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Use of nanofiber filter for air filtration
Straka, Petr ; Hlaváč,, Jaroslav (referee) ; Kabrhel,, Michal (referee) ; Malá, Jitka (advisor)
The doctoral thesis „Using of nanofiber filter for air filtration“ is focused on application of nanofiber filter for air filtration under demanding conditions of water supply facilities. The main aim of the filter application is to decrease the secondary contamination of the indoor environment of the water accumulation tanks. The nanofiber filters are distinguished by high filtration efficiency of pollutants, dust particles and organic impurities. The contaminants don´t have to be unhealthy but they can be used for spore and microorganisms delivery to the system. They are served frequently as a reproduction substrate of microorganisms. All these factors negatively affect the water quality. The research includes formation of suitable testing methodology, pilot unit construction and operation, short-term testing and evaluation of nanofiber filters and commonly used filters and long term testing and verification of nanofiber filter attributes and quality. Furthermore the filter´s characteristics and filtration efficiency for characteristic pollutants were evaluated. Short-term and long-term experimental testing proved suitability of nanofiber filters use in water supply facilities. Interception of reported pollution indicators was reported on similar or higher level for application of nanofiber filter than for application of commonly used filter. Measured values of higher pressure difference of nanofiber filter were indicated as still adequate for use in water supply facilities. No operation difficulties, failures neither filter´s damage were reported during testing of nanofiber filters.
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Ultrasound desintegrator of concrements
Straka, Petr ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is focused on the methodes of crushing kidney’s concrements with continual wave for the frequency 27 kHz and the intensity of ultrasound 10 W/cm2. The main aim is design of the ultrasound head with layer converter and design circuitry. First part of this work describes physical principle of ultrasound, ultrasound waves and methods by which could be remove kidney’s concretions. Practical part of this work is focused on compreshive design of ultrasound crushing system. In the introdiction is analyzed the proposal of applicator and the next step decscribing proposal excitation generator. The work contains results of simulation which was done on proposal curcuit, drawings of scheme, list of components and drawing of PCB.
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Use of nanofiber filter for air filtration
Straka, Petr ; Hlaváč,, Jaroslav (referee) ; Kabrhel,, Michal (referee) ; Malá, Jitka (advisor)
The doctoral thesis „Using of nanofiber filter for air filtration“ is focused on application of nanofiber filter for air filtration under demanding conditions of water supply facilities. The main aim of the filter application is to decrease the secondary contamination of the indoor environment of the water accumulation tanks. The nanofiber filters are distinguished by high filtration efficiency of pollutants, dust particles and organic impurities. The contaminants don´t have to be unhealthy but they can be used for spore and microorganisms delivery to the system. They are served frequently as a reproduction substrate of microorganisms. All these factors negatively affect the water quality. The research includes formation of suitable testing methodology, pilot unit construction and operation, short-term testing and evaluation of nanofiber filters and commonly used filters and long term testing and verification of nanofiber filter attributes and quality. Furthermore the filter´s characteristics and filtration efficiency for characteristic pollutants were evaluated. Short-term and long-term experimental testing proved suitability of nanofiber filters use in water supply facilities. Interception of reported pollution indicators was reported on similar or higher level for application of nanofiber filter than for application of commonly used filter. Measured values of higher pressure difference of nanofiber filter were indicated as still adequate for use in water supply facilities. No operation difficulties, failures neither filter´s damage were reported during testing of nanofiber filters.
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Modulation of time dispersion of femtosecond laser pulses
Vyhlídka, Štěpán ; Straka, Petr (advisor) ; Ostatnický, Tomáš (referee)
In the presented thesis the topic of femtosecond pulse dispersion and methods of characterizing pulse profile are briefly introduced. Then, a functionality of a spatial light modulator is described. The spatial light modulator was used in an experimental scheme called the pulse shaper, which allowed independent amplitude and phase modulation of pulses. Duration and dispersion of pulses was measured by two methods called MIIPS and PICASO. MIIPS was also used for a reconstruction of a spectral phase of pulses. The autocorrelator was constructed on a design of the Mach-Zehnder interferometer. The duration of the shortest measured pulse (13.3 ± 0.5) fs was retrieved from measured interferometric autocorrelations by PICASO. Furthermore, theoretical dependence of pulse duration on the group delay dispersion was confirmed for pulses shorter than 120 fs. The group velocity dispersion was measured for fused silica windows and for a pair of diffraction gratings in the pulse shaper. Both values confirmed theoretical expectations.
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Ultrasound desintegrator of concrements
Straka, Petr ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is focused on the methodes of crushing kidney’s concrements with continual wave for the frequency 27 kHz and the intensity of ultrasound 10 W/cm2. The main aim is design of the ultrasound head with layer converter and design circuitry. First part of this work describes physical principle of ultrasound, ultrasound waves and methods by which could be remove kidney’s concretions. Practical part of this work is focused on compreshive design of ultrasound crushing system. In the introdiction is analyzed the proposal of applicator and the next step decscribing proposal excitation generator. The work contains results of simulation which was done on proposal curcuit, drawings of scheme, list of components and drawing of PCB.
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Proposal of ultra-high-power beams at the kilojoule iodine laser PALS
Novák, Ondřej ; Divoký, M. ; Böhm, P. ; Smrž, M. ; Turčičová, Hana ; Straka, Petr
The iodine kJ laser PALS is widely used by users. To extend the scope of the experiments, a proposal of new ultra-high-power (UHP) beams was done in detail. The model of the design is based on routine parameters of the laser PALS and on state-of-the-art of the ultra-high-power beams generation. Using the OPCPA technique, we propose two new alternative UHP beams at PALS with powers of 100 TW and 1 PW, respectively, including a pulse compressor and new front-end amplifiers. The amplification chain was simulated using coupled wave equations for optical parametric amplification. Layout of the two new beams in the existing PALS laser hall was also proposed.
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Prodlužovač impulsů s vysokou spektrální a výkonovou propustností
Divoký, M. ; Smrž, M. ; Straka, Petr
We present a pulse stretcher based on modified Öffner triplet using an off-plane (conical) diffraction under the Littrow configuration. Our system was ray-traced and the results are comparable with a similar design using in-plane diffraction. A slight conical diffraction is not a serious problem which was demonstrated by stretching the 10-fs pulses from a Ti:sapphire laser to ~300 ps and backcompressing them to 16 fs with a high power throughput over the system and low distortion of the pulses.
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