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The present study evaluates two fetal individuals (B532 and B625) from the Kellis 2 cemetery (Roman period circa A.D. 50 A.D. 450), Dakhleh Oasis, Egypt, that display skeletal anomalies that may explain their death. Both individuals exhibit bowing of the long bones in addition to other skeletal deformities unique to each individual. To assess these pathologies a differential diagnosis based on the congenital occurrence of long bone bowing is developed. Long bone bowing is selected because it is the more prevalent abnormality in the paleopathological literature and the other abnormalities are not as easily identifiable in the literature. For the purposes of this study, the differential diagnosis is defined as a process of comparing the characteristics of known diseases with those shared by an archaeological specimen, in the anticipation of diagnosing the possible condition. It is expected that the differential diagnosis will assist in providing a thorough assessment of each skeleton and yield a possible diagnosis for the condition(s). Macroscopic and radiographic analyses are used to document and examine the bone abnormalities for each individual and compare the results with the developed differential diagnosis. Results suggest that the bent long bones of B532 were caused by osteogenesis imperfecta whereas the cause of the bent long bones of B625 is not clear. Further analyses of B625, including the pathologic abnormalities of its skull, suggest that the neural tube defect iniencephaly with associated encephalocele was the likely cause of the observed skeletal abnormalities. The abnormalities of the long bones complicate estimations of the age-at-death of these two individuals, thus the pars basilaris bone was used to assess age estimation. A population sample of 37 Kellis 2 fetal individuals allowed for the development of linear regression formulae of the pars basilaris measurements for long bone length estimates and a comparison of which would provide the most accurate age estimate. Finally, the diagnoses of the fetal specimens are considered in relation to the cultural aspects and disease pattern of the Kellis 2 cemetery

The goal of the research conducted for this master's thesis is to understand if active thermography is a suitable technique to detect (identify) and measure (approximate depth and or size) defects in additive manufacturing (AM) processes. Although other non-destructive measurement techniques exist, active thermography is an attractive option for AM applications because of the short measurement times that could be implemented between each layer of a print, and because of the relatively inexpensive equipment required. However, pulse thermography is typically applied to detect larger defects (>1 mm) in materials with high thermal conductivity. It was uncertain if active thermography was sensitive enough to detect the small defects (μm) commonly introduced during AM. Defects of this size are common in AM, and their presence significantly impacts the mechanical properties of the final part. For this reason, the detection limits of active thermography in common AM materials were investigated. Numerical models were created to simulate the heat transfer during active thermography in AM structures (polymer and stainless steel) with defects of varying size. The models included non-ideal conditions such as spectral in-depth absorption of the irradiative pulse and free convection from the object's surface. The spectral properties of acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyamide 12 (PA 12) were measured (see chapter 2) and used in the numerical models. The numerical data indicates that active thermography is sensitive enough to detect the existence of defects smaller than 100 μm in AM materials (see chapter 3). Furthermore, it demonstrates that the defect aspect ratio (defect diameter divided by defect depth) for which traditional 1D thermography models may be used to approximate the depth of defects in 3D systems is approximately 6 (see chapter 4). In addition, the depth of defects with lower aspect ratios (~4) may also be approximated with relatively low error (~10% error). Non-ideal systems (those with convection and spectral in-depth absorption) were simulated, and figures are provided which facilitate the approximation of defect depth using simple, ideal thermography models. Active thermography has shown potential as being an efficient technique for detecting and measuring small defects common in AM.

Das Ziel dieser Arbeit ist, die elektronischen Eigenschaften von CZTS zu verstehen. Ein leistungsfahigesWerkzeug zu diesem Zweck ist die Rontgen-Nahkanten Absorptions-Spektroskopie (XANES). Die Interpretation von XANES-Spektren komplexer Materialien ist nicht trivial und erfordert daher theoretische Modellierung. Alle Rechnungen in dieser Arbeit wurden mittels der im exciting Code implementierten Linearized-Augmented-Plane- Wave-Methode, welche alle Elektronen gleichberechtigt behandelt, durchgefuhrt. Die genaue Beschreibung der Anregungen von Kernzustanden wird durch ein zweistufiges Verfahren erreicht. Zunachst wird die elektronische Struktur berechnet, indem die Kohn-Sham-Gleichungen (KS) der Dichtefunktionaltheorie (DFT) gelost werden. Die Absorptionsspektren unter Berucksichtigung der Elektron-Loch-Wechselwirkung (e-h) werden durch die Losung der Bethe-Salpeter Gleichung (BSE) der Vielteilchen-Storungstheorie (MBPT) unter Einsatz der KS-Zustonde als Ausgangspunkt beschrieben. / The aim of this work is to understand the electronic properties of CZTS. X-ray absorption near edge structure (XANES) is a powerful tool for this purpose. Interpreting XANES of complex materials is nontrivial and thus requires theoretical modeling. Here, all the calculations are performed using an all-electron full-potential augmented plane-wave method as implemented in the exciting code. The accurate description of the core level excitations is performed by a two-step procedure. First, the electronic structure is calculated by solving the Kohn-Sham (KS) equation of density functional theory (DFT). The absorption spectra including electron-hole (e-h) is described by the solution of the Bethe-Salpeter equation (BSE) of many-body perturbation theory (MBPT) using the KS states as starting point.

<p dir="ltr">The process of metal additive manufacturing is characterized by the layer-by-layer construction of components, where each individual layer may be subjected to distinct thermal variations, resulting in differences in cooling rates and thermal gradients. These variations can impact the microstructure and, subsequently, mechanical properties of the final product, especially as the height of the build increases. In the present investigation, an evaluation was undertaken to ascertain the impact of build height on the structural integrity of Ti-6Al-4V samples produced using the laser powder bed fusion (LPBF) technique. The study encompassed a comprehensive examination of microstructural features, the microhardness measurement, as well as an evaluation of defect characteristics including size, location, and distribution, with respect to the build height. Tensile and fatigue tests were conducted to elucidate the potential dependence of fatigue and tensile failures on the build height. Two groups of specimens were fabricated: the first, underwent continuous fabrication, while the second involved a pause at the half height, with the process resuming after a 24-hour interval. The results of this investigation unveiled a discernible influence of the height of the build on the structural integrity of components under cyclic loading. Most fatigue specimens were observed to exhibit failure in the upper portion of the gage section with respect to the build direction. Analyses of microstructure revealed a consistent grain morphology in alignment with the build direction, and a uniform distribution of hardness throughout the build height was noted. However, for the specimens in the first group, more process-induced defects were detected within the top half of the gage section in comparison to the bottom half, while there was no noticeable difference in the distribution of defects in the second group. The results suggest that in LPBF process, as the build height is increased, there is a higher likelihood of process-induced defect formation, ultimately resulting in a reduction in structural integrity at greater build heights.</p>

In this project, the possibility of using thermography as a non-destructive testing tool in the manufacturing process of boats and to assess the quality of end-of-life composite structures has been explored. To do so, a literature surview regarding the current applications of thermography and the techniques currently used for quality control in the boats industry has been conducted. Additionally, the set-up of the thermal camera has been improved for the testing and measurements on several composite parts have been performed. Here, the resulting images were analysed regarding different features important for the intended new application, such as existence of delamination, bonding quality, and fibre orientations. The technique appears to be well suited to evaluate the bonding quality in case of glass fibre composite plates and to detect delaminations and other defects in such. Regarding the fibre orientation more studies are needed to judge the practicality.

Diamond possesses unique physical properties which give it great potential as a solid state framework for quantum sensors. Despite a worldwide research and development effort, the primary factors limiting its wider implementation are the technical difficulties related to high quality synthesis and device manufacture. In this work, as a first objective, laboratory diamond synthesis is explored with the aim to achieve single crystal diamond of high quality. A suite of characterization methods is implemented to evaluate and understand the physical qualities of synthesized diamond. Through a measurement process, a procedure for improving diamond growth is presented. As a secondary objective, a diamond-based defect which can be functionalized as a quantum sensor is investigated. The negatively charged silicon vacancy defect (SiV⁻) in diamond is explored for its potential use as a quantum high pressure/low temperature sensor. This SiV⁻ defect is optically accessible by photoluminescence. This optical emission arising from the SiV⁻ defect is studied under high pressures (up to 17 GPa) and low temperatures (down to 11 K). More specifically, the emission corresponding to SiV⁻ zero phonon line and local vibrational mode and their respective change as a function of pressure and temperature are recorded. This work indicates a promising potential for the SiV⁻ defect as a useful quantum sensor, especially in the context of extreme conditions research.

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