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1

Kodad, Daniel. "Impaktor pro laboratorní záchyt jemných částic." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443199.

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The focus of this master’s thesis is the issue of fine dust particles suspended in the air and their measurement. The thesis explains the basic characteristics of fine particles and the rules, which they follow. The section then examines the health risks of inhaled particles. Next is explained the influence of particles in the air on the environment, the historical development of the air pollution in the Czech Republic and the most important pollutants. After that is described the legislation, which frames the limits for pollutants suspended in the air. In the practical part is described the methods for calculation the geometry of cascade impactor, the design of three-stage impactor and finally the comparison with professional impactor. The designed impactor was then constructed and tested with wood burning stove as a source of particles.
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2

Kadrmas, Lukáš. "Homogenní kapota - chování při nárazech impaktorem hlavy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228590.

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This thesis deals with the subject of crash tests Euro NCAP, concretely child-head impact test to the car bonnet. Object of thesis is make homogeneous car bonnet, where will remove stiffness places and also the bonnet global stiffness won´t be worst. The bonnet must carry out limits for pedestrian protection.
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Coufal, Tomáš. "Studie vlivu vlastností materiálu na simulaci nárazu hlavy chodce na kapotu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228589.

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The thesis describes the complex of basic testing procedures conducted by Euro NCAP company with a view to the examination of pedestrian protection in accordance with EEVC WG 17 and topical instruments used at passenger vehicles for pedestrian protection. It includes a detailed procedure of the creation of an adult head impactor including its certification and the formation of its impact on the bonnet of the vehicle. It is specialized in the studies how material properties influence the size of HIC criterion.
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4

Jaška, Lukáš. "Simulace nárazu vozidla na dolní končetinu chodce." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-377357.

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This thesis seeks to simulate the impact on the human foot on the car bumper. The opening section deals with requirements as to the current passive safety features aiming to mitigate the consequences of such impact. The thesis also describes the construction of a human foot impactor, its certification via both static and dynamic tests, a simulation of the cash test and its evaluation. The designed model as well as the simulation procedure have been led according to the current Euro NCAP specifications.
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Kysilko, Vít. "Optimalizace HIC kritéria při nárazu impaktorem hlavy na kapotu auta." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230463.

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Kvůli stále značnému počtu usmrcených chodců při dopravních nechodách se výrobci automobilů snaží pomocí vhodné konstrukce automobilu zmírnit následky způsobené nehodou. Při srážce impaktoru hlavy s kapotou automobilu dochází ke zpomalení impaktoru a na toto zpomalení je aplikováno HIC kitérium. HIC kritérium vyhodnocuje míru možnosti poranění hlavy při srážce. Cílem diplomové práce je výběr nejvhodnějšího časového průběhu zpomalení dětského impaktoru hlavy při srážce s kapotou automobilu Škoda Superb II z hlediska HIC kritéria a navržení konstrukčních úprav kapoty a okolních částí, které se dostanou do kontaktu tak, aby se skutečný průběh blížil teoretické fyziologicky přípustné variantě. Pro výpočtové modelování úlohy byla použita explicitní varianta metody konečných prvků (MKP). V první části práce jsou analyzovány data ze simulací úderu impaktoru dětské hlavy na kapotu auta, zvlástě pak analýzy částí energie spotřebované kapotou při srážce s impaktorem. Tyto data byly poskytnuté firmou Škoda Auto a.s. Další část se zaobírá návrhem křivek zpomalení se sinusovým, čtvercovým a trojúhelníkým tvarem. Dále je také navržena 2 vrcholová trojúhelníhová křivka zpomalení, jež je pomocí parametrů modifikovatelná. Optimalizací aproximovaného modelu geometrie kapoty automobilu při dopadu impaktoru hlavy na navržený model geometrie kapoty je zajištěno podobné shody s dříve optimalizovanou 2 vrcholovou trojúhleníkovou křivkou zpomalení. V další části je použit originální model geometrie kapoty automobilu Škoda Superb II a další optimalizace modelu geometrie kapoty vůči optimálnímu časovému průběhu zpomalení.
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6

Václavík, Ondřej. "Studium otěruvzdorných vrstev vytvořených laserovým naplavováním pomocí metody dynamického rázového impaktoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230536.

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Diploma thesis studies the layers created by laser cladding and method of testing abrasion resistance of these layers using the method of dynamic shock impactor. In the theoretical part describes laser technologies and their applications, hardness testing and methods of testing of coatings. Proposed by the mechanical testing of the selected materials were carried out and evaluated in the experimental part. The conclusion summarizes final results of the experiment.
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Mišík, Ondrej. "Inhalátory a nebulizátory pro použití v medicíně: principy, spolehlivost a provozní parametry." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399566.

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An issue of inhalation therapy is a complex topic, actively discussed in last decades, and its progress in various scientific fields is more than required. First part of this thesis brings a theoretical introduction into principles of aerosol therapy and into the requirements resulting from them. Commonly available technologies of inhalers and nebulisers for medical usage, parameters that determinate their effectivity are briefly described. Usage mistakes influencing the effectivity of inhalation are discussed, as well. Second part deals with experimental measurements of aerosol that selected inhalers generate. It also describes difficulties connected with the methods of these measurements, with sampling and following analyses. Gained results are compared with an available literature.
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8

Václavík, Jiří. "Posouzení informačního systému ve společnosti Impakt fitness a návrh změn." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-414323.

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This diploma thesis analyses a company providing complex sport services in a Vyškov region. The analysis assesses the information system of the organization to understand its position. It identifies the strengths, weaknesses, opportunities, and threats to use it as a foundation for a new company IT strategy.
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Wernet, Ruth [Verfasser], and M. [Akademischer Betreuer] Seipenbusch. "Impaktion und Fragmentierung von Nanopartikeln im Niederdruck und Hochvakuum / Ruth Wernet ; Betreuer: M. Seipenbusch." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1166234223/34.

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Correia, Lukus Meides Sarmento. "Impacto do desenvolvimento do turismo nas condições socioeconómicas e ambientais no subdistrito de Tutuala." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/13029.

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O Plano Estratégico de Desenvolvimento Nacional de Timor- Leste abrange três áreas fundamentais: capital social, desenvolvimento de infra-estruturas e desenvolvimento económico. O sector do turismo foi considerado desde logo como um sector importante para este plano por trazer benefícios económicos e gerar emprego para os jovens, com especial incidência no Subdistrito de Tutuala, Distrito de Lautem o qual é apontado como uma referência turística na zona mais leste do país. O propósito deste trabalho é efetuar um estudo de opiniões e repercussões socioeconómicos e ambientais que o desenvolvimento do turismo terá na referida zona. A zona selecionada para o seu desenvolvimento é atualmente conhecida como o sítio mais lindo e premiado pela natureza sendo assim um pólo de atração turística. O presente estudo consiste numa pesquisa exploratória, quantitativa e documental, recorrendo-se, para tal, a dados secundários existentes nos organismos públicos e privados, além de consultas a artigos, dissertações, teses, entre outros e a dados primários obtidos através da realização de entrevistas semi-estruturadas e de questionários. Os resultados deste estudo revelaram que, a falta de planeamento, recursos humanos, instalações e as infra-estruturas para incentivar atividades de desenvolvimento do turismo, causaram a baixa participação da comunidade local no seu desenvolvimento económico. Os impactos decorrentes das atividades turísticas não foram consideradas nocivas para o meio ambiente, mas também se concluiu que o processo de desenvolvimento turístico naquela zona ainda não teve impactos na optimização das necessidades da comunidade locais; IMPAKTO DO DESENVOLVIMENTO NO KONDISAUN EKONOMIKO E SOCIAL IHA SUBDISTRITU DE TUTUALA REZUMU: Planu estratégiku desenvolvimentu nacional de Timor-leste difini ba sektor importante tolu hanesan; kapital social, infrasterutura, desenvolvimentu ekonómiku. Sektor turismo nu'udar área ida importante atu bele promove no hasai kresimento ekonómiko povo nian liu-liu iha área rural hanesan iha subdistrito de Tutuala, ne'ebé ema hotu konsidera hanesan fatin furak liu iha parte loro sa'e Timor-Leste nian. Motivo husi estudu ida ne'e atu bele tetu impaktus socioekonomiko, no ambintal ne'ebé afekta ba prosesu desenvolvimento turismo iha zona ida ne'e. Zona ida-ne'e mos sai nu'udar tarjetu ba estudu ne'e, tamba iha zona ida ne'e sai nu'udar fatin furak liu hodi dada ema turistas liur sira atu mai visita. Peskisa ida-ne'e e uza metodu explorativa kuantitavia, dukumental, uza dadus primaria no sekundaria ne'ebé iha orgaun publikus e privadus, nomós halo konsulta ba artigus, teze no sira seluk tan. Resultadu ne'ebé hetan husi pesquisa ne'e hatudu katak sei iha limitasaun barak iha parte rekusus humanus, no plano ne'ebé diak atu bele jere modelu servisu iha fatin turismo, seidauk iha partisipasaun másimu husi komunidade ba atividade turismo nian. Iha parte ekonomiko seidauk iha rendimentu diak atu bele sustenta moris loron-loron nian. Impaktus husi ambiental nian seidauk iha ameasa seriu durante ne'e, tanba atividade ne'ebé iha ona seidauk lori resultadu diak hanesan iha fatin seluk ne'ebé atividade turistika sai nu'udar dalan diak atu bele hetan osan sai moris diak liu.
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11

Erhart, Tobias. "Strategien zur numerischen Modellierung transienter Impaktvorgänge bei nichtlinearem Materialverhalten." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11730049.

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12

Holsten, Anne. "Climate change vulnerability assessments in the regional context." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6683/.

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Adapting sectors to new conditions under climate change requires an understanding of regional vulnerabilities. Conceptually, vulnerability is defined as a function of sensitivity and exposure, which determine climate impacts, and adaptive capacity of a system. Vulnerability assessments for quantifying these components have become a key tool within the climate change field. However, there is a disagreement on how to make the concept operational in studies from a scientific perspective. This conflict leads to many still unsolved challenges, especially regarding the quantification and aggregation of the components and their suitable level of complexity. This thesis therefore aims at advancing the scientific foundation of such studies by translating the concept of vulnerability into a systematic assessment structure. This includes all components and implies that for each considered impact (e.g. flash floods) a clear sensitive entity is defined (e.g. settlements) and related to a direction of change for a specific climatic stimulus (e.g. increasing impact due to increasing days with heavy precipitation). Regarding the challenging aggregation procedure, two alternative methods allowing a cross-sectoral overview are introduced and their advantages and disadvantages discussed. This assessment structure is subsequently exemplified for municipalities of the German state North Rhine-Westphalia via an indicator-based deductive approach using information from literature. It can be transferred also to other regions. As for many relevant sectors, suitable indicators to express the vulnerability components are lacking, new quantification methods are developed and applied in this thesis, for example for the forestry and health sector. A lack of empirical data on relevant thresholds is evident, for example which climatic changes would cause significant impacts. Consequently, the multi-sectoral study could only provide relative measures for each municipality, in relation to the region. To fill this gap, an exemplary sectoral study was carried out on windthrow impacts in forests to provide an absolute quantification of the present and future impact. This is achieved by formulating an empirical relation between the forest characteristics and damage based on data from a past storm event. The resulting measure indicating the sensitivity is then combined with wind conditions. Multi-sectoral vulnerability assessments require considerable resources, which often hinders the implementation. Thus, in a next step, the potential for reducing the complexity is explored. To predict forest fire occurrence, numerous meteorological indices are available, spanning over a range of complexity. Comparing their performance, the single variable relative humidity outperforms complex indicators for most German states in explaining the monthly fire pattern. This is the case albeit it is itself an input factor in most indices. Thus, this meteorological factor alone is well suited to evaluate forest fire danger in many Germany regions and allows a resource-efficient assessment. Similarly, the complexity of methods is assessed regarding the application of the ecohydrological model SWIM to the German region of Brandenburg. The inter-annual soil moisture levels simulated by this model can only poorly be represented by simpler statistical approach using the same input data. However, on a decadal time horizon, the statistical approach shows a good performance and a strong dominance of the soil characteristic field capacity. This points to a possibility to reduce the input factors for predicting long-term averages, but the results are restricted by a lack of empirical data on soil water for validation. The presented assessments of vulnerability and its components have shown that they are still a challenging scientific undertaking. Following the applied terminology, many problems arise when implementing it for regional studies. Advances in addressing shortcomings of previous studies have been made by constructing a new systematic structure for characterizing and aggregating vulnerability components. For this, multiple approaches were presented, but they have specific advantages and disadvantages, which should also be carefully considered in future studies. There is a potential to simplify some methods, but more systematic assessments on this are needed. Overall, this thesis strengthened the use of vulnerability assessments as a tool to support adaptation by enhancing their scientific basis.
Die Anpassung von Sektoren an veränderte klimatische Bedingungen erfordert ein Verständnis von regionalen Vulnerabilitäten. Vulnerabilität ist als Funktion von Sensitivität und Exposition, welche potentielle Auswirkungen des Klimawandels darstellen, und der Anpassungsfähigkeit von Systemen definiert. Vulnerabilitätsstudien, die diese Komponenten quantifizieren, sind zu einem wichtigen Werkzeug in der Klimawissenschaft geworden. Allerdings besteht von der wissenschaftlichen Perspektive aus gesehen Uneinigkeit darüber, wie diese Definition in Studien umgesetzt werden soll. Ausdiesem Konflikt ergeben sich viele Herausforderungen, vor allem bezüglich der Quantifizierung und Aggregierung der einzelnen Komponenten und deren angemessenen Komplexitätsniveaus. Die vorliegende Dissertation hat daher zum Ziel die Anwendbarkeit des Vulnerabilitätskonzepts voranzubringen, indem es in eine systematische Struktur übersetzt wird. Dies beinhaltet alle Komponenten und schlägt für jede Klimaauswirkung (z.B. Sturzfluten) eine Beschreibung des vulnerablen Systems vor (z.B. Siedlungen), welches direkt mit einer bestimmten Richtung eines relevanten klimatischen Stimulus in Verbindung gebracht wird (z.B. stärkere Auswirkungen bei Zunahme der Starkregentage). Bezüglich der herausfordernden Prozedur der Aggregierung werden zwei alternative Methoden, die einen sektorübergreifenden Überblick ermöglichen, vorgestellt und deren Vor- und Nachteile diskutiert. Anschließend wird die entwickelte Struktur einer Vulnerabilitätsstudie mittels eines indikatorbasierten und deduktiven Ansatzes beispielhaft für Gemeinden in Nordrhein-Westfalen in Deutschland angewandt. Eine Übertragbarkeit auf andere Regionen ist dennoch möglich. Die Quantifizierung für die Gemeinden stützt sich dabei auf Informationen aus der Literatur. Da für viele Sektoren keine geeigneten Indikatoren vorhanden waren, werden in dieser Arbeit neue Indikatoren entwickelt und angewandt, beispielsweise für den Forst- oder Gesundheitssektor. Allerdings stellen fehlende empirische Daten bezüglich relevanter Schwellenwerte eine Lücke dar, beispielsweise welche Stärke von Klimaänderungen eine signifikante Auswirkung hervorruft. Dies führt dazu, dass die Studie nur relative Aussagen zum Grad der Vulnerabilität jeder Gemeinde im Vergleich zum Rest des Bundeslandes machen kann. Um diese Lücke zu füllen, wird für den Forstsektor beispielhaft die heutige und zukünftige Sturmwurfgefahr von Wäldern berechnet. Zu diesem Zweck werden die Eigenschaften der Wälder mit empirischen Schadensdaten eines vergangenen Sturmereignisses in Verbindung gebracht. Der sich daraus ergebende Sensitivitätswert wird anschließend mit den Windverhältnissen verknüpft. Sektorübergreifende Vulnerabilitätsstudien erfordern beträchtliche Ressourcen, was oft deren Anwendbarkeit erschwert. In einem nächsten Schritt wird daher das Potential einer Vereinfachung der Komplexität anhand zweier sektoraler Beispiele untersucht. Um das Auftreten von Waldbränden vorherzusagen, stehen zahlreiche meteorologische Indices zur Verfügung, welche eine Spannbreite unterschiedlicher Komplexitäten aufweisen. Bezüglich der Anzahl monatlicher Waldbrände weist die relative Luftfeuchtigkeit für die meisten deutschen Bundesländer eine bessere Vorhersagekraft als komplexere Indices auf. Dies ist er Fall, obgleich sie selbst als Eingangsvariable für die komplexeren Indices verwendet wird. Mit Hilfe dieses einzelnen meteorologischen Faktors kann also die Waldbrandgefahr in deutschen Region ausreichend genau ausgedrückt werden, was die Ressourceneffizienz von Studien erhöht. Die Methodenkomplexität wird auf ähnliche Weise hinsichtlich der Anwendung des ökohydrologischen Modells SWIM für die Region Brandenburg untersucht. Die interannuellen Bodenwasserwerte, welche durch dieses Modell simuliert werden, können nur unzureichend durch ein einfacheres statistisches Modell, welches auf denselben Eingangsdaten aufbaut, abgebildet werden. Innerhalb eines Zeithorizonts von Jahrzehnten, kann der statistische Ansatz jedoch das Bodenwasser zufriedenstellend abbilden und zeigt eine Dominanz der Bodeneigenschaft Feldkapazität. Dies deutet darauf hin, dass die Komplexität im Hinblick auf die Anzahl der Eingangsvariablen für langfristige Berechnungen reduziert werden kann. Allerdings sind die Aussagen durch fehlende beobachtete Bodenwasserwerte zur Validierung beschränkt. Die vorliegenden Studien zur Vulnerabilität und ihren Komponenten haben gezeigt, dass eine Anwendung noch immer wissenschaftlich herausfordernd ist. Folgt man der hier verwendeten Vulnerabilitätsdefinition, treten zahlreiche Probleme bei der Implementierung in regionalen Studien auf. Mit dieser Dissertation wurden Fortschritte bezüglich der aufgezeigten Lücken bisheriger Studien erzielt, indem eine systematische Struktur für die Beschreibung und Aggregierung von Vulnerabilitätskomponenten erarbeitet wurde. Hierfür wurden mehrere Ansätze diskutiert, die jedoch Vor- und Nachteile besitzen. Diese sollten vor der Anwendung von zukünftigen Studien daher ebenfalls sorgfältig abgewogen werden. Darüber hinaus hat sich gezeigt, dass ein Potential besteht einige Ansätze zu vereinfachen, jedoch sind hierfür weitere Untersuchungen nötig. Insgesamt konnte die Dissertation die Anwendung von Vulnerabilitätsstudien als Werkzeug zur Unterstützung von Anpassungsmaßnahmen stärken.
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Krüger, Lutz. "Untersuchungen zum Festigkeits-, Verformungs- und Versagensverhalten der Legierung Ti-6-22-22S in Abhängigkeit von der Temperatur, der Dehngeschwindigkeit und dem Spannungszustand." Doctoral thesis, Universitätsbibliothek Chemnitz, 2001. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200100265.

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Untersuchung des Verhaltens der Fließspannung und der Verformungsfähigkeit der Titanlegierung Ti-6-22-22S in Abhängigkeit von der Temperatur, der Dehngeschwindigkeit und dem Spannungszustand. Nachweis der thermischen Aktivierung der Versetzungsbewegung bis zu Dehngeschwindigkeiten von 10^5 1/s für diesen Werkstoff. Beschreibung des Versagens als Funktion der Temperatur, der Dehngeschwindigkeit und des Spannungszustandes. Erarbeitung einer Prüfmethode zur Charakterisierung des Scherverhaltens unter hohen überlagerten Druckbelastungen.
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Verš, Evelin. "Development of impact-induced hydrothermal system at Kärdla impact structure /." Tartu, Estonia : Tartu University Press, 2006. http://dspace.utlib.ee/dspace/bitstream/10062/187/1/verzevelin.pdf.

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Dostálová, Dagmar. "Využití různých frakcionačních technik pro studium struktury ICP." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-217144.

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Impact E/P copolymer (ICP) is produced using gas-phase polymerization catalysed by Ziegler-Natta catalysts. This material with its excellent mechanical properties is used in many industries, for example in automotive industry to produce bumpers or instrument panels. Its properties depend on chemical structure which was analysed using DSC, 13C NMR and GPC. It was used 6 different samples of ICP for studies, the chosen samples have different ratio between ethylene and propylene in their copolymer phase. The samples were fractionated using preparative TREF and solvent extraction to obtain fractions, which composition depends on elution temperature. Obtained fractions and original samples were subsequently analysed using above-mentioned methods.
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Václavík, Tomáš. "Návrh a dispoziční uspořádání vysokotlaké čerpací stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228753.

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The aim of diploma thesis is design and lay-out of high pressure pumping station with plunger pumps for splash of scales from slabs of hot-rolled. Theoretic (introduction) part of this thesis contain description of formation of scales and description of ways how it is possible remove these scales. And this part contains also explication of effect of water jet on solid material. The practical part of diploma thesis is focused on design of pumping station including of dimensioning of machinery. Part of this work is also technical documentation for proposed pumping station and specification of main machines and devices.
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Hrabovský, Jozef. "Kvantifikace mechanismů hydraulického odstranění okují." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234002.

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The issue of descaling is an important part of the forging and heat treatment of steel and semi products of steel production. Rising of new information and study of this process can increase efficiency and improve the surface quality after descaling. This thesis is focused on the mechanisms of the high pressure hydraulic descaling qualification and study of the chemical compounds of which the scales grown. To achieve all goals of this work and to get a comprehensive view of descaling process, few experimental measurements and numerical analyses were performed. All experimental measurements were focused on obtaining data about fundamental parameters and effects of the hydraulic descaling. The data obtained from measurements were applied to numerical analyses, which aimed to discover a deeper relation and to confirm the experimental results. This thesis can be divided into two main parts. The first part is devoted to parameters of the water jet study. The main studied characteristics of the high pressure hydraulic water jet were heat transfer coefficient and impact pressure at different modes such as standard or pulsating water jet. Experimentally measured data of these parameters were applied in numerical analyses. The numerical analyses were focused on studying the impact of the water jet parameters on the stresses in the oxide scale layers. A further water jet analysis was focused on the influence of the individual parts of the hydraulic system (such as water chamber or stabilizer) on its characteristics. In this part different types of the water chambers in combination with different types of stabilizers on the impact pressure values were investigated. These measurements were supported by fluid flow analysis through the hydraulic system. The second part of this work was focused on getting mechanical properties of the oxide scales from specimens prepared from standard structural steel and specimens from silicon steel. In this thesis, the influence of various parameters and characteristics was studied on these two types of steel. Mechanical properties of oxide scale structures were carried out by the Small Punch Test method. To obtain the fundamental mechanical properties such as Young´s modulus, yield strength and ultimate strength, material parameters based on the measured data were optimized. The whole work was carried out in order to get valuable and comprehensive results about high pressure hydraulic descaling process and influencing factors as well as about oxide scales themselves.
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Curosu, Iurie. "Influence of fiber type and matrix composition on the tensile behavior of strain-hardening cement-based composites (SHCC) under impact loading." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233204.

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Strain-hardening cement-based composites (SHCC) are a special class of fiber-reinforced concrete which develop multiple, fine cracks when subjected to increasing tensile loading, reaching strain capacities of up to several percent. The tensile behavior of SHCC is a result of a purposeful material design accounting for the mechanical and physical properties of the cementitious matrix, of the reinforcing fibers and of their interaction. The exceptionally high energy dissipation through inelastic deformations before reaching tensile strength makes SHCC suitable for manufacturing or strengthening of structural elements which may be subjected to impact loading. However, the tensile behavior of SHCC is highly strain rate dependent, both in terms of tensile strength and strain capacity. The different strain rate sensitivities of the constitutive phases of SHCC (matrix, fiber and interfacial bond) lead to disproportionate dynamic alteration of their mechanical properties under increasing strain rates and, consequently, to an impairment of the micromechanical balance necessary for strain-hardening and multiple cracking. Thus, high energy dissipation under impact loading can only be ensured through a targeted material design. This work presents a series of mechanical experiments at different strain rates and different scales of investigation with the goal of developing a qualitative and quantitative basis for formulating material design recommendations for impact resistant SHCC. Three different types of SHCC were investigated, consisting of two types of polymer fibers (polyvinyl-alcohol and high-density polyethylene) and cementitious matrices (normal-strength and high-strength). Uniaxial tension experiments were performed on SHCC specimens and on non-reinforced matrix specimens with different testing setups at strain rates ranging from 10-4 to 150 s-1. Besides the measured mechanical properties, special attention was paid to the crack patterns and the condition of fracture surfaces. Additionally, micro-scale investigations were performed to quantify the strain rate dependent changes in the mechanical behavior of individual component phases, i.e., matrix, fibers and fiber-matrix bond. The results obtained from the micromechanical investigations were used in an analytical model for crack bridging. The model links the micromechanical parameters and their strain rate sensitivities to the single-crack opening behavior under increasing displacement rates, making it useful for material design purposes. If given an extensive experimental basis for the fracture mechanical properties of the non-reinforced cementitious matrices, the model can be extended for predicting the strain capacity (multiple cracking) of SHCC under different strain rates
Die hochduktilen Betone (Engl.: Strain-Hardening Cement-based Composites – SHCC) bilden eine besondere Klasse von Faserbetonen, die eine multiple Rissbildung unter zunehmenden Zugspannungen aufweisen, was zu einer sehr hohen Bruchdehnung führt. Das dehnungsverfestigende, hochduktile Zugverhalten der SHCC wird durch eine gezielte Materialentwicklung erreicht, die die mechanischen und physikalischen Eigenschaften der zementgebundenen Matrizen, der Kurzfasern und deren Zusammenwirkung berücksichtigt. Das außergewöhnliche Energieabsorptionsvermögen der SHCC durch plastische Verformungen vor dem Erreichen der Zugfestigkeit qualifiziert diese Verbundwerkstoffe für die Herstellung oder Verstärkung von Bauteilen, die Impaktbeanspruchungen ausgesetzt sein könnten. Jedoch weisen SHCC sowohl bezüglich deren Zugfestigkeit als auch deren Dehnungskapazität ein ausgeprägtes dehnratenabhängiges Verhalten auf. Unter zunehmenden Dehnraten führen die unterschiedlichen Dehnratensensitivitäten der gestaltenden Phasen von SHCC (Matrix, Faser und deren Verbund) zur Beeinträchtigung des mikromechanischen Gleichgewichts, welches für die Dehnungsverfestigung und multiple Rissbildung erforderlich ist. Eine hohe Energiedissipation unter Impaktbeanspruchungen kann deshalb nur durch eine gezielte Materialentwicklung der SHCC hinsichtlich deren Verhaltens unter hohen Dehnraten gewährleistet werden. Die vorliegende Arbeit umfasst eine Reihe von experimentellen Untersuchungen mit verschiedenen Dehnraten und an unterschiedlichen Betrachtungsebenen, mit dem Ziel eine qualitative und quantitative Basis für Empfehlungen zur Materialentwicklung von Impakt-resistenten SHCC zu schaffen. Drei verschiedene SHCC-Zusammensetzungen wurden untersucht. Die Referenz-Zusammensetzung aus einer normalfesten zementgebundenen Matrix und Polyvinyl-Alkohol-Kurzfasern wurde mit zwei unterschiedlichen SHCC verglichen (hochfest und normalfest), die mit Kurzfasern aus hochdichtem Polyethylen bewehrt wurden. Einaxiale Zugversuche wurden an SHCC-Proben und unbewehrten Matrix-Proben mit verschiedenen Prüfvorrichtungen bei Dehnraten von 10-4 bis 150 s-1 durchgeführt. Zusätzlich zu den gemessenen mechanischen Eigenschaften wurden die Rissbildung und die Bruchflächen detailliert untersucht. Darüber hinaus wurden mikromechanische Untersuchungen durchgeführt, um die Dehnratensensitivität der einzelnen Phasen, d.h. Matrix, Faser und deren Verbund zu beschreiben. Die aus den mikromechanischen Untersuchungen erzielten Ergebnisse wurden als Eingangswerte in einem analytischen Einzelriss-Modell verwendet. Das entwickelte Modell verbindet die mikromechanischen Parameter und deren Dehnratenabhängigkeit mit dem Rissöffnungsverhalten von SHCC bei zunehmenden Verschiebungsraten. Das macht es vorteilhaft für Materialentwicklungszwecke. Das Modell kann für die Vorhersage der Dehnungskapazität von SHCC bei diversen Dehnraten weiterentwickelt werden, wenn eine umfassende experimentelle Basis für die bruchmechanischen Eigenschaften der Matrizen vorliegt
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19

Votavová, Helena. "Vývoj nových přístupů v odstraňování okují při kontinuální výrobě oceli s využitím vysokotlakého vodního paprsku." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401607.

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The thesis summarizes general and up-to-date knowledge of descaling during the continuous production of the hot-rolled steel and proposes further streamlining of this process in industrial production. The first chapter of the thesis deals with the origin, structure and physical properties of the scales. The second chapter describes the principles of descaling by using a high pressure flat water jet. The third chapter introduces the principles of the experimental methods and describes the used laboratory equipment. The fourth chapter summarizes the description of the particular experiments and their evaluation, and thus represents the focus of the dissertation. It is divided into six sections which independently solve predefined objectives of the dissertation. The first section focuses on the height and structure development of the scales on 54SiCr6 and HDT580X steels. It has been proven that the height of the formed scales increases with the time and temperature of the oxidation. The layered nature of the scales was verified at the same time. The second section examines the effect of the nozzle stabilizer on the focussing and distribution of the impact pressure of the nozzle. Experiments have shown that increase of 11 % of an average maximum nozzle pressure can be achieved, depending on the type of nozzle and the length of the stabilizer. The third section deals with the analysis of shadowgraphy images of water jet structures of the nozzles. A script was developed for analysis of these shadowgraphy photos by an adaptive thresholding. The findings are correlated using a regression analysis with an average heat transfer coefficient. It has been reported that most of the standard nozzle configurations produced disintegrated stream of little droplets at the height of the rolled surface. The fourth section focuses on the area of water jet overlap, especially the area of the so-called washout, where the impact pressure of one nozzle is reduced by the nozzle stream of the other. The influence of the pressure change and the mutual displacement of the nozzles is investigated. The analysis showed that the change of pressure did not have any effect on the percentage of reduction of the impact pressure in the area of the washout. It has been shown that if the area of the washout is wide the descaling efficiency in this area may be reduced. The fifth section builds on the previous section and focuses directly on the areas of waterjet overlaps. The influence of the change of rotation and pitch of the nozzles is studied. Experiments have shown that small changes in nozzle pitch do not have a significant impact on impact pressure and heat transfer coefficient. The effect of nozzle rotation, on the other hand, was a significant factor for the efficiency and homogeneity of the descaling of the surface. The last section deals with the effect of the rolling speed on the heat transfer coefficient in the descaling process. The regression model has shown that with a higher rolling speed there is a reduction in the average heat transfer coefficient. Conclusion summarizes the results of the dissertation and proposes which findings can be used in the industry to make the descaling process more effective.
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20

Morén, David, and Georg Pehrs. "Study of Vehicle-to-Pedestrian Interactions with FEM – Evaluation of Upper Leg Test Methods using a Human Body Model." Thesis, KTH, Skolan för teknik och hälsa (STH), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123953.

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The European New Car Assessment Programme (Euro NCAP) performs several different tests to evaluate vehicles and rate their safety. Some of these tests are subsystem tests made to mimic different body parts of a pedestrian in an interaction with a vehicle. However, some criticism to the test method for the upper leg has been presented, stating that there is a discrepancy between this test method and a real-life interaction. Therefore, a modified test method for the upper leg has been proposed. The aim of this thesis was to evaluate the upper leg test method used today by Euro NCAP, and compare it with the proposed modified test method as well as to computer simulations with a Human Body Model (HBM). The evaluation was performed by comparing different parameters obtained in the two test methods. These have also been compared to computer simulations using a HBM in interaction with a passenger vehicle model. Prior to the evaluation of the test methods, the HBM was positioned into different stances to mimic postures in the human walking cycle. The vehicle model was positioned at four different heights, and three different impact points along the bonnet were used. The results showed that the different methods had their own advantages for some parameters. However, no general conclusion of which method showed the closest correlation to the HBM reference simulations could be determined.
European New Car Assessment Programme (Euro NCAP) utför flera olika tester för att utvärdera fordon och betygsätta deras säkerhet. Några av dessa tester sker med delsystem skapade för att efterlikna olika kroppsdelar hos en fotgängare i en kollision med ett fordon. Viss kritik har dock riktats mot testmetoden för lårben och höft, då studier visat att det finns en skillnad mellan testmetoden och en verklig kollision. En modifierad testmetod för lårbenet och höften har därför föreslagits. Syftet med detta examensarbete har varit att utvärdera testmetoden för lårben och höft, som idag används av Euro NCAP, och jämföra den med den föreslagna modifierade testmetoden men även datorsimuleringar med en humanmodell. Utvärderingen har genomförts genom att jämföra olika parametrar som erhållits från de två testmetoderna. Dessa parametrar har även jämförts med datorsimuleringar av fotgängarkollisioner med en humanmodell och en bilmodell. Humanmodellen positionerades i olika kroppsställningar innan utvärderingen av testmetoderna genomfördes. Detta för att efterlikna verkliga positioner i en mänsklig gångcykel. Bilmodellen positionerades vid fyra olika höjder och tre träffpunkter längs motorhuven användes. Resultaten visade att båda metoderna hade fördelar gentemot varandra för vissa parametrar. Ingen generell slutsats kunde dock dras om vilken metod som visade närmast korrelation till referenssimuleringarna med humanmodellen.
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21

Molčan, Filip. "Vliv omezujících stěn na proudění z ventilační vyústky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378274.

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The goal of this work is to experimentally assess the influence of limiting walls of Škoda Octavia 3 automobile cabin to the air jet flowing from the right-front situated automotive vent which is part of a car dashboard. The experiment is performed by the smoke visualization method. There is a single construction option measured for an experiment. The setup of the vanes direction and the air flow rate are modified for this option. The experiment is divided into two phases. In the first phase, the visualization of the free air flow is conducted. In the second phase, exit plates are constructed and consequently, the visualization of the wall-jet flow is conducted. The results of both are compared to each other. The results imply that the influence of the surrounding surfaces must be taken into account with the increasing flow rate for the vanes set in the direction of upper-right, middle-right, and middle-middle. There is a direct interaction between the flow and exit plates (the flow impact, the Coanda effect). The free flow does not contain the information about the mutual interaction between the flow and the exit plates, as it is in the case of the wall-jet flow. In the case of the wall-jet flow, the opening of the flow takes place due to the effect of the impact and the subsequential suction caused by the Coanda effect. The exit plates substituting the car dashboard and the front window contribute to the prevention of the air intake from surrounding space and consequently to earlier flow opening from the vent. The present work also contains the measurement methodology and the image evaluation, the comparison with previous free flow measurements (70% match) and the comparison to the measurement of hot-wire anemometry method.
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22

Odehnal, Ondřej. "Simulace průrazů kompozitních panelů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318146.

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This master thesis focuses on modelling and simulation of impact tests of composite panels. Simulations and analysis were made by using Finite Element Method in software MSC Patran and Dytran. The first part of the thesis deals with describing the properties of composite panels during impact testing and other cases of impacts on composite structures. Next part deals with the used models and results from Dytran. These results are compared with experimental data from real low-velocity impact tests. Part of the thesis is devoted to impact on panels with the stacking sequences which is supposed to be used for design of air duct for airplane Aero L-39NG.
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23

Rootenberg, Cindy. "A model of perceived impacts of tourism on residents' quality of life in selected towns / C. Rootenberg." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9825.

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Worldwide tourism has become one of the largest and fastest growing industries. Specifically in the South African context, this growth has been confirmed in recent statistics. However, the growth in the tourism industry does not occur without challenges. It brings both benefits and costs to the residents of a host community, consequently generating both positive and negative tourism impacts. Further, it is recognised that once a community becomes a tourism destination, the lives of the residents are influenced by that particular development; thus effecting their Quality of Life (QoL). Only minimal research has, however, been conducted to determine the influence of the perceived impacts of tourism on residents’ QoL, especially in the South African context. A number of theoretical frameworks have been developed in tourism to signify how the perception of or reactions towards tourism of residents in a host community are influenced at any particular stage of development. Pertaining to QoL, various theoretical models have also been created to describe the functioning of the construct. Although theoretical frameworks have been developed that are distinct to tourism and QoL; to date an integrated approach does not exist that explores the influence of tourism on residents’ QoL. In addition to the lack of an integrated approach in literature, the permanency of tourism products too have not yet been examined in literature. Further, permanency has not been examined in order to determine the influence of tourism impacts on residents’ QoL in selected towns, one being a permanent tourism product (PTP) and the other a nonpermanent tourism product (N-PTP). From the above, it can be seen that three theoretical and practical issues exist: (1) only a modest amount of research has been done to determine the influence of tourism impacts on residents’ QoL; (2) an integrated approach does not exist signifying the relationship between tourism impacts and QoL and; (3) permanency as a differentiation factor has not been investigated in host communities. By addressing these issues, a significant contribution will be made to literature, together with the ensuing practical contributions. Therefore, the main goal of the study was to develop a model to indicate the influence of perceived impacts of tourism on residents’ QoL in selected towns; these having specific differentiation made between a PTP and N-PTP. In order to achieve the goal of the study, five objectives were formulated: The first objective was to analyse theoretical frameworks of tourism and QoL and to identify a particular theoretical framework for the study. Specifically, the Social Exchange Theory (SET) was selected from the theoretical frameworks of tourism, while the Bottom-up Spillover theory was designated as it is peculiar to QoL frameworks. Therefore, the derived theoretical framework indicated that an ‘exchange’ process occurs between tourism development and the residents of the host community. More specifically, social exchange arises between the perceived impacts of tourism and life domains in order to establish the QoL of residents in host communities. The second objective was to analyse tourism both as an industry and product in a host community through a review of existing literature. From the literature review, it can be seen that tourism is a growing industry and product, not only internationally but also in the South African context. Permanency as a characteristic was explored comprehensively to define a tourism product while maintaining the differentiation between a PTP and N-PTP. Residents of a host community are noted as important roleplayers in the tourism industry as tourism impacts affect them in PTP and in N-PTP. This importance is emphasised as residents of a host community: (1) influence the tourism experience; (2) determine the attractiveness of a destination and; (3) control the sustainability of tourism in a host community. The third objective was to analyse QoL and its relation to the residents of a host community, once more, through a literature review. From the review, it was observed that QoL has different definitions and views, some more intricate than others. For the purpose of the study, it was determined that QoL can be described appropriately through the Bottom-up Spillover theory. Therefore, QoL is determined through the collaboration of various life domains that, further, may be either objective or subjective in nature. When examining the relationship between tourism development and QoL, it was established that tourism, through tourism products, produces effects that will influence various life domains, consequently determining the QoL of residents in a host community. As with tourism impacts, the QoL of the host community’s residents will subsequently: (1) influence the tourism experience; (2) determine the attractiveness of a destination and; (3) ensure the sustainability of tourism in a community. The fourth objective was to analyse the influence of the economic, environmental, social and cultural impacts of tourism on residents’ QoL and to differentiate between a PTP and N-PTP by using an empirical study. Having in mind that the main goal of the study was to develop a model, Confirmatory Factor Analysis (CFA) and Structural Equation Modelling were conducted on the data. The models, constructed separately for tourism impacts and QoL, were subsequently integrated to determine the influence of the perceived impacts of tourism on residents’ QoL. The model with good model fit statistics and supportive of underlying theory was thereafter accepted for further analysis in order to attain comprehensively the main goal of the study. Thereafter, model development tested permanency of tourism products by specifically determining the influence of perceived impacts of tourism on residents’ QoL in selected towns (PTP and N-PTP). From the latter exercise, no practically significant differences were found between a PTP and N-PTP. Therefore, the model constructed as Stage 3 was accepted as the final model of the study and was given the title of Root’s model of Community TourQoL (CTQ). Specifically, the model signified that positive economic, environmental, social and cultural impacts influence residents’ QoL, while negative environmental and social impacts do not influence residents’ QoL in host community. Furthermore, the model showed that no differences were found between a PTP and N-PTP regarding the influence of perceived impacts of tourism on residents’ QoL. The fifth and final objective was to draw conclusions, indicate contributions, formulate recommendations and present limitations peculiar to the study. The greatest significance of the study is seen in the practical contributions of the study, specifically, the development of Root’s model of Community TourQoL (CTQ). Community and tourism planners and/management can implement the model in both PTP and N-PTP to enhance the positive impacts of tourism; while minimising negative impacts, in order to improve residents’ QoL.
Thesis (PhD (Tourism Management))--North-West University, Potchefstroom Campus, 2013.
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24

Vavrečka, Lukáš. "VLIV PARAMETRŮ VYSOKOTLAKÉHO OSTŘIKU NA KVALITU ODOKUJENÍ." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233948.

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This work is focussed on hydraulic descaling of hot surfaces. Hydraulic descaling is a process when layers of oxides are removed from hot steel surfaces during continuous rolling. High pressure water beam is used. Quality of descaled surfaces is important for final quality of rolled product. Insufficient descaling causes drop of final quality, degradation of rolls and lost of yields. High-pressure water beam has two effects on a scale layer. The first effect is mechanical caused by impact pressure. The second one is a relatively intensive thermal shock depending on a set of parameters (water pressure, nozzle type, distance from the surface, inclination angle, speed of product moving). There are a lot of theories about principles of scales removing. Main task of this work is to make it clear which theory is acceptable and which is just ,,theory”. For this purpose mathematical modelling and experimental work were used. In experimental part, three types of experimental measurement were done. First one, measurement of dynamical effect of water beam – impact pressure. Second one, measurement of temperature drop when a product is passing under the nozzle. Measured data (temperatures) from this measurement are evaluated with inverse task and heat transfer coefficient is obtained. And the third experimental measurement is simulation of whole process of descaling. Quality of descaled surfaces is valuated according to amount of remained oxide scales. Data from firs and second experimental measurement are used as boundary conditions for mathematical modelling. For mathematical simulations, FEM (finite element method) system ANSYS was used. Obtained data from experimental measurement were applied on 2D and 3D models of basic steel material with layer of scale. Influence of theses data on final temperature, stress and strain fields were observed.
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25

Weidemeyer, Sven. "Taxonomie, Paläoökologie und Paläobiodiversitätsdynamik benthischer Mollusken an der Kreide-Paläogen-Grenze von Patagonien." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/16031.

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Aus Patagonien lagen bisher wenige Daten zu paläoökologischen Veränderungen und zur Paläobiodiversität an der Kreide-Paläogen (K/Pg)-Grenze vor. Um diese Lücke zu schließen, wurden in den argentinischen Provinzen Neuquén und Chubut zahlreiche Profile im Bereich der K/Pg-Grenze detailliert beprobt. Während einer Planktonkrise, wie sie für die K/Pg-Grenze angenommen wird, werden für benthische Mollusken folgende Entwicklungen erwartet: 1. eine Abnahme der Individuenzahlen der Benthosorganismen, 2. eine Abnahme der vom Plankton als Nahrungsquelle direkt abhängigen Organismen, 3. eine Abnahme der Benthonten mit planktotrophen Larvalstadien, 4. eine Abnahme der mittleren Körpergröße der Individuen benthischer Faunengemeinschaften und 5. eine Abnahme der Organismen mit hoher Stoffwechselrate bzw. aktiver, mobiler Lebensweise. Tatsächlich waren die hungerresistenten Gruppen der Nuculoida (flach-infaunale Depositfresser) und der Lucinidae (Chemosymbionten) im Danium signifikant häufiger als im Maastrichtium, während der Faunenanteil der Suspensionsfresser im Danium im Vergleich zum Maastrichtium signifikant niedriger ist. In den Faunengemeinschaften des Daniums von Bajo de Añelo konnten Abnahmen der Individuenzahlen, der mittleren Mobilität und der mittleren Größe festgestellt werden. Die beobachteten paläoökologischen Veränderungen zeigen somit eine Selektivität, die sich auch in der Paläobiodiversitätsdynamik widerspiegelt. Auch hier sind Suspensionsfresser, die direkt vom Planktonangebot abhängig sind, stärker betroffen als Chemosymbionten und flach-infaunale Depositfresser. Die Aussterberaten für Bivalven sind mit 28% moderat. Insgesamt sind die festgestellten Selektivitätsmuster konsistent mit den zu erwartenden Folgen einer Planktonkrise. Trotz einiger regionaler Unterschiede handelte es sich um ein globales Ereignis an der K/Pg-Grenze, das Nord- und Südhalbkugel gleichermaßen betroffen hat.
From Patagonia only a few data on palaeoecological changes and on palaeobiodiversity at the Cretaceous/Paleogene (K/Pg)-boundary are available so far. Therefore detailed samples in different K/Pg-sections in the Argentinian provinces of Neuquén and Chubut were taken to increase the data set for this region. The following trends are expected from a crisis of primary productivity in the aftermath of the K/Pg-boundary: 1. a reduction in the number of individuals of benthic organisms, 2. a decrease in the relative abundance of organisms which rely directly on photosynthesis, 3. a lower proportion of individuals with planktotrophic larval stages, 4. a reduction in the average body size of individuals within palaeocommunities and 5. an increased abundance of organisms with low metabolic rates or inactive lifestyles. In fact the proportion of the starvation-resistant groups of the Nuculoida (shallow-infaunal deposit feeders) and Lucinidae (chemosymbionts) were significantly higher in the Danian compared to the Maastrichtian. In contrast to this, the proportion of suspension feeders in the palaeocommunities was significantly lower in the Danian in comparison with the Maastrichtian. In the Danian benthic assemblages of the Bajo de Añelo area, a decrease in number of individuals, mean mobility and mean size was recognised after the K/Pg-boundary. Thus the palaeoecological changes display a selectivity, which is also reflected in the palaeobiodiversity. Suspension feeders, which depend directly on plankton particles from the water column, show higher extinction rates than chemosymbionts and shallow-infaunal deposit feeders. The extinction rates of Patagonian bivalves are moderate (28%). Overall, the recognized selectivity patterns are consistent with the expected aftermath of a crisis in primary productivity. Despite some local differences, the results argue for a global event at the K/Pg-boundary during which the northern and southern hemispheres were similarly affected.
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26

Bilarev, Todor. "Feedback Effects in Stochastic Control Problems with Liquidity Frictions." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19592.

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In dieser Arbeit untersuchen wir mathematische Modelle für Finanzmärkte mit einem großen Händler, dessen Handelsaktivitäten transienten Einfluss auf die Preise der Anlagen haben. Zuerst beschäftigen wir uns mit der Frage, wie die Handelserlöse des großen Händlers definiert werden sollen. Wir identifizieren die Erlöse zunächst für absolutstetige Strategien als nichtlineares Integral, in welchem sowohl der Integrand als der Integrator von der Strategie abhängen. Unserere Hauptbeiträge sind hier die Identifizierung der Skorokhod M1 Topologie als geeigneter Topologue auf dem Raum aller Strategien sowie die stetige Erweiterung der Definition für die Handelserlöse von absolutstetigen auf cadlag Kontrollstrategien. Weiter lösen wir ein Liquidierungsproblem in einem multiplikativen Modell mit Preiseinfluss, in dem die Liquidität stochastisch ist. Die optimale Strategie wird beschrieben durch die Lokalzeit für Reflektion einer Diffusion an einer nicht-konstanten Grenze. Um die HJB-Variationsungleichung zu lösen und Optimalität zu beweisen, wenden wir probabilistische Argumente und Methoden aus der Variationsrechnung an, darunter Laplace-Transformierte von Lokalzeiten für Reflektion an elastischen Grenzen. In der zweiten Hälfte der Arbeit untersuchen wir die Absicherung (Hedging) für Optionen. Der minimale Superhedging-Preis ist die Viskositätslösung einer semi-linearen partiellen Differenzialgleichung, deren Nichtlinearität von dem transienten Preiseinfluss abhängt. Schließlich erweitern wir unsere Analyse auf Hedging-Probleme in Märkten mit mehreren riskanten Anlagen. Stabilitätsargumente führen zu strukturellen Bedingungen, welche für ein arbitragefreies Modell mit wechselseitigem Preis-Impakt gelten müssen. Zudem ermöglichen es jene Bedingungen, die Erlöse für allgemeine Strategien unendlicher Variation in stetiger Weise zu definieren. Als Anwendung lösen wir das Superhedging-Problem in einem additiven Preis-Impakt-Modell mit mehreren Anlagen.
In this thesis we study mathematical models of financial markets with a large trader (price impact models) whose actions have transient impact on the risky asset prices. At first, we study the question of how to define the large trader's proceeds from trading. To extend the proceeds functional to general controls, we ask for stability in the following sense: nearby trading activities should lead to nearby proceeds. Our main contribution in this part is to identify a suitable topology on the space of controls, namely the Skorokhod M1 topology, and to obtain the continuous extension of the proceeds functional for general cadlag controls. Secondly, we solve the optimal liquidation problem in a multiplicative price impact model where liquidity is stochastic. The optimal control is obtained as the reflection local time of a diffusion process reflected at a non-constant free boundary. To solve the HJB variational inequality and prove optimality, we need a combination of probabilistic arguments and calculus of variations methods, involving Laplace transforms of inverse local times for diffusions reflected at elastic boundaries. In the second half of the thesis we study the hedging problem for a large trader. We solve the problem of superhedging for European contingent claims in a multiplicative impact model using techniques from the theory of stochastic target problems. The minimal superhedging price is identified as the unique viscosity solution of a semi-linear pde, whose nonlinearity is governed by the transient nature of price impact. Finally, we extend our consideration to multi-asset models. Requiring stability leads to strong structural conditions that arbitrage-free models with cross-impact should satisfy. These conditions turn out to be crucial for identifying the proceeds functional for a general class of strategies. As an application, the problem of superhedging with cross-impact in additive price impact models is solved.
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27

Kozáková, Jana. "Vliv lokálního topení na kvalitu ovzduší ve vnitřním a venkovním prostředí malého sídla." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297658.

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Increased concentrations of particulate matter do not occur in urban areas only, they occur in winter time episodes of high concentrations in small settlements, as well. It is probably caused by usage of solid fuels in domestic heating. The indoor air quality is closely influenced by the outdoor air pollution. Concentrations of size-separated PM were measured by a cascade impactor (PCIS) during two winter and one summer seasons in the years 2009 and 2010 in a village Svrčovec situated near the town Klatovy. Continuous concentrations of PM2.5 were measured in parallel by using a commercial photometer DustTrak. Following meteorological parameters were monitoring - temperature, relative humidity, wind velocity, wind direction, precipitation and sun radiation. The presence of persons and their activities in the house were noted. The average PM10 concentrations in Svrčovec were higher than average PM10 concentration in Klatovy. The summer average PM10 concentrations in Svrčovec were lower than the concentrations in the town (15.5 μg/m3, 17.4 μg/m3) and the winter PM10 concentrations in Svrčovec were significantly higher (31.1 μg/m3, 24.3 μg/m3). The average indoor concentrations (PM10 and PM2.5) were lower in the summer (9.6 μg/m3, 8.3 μg/m3) than in the winter season (24.0 μg/m3, 20.7...
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Kozáková, Jana. "Studium velikostně rozlišeného atmosférického aerosolu pomocí kaskádních impaktorů." Doctoral thesis, 2018. http://www.nusl.cz/ntk/nusl-392478.

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This dissertation includes two main research projects: 1) the investigation of the intermodal fraction and 2) the influence of regional air pollution transport on Ostrava. Introduction and aim of the first project. Fine and coarse particulate matter (PM) of atmospheric aerosol are considered as separate pollutants and overlap in the particle size range of about 1 - 2.5 μm (aerodynamic diameter dae; PM1-2.5) which represents the intermodal fraction. Sources of both fine and coarse fractions contribute to PM1-2.5 to different extents due to changing meteorological and spatial conditions. Therefore, there is an ongoing discussion as to whether PM1 should be included for monitoring as an additional fine particulate pollutant by the ambient air quality standard. The intrusion of the one fraction to the other one can lead to some inaccuracies in the source apportionment, epidemiological and exposure studies. The aim of the first project was to examine the associations between PM1-2.5 and the coarse (PM2.5-10 or PM>2.5)/fine (PM1) fraction under different meteorological conditions at various sites in the Czech Republic during winter and summer seasons. Introduction and aim of the second project. The EU air quality standards have been frequently exceeded in one of the European air pollution hot spots:...
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Fanta, Ondřej. "Biomechanická odpověď na impaktní zátěž crania." Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-275635.

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Biomechanical response to the impact cranio burden is especially closely related topic the biomechanics of head injuries on impact, often in a car accident. Acquired knowledge can be applied in all activities in which there is a head on collision obstacle. Mechanisms responsible accidents in sports, such as falls cycling, lyžích or due to the nature of sport itself, eg. boxing, rugby, ice hockey, etc. The study has to outline a comprehensive overview and sequence of events and biomechanical patterns, which occurs when the head impact into obstacles. The main challenge will be to physically and biomechanically describe the sequence of injuries on impact and maximize the přiblížit to real injury that created obstacles to the head impact (windshield, dashboard, steering wheel, airbag, roadway, rival, fist, rail, ...). An essential part of understanding the basic knowledge anatomy of the head and Traumatology, certain specifics of injuries in traffic accidents and in frontal collision and biomechanical evaluation of head injuries. We will experiment impinging load and after analyzing the physical and biomechanical data will be recorded values, especially the value of HIC ("Head Injury Criterion") correlated with AIS ("Abbreviated Injury Scaled ') table and compared with the correlations from the literature. The...
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Sedláček, Jozef. "Metodické možnosti posuzování vizuálního impaktu v procese EIA." Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-425536.

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The aim of the thesis is to propose a methodical approach that would include aspects of visual landscape assessment, emphasis on historical and perceptual values of the area and was applicable in the EIA process. The aim is the applicability of the proposed methodology in the assessment of new projects by the management of heritage care, especially in the process of environmental impact assessment (where the management of heritage care is concerned by the state administration body concerned), but also in other proceedings. The procedure should not replace subjective assessment or landscape survey, but create objective evidence for the decision and serve to negotiate between the investor and the state administration bodies concerned. The procedure should use geographic information systems, including current data bases and functionalities.
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Badal, Tomáš. "Impakt zvěře na dřeviny na LHC Lesy města Prostějova." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-93473.

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Scholtz, Marco. "A critical assessment of the social impacts of tourism in selected South African communities / Marco Scholtz." Thesis, 2014. http://hdl.handle.net/10394/11974.

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Understanding the social impacts of tourism is important as it enables tourism managers and developers to manage the impacts toward fostering vital community support for the industry. More so the distinction between the tangible and intangible social impacts can refine tourism management, development and marketing processes. The measurement and management of these impacts are fairly straight forward in developed countries. However in developing countries, such as South Africa, more challenges exist in identifying and managing their impacts to the benefit of a wider community. South Africa has one of the most unequal distributions of income in the world as well as a very high unemployment rate which all complicates the understanding and management of these impacts. All factors taken into account create prevailing socio-political, economic as well as cultural barriers. This translates into community members not necessarily obtaining tangible benefits from the tourism industry such as increased levels of income, job creation and infrastructure development for instance, which is the ideal situation. The social exchange theory explains that these residents might as a result deter their support for the tourism industry. However it is important to determine which types of benefits will lead to increased levels of community support and therefore the following research questions can be formulated: “What are the tangible and intangible social impacts of tourism on communities and how strong is the role they play in fostering community support for the tourism industry?” Therefore the primary goal of this thesis was to conduct a critical assessment of the social impacts of tourism on selected communities with reference to the tangible and intangible impacts. This primary goal was reached through the achievement of four objectives. The first objective was a critical analysis of literature pertaining to sociology and how communities perceive tourism from a sociological perspective. The review analysed communities’ roles in tourism, barriers that hinder them from partaking in the industry as well as recommendations that were made to overcome the barriers. The term “social impact” as well as models that explain how and why social impacts take place, were analysed. This objective provided a foundation for the rest of the study in terms of social impacts of tourism on communities. The second objective was to critically analyse the social impacts that originate as a result of tourism activity, but to interpret it from a tangible contrasted with intangible point of view. This was done in order to create a better understanding what role tangible and intangible social impacts play, as well as how strong a role it plays in influencing community perceptions. The third objective was to determine the residents’ perceptions of tangible and intangible social impacts of tourism on three tourism dependent communities in South Africa as well as to determine the variables that influence the perceptions of these impacts. This was done with the aim of creating a model for measuring the tangible and intangible social impacts of tourism which will allow for improved marketing and managing of tourism in South African communities. The distinction between the tangible and intangible social impacts of tourism in mind, a selfadministered questionnaire was distributed in three tourism-dependent communities in South Africa by means of probability sampling within stratified sampling. The communities included in the research were Clarens (n=251), Soweto (n=375) and Jeffreys Bay (n=417). The questionnaires were captured in Microsoft Excel and analysed in the IBM Statistical Package for Social Sciences (SPSS v 20.0.0), while the software package, Analysis of Moment Structures (AMOS v 21.0.0) was utilised for the Structural Equation Model (SEM). The analysis of the data was done over three phases. The first phase was exploratory research which included the use of two-way frequency tables for compiling a combined community profile as well as two Exploratory Factor Analyses to explore the ways in which tangible and intangible social impacts can be grouped. In the second phase, Confirmatory Factor Analyses (CFA) revealed the theoretical model with four reliable tangible social impacts and two reliable intangible impacts. The tangible social impacts included: environmental improvement; environmental degradation; cost of daily living; and economic improvement while the intangible social impacts included: community upliftment and pride and community protection and education. The intangible social impact, community upliftment and pride was perceived as the most important impact, thus revealing the power of intangible social impacts for fostering community support for tourism. Significant to this study it was found that community members remained supportive of the industry, even if they are not directly involved in it. It was furthermore found that the communities are not homogenous which holds major implications for tourism planners and managers. This resulted in further analyses to compare the communities. Analyses were done in order to determine the influence of variables such as tourism perceptions, involvement in the tourism industry as well as residents’ levels of education on the perceptions of the tangible and intangible social impacts of tourism. Very few instances were found where these aspects acted as strong predictors of the perceptions of tangible and intangible social impacts of tourism. During the third and final phase, a model was developed for measuring the relationships between the tangible and intangible social impacts of tourism. This innovative model has been optimised so that it can be applied to other tourism dependents communities in South Africa. This model can thus assist tourism planners and managers to understand the tangible and intangible impacts as a result of tourism in the designated communities as well as how these communities will perceive the impacts. This model thus serves as a tool for maximising the positive social impacts created by tourism and minimising the negative, thus contributing to the sustainable development of the industry. The last objective was to draw conclusions and make recommendations with regard to the objectives of the study. The contributions of the study were also discussed as part of this objective. It was determined that this study makes multiple contributions towards social impact literature in tourism, towards the applicable methodology of determining social impacts in developing countries as well as practical contributions that will inform future planning and development in communities. This thesis firstly contributed towards the literature by distinguishing between tangible and intangible social impacts within a tourism and developmental context. These categorised social impacts can also be used in future research as it contributes to the research methodology through the development of a questionnaire that can measure the tangible and intangible social impacts of tourism within a South African context. This measuring instrument can also be used in future research. The finding which revealed that the intangible element (community upliftment and pride) was the most important to local residents has implications for tourism planning and development. It is therefore a factor that should be taken into account in future research. There are also several practical implications for tourism marketers, managers and developers. The development of the tangibleintangible impact model provides the latter with an instrument that can be used to measure and effectively manage the various social impacts of tourism. It is clear that communities cannot be seen as homogeneous, therefore individual planning should be done based on the character and composition of the applicable communities.
PhD (Tourism Management), North-West University, Potchefstroom Campus, 2014
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33

Mareček, Lukáš. "Ekologické aspekty impaktu hrabošů (Microtus spp.) a norníka rudého na výsadby buku lesního v pohoří Hrubý Jeseník." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-178731.

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In the mountains Hrubý Jeseník was the 18 monitoring plots in the years 2010-2013 conducted tramping of small mammals, inventory damage gnaw the bark of the beech forest plantations and the measured data to investigate the factors influencing the impact of small mammals. Small mammals were then evaluated in terms of dominance, impact on planting and statistically analyzed factors affecting impact. The results show that the dominant group were representatives Arvicolinae (n= 512, 62.4%): Clethrionomys glareolus (n= 306, 37.3%), Microtus agrestis (n= 181, 22.1%), Microtus arvalis (n=23, 2.8%), Microtus subterraneus (n= 2, 0.2%). In terms gnaw the bark of trees to damage most often involved in Microtus agrestis and Microtus arvalis, causing minor damage also Clethrionomys glareolus. Altitude, exposition, composition and character of the herb layer and abundance of voles are significant factors which can affect the impact of small mammals. This information can be useful for forest management, which can reduce the risk of the forest damage occurrence and decrease costs of silvicultural operations.
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Chytilová, Martina. "Vliv stabilizačních cvičení pletence ramenního na svalovou aktivitu při přímém impaktu u hráčů ragby se subakromiálním impingement syndromem." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-349033.

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Title: The effect of shoulder girdle stabilization exercises on muscle activity during direct impact in rugby players with sub-acromial impingement syndrome Objectives: Comparison of muscle activity during direct impact while performing the rugby tackle to tackle bag and to player using amplitude analysis of electromyographic signal (EMG) before and after intervention programme for players with subacromial impingement syndrome (SIS). Application of intervention programme consisting stabilization excercises for shoulder complex and activation of deep stabilization muscles of the spine. Methods: Theoretical part contains topics about shoulder girdle, rugby and rugby injuries, mainly subacromial impingement syndrome and electromyography. Mentioned issues are included into the thesis due to the research of current literature from international sources and studies. Practical part regards the aplication of three- months long intervention programme for eight rugby players at junior national level with diagnosis of SIS, when pre-testing a post-testing is realized by clinical tests and EMG measurement. Results: Intervention programme was sufficient for changes of EMG amplitude values expressed as percentage of maximal voluntary isometric contraction (MVIC) in some of rugby players with SIS only for some...
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35

Baláž, Gabriel. "Distribuce jelení zvěře v závislosti na typu vegetace a její vliv na keřové patro." Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-86661.

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36

Klaclová, Marie. "Drobní zemní savci hospodářských lesních porostů Jeseníků." Master's thesis, 2008. http://www.nusl.cz/ntk/nusl-95148.

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37

Slanina, Libor. "Faktory ovlivňující míru okusu spárkatou zvěří na jedlových kulturách." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-88580.

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38

Lulák, Martin. "Vývoj reliéfu v oblasti impaktního kráteru Siljan." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-335134.

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Impact events and associated processes can significantly reshape the natural environment of the Earth and other bodies in the Solar system. The Siljan impact crater in the middle of Sweden was created in late Devonian and it is the biggest known morphostructure of this kind in Europe. The presented paper aims at the relief evolution of the Siljan impact crater area. Landforms of the region are studied, including relicts of the impact event, and main stages of relief evolution from the Paleozoic to the present are determined. Special attention is focused to discussion about the range and types of erosional and denudational processes in relation to the level of preservation of morphological and geological indices about the Devonian impact. Ascertained knowledge about relicts of the Siljan impact event are compared with selected impact craters on the Earth, the Moon and Mars.
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KUDRLIČKOVÁ, Martina. "Tradice a zvyklosti jako udržitelný produkt cestovního ruchu." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-367495.

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This diploma thesis, which is called Tradition and habits as a sustainable product of tourism, deals with the analysis of traditions in Českobudějovicko, focuses more on the tradition of fishing and fish farming. It focuses more on the producers and suggests a sustainable tourism product. The aim of the thesis is to propose a sustainable tourism product in the chosen destination of Českobudějovicko with the expression of economic impacts, based on the analysis of traditions and customs offers. The partial objective is to analyze the supply of fishery and fishery producers in connection with tourism use.
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40

Kozáková, Radka. "Krajinna raného středověku a její změny s nástupem kolonizace." Doctoral thesis, 2011. http://www.nusl.cz/ntk/nusl-311343.

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Landscape transformation that occurred during the Middle Ages in western and central Europe is reflected in all pollen diagrams. An event that was so striking and widespread was used by Firbas to distinguish a biostratigraphical period called the Younger Subatlantic (zone X; Firbas 1949). High Medieval landscape transformation is connected with rapid colonization in our area that resulted in extensive deforestation and intensified agriculture. During the first half of the 13th century, the settlement network was already stabilized and was very similar to the current state and was reaching also mountain areas (Klápště 1994). New organization and changes in land ownership, as well as a need for more effective agriculture, resulted in the connecting of small fields into larger ones and in an increase of cultivated area (Klápště 2006). The use of the land was different, and for the first time complete (Bakels 2009). During a few centuries anthropogenic factors that were enormously enhanced throughout the 13th century, formed a cultural landscape that was much more similar to the landscape of today than to the landscape of, for instance, the 9th century. This doctoral thesis is focused on the Early Medieval landscape in the Czech lands and its transformation that culminated during the 13th and 14th...
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Panská, Šárka. "Vliv hyperkinetické zátěže na vybrané mechanické změny axiálního systému člověka." Doctoral thesis, 2019. http://www.nusl.cz/ntk/nusl-404798.

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Title: Influence of Hyperkinetic Load on Selected Mechanical Changes of Human Axial System. Objectives: The main aim of this thesis is to determine the influence of hyperkinetic load on the change of selected mechanical properties of the rhythmic gymnastic axial system based on the sophisticated use of the Transfer Vibration through Spine (TVS) method. Methods: The following experimental methods were used to identify changes in rheological properties of AS and to assess load intensity: 1) TVS method; 2) software for evaluating and analyzing vibration tests of heterogeneous systems; 3) kinematic and dynamic motion analysis using:  2D motion video recording,  QUALISYS 3D motion analysis system,  KISTLER, to analyze dynamic human-surroundings interactions. Results: Pilot studies and the main experimental part of the thesis have shown that the use of the TVS method can identify both short-term and longitudinal changes of AS mechanical properties. Due to the hyperkinetic load, the selected mechanical properties of the rhythmic AS are changed. The gymnastic apparatus reacts to the training load by reducing the rheological parameters, especially the damping coefficient b and the viscosity µ. After regeneration, which is on the following day, the parameters return to the default values. The impact load...
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42

Půlpánová, Petra. "Měření dopadu dokumentárních filmů na postoje a chování diváků." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-357637.

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The thesis deals with measuring impact of documentary films on attitudes and behavior of the audience. The theoretical basis of this thesis is the assumption that social impact is a dynamic process where the engagement of an individual can lead to change of attitudes and behavior, and the individual's influence on others can change the society. Another assumption is that the impact on an individual is influenced by emotional and rational involvement. The third assumption is that the impact on the viewer changes over time when the extent of short-term impact after seeing the movie is bigger than extent of the impact measured with delay. The analytical part is devoted to the application of the method of repeated questioning, which allows to capture the development of the impact on the viewer over time. Within this thesis, a secondary analysis of quantitative data gathered in research of impact of films on ecological topic screened in film festival One World has been conducted. In addition, a thematic analysis of the in-depth interviews was conducted. These interviews have been carried out in order to establish the reasons and ways in which films impact the viewers. The conclusion of this thesis is that differences can be observed between the short and long-term impact on viewers in specific areas of...
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Halžová, Daniela. "Geomorfologické aspekty výskytu vltavínů ve střední Evropě." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-368045.

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GEOMORPHOLOGICAL ASPECTS OF THE OCCURRENCE OF MOLDAVITES IN THE CENTRAL EUROPE ABSTRACT: In the presented paper, geomorphological aspects of the occurrence od moldavites are evaluated. The origin od moldavites in the Miocene and position of their main finding places in Czechia is described. For studies and documentation of morphology of the surface of moldavites was used the collection of the Faculty od Science at Charles University. Special attention during field geomorphic servey of finding places of moldavites was attend to the localities between settlements Ločenice, Nesměň and Chlum nad Malší. Main features od the natural environment were identified as well as recent changes of landforms caused by prohibited and legal extraction of moldavites. All notable finding places of moldavites in the southern Bohemia are affected by these anthropogenic changes of the landscape. It is discussed that absence of moldavites in some denuded areas of the region where they are occurring can indicate a range of rocks exhumation since the upper Miocene. On the contrary, it is suggested thah morphostratigraphical significance od sporadic findings of moldavites many kilometres from primary localities is limited by a low resistance of the shape and volume of moldavites in relation to fluvial transport. However, very...
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Kaiserová, Tereza. "Fosfan a oxid dusný jako falešně pozitivní biosignatury ve spektrech planet." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-449041.

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5 Abstract This study is dedicated to evaluating the potential for a novel pathway of abiotic synthesis of phosphine (PH3) from phosphorus trioxide (P4O6) by a photocatalytic mechanism on aerosols. The mechanism might explain the recent possible detection of phosphine on Venus. This scenario has recently been suggested theoretically by our team based on an analogy with methane production form carbon dioxide on acidic photochemically-active surfaces of materials, which may account for a possible source of methane on Mars. Methane, just like phosphine, was suggested as an indicator of life on terrestrial planets, including Mars. The theoretical testing of photochemical phosphine generation suggests that even if this gas is present in the atmosphere of Venus it cannot be considered as an indicator of life until the suggested mechanism is excluded theoretically, or by experimental results, or direct evidence of life on Venus. This thesis will be followed by preparation of sophisticated experiments and intensive laboratory research addressing this. Furthermore, the role of nitrous oxide as another false positive biosignature was evaluated in this study. The presence of nitrous oxide can also be explained by processes other than biological, particularly on early planets. This study specifically demonstrates the...
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Hladík, Marek. "Studie ekosystémových dopadů invaze bolševníku velkolepého (Heracleum mantegazzianum)." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297259.

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The present study deals with ecological impact of giant hogweed (Heracleum mantegazzianum) invasion in Slavkovský les area. Being one of the prominent invasive species with significant impact on human health it has been subjected to a wide research. In spite of that little is known about its impact on the invaded ecosystem. My research was therefore focused on analysis of the ecosystem impact, particulary 1) microclimatic measurements of temperature and soil moisture and their comparisons between invaded and noninvaded vegetation, 2) comparison of germination and survival of model plant species sowed into invaded and noninvaded plots and 3) study of the effect of H. mantegazzianum presence on model species seed production. Results have shown significant alteration of microclimate due to H. mantegazzianum invasion. Further research is needed to resolve what impact it may pose to species in invaded communities. The effect of Heracleum mantegazzianum presence on germination and survival of model species was not significant. Similarly, seed production of model plants was not significantly affected.
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46

Curosu, Iurie. "Influence of fiber type and matrix composition on the tensile behavior of strain-hardening cement-based composites (SHCC) under impact loading." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30801.

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Strain-hardening cement-based composites (SHCC) are a special class of fiber-reinforced concrete which develop multiple, fine cracks when subjected to increasing tensile loading, reaching strain capacities of up to several percent. The tensile behavior of SHCC is a result of a purposeful material design accounting for the mechanical and physical properties of the cementitious matrix, of the reinforcing fibers and of their interaction. The exceptionally high energy dissipation through inelastic deformations before reaching tensile strength makes SHCC suitable for manufacturing or strengthening of structural elements which may be subjected to impact loading. However, the tensile behavior of SHCC is highly strain rate dependent, both in terms of tensile strength and strain capacity. The different strain rate sensitivities of the constitutive phases of SHCC (matrix, fiber and interfacial bond) lead to disproportionate dynamic alteration of their mechanical properties under increasing strain rates and, consequently, to an impairment of the micromechanical balance necessary for strain-hardening and multiple cracking. Thus, high energy dissipation under impact loading can only be ensured through a targeted material design. This work presents a series of mechanical experiments at different strain rates and different scales of investigation with the goal of developing a qualitative and quantitative basis for formulating material design recommendations for impact resistant SHCC. Three different types of SHCC were investigated, consisting of two types of polymer fibers (polyvinyl-alcohol and high-density polyethylene) and cementitious matrices (normal-strength and high-strength). Uniaxial tension experiments were performed on SHCC specimens and on non-reinforced matrix specimens with different testing setups at strain rates ranging from 10-4 to 150 s-1. Besides the measured mechanical properties, special attention was paid to the crack patterns and the condition of fracture surfaces. Additionally, micro-scale investigations were performed to quantify the strain rate dependent changes in the mechanical behavior of individual component phases, i.e., matrix, fibers and fiber-matrix bond. The results obtained from the micromechanical investigations were used in an analytical model for crack bridging. The model links the micromechanical parameters and their strain rate sensitivities to the single-crack opening behavior under increasing displacement rates, making it useful for material design purposes. If given an extensive experimental basis for the fracture mechanical properties of the non-reinforced cementitious matrices, the model can be extended for predicting the strain capacity (multiple cracking) of SHCC under different strain rates.
Die hochduktilen Betone (Engl.: Strain-Hardening Cement-based Composites – SHCC) bilden eine besondere Klasse von Faserbetonen, die eine multiple Rissbildung unter zunehmenden Zugspannungen aufweisen, was zu einer sehr hohen Bruchdehnung führt. Das dehnungsverfestigende, hochduktile Zugverhalten der SHCC wird durch eine gezielte Materialentwicklung erreicht, die die mechanischen und physikalischen Eigenschaften der zementgebundenen Matrizen, der Kurzfasern und deren Zusammenwirkung berücksichtigt. Das außergewöhnliche Energieabsorptionsvermögen der SHCC durch plastische Verformungen vor dem Erreichen der Zugfestigkeit qualifiziert diese Verbundwerkstoffe für die Herstellung oder Verstärkung von Bauteilen, die Impaktbeanspruchungen ausgesetzt sein könnten. Jedoch weisen SHCC sowohl bezüglich deren Zugfestigkeit als auch deren Dehnungskapazität ein ausgeprägtes dehnratenabhängiges Verhalten auf. Unter zunehmenden Dehnraten führen die unterschiedlichen Dehnratensensitivitäten der gestaltenden Phasen von SHCC (Matrix, Faser und deren Verbund) zur Beeinträchtigung des mikromechanischen Gleichgewichts, welches für die Dehnungsverfestigung und multiple Rissbildung erforderlich ist. Eine hohe Energiedissipation unter Impaktbeanspruchungen kann deshalb nur durch eine gezielte Materialentwicklung der SHCC hinsichtlich deren Verhaltens unter hohen Dehnraten gewährleistet werden. Die vorliegende Arbeit umfasst eine Reihe von experimentellen Untersuchungen mit verschiedenen Dehnraten und an unterschiedlichen Betrachtungsebenen, mit dem Ziel eine qualitative und quantitative Basis für Empfehlungen zur Materialentwicklung von Impakt-resistenten SHCC zu schaffen. Drei verschiedene SHCC-Zusammensetzungen wurden untersucht. Die Referenz-Zusammensetzung aus einer normalfesten zementgebundenen Matrix und Polyvinyl-Alkohol-Kurzfasern wurde mit zwei unterschiedlichen SHCC verglichen (hochfest und normalfest), die mit Kurzfasern aus hochdichtem Polyethylen bewehrt wurden. Einaxiale Zugversuche wurden an SHCC-Proben und unbewehrten Matrix-Proben mit verschiedenen Prüfvorrichtungen bei Dehnraten von 10-4 bis 150 s-1 durchgeführt. Zusätzlich zu den gemessenen mechanischen Eigenschaften wurden die Rissbildung und die Bruchflächen detailliert untersucht. Darüber hinaus wurden mikromechanische Untersuchungen durchgeführt, um die Dehnratensensitivität der einzelnen Phasen, d.h. Matrix, Faser und deren Verbund zu beschreiben. Die aus den mikromechanischen Untersuchungen erzielten Ergebnisse wurden als Eingangswerte in einem analytischen Einzelriss-Modell verwendet. Das entwickelte Modell verbindet die mikromechanischen Parameter und deren Dehnratenabhängigkeit mit dem Rissöffnungsverhalten von SHCC bei zunehmenden Verschiebungsraten. Das macht es vorteilhaft für Materialentwicklungszwecke. Das Modell kann für die Vorhersage der Dehnungskapazität von SHCC bei diversen Dehnraten weiterentwickelt werden, wenn eine umfassende experimentelle Basis für die bruchmechanischen Eigenschaften der Matrizen vorliegt.
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Quast, Matthias. "Betondruckfestigkeit unter zweiaxialer dynamischer Belastung." 2018. https://tud.qucosa.de/id/qucosa%3A70884.

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Zur Beantwortung der Frage, wie sich die festigkeitssteigernden Effekte aus mehraxialer und dynamischer Druckbelastung in Beton überlagern wurde ein weltweit einzigartiger zweiaxialer Split-Hopkinson-Bar entwickelt. Es wurden umfangreiche Versuchsserien mit insgesamt mehr als 2500 Einzelversuchen durchgeführt. Ermittelt wurden dabei die ein- und zweiaxialen statischen und dynamischen Betondruckfestigkeiten zweier Betone der Druckfestigkeitsklassen C20/25 und C40/50. Die Versuchsergebnisse wurden hinsichtlich der Festigkeitsentwicklung in Abhängigkeit vom Spannungsverhältnis und der Dehnrate ausgewertet. Die Ergebnisse aus den zweiaxialen dynamischen Betondruckversuchen konnten als dreidimensionale Abhängigkeit der Spannungen in beiden Belastungsachsen von der Dehnrate für jede der beiden Betonsorten abgebildet werden. Aus den Ergebnissen wurde ein Ingenieurmodell für jede Betonsorte entwickelt, welches die Betondruckfestigkeitsentwicklung in Abhängigkeit vom Spannungsverhältnis und der Dehnrate beschreibt. Mit zunehmender Dehnrate wird die zweiaxiale Ergebniskurve um einen zusätzlichen, dynamischen Anteil der Festigkeitssteigerung vergrößert. Dabei kommt es aber nur zu einer teilweisen Überlagerung der beiden betrachteten festigkeitssteigernden Einflüsse. Eine Abschätzung der Größenordnung der jeweiligen Einflüsse aus Mehraxialität und hoher Belastungsgeschwindigkeit konnte durch eine entsprechend differenzierte Auswertung vorgenommen werden. Die Untersuchung der Bruchstücke der zerstörten Probekörper zeigte, dass die Verteilung der Partikelgröße stark von der Dehnrate abhängig ist. Im Gegensatz dazu hängt die Partikelgeometrie und die Form und Masse der entstehenden Kernbruchstücke vom Spannungsverhältnis ab.
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48

Drásal, Zbyněk. "Meření CP narušení na experimentu Belle v rozpadech B0 → ŋcK0S metodou tzv. časové analýzy, optimalizace vrcholového detektoru pro expriment Belle II." Doctoral thesis, 2014. http://www.nusl.cz/ntk/nusl-326188.

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Title: Measurement of Time-Dependent CP Violation in B0 → ηcK0 S at Belle Experi- ment, Optimization Studies of the Belle II Vertex Detector Author: Zbyněk Drásal Department: Institute of Particle and Nuclear Physics Supervisor: Dr. Zdeněk Doležal, IPNP Supervisor's e-mail address: Zdenek.Dolezal@mff.cuni.cz Abstract: This doctoral thesis deals with two independent topics. In the first part we present a measurement of branching ratio(s) and time-dependent CP violation parame- ters in B0 (B± ) → ηcK0 S(K± ), ηc → p¯p. The values of CP violation parameters have been found as follows: sin 2φ1, denoted as an SCP parameter, equals: SCP = 0.68+0.38 −0.46±0.13syst, the direct CP violation parameter, denoted as an ACP , is: ACP = 0.00+0.23 −0.31 ± 0.08syst. These results have been obtained with the final data sample of 772×106 B ¯B pairs collected at Υ(4S) resonance with a Belle detector at the KEKB e+ e− asymmetric collider machine in Japan. In the second part, we present our approach to the Monte Carlo (MC) simula- tion of Belle II vertex detector and its response to high energy particles. Belle II represents an upgrade of current Belle experiment and its designed vertex detector will consist of 2 layers of Depfet pixel detectors (PXD) and 4 layers of double-sided silicon micro-strip detectors (SVD). The MC...
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49

Christelová, Alžběta. "Hodnocení vědy a výzkumu na Ústavu vědeckých informací 1. lékařské fakulty Univerzity Karlovy v Praze." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297570.

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The thesis focuses on the evaluation of Research and Development in the Czech Republic. The introductory part of thesis highlights the recency of the topic and describes the quantitative and qualitative methods of assessing outlets of science. The second part of the thesis discusses in detail the evaluation of science in the Czech Republic; the legislative framework and the evaluation of Research and Development are mentioned. The third chapter shows the evaluation of institutional Research and Development and uses the 1st Faculty of Medicine of Charles University in Prague as an example. The core of the thesis is the fourth chapter with an analysis of selected primary scientometric data. The final part summarizes the entire topic and highlights some problem areas [Author's abstract].
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50

Troupová, Alžběta. "Scientometrické hodnocení vědy se zaměřením na Českou republiku." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297240.

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(in English) The master thesis is focused on the scientometric methods of research and development evaluation and their use in particular system applied in the Czech Republic. Its introductory part presents the field of scientometrics, scientometric and bibliometric indicators and citation indices. Chapter 7 deals with research and development evaluation in Czech Republic, especially with Research Evaluation Guidelines and describes its assesment rules, results and changes due to its annual actualization. A battle of wills between the Guidelines supporters and opponents is the topic of chapter 8, in particular in the context of reallocation of institutional funding according to the Guidelines. Ideas and opinions of prominent scientists and policymakers are being presented followed by brief treatise on Czech system of research and development evaluation audit carried out by the company Technopolis Limited. In the conclusion the author summarizes and debates positives and negatives of the Czech system of science evaluation.
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