Defect-induced ferromagnetism is attracting intensive research interest. It not only challenges the traditional opinions about ferromagnetism, but also has some potential applications in spin-electronics. SiC is a new candidate for the investigation of defect-induced ferromagnetism after graphitic materials and oxides due to its high material purity and crystalline quality. In this thesis, we made a comprehensive investigation on the structural and magnetic properties of ion implanted and neutron irradiated SiC sample. In combination with X-ray absorption spectroscopy and first-principles calculations, we try to understand the mechanism in a microscopic picture. For neon or xenon ion implanted SiC, we identify a multi-magnetic-phase nature. The magnetization of SiC can be decomposed into paramagnetic, superparamagnetic and ferromagnetic contributions. The ferromagnetic contribution persists well above room temperature and exhibits a pronounced magnetic anisotropy. We qualitatively explain the magnetic properties as a result of the intrinsic clustering tendency of defects. By combining X-ray magnetic circular dichroism and first-principles calculations, we clarify that p electrons of the nearest-neighbor carbon atoms around divacancies are mainly responsible for the long-range ferromagnetic coupling. Thus, we provide a direct correlation between the collective magnetic phenomena and the specific electrons/orbitals. With the aim to verify if the defect-induced magnetization can be increased by orders of magnitude, i.e., if a sample containing defects through its bulk volume can persist ferromagnetic coupling, we applied neutron irradiation to introduce defects into SiC. Besides a weak ferromagnetic contribution, we observe a strong paramagnetism, scaling up with the neutron fluence. The ferromagnetic contribution induced by neutron irradiation only occurs in a narrow fluence window or after annealing. It seems non-realistic to make the bulk specimens ferromagnetic by introducing defects. Instead, we speculate that defect-induced ferromagnetism rather locally appears in particular regions, like surface/interface/grain boundaries. A comparable investigation on neutron irradiated graphite supports the same conclusion.

The safety and performance of nuclear plant relies, among others, on the quality of nuclear fuel. The quality fulfilling designed criteria of the fuel in use is inspected and reported on periodically. Visual inspection focuses on the condition of the fuel based on its visual properties. During the inspection, the fuel is being recorded and analysed by the inspector. The current state of the fuel assemblies is compared to the historical statistics which helps do decide whether this particular assembly remains or gets replaced. This thesis describe a project initiated by Centrum Výzkumu Řež focusing on digital image processing methods application to visual inspection process. The result of the project is a tool that accelerates the process of report making. Firstly, it transforms the inspection video into one image overview and highlight a significant part (more than 95%) of possible defects to the inspector. 1

The diploma thesis on the topic of Comprehensive rehabilitation of people with visual impairment gives an overview of the possibilities and importance of comprehensive rehabilitation for this target group. In the introductory part of my work I will focus on the definition of vision, visual impairment and comprehensive rehabilitation for people with visual impairment and possibilities of social services. In the final part there are interviews conducted by clients and staff of provided focused services of social rehabilitation. The aim of the thesis is to describe the psychosocial issue of a person with visual impairment and to give an overview of the possibilities and importance of comprehensive rehabilitation for this target group.

Customers today demand products of high quality, and industries must cope with issues related to that to stay competitive. Therefore, an endeavor to achieve zero defects and to work with zero defect manufacturing (ZDM) is common in industries today. ZDM aims to reduce the number of failures within a manufacturing process and thus only producing faultless products. Since defected items result in unexpected work, extra costs, claims and unsatisfied customers, it is important to avoid that in order to secure the company’s market share. Even though it implies challenges, companies must work with ZDM and quality tools to stay competitive. However, there is a gap between the literature of ZDM and how to accomplish ZDM in practice, which makes it hard for companies to apply the method. Hence, this thesis aims to address this gap and present how the human factors and quality contribute to the goal of zero defects. When working with a manually driven manufacturing setting, human factors must be considered as an important aspect. Mistakes will occur as long as humans work with the products, but the prerequisites for doing right must be as good as possible to be able to decrease the number of mistakes. Another factor to consider is the internal quality of different processes to ensure that customer demands are achieved through all stages. This study focused on finding suggestions for improvements towards zero defects in manual assembly and to present general improvement actions. The thesis is based on three main fields: ZDM, quality and human factors. The findings are connected both to literature searches made within these fields, but also through a case study at the focal company. In the analysis chapter, the reader is provided with information about how the specified problem areas are linked together and to the three main fields. By combining the literature search with a case study at a focal company, findings could be detected, collected and analyzed. Four areas could be identified in the analysis and highlighted in the discussion of the research questions. The highlighted areas were further used as a foundation to establish suggestion within the important areas. These acts as practical guidelines for how to reach zero defects in an existing production with the goal of minimizing the implementation gap of ZDM.

Machine learning techniques are being applied to many data-intensive problems because they can accurately provide classification of complex data using appropriate training. Often, the performance of machine learning can exceed the performance of traditional techniques because machine learning can take advantage of higher dimensionality than traditional algorithms. In this work, acoustic data sets taken using a rapid scanning technique on concrete bridge decks provided an opportunity to both apply machine learning algorithms to improve detection performance and also to investigate the ways that training of neural networks can be aided by data augmentation approaches. Early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs of concrete bridges. In order to inspect for non-visible internal cracking (called delaminations) of concrete bridges, a rapid inspection method is needed. A six-channel acoustic impact-echo sounding apparatus is used to generate large acoustic data sets on concrete bridge decks at high speeds. A machine learning data processing architecture is described to accurately detect and map delaminations based on the acoustic responses. The machine learning approach achieves accurate results at speeds between 25 and 45 km/h across a bridge deck and successfully demonstrates the use of neural networks to analyze this type of acoustic data. In order to obtain excellent performance, model training generally requires large data sets. However, in many potentially interesting cases, such as bridge deck defect detection, acquiring enough data for training can be difficult. Data augmentation can be used to increase the effective size of the training data set. Acoustic signal data augmentation is demonstrated in conjunction with a machine learning model for acoustic defect detection on bridge decks. Four different augmentation methods are applied to data using two different augmentation strategies. This work demonstrates that a "goldilocks" data augmentation approach can be used to increase machine learning performance when only a limited data set is available. The major technical contributions of this work include application of machine learning to acoustic data sets relevant to bridge deck inspection, solving an important problem in the field of nondestructive evaluation, and a more generalized approach to data augmentation of limited acoustic data sets to expand the classes of acoustic problems that machine learning can successfully address.

Epitaxial anatase TiO2 thin films were grown by pulsed laser deposition and ion beam sputter deposition, on STO and LAO substrates. Their phases and the crystallographic orientations were confirmed using X-ray diffraction measurements; the impurities concentration of the samples were examined using particle induced X-ray emission. The impurity concentration is too low to be the origin of the measured ferromagnetic signal after irradiation with low energetic ions. The as-grown samples show a small ferromagnetic signal without magnetic anisotropy and with Curie temperatures of TC ≈ 450 K. The origin of this magnetic signal may be related to a lattice mismatch between substrate and film and the resulting induced defects, defects generated during the growth process or annealing, or impurities. Irradiation with low energy Ar+ ions was shown to be a simple way to induce magnetism in anatase thin films. After the first irradiation, the magnetic moment at saturation increases by one order of magnitude with a high Curie temperature of TC ≈ 792 K. Further, a considerable out-of-plane magnetic anisotropy in the magnetization has been found. When increasing the irradiation fluence, the magnetic moment increases further until saturation is reached, whereas TC was reduced and the anisotropy vanished. XAS and XMCD experiments of the O K and Ti L3,2 absorption edges showed that the magnetic moment arises at the Ti 3d shell and not at the oxygen. The obtained magnetic moment per Ti di-Frenkel pair (FP) of m ≈ 2 µB agrees with literature reports. XAS and XMCD calculations of Ti di-FPs within an anatase lattice are in agreement with the results and the assumption that di-Frenkel pairs are responsible for the observed magnetism and anisotropy. Magnetic force microscopy proved the existence of oppositely aligned magnetic domains with out-of-plane magnetization directions. This explains the low remanence of these samples. The production method is efficient and non-destructive, and can be easily combined with other techniques, such as electron beam lithography. This allows the production of arbitrary magnetic patterns with perpendicular magnetic anisotropy at the anatase surface. There are some questions that could not be answered in depth, e.g. the connection between irradiation fluence and ion energy, and the saturation magnetic moment as well as the strength of the perpendicular magnetic anisotropy. More systematic experiments are necessary, preferably using a more sophisticated setup. The electric transport properties of single TiO2 nanotubes were measured. The temperature dependence of the resistance of the polycrystalline anatase nanotubes show a Mott variable range hopping behaviour. The results obtained with two contacts indicate the existence of a potential barrier between the Cr/Au contacts and samples surfaces. Impedance spectroscopy at room temperature indicates that the electronic transport of these polycrystalline tubes is dominated by the grain cores. Similar experiments were conducted on ZnO nanowires. The measurements were done on the as-prepared and after low-energy ion irradiation. The temperature dependence of the resistance of the wire before irradiation, can be described by two processes in parallel; the fluctuation induced tunneling conductance and an usual thermally activated process. Electron backscatter diffraction confirms the existence of different crystalline regions. After irradiation an additional thermally activated process appears that can be explained by taking into account the impurity band splitting. The previously mentioned experimental findings and methods where then applied to several different TiO2 nanotubes. Amorphous nanotubes were anodically grown on titanium foil and partially annealed to obtain anatase samples. Non-linear current–voltage characteristics were explained using the fluctuation induced tunneling conduction model. A clear enhancement of the conductance was induced in an insulating anatase nanotube through low-energy Ar/H ion irradiation. Confocal Raman spectroscopy shows that the annealed samples were in anatase phase and a blueshift due to phonon confinement was observed. Magnetic force microscopy is well known and established method to investigate magnetic samples of nanometer size. Focused electron beam induced deposition of cobalt was used to functionalize atomic force microscopy Akiyama tips for application in magnetic force microscopy. The grown tips have a content of ≈ 90 % Co after exposure to ambient air. In order to investigate the magnetic properties of the tips, current loops were prepared. Magnetic Akiyama tips open new possibilities for wide-range temperature magnetic force microscopy measurements. To continue the work on magnetic nanotubes, further experiments with single nanotubes would be interesting. These samples could be characterized with the help of MFM measurements or NV magnetometry. Also, experiments on nanotube bundles can be of interest, since the fabrication, irradiation and measurements of such more robust samples is easier to implement.:Declaration of Authorship iii List of Publications v Abstract vii Acknowledgements ix 1 Introduction 1 1.1 Defect-Induced Magnetism in Oxides . . . . . . . . . . . . . . . . . . . 1 1.1.1 Open Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Exchange Interactions and Magnetic Anisotropy . . . . . . . . . . . . . 3 1.3 Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.4 Magnetic Force Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.5 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Introduction to Magnetism 7 2.1 Orbital Magnetic Moment . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Spin Magnetic Moment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3 Localized Electron Model . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4 Spin-Orbit Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.5 Multiplets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.6 Classes of Magnetic Materials . . . . . . . . . . . . . . . . . . . . . . . . 11 2.6.1 Diamagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.6.2 Paramagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.6.3 Antiferromagnetism . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.6.4 Ferromagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.6.5 Ferrimagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.7 Exchange Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.7.1 Coulomb Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.7.2 Direct Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.7.3 Superexchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.7.4 Ferromagnetic Superexchange . . . . . . . . . . . . . . . . . . . 22 2.7.5 Double Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.7.6 Orbital Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.8 Magnetism in Transition Metal Oxides . . . . . . . . . . . . . . . . . . . 27 2.8.1 Oxygen Coordination . . . . . . . . . . . . . . . . . . . . . . . . 28 2.8.2 Crystal Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.8.3 Weak-Field Solution for Single Electron . . . . . . . . . . . . . . 29 2.8.4 Interionic Exchange Interaction . . . . . . . . . . . . . . . . . . . 34 2.9 Magnetic Anisotropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.9.1 Cubic Symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.9.2 Tetragonal Symmetry . . . . . . . . . . . . . . . . . . . . . . . . 39 xii 2.10 Defect-Induced Magnetism in TiO2 . . . . . . . . . . . . . . . . . . . . . 40 3 Defect Induced Magnetism in TiO2 Anatase Thin Films 43 3.1 Strong out-of-plane magnetic anisotropy in ion irradiated anatase TiO2 thin films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 3.2 Titanium 3d ferromagnetism with perpendicular anisotropy in defec- tive anatase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 4 Defect Induced Magnetism and Electrical Properties of TiO2 and ZnO Nan- otubes 69 4.1 Electrical properties of ZnO single nanowires . . . . . . . . . . . . . . . 71 4.2 Electrical transport properties of polycrystalline and amorphous TiO2 single nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 4.3 Functionalized Akiyama tips for magnetic force microscopy measure- ments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 5 Summary and Outlook 93 Bibliography 99

A comparison was made of bacteriophage MS2 RNA translation in infected Escherichia coli cells and in a defined cell-free system. A number of temperature-sensitive mutants were used as hosts for viral RNA translation at permissive and restrictive temperatures. The amount of viral coat protein synthesis was determined after gel electrophoresis of proteins from the cell lysates. These results were compared to those obtained with cell-free translation assays conducted with ribosomes isolated from the same mutants. Compared with control cells, a reduced activity in vivo and in vitro was found for each mutant examined at elevated temperatures. A good correlation between the two types of translational assays was observed. These findings are discussed in terms of the translational defects known to be a characteristic of some of these mutant strains.

No description available.

<p>In the thesis we are concerned with actual problems on palindromic subwords and palindromic factors of finite and infinite words. The main course of the research are the ways of determining which of two given words is &ldquo;more palindromic&rdquo; than the other one, that is, defining a measure for the degree of &ldquo;palindromicity&rdquo; of a word. Particularly, we pay attention to two actual approaches: the so-called MP-ratio and the so-called <em>palindromic defect</em>, and answer several open questions about them.<br /><br />Namely, concerning the MP-ratio, a few plausible-looking question have been asked in the literature, which would have, if answered positively, made computations of MP-ratios significantly simpler. We add one more related question to these ones, and then show that, rather unexpectedly, all these questions have negative answer.<br /><br />Concerning the palindromic defect, the main result of this work is a construction of an infinite class of infinite words that have several properties that were sought after in some recent works in this area. Among the most interesting facts is that that all these words are aperiodic words of a finite positive defect, having the set of factors closed under reversal---in some recent works, the construction of even a single word having these properties turned out to be quite hard. Using these words, which we are calling <em>highly potential words</em>, we check the validity of several open&nbsp; conjectures, and for several of them we find out that they are false.</p> / <p> U tezi razmatramo aktuelne probleme u vezi s palindromskim podrečima i palindromskim faktorima konačnih i beskonačnih reči. Glavni pravac istraživanja jesu kriterijumi za određivanje koja od dve date reči je &bdquo;palindromičnija&ldquo; od druge, tj. određivanje stepena &bdquo;palindromičnosti&ldquo; date reči. Akcenat stavljamo na dva aktuelna pristupa: tzv. <em>MP-razmeru</em> i tzv. <em>palindromski defekt</em>, i odgovaramo na vi&scaron;e otvorenih pitanja u vezi s njima.<br /> <br /> Naime, u vezi sa MP-razmerom u literaturi je postavljeno vi&scaron;e pitanja, intuitivno uverljivih, koja bi, u slučaju pozitivnog razre&scaron;enja, znatno pojednostavila izračunavanje MP-razmere. Ovim pitanjima dodajemo jo&scaron; jedno srodno, a zatim pokazujemo da, prilično neočekivano, sva ova pitanja imaju negativan odgovor.<br /> <br /> U vezi s palindromskim defektom, glavni rezultat rada je konstrukcija beskonačne klase beskonačnih reči koje imaju vi&scaron;e osobina za kojima je iskazana potreba u skora&scaron;njim radovima iz ove oblasti. Među najzanimljivije spada činjenica da su sve aperiodične reči konačnog pozitivnog defekta, i da im je skup faktora zatvoren za preokretanje &ndash; u nekim skora&scaron;njim radovima konstrukcija makar jedne reči s ovim osobinama pokazala se kao prilično te&scaron;ka. Pomoću ovih reči, koje nazivamo <em>visokopotencijalne reči</em>, ispitujemo validnost vi&scaron;e otvorenih hipoteza, i za vi&scaron;e njih ustanovljavamo da nisu validne.</p>

This research aims to investigate the application of infrared thermography (IRT) as a method of nondestructive evaluation (NDE) for the detection of defects in the rail base area. Rails have to withstand harsh conditions during their application. Therefore, defects can develop in the base area of rails due to stresses such as bending, shear, contact, and thermal stresses, fatigue, and corrosion. Such defects can cause catastrophic failures in the rails, ultimately leading to train derailments. Rail base defects due to fatigue and corrosion are difficult to detect and currently there are no reliable or practical non-destructive evaluation (NDE) methods for finding these types of defects in the revenue service. Transportation Technology Center, Inc. (TTCI) had previously conducted a research on the capability of flash IRT to detect defects in rail base area based on simulation approach. The research covered in this thesis is the continuation of the same project.In this research, three rail samples were prepared with each containing a notched-edge, side-drilled holes (SDHs), and bottom-drilled holes (BDHs). Two steel sample blocks containing BDHs and SDHs of different sizes and depths were also prepared. Preliminary IRT trials were conducted on the steel samples to obtain an optimal IRT setup configuration. The initial inspections for one of the steel samples were outsourced to Thermal Wave Imaging (TWI) where they employed Thermographic Signal Reconstruction (TSR) technique to enhance the resulting images. Additional inspections of the steel samples were performed in the Southern Illinois University-Carbondale (SIUC) facility. In case of the rail samples, the SDHs and the notched-edge reflectors could not be detected in any of the experimental trials performed in this research. In addition, two more rail samples containing BDHs were prepared to investigate the detection capabilities for three different surface conditions: painted, unpainted, and rusted. The painted surface provided a best-case scenario for inspections while the other conditions offered further insight on correlating the application to industry-like cases.A 1300 W halogen lamp was employed as the heat source for providing continuous thermal excitation for various durations. Post-processing and analysis of the resulting thermal images was performed within the acquisition software using built-in analysis tools such as temperature probes, Region of Interest (ROI) based intensity profiles, and smoothing filters. The minimum defect diameter to depth (aspect) ratio detected in preliminary trials for the steel sample blocks were 1.0 at a diameter of 4.7625 mm (0.1875 in) and 1.5 at a diameter of 3.175 mm (0.125 in). For the inspection of painted rail sample, the longest exposure times (10 sec) provided the best detection capabilities in all sets of trials. The three holes having aspect ratio greater or equal to 1.0 were indicated in the thermal response of the painted and rusted samples while only the two holes having aspect ratio greater or equal to 1.5 were indicated in the unaltered sample. Indications of reflectors were identified through qualitative graphical analysis of pixel intensity distributions obtained along a bending line profile. The results obtained from the painted sample provided a baseline for analyzing the results from the unpainted and rusted rail samples. This provided an insight on the limitations and requirements for future development. The primary takeaway is the need for an optimized heat source. Poor contrast in the resulting image for the unpainted and rusted rail samples is experienced due to both noise and lack of penetration of the heat energy. This could have been due to decreased emissivity values. Moreover, the excitation method employed in this research does not comply with current industry standards for track clearances. Therefore, exploration of alternative excitation methods is recommended.