This thesis is focused on a firmware for robotic vehicle based on the ARM Cortex-M3 architecture that is running a real-time operating system (RTOS). Theoretical part describes available solutions of embedded RTOS and concrete HW implementation of the robotic vehicle. There is also comparison of the three selected RTOS with their measurements. Result of this thesis is base firmware compounded by a program modules that controls HW parts. There is also a sample PC and firmware application that extends base firmware. This sample application is able to communicate with robotic vehicle, control wheel motion and measure process data.

This master’s thesis focuses on the minimisation of losses by calculation of optimum slip frequency of induction motor. The next point of this master‘s thesis is supersaturation. Supersaturation must be solved for the size of losses, because of the effect that is cause of the losses, when current increases with saturation. However current is not increase proportionally with increasing saturation, but increases several times more. This problem is included in the calculation of the slip frequency. Optimum of slip frequency is solve for modified gamma model of induction machine. In the main point of this thesis is outlined the process, how the optimum can be found. With same process were already were found the equations, but they were too extensit. In the end is solved the optimum of slip frequency be minimum of the flux density.

Multiple step tests under cyclic strain control have been performed using cylindrical specimens of cast polycrystalline Inconel 738LC superalloy at 23, 700, 500, 800 and 900 °C in laboratory atmosphere to obtain cyclic stress-strain curves. During cyclic straining of specimen were obtained cyclic hardening-softening curves. Their progress changed with temperature and strain amplitude. Evaluated cyclic stress-strain curves are shifted to lower stresses with increasing temperature. Surface relief was observed in fatigued specimens under SEM and metalography under optic microscopy. Slip markings were studied on specimen surface fatigued at 700 °C .Stress-strain response is compared and discussed in relation to the surface observations - persistent slip markings.

Work tackles the general design systems of automatic control of engine power and braking effects so that avoid any unnecessary dangerous situations and to improve the driving characteristics and suppression causes of accident due to bad decisions of driver. Is required to propose a general system based on the draft sensors and control circuits, their relationships, design control processor, which will be without the knowledge of the driver intervene in driving motorcycle.

This master thesis aims to study the possibilities of eliminating, or separation of ammonium shares from technological water of plants, where is introduced a secondary method of flue gas denitrification (SCR, SNCR). The need for elimination of ammonium shares arose after introduction of emission cap, which have been tightened since January 2015. The denitrification technologies were installed on devices that did not comply with the new limits. The theoretical part of the thesis deals with the description of combustion processes, as a fluid, and high temperature combustion of solid fuels, mechanisms of emissions and their reduction options. At the conclusion of the theoretical part is discussed the contents of the ammoniacal nitrogen in waters used in electricity and heating facilities to transport, or from which are separated by solid products of some processes such as desulphurization. There are also discussed some options for removal of ammonium salts from technological waters. Experimental part deals with finding appropriate method of determination of ammoniacal nitrogen, and the possibilities of its elimination by conversion to insoluble compound. Last but not least, the work deals with the evaluation of the sustainability of the proposed solutions. And as well as the real possibilities of their application in practice.

Die Dissertation beschäftigt sich mit der grundlagenorientierten Untersuchung reibdauerbeanspruchter Stahl-Kontakte und deren Festigkeitsbewertung. Die Besonderheit bei der Bewertung reibdauerbeanspruchter Kontakte stellt die zusätzlich zur spannungsmechanischen Beanspruchung vorliegende tribologische Beanspruchung des Werkstoffes dar. Die ursächlich auf eine Anrissinitiierung in der Bauteiloberfläche zurückzuführende niedrigere Ermüdungsfestigkeit reibdauerbeanspruchter Bauteilverbindungen, zeigt sich in Abhängigkeit des Fugendrucks, des Schlupfes und des Werkstoffes. Basierend auf den genannten Einflussgrößen konnte in der vorliegenden Arbeit ein Berechnungsverfahren erarbeitet werden, welches eine betriebssichere Auslegung reibdauerbeanspruchter Fügeverbindungen ermöglicht. Das Verfahren basiert auf dem örtlichen Konzept der FKM-Richtlinie „Rechnerischer Festigkeitsnachweis für Maschinenbauteile“ und implementiert den Schadenfall der Reibdauerermüdung durch einen Oberflächeneinflussfaktor, dem sogenannten Reibkorrosionsfaktor. Die tribologischen Beanspruchungsparameter Schlupf und Fugendruck werden dabei über eine Worst-Case-Betrachtung berücksichtigt. Durch eine von der Zugfestigkeit des Grundwerkstoffes abhängige Darstellung des Reibkorrosionsfaktors, konnte darüber hinaus eine systemspezifische Berechnung der Ermüdungsfestigkeit erreicht werden. Die Validierung des Berechnungsverfahrens erfolgte an einer Pleuelverbindung. / The doctoral thesis investigates basically the fretting fatigue strength of steel contacts and their strength assessment. Especially the tribological loading conditions which are present at the contact surface cause a specific method of the strength assessment of joined contacts. In this context, the lower fatigue strength of component connections under tribological loading conditions, which is the result of crack nucleation at the component surface, depends on the contact pressure, the slip and the basic-material. Based on these parameters, a calculation method was developed in the present study which allows a reliable design of component connections under fretting conditions. This method is based on the local concept of the FKM-guideline 'Rechnerischer Festigkeitsnachweis für Maschinenbauteile' and introduces the fretting fatigue failure mechanism by a surface factor, the so-called fretting factor. These fretting factors are calculated empirically and based on a worst-case approach of the tribological parameters slip and contact pressure. Furthermore it is possible to determine the fretting factor according to the tensile strength of the basic-material. As a result of this, it is possible to calculate the system-specific fretting fatigue strength of joined steel-components. The improved calculation accuracy of the strength assessment was validated on connecting rods.

The aim of this work is the development of mechanical models on a mesoscopic level for the analytical description of the material properties of textile reinforced concrete (TRC). For the modelling of the heterogeneous structure of TRC the concept of representative volume elements (RVE) is used. RVEs are representative for the mesoscopic structure. The overall material behaviour on the macroscopic level is obtained by means of homogenisation of the heterogeneous material behaviour on the mesoscopic level. Based on the micro mechanical solution of the elastic field of an ellipsoidal inclusion according to Eshelby a model for the determination of the material behaviour for multi-directional reinforced finegrained concrete is developed. An effective field approximation considers the interaction of the differentially orientated reinforcements in an averaged sense. Microcracks are included by additional strains in the representative volume element. The average interaction between the microcracks and the reinforcements is considered by an effective field approximation. As a criteria for the initiation of the macro cracking a critical microcrack density parameter is implemented in the mechanical model. The microcracks accumulate to macrocracks if the microcrack density parameter in the RVE exceeds this critical value. For the mechanical modelling of the bond behaviour between roving and matrix after macro cracking a multiple linear shear stress-slip relation is used. This shear stress-slip relation considers adhesion, damage and failure of the interface between roving and matrix. Hence experimentally measured pullout force-displacement curves can be simulated realistically. / Gegenstand dieser Arbeit ist die Entwicklung mechanischer Modelle auf der Mesoebene zur analytischen Beschreibung des makroskopischen Materialverhaltens von textilbewehrtem Feinbeton. Für die Modellierung der heterogenen Struktur wird das Konzept der repräsentativen Volumenelemente (RVE), die für die Mesostruktur des betrachteten Verbundwerkstoffes repräsentativ sind, verwendet. Der Übergang von dem heterogenen Materialverhalten auf der Mesoebene zum mittleren Materialverhalten auf der Makroebene erfolgt mittels Homogenisierung. Auf Basis der mikromechanischen Grundlösung für ellipsoidförmige Einschlüsse nach Eshelby wird ein Modell entwickelt, das die Ermittlung des Materialverhaltens von multidirektional bewehrtem Feinbeton ermöglicht. Durch die Anwendung einer Effektive-Feld-Theorie wird die gegenseitige Beeinflussung der unterschiedlich orientierten Bewehrungen in einem gemittelten Sinn betrachtet. Die ab einer bestimmten makroskopischen Beanspruchung entstehenden Mikrorisse berücksichtigt das mechanische Modell über einen durch die Mikrorisse hervorgerufenen zusätzlichen Verzerrungsanteil im RVE. Mittels der verwendeten Effektive-Feld-Theorie kann eine mittlere Beeinflussung zwischen den Mikrorissen und der Rovingbewehrung erfasst werden. Für den Übergang von der Mikrorissbildung zur Makrorissbildung wird für das mechanische Modell der Begriff einer maximalen Mikrorissdichte eingeführt. Überschreitet die Mikrorissdichte im RVE diesen maximalen Wert, vereinigen sich die Mikrorisse zu Makrorissen. Zur Beschreibung des mechanischen Verbundverhaltens zwischen Roving und Matrix beim Rovingauszug am Makroriss wird eine multilineare Schubspannungs-Schlupf-Beziehung verwendet, welche die Schädigung des Roving-Matrix-Verbundes bis hin zum vollständigen Versagen erfasst. Damit lassen sich experimentell ermittelte Kraft-Verformungskurven an Zugproben wirklichkeitsnah abbilden.

Im Mittelpunkt der vorliegenden Arbeit steht die gezielte Analyse des Verbundverhaltens zwischen Bewehrungsstahl und Beton unter kombinierter Beanspruchung aus Ermüdung und Querzug. Den Hintergrund bilden Stahlbetonbauteile, wie z. B. Fahrbahnplatten von Verbundbrücken, welche einen zweiaxialen Lastabtrag unter nicht vorwiegend ruhenden Belastungen aufweisen. Die Untersuchungen für normal- und hochfesten Beton erfolgten an Ausziehkörpern mit einem durch Querzugspannungen hervorgerufenen Längsriss entlang des Bewehrungsstabes. Das Versuchsprogramm beinhaltete hochzyklische Schwellversuche mit unterschiedlichen Schwingspielen und variierenden Längsrissbreiten bis zu einer Million Lastwechseln. Anhand der Entwicklung des Schlupfes zwischen Bewehrungsstab und Beton konnte eine deutliche Abhängigkeit des Verbundwiderstandes vom Querzug beobachtet werden. Aufbauend auf der Schlupfentwicklung erfolgt die Ableitung von normierten Wöhlerlinien der Verbundermüdung. Diese Wöhlerlinien können direkt in Beziehung zu den Wöhlerlinien der Betonstahlermüdung gesetzt werden und vereinfachen die Erstellung von Dauerfestigkeitsdiagrammen für Bemessungszwecke. Es wird deutlich, dass die Ermüdungsfestigkeit des Verbundes durch das Vorhandensein eines Längsrisses gegenüber der Betonstahlermüdung verstärkt an Bedeutung gewinnt. / The main focus of the present work is the specific analysis of the bond behaviour between reinforcement and concrete under combined loading due to fatigue and transverse tension. The background is formed by reinforced concrete elements such as bridge decks of steel-concrete composite bridges, which show a biaxial load bearing behaviour under not predominantly monotonic loading. The investigations for both normal strength and high performance concrete were conducted on pull-out specimens with a longitudinal crack along the reinforcing bar caused by transverse tensile stresses. The experimental program included high cyclic tests with different stress ranges and varying longitudinal crack widths up to one million load cycles. By means of the slip development, a definite dependency of the bond strength on the transverse tension could be observed. Based on the slip development, normalised S-N curves for bond fatigue have been deduced. These S-N curves can be set in direct relation to the S-N curves for steel fatigue and simplify creating constant life diagrams for design purposes. It becomes clear that the bond fatigue strength, due to an existing longitudinal crack, gains in importance in comparison to the fatigue strength of the reinforcing steel.

Dieser Beitrag befasst sich mit der experimentellen und analytischen Bestimmung der Verankerungslängen textiler Bewehrungsstrukturen einer Textilbetonverstärkungsschicht. Die experimentelle Untersuchung des Verbundverhaltens erfolgte anhand von Pull-Out-Versuchen. Die analytische Betrachtung des Verbundproblems geschieht aufbauend auf multilinearen Lösungen der Verbunddifferentialgleichung anhand der experimentell ermittelten Kraft- Rissöffnungs-Beziehungen. Mit Hilfe eines separaten Modells wird aus der so ermittelten Verbundspannungs-Schlupf-Beziehung (VSB) die zur Verankerung einer entsprechenden Kraft F erforderliche Verankerungslänge lE bestimmt. Die Überprüfung der Berechnung erfolgt anhand von unabhängig in experimentellen Versuchen zur Bestimmung der Verankerungslänge ermittelten Werten. Es konnte eine gute Übereinstimmung der berechneten mit den versuchstechnisch bestimmten Verankerungslängen festgestellt werden.

Plasticity in crystalline solids is controlled by the microscopic line defects known as “dislocations”. Decisive role of dislocations in crystal plasticity in addition to fundamentals of plastic deformation are presented in the current thesis work. Moreover, major features of numerical modeling method “Discrete Dislocation Dynamics (DDD)” technique are described to elucidate a powerful computational method used in simulation of crystal plasticity. First part of the work is focused on the investigation of strain rate effect on the dynamic deformation of crystalline solids. Single crystal copper is chosen as a model crystal and discrete dislocation dynamics method is used to perform numerical uniaxial tensile test on the single crystal at various high strain rates. Twenty four straight dislocations of mixed character are randomly distributed inside a model crystal with an edge length of 1 µm subjected to periodic boundary conditions. Loading of the model crystal with the considered initial dislocation microstructure at constant strain rates ranging from 103 to 105s1 leads to a significant strain rate sensitivity of the plastic flow. In addition to the flow stress, microstructure evolution of the sample crystal demonstrates a considerable strain rate dependency. Furthermore, strain rate affects the strain induce microstructure heterogeneity such that more heterogeneous microstructure emerges as strain rate increases. Anisotropic characteristic of plasticity in single crystals is investigated in the second part of the study. Copper single crystal is selected to perform numerical tensile tests on the model crystal along two different loading directions of [001] and [111] at two high strain rates. Effect of loading orientation on the macroscopic behavior along with microstructure evolution of the model crystal is examined using DDD method. Investigation of dynamic response of single crystal to the mechanical loading demonstrates a substantial effect of loading orientation on the flow stress. Furthermore, plastic anisotropy is observed in dislocation density evolution such that more dislocations are generated as straining direction of single crystal is changed from [001] to [111] axis. Likewise, strain induced microstructure heterogeneity displays the effect of loading direction such that more heterogeneous microstructure evolve as single crystal is loaded along [111] direction. Formation of slip bands and consequently localization of plastic deformation are detected as model crystal is loaded along both directions. / <p>QC 20151015</p>