nanowires, through the measurement itself to micromagnetic simulations of the investigated samples. We observed the cores of magnetic vortices, tiny objects, both with commercial and our home-coated probes. Even domain walls in nanowires 50 nm in diameter were captured with this technique. We prepared functional probes with various magnetic coatings: hard magnetic Co, CoCr and soft NiFe. Hard probes give better signal, whereas the soft ones are more suitable for the measurement of soft magnetic structures as they do not influence significantly the imaged sample. Our probes are at least comparable with the standard commercial probes. The simulations are in most cases in a good agreement with the measurement and the theory. Further, we present our preliminary results of the probe-sample interaction modelling, which can be exploited for the simulation of magnetic force microscopy image even in the case of probe induced perturbations of the sample.
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Development and use of non-destructive testing methods from the point of view of forensic engineering
Bílek, Petr ; Vala, Jiří (referee) ; Vodička, Jan (referee) ; Hobst, Leonard (advisor)
Concretes reinforced by, using distributed steel reinforcements (fibres) are known as fibre-concrete. In case of disturbances or accidents of concrete structures reinforced with wires, it is necessary to carefully examine the actual implementation of dispersed reinforcement. Fibre concretes belong to modern building materials whose possible applications have not been fully utilized so far. Have been mainly used for floor structures loaded with factory halls and warehouses. Recently, thanks to well-known physical and mechanical properties of fibre-concrete, there were numerous attempts of designers, and namely investors, to utilize this kind of materials for support structures either. Favorable properties of wire-concrete can be utilized if there is a necessity to increase the resistance of concrete to stresses exceeding its strength, cyclic stress or impact stress. Daily practice shows to prove that the applications of fibre-concrete in such structures lead to the economic success. Necessary condition for successful application of steel fiber reinforced concrete in constructions however consists in its uniform dispersion, a homogeneous distribution of the wires throughout the volume of the structure. In case of inappropriate processing and deposition of the mixture during the manufacturing process fiber-concrete structures, the fibers are often unevenly distributed. Wires itself represent unfavourably shaped mixture components and they are extremely deteriorating its workability. A grouping of wires may be encountered as well, which reduces the overall homogeneity and the quality of steel fiber-concrete structures. If the homogeneity of fibre-concrete is not kept, the material possess different properties in various parts of the structure (for example, tensile strength), which can lead to defects in the structure (generation and development of cracks). The relevant lower reliability of the structure which is caused by unequal distribution of fibres (wires) in concrete volume can lead to damage of the property as well as the safety and the human lives can be jeopardized. Hence it is necessary to secure the effective control of the fibre-concrete homogeneity in ready support fibre-concrete structures. Contemporary homogeneity control is still ongoing on fresh blends, but if the fibre-concrete hardened and is a part of the construction, no known reliable methods are currently in available to test the homogeneity of the fibre-concrete on the structure without its destruction. The methods developed to control the concentration of wires in wire-concrete structures are based mostly on magnetic or electromagnetic properties of wires. The thesis deals with the development of the magnetic method in situ using permanent magnets for monitoring the distribution of fibers in hardened steel fiber-concrete structures. The test principle is based on measurements of the changes in magnetic field strength of permanent magnets which are induced by a change in wire distribution in steel fibre-concrete structure. Test is characterized as a so called local- failure- test using a small diameter core drill. In this sense it is a semi-destructive method.
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Probe for RFID cards tests at 13.56 MHz
Zigo, Viktor ; Vychodil, Josef (referee) ; Derbek, Vojtěch (advisor)
This thesis deals with RFID technology and the tag design for RFID device testing on the frequency of 13, 56 MHz. Everything regarding testing of such devices is described in ISO 18047-3 Standard. The target of this thesis is to design and construct the impedance matching (probe) between a proof coil and SW radio USRP N200 and the principles of this probe design are explained.
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Secure Transport of NetFlow and IPFIX Records
Štěpánek, Adam ; Grégr, Matěj (referee) ; Podermański, Tomáš (advisor)
This bachelor thesis deals with an IP flow based data network monitoring system. It presents the architecture of the NetFlow based monitoring, explains the basic terms, the NetFlow protocol and its alternatives. Further, weak spots of the monitoring systems are determined and a conceptual solution is proposed. This solution is implemented and described in detail. Finally, testing methods and results are discussed and the possibilities of further development and optimization are proposed.
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Wi-Fi Password Cracking
Šopf, Petr ; Tisovčík, Peter (referee) ; Orsák, Michal (advisor)
This bachelor's thesis deals with the issues of Wi-Fi networks security. The first part of thesis is about security options and issues related to those options. Next part compares most used tools for Wi-Fi attacks and lists features of those tools. Best tool is then used and software for sniffing communication between access point and client is created. Sniffing tool is created in two version, one version is used for standalone devices and another one for probe developed on FIT BUT.
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Design of Lacquer Thickness Meter
Rzyman, Michal ; Sládek, Josef (referee) ; Rubínová, Dana (advisor)
This bachelor thesis deals with the design of a device designed to measure the thickness of the paint. The aim of the thesis is to design a device that is visually attractive and has a well-designed ergonomics. The result of the work is a hand-held device that comes out of the shape of a pen. The grip parts are designed from soft plastic and the buttons are appropriately spaced. The whole device is designed in an elegant shape inspired by the automotive industry. Particular benefits for this area can be, above all, these things. Compact shaping, using the latest technology, namely USB type C, electronic gyroscope or Transreflex LCD display. The overall benefit of the work is a different new look at the traditional design and the whole concept of measuring devices.
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Verification technology BioSealing by EIS method
Fránková, Hana ; Novotná, Jitka (referee) ; Pařílková, Jana (advisor)
Diploma thesis is dealing with recognition of Biosealing technology using electrical impedance spektrometry method. BioSealing is an innovative method of soil body reconstruction, which uses stimulation of soil bacterial activity to seal the leakage. The method was developed in the Netherlands and it was used in conditions of the Czech Republic in years 2015 and 2016 on the Hornice water work. This earth dam was monitored by electrical impedance spectrometry by apparatus with device Z-meter IV in this period and the data are processed and assessed in this diploma thesis.
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Using measuring probes ( for tools and workpieces) for production machine of range of products firm TOS KUŘIM
Kohút, Josef ; Holub, Michal (referee) ; Opl, Miroslav (advisor)
The purpose of this dissertation is to familiarize the reader with basic recognition of machine measuring probes for tools and workpieces. Namely then in area of measurement on CNC machining centers. Both recognition from aspects of principle of function of sensing elements and type of transmition to control system, and recognition from constructional aspects are described here. Further it puts mind on equipment of machine probes (touches etc.) and rules for best selection of this equipment. Next part of this work describes selection of appropriate probes, for universal machines from production of firm TOS Kuřim. Last part deals with testing of designed measuring system for concrete machine from production of firm TOS Kuřim. His typical composition, evaluation of tests results and achieved accuracy is also described here.
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