Text in English / The destructive nature of conventional analytical techniques, coupled with the finite nature of ancient/historical artefacts, has long restricted technical examinations of museum collections, mainly due to ethical constraints. However, over the past few decades, the application of Non-Destructive Evaluation (NDE) techniques has become increasingly popular within the fields of archaeology and cultural heritage diagnostics. The application of such techniques has facilitated the examination of objects that have long remained uninvestigated. However, this positive development also held a slight drawback, in that researchers tend to now focus on technical analyses alone, while excluding more traditional means of analyses, such as comparative stylistic analysis and surface investigation. By employing a combination of stylistic analysis, visual surface investigation (by means of SLR photography and digital microscopy) and nuclear imaging (by means of Microfocus X-Ray Computed Tomography), the thesis sets out to justify the application of mixed methodologies as part of a more holistic integrated authentication approach. Thus stated, the thesis presents a mixed-methodological approach towards the analysis of selected metal objects from the Ditsong National Museum of Cultural History in Pretoria, South Africa. The objects under investigation include a small collection of ancient Egyptian bronze statuettes, a Samurai helmet (kabuto) and mask (menpó), a European gauntlet, and an Arabian dagger (jambiya/khanjar). While all the objects are curated as part of the museum‘s archaeology and military history collections, the exact production dates, manufacturing techniques and areas of origin remain a mystery. By using a combination of techniques, the thesis aims to identify diagnostic features that can be used to shed light on their relative age, culturo-chronological framework and, by extension, their authenticity. / Old Testament and Ancient Near Eastern Studies / D. Litt. et Phil.(Ancient Near Eastern Studies)

Polygonal cryogenic structures cannot be investigated with conventional methods as they could be harmed during measurement. A real3D GPR and ERT non-destructive surveys were used to examine and prove applicability for topsoil covered ice-wedge pseudomorphs and coarse-grained sorted polygons (patterned ground). A list of processing tools and algorithm suitable for such environments was created and tested. The benefits of 3D measurements are illustrated on horizontal slices and pseudo3D visualisation of 3D Cube. Basic morphometry characteristics of both forms were collected. Abilities of geophysical imaging for advanced shape characterisations are discussed, too. The low-frequency measurements gave better results at both sites. Pseudomorphs, 2 wide and up to 6,5 long, were found penetrating depth bigger than 3,5 . Sorted polygons, 2,5 wide in diameter, were depicted locked by stony ring of width around 1 . Sorting depth extends up to 0,54 depth for sure, perhaps more.

Die dielektrischen Eigenschaften, also die Interaktion mit elektrischen Feldern, sind ein wichtiger Qualitätsparameter der Matrix in Faserverbundmaterialien und allgemein in Harzen. Sie werden bisher mit Hilfe von kapazitiven Verfahren oder Hochfrequenzverfahren wie z. B. der Mikrowellentechnik gemessen. Allerdings können beide Verfahren nicht an elektrisch leitfähigen Materialien wie Kohlenstofffaserverstärkten Kunststoffen (CFK) eingesetzt werden und auch bei der Anwendung der Methoden an Kunststoffen oder elektrisch isolierenden Faserverbundmaterialien gibt es Nachteile. So benötigt die kapazitive Messtechnik meist eine spezielle Probenpräparation für quantitative Messungen und erreicht eine vergleichsweise schlechte Ortsauflösung beim Permittivitätsmapping. Die vorliegende Arbeit widmet sich daher der Untersuchung einer alternativen, in diesem Kontext neuen Methode zur Charakterisierung dielektrischer Eigenschaften: Die Hochfrequenzwirbelstrommesstechnik, welche bisher zur Messung der elektrischen Leitfähigkeit und magnetischen Permeabilität genutzt wird, wird theoretisch und praktisch hinsichtlich ihres Anwendungspotentials zur Permittivitätsmessung an Epoxidharzen und Faserverbundwerkstoffen diskutiert. Dabei werden zuerst Grundlagen wie Anwendungsfelder für die Nutzung dielektrischer Eigenschaften von Harzen und Verbundwerkstoffen zur Qualitätssicherung bzw. gängige Messverfahren erläutert. Anschließend wird theoretisch gezeigt, warum dielektrische Eigenschaften auf das Hochfrequenzwirbelstrom (HFWS)-Signal wirken. Dabei werden sowohl die Maxwell-Gleichungen genutzt, als auch Finite Elemente (FE)-Simulationen. Der Schwerpunkt der Forschungsarbeit liegt dann auf der experimentellen Untersuchung der Permittivitätsmessung mittels HFWS. Es werden verschiedene Anwendungsfälle betrachtet: von zeitlich kontinuierlichen Permittitivitätsänderungen (am Beispiel der Aushärtung von Epoxidharzen), über lokale Permittivitätsabweichungen (in Folge von Defekten, Textureigenschaften oder thermischen Überlasten) bis hin zu quantitativen Permittivitätsmessungen (zur Materialcharakterisierung bzw. Alterungsuntersuchung). Dabei kann gezeigt werden, dass es möglich ist, die Permittivität von Faserverbundwerkstoffen und Epoxidharzen mittels HFWS zu charakterisieren, selbst wenn das zu prüfende Material elektrisch nicht leitfähig ist.

Syftet med denna studie är att genom intervjuer med företrädare för svenska elitidrottsklubbar, inom fotboll och ishockey, beskriva vilka ekonomiska åtgärder som vidtagits på grund av intäktsbortfallen till följd av Covid19-pandemin, samt vilka konsekvenser det har haft för klubbarnas finansiering och deras syn på risker med finansieringen. Pandemin har medfört ekonomiska påfrestningar med stora intäktsbortfall, vilket har satt klubbarnas finansiella verksamhet på prov. En verksamhet som redan präglas av idrottens ekonomiskt destruktiva konkurrens. Studien utfördes genom kvalitativ metod med en abduktiv ansats. Empiriinsamling skedde via fem semistrukturerade intervjuer med representanter från svenska elitfotbolls- och elithockeyklubbar, samt kringliggande organ som har direkt samröre med klubbarna. Intäktsbortfallen har framkallat ekonomiska åtgärder hos klubbarna i form av kostnadsbesparingar och alternativa intäkter, samt en mer kontinuerlig budgetering utifrån olika scenarion, baserade på eventuella restriktioners omfattning. Klubbarna anser att de har klarat sig bra rent ekonomiskt under pandemin. Detta härleds dock främst till stöd och bidrag från intressentgrupper som bidragit till deras ekonomiska motståndskraft. Trots att elitidrottsklubbarnas finansieringssätt visar sig vara riskfyllt, framför studien att klubbarna inte tar detta i beaktning då de kan förlita sig på stöd från intressentgrupperna vid tider av finansiella svårigheter. / The purpose of this study is to describe, through interviews with representatives of Swedish elite sports clubs in football and ice hockey, what financial measures have been taken due to loss of income as a result of the Covid-19 pandemic, and what consequences it has had for the clubs financing and their view of the risks with their financing. The pandemic has brought economic constraints on the sports clubs, due to large losses of income, which has put their financial activities to the test. Activities that are already characterised by the economically destructive competition of sport. The study used a qualitative method with an abductive approach. The empirical data was collected by conducting five semi structured interviews with representatives from the sports clubs themselves, and also from surrounding organisations with direct association with the clubs. The loss of income has resulted in measures such as cost reduction, finding alternative income sources and a more continuous budgetary planning, based on scenarios of possible restrictions. The clubs consider themselves to have endured the economic constraints, brought by the pandemic, fairly well. However, the main contributing factor to the clubs economic resilience is support from interest groups. Even though the way elite sports clubs are financed is considered to be risky, the findings of this study show that the clubs do not take this into consideration because they can rely on economic support from these interest groups in times of financial distress.

According to the 2019 Canadian infrastructure report card, a concerning amount of municipal infrastructure is in poor or very poor condition. The infrastructure in this condition requires immediate action for rehabilitation or replacement. For concrete infrastructure, an effective repair can extend its service life and ensure that the services it provides continue to meet the community expectations. However, unfavorable environmental factors such as repeated/cyclic loads and freezing and thawing cycles adversely affect the bond between substrate concrete and repair materials, which lowers the structural capacity of repaired structures. So far, researchers have found that bond strength of repair can be affected by surface roughness, surface moisture, chemical adhesion or cohesion, curing regime, properties of substrate and repair materials, use of bond agent, and curing regimes. These findings are mostly based on the studies that focused on cold-jointed cylinders or beams, but in real-life repair situations, repairs of beams or slabs are located at either tension or compression side of the structure. Currently, there is no comprehensive study that investigates the bond of concrete repair under a combination of freezing and thawing and repeated/cyclic loading conditions. In addition, it is challenging to provide a rapid and non-destructive evaluation of the bond deterioration of repair materials. To address these issues systematically, this dissertation breaks the task into four phases. Phase (I) focuses on the development of an engineered “crack-free” repair mix that contains polypropylene (PP) fiber. A novel method is used to surface treat the PP fibers with supplementary cementitious materials. The effectiveness of surface-treating fibers for improved bond strength and reduced cracking is investigated. The compressive, tensile, and flexural strength of this engineered repair mix are determined and compared with two commercially available repair materials. The results from Phase I show that by adding 0.2% (by weight) Metakaolin-treated fibers into concrete mix, the compressive strength improves by up to 15.7% compared to mixes with untreated fibers. This study achieved a strength increase of 13.5% as compared to the reported 3.3% in other studies that use 25 times the amount of metakaolin used in this study. The experimental results confirm that at 0.2% dosage level, the use of novel surface treating technique is a cost-effective way to improve the strength of repair materials. Phase (II) focuses on characterizing the bond strength of various repair systems after freezing-thawing (FT) damage using both non-destructive and destructive methods. Two innovative sounding methods, which overcome the subjectivity of the traditional chain drag method, are used to evaluate FT damage non-destructively. In the experimental study, beams with a U-shaped cut are made to simulate conditions experienced by a concrete structure during a typical repair project. Three types of repair materials are used including cementitious repair concrete, cementitious repair mortar, and polymer-modified cementitious mortar. After up to 300 cycles of freeze-thaw exposure, resonant frequency and bond flexural strength of the prismatic specimens are determined. The empirical equations relating Non-destructive test (NDT) measurements and flexural bond strength of the repaired structures after freeze-thaw (FT) exposure are proposed. The results from Phase II show that the change in dynamic modulus of elasticity determined from NDTs agrees well with the change in other measurements including flexural bond strength, interfacial crack width, and mass loss after freeze-thaw exposure. In this study, linear relationships are established between dynamic modulus of elasticity and flexural bond strength for both cementitious and polymer-modified cementitious repair mortar with a coefficient of determination ranging between 0.87 and 0.95. The proposed empirical models can be used to predict bond flexural strength of repaired structures based on NDT measurement. Also, it was found that the samples repaired with polymer-modified cementitious mortar (Mix P) have superior FT resistance compared to other repaired samples. Phase (III) focuses on investigating the structural capacity and bond performance of repaired beams after cyclic/repeated loading. To accelerate the test process, a novel modified loading regime consisting of cycle groups of increasing cyclic/repeated stress amplitude is proposed. The models proposed by literature and current codes and standards are used to validate the results. Phase (IV) focuses on the development of the damage models for both individual and combined FT and cyclic loading exposure on repaired concrete structures. The results in phase III show the feasibility of using the Palmgren-Miner rule and Goodman linear model to estimate the fatigue life of repaired structures. This was confirmed within the context of this study. This study established the usefulness of using groups of increasing cyclic stress amplitude to accelerate the fatigue test process. The two-million cycle fatigue endurance limit estimated using cycle groups of Mix S (70.8%) was very similar to what was reported in the literature (71%) using the traditional time-consuming cyclic loading method. This study found that the formulas proposed by CSA 23.3 can effectively predict the moment resistance of both intact (control) and repaired RC beams. The ratio of experimental moment resistance values to its predictions ranges from 0.91 to 1.04. Based on the experimental results of previous three phases, an empirical model that predicted the fatigue service life of FT-damaged concrete structures is proposed. Future research requires a more comprehensive study on the FT performance of various polymer-modified cementitious mortars of different mix designs in repairing concrete structures. By increasing the number of tested specimens, a better relationship could be established between destructive and NDT methods. Future research is also required to explore the combined effect of FT and cyclic loading on repaired RC structures experimentally. / Graduate / 2023-03-22

La thèse est dédiée au développement des sondes à base de capteurs magnétorésistifs capable de détecter les trois composantes du champ simultanément pour le contrôle non destructif par courants de Foucault et pour l’imagerie magnétique. Une première partie donne un aperçu de l’état de l’art des capteurs et des méthodes d’imagerie et du contrôle. Dans une seconde partie, la réalisation des sondes trois axes est donnée. Cela a inclus la micro fabrication, la réalisation de l’électronique de lecture, la conception et la réalisation de la partie mécanique et d’émission. Pour cela un travail important de simulation a été nécessaire. L’application de ces sondes sur des cas modèle pour l’imagerie magnétique avec une résolution submillimétrique est ensuite décrite. La sonde proposée dans cette thèse a été aussi utilisée avec succès pour détecter des défauts dans des échantillons d'aluminium et de titane avec un bon rapport signal sur bruit. / The thesis is dedicated to the development of probes based on magnetoresistive sensors capable of detecting the three components of the field simultaneously for eddy current non-destructive testing and for magnetic imaging. A first part provides an overview of the state of the art of sensors, and imaging and control methods. In a second part, the realization of the three-axis probes is given. This included the micro-fabrication, the realization of the reading electronics, the design and realization of the mechanical part and emission. For this, an important simulation work was necessary. The application of these probes to model cases for magnetic imaging with submillimeter resolution is then described. The probe proposed in this thesis has also been used successfully to detect defects in aluminum and titanium samples with a good signal-to-noise ratio.

(EN) Negation, in its many shapes and forms, is an integral part of the history of twentieth-century art. If we look at the world through the dialectical logic of the ever-changing struggle between theses and antitheses, art too comes out as a result of the clash of two inseparable counterparts. Creation is destruction, just like destruction is creation. This diploma thesis tries to explore the broad topic of negation by defining two main interests, which are the topics of destruction and dropping out of the art scene. It sees both cases as a way of revolting against the position of the artist and art in the consumer society of the West. The text handles the phenomenon of destruction in art through multiple examples of artistic movements and the social context after the Second World War and especially during the 1960s, when many artists tried to work with the potential of destruction in art. In the final part devoted to leaving the artistic milieu, the possibility of simultaneously being and not being part of the world of art and the (im)possible future of art in times of climate crisis is explored with the help of the example of Slovak post-practice artist Radim Labuda. Key words: negation in art, destruction art, anti-art, dematerialisation, 20th century art, contemporary art, political art,...

This thesis deals with the diagnosis of a residential building from the late nineteen twenties for the needs of reconstruction. The methods generally used in the diagnosis of structures are briefly described in the theoretical part. More deeply this section describes the methods that were used during this particular research. The practical part deals with the diagnosis of the object itself. The first section describes the layout of the villa, its design solution, its faults and defects detected during the inspection. The next section deals with evaluating the current state of construction materials. Static reports of several structural parts were calculated in the last section.

The dissertation thesis deals with the study of non-destructive acoustic methods as instruments for monitoring and analysing corrosion of reinforcing steel in reinforced concrete elements. Four acoustic methods were selected for this task - the impact-echo method, the nonlinear acoustic spectroscopy method, the acoustic emission method, and the ultrasonic pulse velocity method. To verify the functionality of these methods, testing was carried out on three sets of reinforced concrete samples that had been exposed to the effects of sodium chloride, which corroded the embedded steel reinforcement in these samples. Suitable parameters were proposed for individual acoustic methods to monitor corrosion of the reinforcements. In addition, experiments were designed to demonstrate the ability of the selected acoustic methods to reveal the corrosion of steel reinforcement and its influence on the concrete matrix and to assess the condition of the degraded elements and structures. The analysis of the measurement results based on their comparison shows the advantages and disadvantages of the individual methods and of their practical applications. To verify the results, correlation with common methods that are currently used for the study of corrosion was carried out and included for example the electrical resistivity measurement of the reinforcement and simultaneous monitoring of the sample surface using a confocal microscope to record the development of microcracks during the degradation.

Magnetisch-induktive Techniken finden seit langer Zeit viele Anwendungsfelder in der Medizin, Sicherheitstechnik und der Industrie. Obwohl die technischen Grundlagen seit vielen Jahrzehnten bekannt sind, werden auf Basis detaillierter Analysen spezielle Lösungsansätze verfolgt, die neuartiges Anwendungspotential erschließen sollen. Dazu dienen verbesserte Werkzeuge wie Computersimulationen und analytische Berechnungen sowie neu kombinierte Methoden und Aufbauten aus Leistungselektronik und Signaldetektion. Die Vorteile magnetisch-induktiver Techniken sind dabei u.a., dass sie das Prüfobjekt nicht schädigen, berührungslos arbeiten, robust gegenüber Verschmutzungen und einfach im Aufbau sind. Ein Nachteil dieser Technik ist die unzureichende Auflösung von feinen Strukturen. In der aktuellen Forschung und Entwicklung werden unterschiedliche Spulenanordnungen zur Anwendung in industriellen und medizinischen Fragestellungen untersucht und optimiert. Thema dieser Arbeit ist es, durch Verbesserung der Spuleneigenschaften, neue Anwendungsbereiche für die zerstörungsfreie Materialprüfung zu erschließen. Es wird eine Methode vorgestellt, die Eigenschaften magnetisch-induktiver Tastspulen zu verbessern und so den Aufwand bei der Signalverarbeitung zur Rekonstruktion im Rechner zu reduzieren sowie die Auflösung zu erhöhen. Dazu werden zwei Spulenanordnungen, Transmissions - Tastspulen und Gradiometer - Tastspulen, vergleichend gegenübergestellt und ihre technischen Grenzen aufgezeigt. / Magneto-inductive techniques are found in many fields of application areas so in medicine, security technology and industry. Although the technical basis has been known for many decades, special solutions are pursued on the basis of detailed analysis that should open new application potential. These are enhanced tools such as computer simulations, analytical calculations, new combined methods and structures of power electronics and signal detection. The advantages of magneto-inductive techniques are that they do not damage the test object, are contactless, robust against dirt and simple in construction. A disadvantage of this technique is the insufficient resolution of fine structures. In current research and development different coil assemblies are investigated in industrial and medical applications. The aim of this work is to improve the coil properties by changing geometric constructions and current patterns of the coils, in order to allow a sharper localization of objects in space and to tap new application areas for non-destructive testing. A method to improve the properties of magneto-inductive coils and thus to reduce the effort in signal processing and image reconstruction as well as to increase the resolution is presented. Two different coil assemblies, gradiometer – coils and transmission – coils, are compared and their technical limits shown.