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Mechanics of flow of inhaled fibres in a replica of human airways
Kánská, Jana ; Elcner, Jakub (referee) ; Lízal, František (advisor)
The ability to describe the movement of fibrous particles is essential not only because inhaled fibers can cause serious lung diseases, but also because the fibrous shape of particles could be suitable for inhalable medications. The theoretical part of the work is dedicated to the methods currently used to model the transport of fibers, both in simple cases and in models of human lungs. Furthermore, it summarizes the current state of knowledge in the field of fiber movement a deposition. An overview of experimental and computational studies is provided. In the experimental part, two deposition experiments with polydisperse fibers were conducted. One experiment represented a woman’s breathing during heavy activity, with an effective inhalation flow rate of 127 l/min. The other represented a woman’s normal breathing, with an effective inhalation flow rate of 19.1 l/min. A female lung model was used, created by modifying a male lung model. The results confirmed that with a lower inhalation flow rate, fibers have the potential to penetrate deeper into the lungs, specifically beyond the 7th generation of branching in the tracheobronchial tree. Among the most significant findings is the fact that to ensure effective targeted drug delivery in the case of aerosolized fibrous medications, it is necessary to control the inhalation style, particularly the maximum flow rate.
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Reactive Powder Concrete
Gabko, Miroslav ; Klečka,, Tomáš (referee) ; Hela, Rudolf (advisor)
Reactive powder composites (RPC) have been recently a subject of many researches of modern concrete technology. This type of concrete is very fine and its behaviour exceeds the other types of concrete, therefore there are new possibilities of its use. The design and production of RPC is complex technology process which needs to gain new results in RPC research to get the best features regarding its higher price. This thesis is focused on design of reactive powder concrete (RPC200), which compressive strength is between 200 – 300 MPa. Next goal is to prove the influence of curing regimes like high temperature or pressure, and also check the possibilities of production of low cement reactive powder composite (LCRPC).
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Use of FRP Composites as Reinforcing Material for Concrete
Kratochvílová, Denisa ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
Because FRP composites have high fiber strength and good durability, they are increasingly used for repairs, modernisation and reconstruction of concrete structures. In practice, however there is a risk of premature separation of FRP reinforcement from concrete. This can be avoided by appropriate selecting the fibers and the matrix and the appropriate shape of the reinforcement. The actual materials and consistency of FRP reinforcement with concrete are also covered by this diploma thesis.
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The development of ultra-high strength (UHPC) and reactive powder (RPC) composites
Rundt, Lukáš ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Bachelor’s thesis studies ultra-high strength concrete and reactive powder composites. In theoretical part there are researched and described properties of raw materials used for their production, mainly additions. Design methodology, processing and types of curing are also studied. Psychical mechanic and durability properties of fresh and hardened concrete are described. In practical part 4 mixtures were designed and prepared and their rheological properties, strengths after 7 and 90 days in case of UHPC and strengths after 7, 28 and 60 days in case of RPC were tested.
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Parallel Application Development with Intel Threading Tools
Vadkerti, Ladislav ; Jaroš, Jiří (referee) ; Dvořák, Václav (advisor)
Today's trend in microprocessor design is increasing the number of execution cores within one single chip. Increasing the processor's clock speed reached its limit with growing power consumption. This trend brings new opportunities to software developers, as they can take advantage of real multithreading in their applications. But a lot of new problems to solve appear with threading compared to sequential programming. With proper design, threading can enhance performance by making better use of hardware resources. However, the improper use of threading can lead to performance degradation, unpredictible behavior, or error conditions that are difficult to solve. For this reason Intel developed a suite of tools, that can help software developers to analyze performance and detect coding errors in thread interactions. This thesis focuses on the examination of ways that this tools can be used in multithreaded application development.
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Measurement and analysis of deposition of fibers from mineral wool in respiratory system
Hájek, Ondřej ; Elcner, Jakub (referee) ; Lízal, František (advisor)
This master thesis deals with inhalation of fine particles and fibres into human lungs. This is a scientific field where computer modelling is used to describe the movement of fibres and their deposition in the lungs. However, the results of these simulations must be verified experimentally. The prediction of fibres behaviour is important from a toxicology point of view where it is important to know deposition hot-spots and places where fibres could possibly cause problems. The review of the state-of-the-art is focused on the deposition of particles in human lungs followed with a chapter on fibre as a type of particle, and occupational exposure limits set by different world associations. The last theoretical chapter describes human lungs and its diseases which can evolve when limits for occupational exposure are not met. The experimental chapter consists of a description of the used experimental setup and results from an experiment together with a comparison of results with other similar experiments.
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Properties of fibers based on polyhydroxybutyrate
Štulrajterová, Lujza ; Tocháček, Jiří (referee) ; Přikryl, Radek (advisor)
Táto práca sa zaoberá zvlákňovaním biopolymérov z taveniny. V teoretickej časti sú zhrnuté doterajšie poznatky o zvlákňovaní poly(3-hydroxy butyrátu) (PHB) a poly(mliečnej kyseliny) (PLA). Následne boli zvláknené polymérne zmesi na báze PHB s rôznym zložením, čo umožnilo štúdium vplyvu PLA, zmäkčovadiel a ich množstva na vlastnosti pripravených vlákien. Boli použité tri komerčné zmäkčovadlá (ATBC, PEG, A6) a dva experimentálne syntetizované. Zvláknenie bolo prevedené na troch rôznych zvlákňovacích linkách. Konvenčné zvlákňovacie linky s odťahovými rýchlosťami nad 150 m/min sa preukázali ako nevhodné pre spracovanie našich zmesí. Kvôli nedostatočnej pevnosti taveniny sú potrebné nízke odťahové rýchlosti. Boli pripravené vlákna s dĺžiacim pomerom 6,4; ktoré boli následne analyzované pomocou GPC, MDSC a ťahovej skúšky. Na základe nameraných teplôt skelného prechodu zmäkčovadlá ATBC a PEG vykázali lepšiu schopnosť zmäkčiť skúmané PLA/PHB zmesi. Vlákna obsahujúce A6 vykazovali najvyššiu pevnosť v ťahu (250 MPa) a modul pružnosti (2,7 GPa). Nakoniec bol skúmaný vplyv starnutia, tepla a vriacej vody na mechanické vlastnosti týchto vlákien.
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In Vitro Study of the Effect of Particle Characteristics and Flow Rate on Regional Deposition in Human Airways
Bělka, Miloslav ; Adamec, Vladimír (referee) ; Farkas, Árpád (referee) ; Jedelský, Jan (advisor)
Dlouhodobé vdechování částic může přispívat ke vzniku nebo zhoršení nejrůznějších plicních onemocnění. Na druhou stranu, vdechování léčiv je často používanou metodou podávání léků proti astmatu a jiným nemocem dýchacího ústrojí. V obou případech je důležité dobře porozumět mechanismům, na jejichž základě funguje pohyb částic a jejich usazování v dýchacích cestách. Cílem této disertační práce bylo získat nová experimentální data depozice částic a analyzovat vliv tvaru částic a průtoku vzduchu na depozici. Byla studována depozice porézních a vláknitých částic v realistickém modelu dýchacích cest. Porézní částice byly vyrobeny různými metodami, např. sprejovým sušením nebo metodou krystalizace. Takto vyrobené částice byly použity při depozičních experimentech. Detekce částic byla provedena pomocí UV/VIS spektrofotometrie. Vláknitý aerosol byl vytvořen rozdrcením skelné vaty. Takto vzniklé vláknité částice byly několikrát prosety přes řadu sít a dále roztříděny podle délky pomocí klasifikátoru pracujícím na principu dielektroforézy. Následná depozice byla vyhodnocena použitím mikroskopie s fázovým kontrastem. Ke zrychlení analýzy byl vyvinut program, který dokáže na základě analýzy obrazu najít a spočítat vlákna. Výsledky experimentu byly použity k určení depozičních charakteristik. S jejich pomocí pak byl kvantifikován vliv tvaru částic a průtoku na míru usazování. Depoziční účinnost částic rostla v závislosti na Stokesově čísle, což poukazuje na vliv setrvačnosti při usazování částic. Bylo prokázáno, že depoziční účinnost porézních částic je podobná té u částic kulových při stejném Stokesově čísle. Vláknité částice se usazovali méně efektivně v porovnání s kulovými částicemi majícími stejné Stokesovo číslo. Jelikož byly okrajové podmínky dostatečně popsány a model plic je k dispozici i v digitální podobě, je možné data použít k validaci výsledků numerických simulací.
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Reactive powder composites and cement composites without macropores
Panenková, Monika ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the design principles and manifacture of ultra performance concrete (UHPC), reactive powder composites (RPC) and other fine-grained materials, such as Macro defect free (MDF) or Densified systems with small particles (DSP). Theoretical part of this work is focused on the requirements of properties and composition UHPC and RPC and methodology of their design principles. Experimental part describes design principles RPC, manufacture of test specimens, testing of certain physical and mechanical properties, such as tensile strenght, bending strenght and compressive strenght and determination chemical character X-ray and thermal analysis.
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Electrospinning of polyvinylidenfluoride based fibers
Hošek, František ; Šťastný, Přemysl (referee) ; Částková, Klára (advisor)
Electrospinning is one of the rapidly developing methods for obtaining fibers of very small thickness. There is a wide-scale use of nanofibers, and it has a great potential in many fields, such as in medicine, biology, chemistry, electronics, environmental protection, energy-harvesting, and other. Polyvinylidene fluoride (PVDF) appears to be a promising material for fiber production for its excellent mechanical and chemical properties. It is a chemically inert substance, very resistant to thermal stress. The aim of this bachelor thesis is the preparation of PVDF fibers by electrospinning and the study of the influence of three different surfactants on the spinnability of PVDF, on the arrangement and the shape of fibers which are formed during electrospinning. The effect of surfactant concentration (1 wt%; 0.5 wt%; 0.25 wt%) on the spinning process at electrical voltages of 25 kV and 50 kV was studied. The theoretical part describes the properties and the division of polymers and looks at polyvinylidene fluoride (PVDF) as a source material in more detail. Furthermore, the electrospinning method is described, including process conditions and external parameters influencing the process of obtaining fibers. The experimental part describes the preparation of samples by electrospinning and their characterization. Fiber thickness, its appearance, arrangement, and the occurrence of defects when using individual surfactants were evaluated. It was found that the used ionic surfactants affect the thickness of the fibers and their morphology. Homogeneous fibers with a predominant arrangement in one direction, without defects, were obtained.
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