Text in Afrikaans / Vrouemisdaad is 'n komplekse sosiale verskynsel. 'n Aspek van vrouemisdaad wat in die onderhawige proef skrif ondersoek word, is om aan die hand van bestaande teoriee te probeer verklaar waarom vroue soveel minder misdaad as mans pleeg. Ten einde antwoorde op die vraag te vind, is 'n kwantitatiewe ondersoek na die gemeenskap se houding rakende die vrouemisdadiger en 'n kwalitatiewe ontleding van die beskikbare literatuur gedoen. 'n Intensiewe verkennende studie van die beskikbare literatuur het getoon dat die gemeenskap, navorsers en akademici bepaalde persepsies huldig oor die vrouemisdadiger wat nie altyd met die werklike beeld strook nie. Alhoewel die getalle van vrouemisdadigers deur die jare toegeneem het, het die tipe misdade wat vroue pleeg weinig verander en die omvang van vrouemisdaad proporsioneel tot die bevolking dieselfde gebly. Geen enkele teorie of benadering op sigself bied 'n algemene verklaring vir die verskynsel van vrouemisdaad nie; dit kan hoogstens as gedeeltelike verklaring dien. 'n Algemene verklaringsmodel vir vrouemisdaad is egter opgestel wat terselfdertyd as samevatting van die geselekteerde teoriee dien. Met behulp van die argivale metode is 'n profiel van die gekommitteerde vrouemisdadiger saamgestel om 'n basiese kennissisteem van die vrouemisdadiger daar te stel. Statisties beduidende verbande is gevind tussen die karakteristieke van die blanke gekommitteerde vrouemisdadiger se huwelikstaat, aantal kinders en bedrog. Die kwantitatiewe ondersoek bestaan uit die ontleding van 516 respondente se persepsies oor die vrouemisdadiger. Uit die resultate van verskeie statistiese tegnieke blyk dit dat die ondersoekgroep, wat blanke respondente van vier voorstede uit struktuurstreekplansel 22 van Pretoria verteenwoordig, bepaalde persepsies en opvattings aangaande die vrouemisdadiger het. Die persepsiemeting het aan die lig gebring dat daar verskille in persepsies bestaan oor die vrouemisdadiger en vrouemisdaad in die blanke gemeenskap bestaan. Hierdie persepsies stem nie ooreen met die beeld wat blyk uit die onderhawige navorsing nie. Statisties beduidende verskille in persepsies tussen manlike en vroulike respondente van die ondersoekgroep is ook gevind. Daar bestaan verder statisties beduidende verskille tussen respondente van verskillende voorstede, onderwyspeile, taalgroepe, en ouderdomsgroepe. / It can be said that female crime is a complex phenomenon. An aspect of female crime that is investigated in this thesis is to explain, with reference to existing theories, why women commit fewer crimes than men. In an attempt to answer this question, a quantitative investigation regarding the attitude of society towards the female criminal as well as a qualitative study of the available literature, was conducted. An intensive exploratory study on female crime indicated that and academics have a certain of the available the community, perception of literature researchers the female criminal which does not always correspond with the facts. Although the number of female criminals has increased through the years the extent of female crime, proportionally to the population size, has remained constant, and the type of crime committed by women has remained relatively unchanged. It seems clear that no single theory or approach can explain female crime, it can at best give a partial explanation. An integrated explanation model for female crime has been compiled which simultaneously serves as a summary of selected theories. By means of the archival research method a profile of the female prisoner was compiled, to be used as a basis for the researcher's scientific knowledge of this phenomenon. Statistically significant relations were found to exist between the characteristics of the white female prisoner's marital status, number of children and fraud. The quantitative investigation consisted of an analysis of the responses of 516 respondents on an attitude scale. The results of various statistical techniques show that the research group, which represents respondents fr6m four suburbs from structure plan cell 22 of Pretoria, reveals certain attitudes and beliefs about the female criminal. This attitude measurement indicated that differences in perceptions regarding the female in the white community do criminal and female exist. Furthermore crime these perceptions do not correlate on the female criminal in with the information gathered this research. Statistically significant differences in attitude were found between male and female respondents, respondents from the different suburbs, with different qualifications, of different language groups, and of different age groups. / Sociology / D. Lit. et Phil. (Kriminologie)

The aim of this degree project has been to examine, analyze and describe which intra-linguistic factors influence how relative clauses are formed in Old English. The key to successfully performing the task of identifying which factors influences the relative causes is to examine how these factors are distributed among the relative clauses in the text. The main focus of this investigation thus was to investigate how the grammatical features of the antecedents of the relative clauses in Old English were distributed. By analyzing a text sample of the work of the Old English writer Ælfric, taken from the Dictionary of Old English Corpus at the University of Toronto, also known as the Toronto Corpus, several features of the antecedent will ideally become evident as influencing factors. The relative clauses that are found to be relevant for this investigation in the Ælfric text sample have been categorized and analyzed in order to identify any grammatical pattern that could indicate which factors influence how relative clauses in Old English are formed. The findings have been analyzed according to quantitative and statistical principles, and the chi-square test has been employed to verify the statistical significance of these findings. By doing this some linguistic factors have been verified as influencing factors.

This master’s thesis deals with technology of wire electrical discharge machining in theoretical and practical level. Theoretical part of the thesis explains in detail the principle of electrical discharge machining, describes functional parts and settings of a current wire EDM machines and also the possibility of using method for production of specific parts. Practical part of the thesis solves manufacturing of gearing on pinion manufactured by wire cutter EXCETEK V650 and statistically evaluates precision parameters on surfaces of the carriers taken by specific technological conditions with the same machine.

Therapeutic horseback riding (THR) uses the horse as a therapeutic apparatus in physical and psychological therapy. This dissertation suggests a more appropriate technique for measuring the effect of THR. A research survey of the statistical methods used to determine the effect of THR was undertaken. Although researchers observed clinically meaningful change in several of the studies, this was not supported by statistical tests. A logistic regression approach is proposed as a solution to many of the problems experienced by researchers on THR. Since large THR related data sets are not available, data were simulated. Logistic regression and t-tests were used to analyse the same simulated data sets, and the results were compared. The advantages of the logistic regression approach are discussed. This statistical technique can be applied in any field where the therapeutic value of an intervention has to be proven scientifically. / Mathematical Sciences / M. Sc. (Statistics)

Therapeutic horseback riding (THR) uses the horse as a therapeutic apparatus in physical and psychological therapy. This dissertation suggests a more appropriate technique for measuring the effect of THR. A research survey of the statistical methods used to determine the effect of THR was undertaken. Although researchers observed clinically meaningful change in several of the studies, this was not supported by statistical tests. A logistic regression approach is proposed as a solution to many of the problems experienced by researchers on THR. Since large THR related data sets are not available, data were simulated. Logistic regression and t-tests were used to analyse the same simulated data sets, and the results were compared. The advantages of the logistic regression approach are discussed. This statistical technique can be applied in any field where the therapeutic value of an intervention has to be proven scientifically. / Mathematical Sciences / M. Sc. (Statistics)

Additive manufacturing (AM) introduces high variability in the microstructure and defect distributions, compared with conventional processing techniques, which introduces greater uncertainty in the resulting fatigue performance of manufactured parts. As a result, qualification of AM parts poses as a problem in continued adoption of these materials in safety-critical components for the aerospace industry. Hence, there is a need to develop precise and accurate, physics-based predictive models to quantify the fatigue performance, as a means to accelerate the qualification of AM parts. The fatigue performance is a critical requirement in the safe-life design philosophy used in the aerospace industry. Fatigue failure is governed by the loading conditions and the attributes of the material microstructure, namely, grain size distribution, texture, and defects. In this work, the crystal plasticity finite element (CPFE) method is employed to model the microstructure-based material response of an additively manufactured Ni-based superalloy, Inconel 718 (IN718). Using CPFE and associated experiments, methodologies were developed to assess multiple aspects of the fatigue behavior of IN718 using four studies. In the first study, a CPFE framework is developed to estimate the critical characteristics of porosity, namely the pore size and proximity that would cause a significant debit in the fatigue life. The second study is performed to evaluate multiple metrics based on plastic strain and local stress in their ability to predict both the modes of failure as seen in fractography experiments and estimate the scatter in fatigue life due to microstructural variability as obtained from fatigue testing. In the third study, a systematic analysis was performed to investigate the role of the simulation volume and the microstructural constraints on the fatigue life predictions to provide informed guidelines for simulation volume selection that is both computationally tractable and results in consistent scatter predictions. In the fourth study, validation of the CPFE results with the experiments were performed to build confidence in the model predictions. To this end, 3D realistic microstructures representative of the test specimen were created based on the multi-modal experimental data obtained from high-energy diffraction experiments and electron backscatter diffraction microscopy. Following this, the location of failure is predicted using the model, which resulted in an unambiguous one to one correlation with the experiment. In summary, the development of microstructure-sensitive predictive methods for fatigue assessment presents a tangible step towards the adoption of model-based approaches that can be used to compliment and reduce the overall number of physical tests necessary to qualify a material for use in application.

<div>In this thesis, the role of location-specific microstructural features in the fatigue performance of the safety-critical aerospace components made of Nickel (Ni)-base superalloys and linear friction welded (LFW) Titanium (Ti) alloys has been studied using crystal plasticity finite element (CPFE) simulations, energy dispersive X-ray diffraction (EDD), backscatter electron (BSE) images and digital image correlation (DIC).</div><div><br></div><div>In order to develop a microstructure-sensitive fatigue life prediction framework, first, it is essential to build trust in the quantitative prediction from CPFE analysis by quantifying uncertainties in the mechanical response from CPFE simulations. Second, it is necessary to construct a unified fatigue life prediction metric, applicable to multiple material systems; and a calibration strategy of the unified fatigue life model parameter accounting for uncertainties originating from CPFE simulations and inherent in the experimental calibration dataset. To achieve the first task, a genetic algorithm framework is used to obtain the statistical distributions of the crystal plasticity (CP) parameters. Subsequently, these distributions are used in a first-order, second-moment method to compute the mean and the standard deviation for the stress along the loading direction (σ_load), plastic strain accumulation (PSA), and stored plastic strain energy density (SPSED). The results suggest that an ~10% variability in σ_load and 20%-25% variability in the PSA and SPSED values may exist due to the uncertainty in the CP parameter estimation. Further, the contribution of a specific CP parameter to the overall uncertainty is path-dependent and varies based on the load step under consideration. To accomplish the second goal, in this thesis, it is postulated that a critical value of the SPSED is associated with fatigue failure in metals and independent of the applied load. Unlike the classical approach of estimating the (homogenized) SPSED as the cumulative area enclosed within the macroscopic stress-strain hysteresis loops, CPFE simulations are used to compute the (local) SPSED at each material point within polycrystalline aggregates of 718Plus, an additively manufactured Ni-base superalloy. A Bayesian inference method is utilized to calibrate the critical SPSED, which is subsequently used to predict fatigue lives at nine different strain ranges, including strain ratios of 0.05 and -1, using nine statistically equivalent microstructures. For each strain range, the predicted lives from all simulated microstructures follow a log-normal distribution; for a given strain ratio, the predicted scatter is seen to be increasing with decreasing strain amplitude and are indicative of the scatter observed in the fatigue experiments. Further, the log-normal mean lives at each strain range are in good agreement with the experimental evidence. Since the critical SPSED captures the experimental data with reasonable accuracy across various loading regimes, it is hypothesized to be a material property and sufficient to predict the fatigue life.</div><div><br></div><div>Inclusions are unavoidable in Ni-base superalloys, which lead to two competing failure modes, namely inclusion- and matrix-driven failures. Each factor related to the inclusion, which may contribute to crack initiation, is isolated and systematically investigated within RR1000, a powder metallurgy produced Ni-base superalloy, using CPFE simulations. Specifically, the role of the inclusion stiffness, loading regime, loading direction, a debonded region in the inclusion-matrix interface, microstructural variability around the inclusion, inclusion size, dissimilar coefficient of thermal expansion (CTE), temperature, residual stress, and distance of the inclusion from the free surface are studied in the emergence of two failure modes. The CPFE analysis indicates that the emergence of a failure mode is an outcome of the complex interaction between the aforementioned factors. However, the possibility of a higher probability of failure due to inclusions is observed with increasing temperature, if the CTE of the inclusion is higher than the matrix, and vice versa. Any overall correlation between the inclusion size and its propensity for damage is not found, based on inclusion that is of the order of the mean grain size. Further, the CPFE simulations indicate that the surface inclusions are more damaging than the interior inclusions for similar surrounding microstructures. These observations are utilized to instantiate twenty realistic statistically equivalent microstructures of RR1000 – ten containing inclusions and remaining ten without inclusions. Using CPFE simulations with these microstructures at four different temperatures and three strain ranges for each temperature, the critical SPSED is calibrated as a function of temperature for RR1000. The results suggest that critical SPSED decreases almost linearly with increasing temperature and is appropriate to predict the realistic emergence of the competing failure modes as a function of applied strain range and temperature.</div><div><br></div><div>LFW process leads to the development of significant residual stress in the components, and the role of residual stress in the fatigue performance of materials cannot be overstated. Hence, to ensure fatigue performance of the LFW Ti alloys, residual strains in LFW of similar (Ti-6Al-4V welded to Ti-6Al-4V or Ti64-Ti64) and dissimilar (Ti-6Al-4V welded to Ti-5Al-5V-5Mo-3Cr or Ti64-Ti5553) Ti alloys have been characterized using EDD. For each type of LFW, one sample is chosen in the as-welded (AW) condition and another sample is selected after a post-weld heat treatment (HT). Residual strains have been separately studied in the alpha and beta phases of the material, and five components (three axial and two shear) have been reported in each case. In-plane axial components of the residual strains show a smooth and symmetric behavior about the weld center for the Ti64-Ti64 LFW samples in the AW condition, whereas these components in the Ti64-Ti5553 LFW sample show a symmetric trend with jump discontinuities. Such jump discontinuities, observed in both the AW and HT conditions of the Ti64-Ti5553 samples, suggest different strain-free lattice parameters in the weld region and the parent material. In contrast, the results from the Ti64-Ti64 LFW samples in both AW and HT conditions suggest nearly uniform strain-free lattice parameters throughout the weld region. The observed trends in the in-plane axial residual strain components have been rationalized by the corresponding microstructural changes and variations across the weld region via BSE images. </div><div><br></div><div>In the literature, fatigue crack initiation in the LFW Ti-6Al-4V specimens does not usually take place in the seemingly weakest location, i.e., the weld region. From the BSE images, Ti-6Al-4V microstructure, at a distance from the weld-center, which is typically associated with crack initiation in the literature, are identified in both AW and HT samples and found to be identical, specifically, equiaxed alpha grains with beta phases present at the alpha grain boundaries and triple points. Hence, subsequent fatigue performance in LFW Ti-6Al-4V is analyzed considering the equiaxed alpha microstructure.</div><div><br></div><div>The LFW components made of Ti-6Al-4V are often designed for high cycle fatigue performance under high mean stress or high R ratios. In engineering practice, mean stress corrections are employed to assess the fatigue performance of a material or structure; albeit this is problematic for Ti-6Al-4V, which experiences anomalous behavior at high R ratios. To address this problem, high cycle fatigue analyses are performed on two Ti-6Al-4V specimens with equiaxed alpha microstructures at a high R ratio. In one specimen, two micro-textured regions (MTRs) having their c-axes near-parallel and perpendicular to the loading direction are identified. High-resolution DIC is performed in the MTRs to study grain-level strain localization. In the other specimen, DIC is performed on a larger area, and crack initiation is observed in a random-textured region. To accompany the experiments, CPFE simulations are performed to investigate the mechanistic aspects of crack initiation, and the relative activity of different families of slip systems as a function of R ratio. A critical soft-hard-soft grain combination is associated with crack initiation indicating possible dwell effect at high R ratios, which could be attributed to the high-applied mean stress and high creep sensitivity of Ti-6Al-4V at room temperature. Further, simulations indicated more heterogeneous deformation, specifically the activation of multiple families of slip systems with fewer grains being plasticized, at higher R ratios. Such behavior is exacerbated within MTRs, especially the MTR composed of grains with their c-axes near parallel to the loading direction. These features of micro-plasticity make the high R ratio regime more vulnerable to fatigue damage accumulation and justify the anomalous mean stress behavior experienced by Ti-6Al-4V at high R ratios.</div><div><br></div>

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