This project describes the role of ritual in the basic entrainment processes of Canadian soldiers. Building on the ecological systems theories of Urie Bronfenbrenner and Roy Rappaport, this project construes human adaptation to occur within multiple interdependent planes of ordered biological, sociostructural, psychosocial and symbolic (even transcendent) meanings and interactions within integrated social ecologies or “living systems.” Rappaport’s theory supports the argument that invariant, embodied actions and impulses not encoded by ritual performers establish social order, values, motivations, competencies, dispositions and representational or symbolic meanings—understood within this project as worldview—circulating within and regulating integrated human ecologies. Ordered sequences of invariant actions and impulses have also come to be conveyed within human phylogenic and ontogenetic developmental processes. This project specifically explores the hypothesis that embodied ritual dynamics pervade the basic entrainment rite of Canadian soldiers. The analysis draws on the ritual theory of Rappaport and the psychosocial developmental theory of Erik Erikson to describe the manner in which innate social regulating impulses and liturgically ordered ritual processes are exploited, in conjunction with predictable human psychosocial developmental imperatives, to build foundational martial dispositions, a spontaneous impulse to radical solidarity and a robust, homogeneous and multivocalic worldview in Canadian soldiers. Such a worldview is adaptive to all aspects of service within the Canadian Armed Forces. The rudimentary martial worldview inscribed upon recruit soldiers and officer candidates forms the foundational background to all subsequent martial meaning and adaptation in so far as it is collectively maintained throughout the military career. This argument maintains that a ritual analysis of adaptive meaning and solidarity among soldiers has profound implications for the structure and direction of future research investigating the persistent and well documented rates of distress, maladaptation and health pathology among serving members of the Canadian Armed Forces.

In dieser Doktorarbeit wird die Magnetisierungsdynamik von strukturierten, weichmagnetischen Einzelschichten aus Permalloy (Ni81Fe19) mittels stroboskopischer Kerrmikroskopie untersucht. Die Dicke der in unterschiedliche Formen (Kreise, Quadrate und Rechtecke) strukturierten magnetischen Schicht beträgt 50 nm bzw. 160 nm. Durch die Verwendung eines gepulsten Lasers als Beleuchtungsquelle wird eine Zeitauflösung erreicht, die unter 25 ps liegt. Parallel zu den Laserpulsen wird die Probe mit gepulsten Magnetfeldern angeregt und die Reaktion der Magnetisierung auf diese schnellen Magnetfeldänderungen wird untersucht. Diese Reaktion der Magnetisierung unterscheidet sich deutlich von einer Anregung mit quasistatischen Magnetfeldern. Durch die stroboskopische Beobachtungsweise sind nur reversible Prozesse sichtbar, irreversible Prozesse werden durch die Mittelung über mehrere Millionen Anregungs- und Beobachtungspulse nicht abgebildet. Dies wird bei der Anregung eines Vortex in einer Kreisscheibe deutlich, bei dem die Magnetisierungsrichtung im Vortexkern durch das gepulste Magnetfeld teilweise geschaltet wird. Dadurch ändert sich der Drehsinn der spiralförmigen Relaxationsbewegung des Vortex, was zu einer Überlagerung der beiden Bewegungen während der Beobachtung führt. Desweiteren wird eine Vervielfältigung von Vortex-Antivortex Paaren in Stachelwänden durch hochfrequente Felder gezeigt. Diese Vervielfältigung führt zur Erzeugung eines neuen, metastabilen Zustandes mit geringerem Stachelabstand. Mit steigender Frequenz des Feldes fällt der Stachelabstand bis auf 30 % des Ausgangswertes. Ab einer Grenzfrequenz, die durch die ferromagnetische Resonanz gegeben ist, kann die Magnetisierung dem Feld nicht mehr folgen und die Wandstruktur ist vergleichbar mit der im quasistatischen Grenzfall. Auch in dickeren Elementen wird diese Erzeugung beobachtet, wo sie zu einer irreversiblen Wandtransformation von der asymmetrischen Blochwand zur Stachelwand führt. Bei der Pulsanregung eines Landau-Domänenzustandes in einem Quadrat kommt es zur Bildung von sichelartigen Domänen an den Ecken des Quadrates. Die Entstehung dieser Domänen geschieht relativ schnell innerhalb einer Nanosekunde. Während der Relaxation der Magnetisierung lösen sich diese neu entstandenen Domänen durch Wandverschiebung wieder auf. Die Auflösung der Domänen geschieht deutlich langsamer als die Entstehung, was durch die unterschiedlichen Mechanismen, die bei der Entstehung (Magnetisierungsdrehung) und Auflösung (Wandverschiebung) der Domänen involviert sind, begründet werden kann. Außerdem kommt es zu einer inkohärenten Drehung der Magnetisierung in der Domäne mit antiparalleler Ausrichtung der Magnetisierung bezüglich des Pulsfeldes. Diese Drehung der Magnetisierung, lateral abwechselnd nach links und rechts, wird durch eine leichte Abweichung der Magnetisierung von einer perfekt homogenen Ausrichtung begünstigt.

Magnetic Resonance Imaging (MRI) is a non-ionizing form of medical imaging which has practical uses in diagnosing, characterizing, and studying diseases in vivo. Current clinical practice utilizes a highly trained radiologist to view MR images and qualitatively diagnose, characterize, or study a disease. There is no easy way to compare qualitative data. That is why developing quantitative measures in MRI show promise. Quantitative measures of disease can be compared across a population, MRI sites, and over time. Osteoarthritis is one disease where those who have it may benefit from the development of quantitative MRI measures. Those benefits may include earlier diagnosis and treatment of the disease or treatment which may halt or even reverse the damage from the disease.The work presented in this dissertation focuses on analyzing and developing new methods of radiofrequency (B1) field mapping to improve quantitative MRI measures. The dissertation opens with an introduction and a brief primer on MRI physics, followed by an introduction to B1 and flip-angle mapping in MRI (Chapters 1-3). Chapter 4 presents a careful statistical analysis of a recent and popular B1 mapping method, the Bloch-Siegert shift (BSS) method, along with a comparison of the technique to other common B1 mapping methods. The statistical models developed in chapter 4 are verified using both Monte Carlo simulation and actual MRI experiments in phantoms. Chapter 5 analyzes and details the potential errors introduced in B1 mapping when a 3D slab-selective excitation is employed. A method for correcting errors introduced by 3D slab-selective B1 mapping is then introduced in chapter 6, along with metrics to quantify the error involved. The thesis closes with a summary of other scientific contributions made by the author in chapter 7. The chapters comprising the bulk of the presented research (4-7) are briefly summarized below. Chapter 4, the statistical analysis of B1 mapping methods, demonstrates the effectiveness of deriving the B1 estimate from the phase of the MR image. These techniques are shown to perform particularly well in low signal-to-noise ratio (SNR) applications. However, there are benefits and drawbacks of each B1 mapping technique. The BSS method deposits a significant amount of radiofrequency (RF) power into the patient, causing a concern that tissue heating may occur. The Phase-Sensitive (PS) method of B1 mapping outperforms the other techniques in many situations, but suffers from significant sensitivity to off-resonance. The Dual-Angle (DA) method is very simple to implement and the analysis is straightforward, but it can introduce significant mean bias in the estimate. No B1 mapping technique performs well for all situations. Therefore, the best B1 mapping method needs to be determined for each situation. The work in chapter 4 provides guidance for that choice. Many B1 mapping techniques rely on a linear relationship between flip angle and transmit voltage. That assumption breaks down when a 3D slab-selective excitation is used. 3D slab-selective excitation is a common technique used to reduce the field-of-view (FOV) in MRI, which can directly reduce scan time. The problem with slab-selective excitation in conjunction with B1 mapping has been documented, but the potential errors in B1 estimation have never been properly analyzed across different techniques. The analysis in chapter 5 demonstrates that the errors introduced in B1 mapping using a slab-selective excitation in conjunction with the ubiquitous DA B1 mapping method can be significant. It is then shown that another B1 mapping technique, the Actual Flip Angle Imaging (AFI) method, doesn't suffer from the same limitation. The analysis presented in Chapter 6 demonstrates that some errors introduced by 3D slab-selective B1 mapping may be modeled and corrected allowing the use of 3D slab-selective excitation to reduce field-of-view, and potentially reduce scan time. The errors are modeled and corrected with a general numerical method using Bloch simulations. The general method is applied to the DA method as an example, but is general and could easily be extended to other methods as well. Finally, a set of metrics are proposed and briefly explored that can be used to better understand the topology and severity of errors introduced into B1 mapping methods. With a better understanding of the errors introduced, the need for correction can be determined. Chapter 7 details other significant ancillary contributions made by the author including: (1) presentation of a new B1 mapping method, the decoupled RF-pulse phase-sensitive B1 mapping method, which has potential for parallel transmit MRI; (2) demonstration of an ultra-short TE method which has potential for imaging Alzheimers brain lesions in vivo; (3) introduction of a new steady-state diffusion tensor imaging technique; (4) phase-sensitive B1 mapping in sodium is demonstrated, a feat not previously demonstrated; (5) a comparison between a dual-tuned and single-tuned sodium coil; (6) introduction of a water- and fat-separation technique using multiple acquisition SSFP; (7) an inter-site and inter-vendor quantitative MRI study is introduced; (8) a relaxation and contrast optimization for laryngeal imaging at 3T is introduced; and (9) diffusion imaging with insert gradients is introduced.

No description available.

<p>In this study, we concentrate on spin-1/2 systems. A series of tools using the Liouville space method have been developed for simulating of NMR of arbitrary pulse sequences.</p> <p>We have calculated one- and two-spin symbolically, and larger systems numerically of steady states. The one-spin calculations show how SSFP converges to continuous wave NMR. A general formula for two-spin systems has been derived for the creation of double-quantum signals as a function of irradiation strength, coupling constant, and chemical shift difference. The formalism is general and can be extended to more complex spin systems.</p> <p>Estimates of transverse relaxation, R₂, are affected by frequency offset and field inhomogeneity. We find that in the presence of expected B₀ inhomogeneity, off-resonance effects can be removed from R₂ measurements, when ||omega||<= 0.5 gamma\,B₁ in Hahn echo experiments, when ||omega||<=gamma\,B₁ in CPMG experiments with specific phase variations, by fitting exact solutions of the Bloch equations given in the Lagrange form.</p> <p>Approximate solutions of CPMG experiments show the specific phase variations can significantly smooth the dependence of measured intensities on frequency offset in the range of +/- 1/2 gamma\,B₁. The effective R₂ of CPMG experiments when using a phase variation scheme can be expressed as a second-order formula with respect to the ratio of offset to pi-pulse amplitude.</p> <p>Optimization problems using the exact or approximate solution of the Bloch equations are established for designing optimal broadband universal rotation (OBUR) pulses. OBUR pulses are independent of initial magnetization and can be applied to replace any pulse of the same flip angles in a pulse sequence. We demonstrate the process to exactly and efficiently calculate the first- and second-order derivatives with respect to pulses. Using these exact derivatives, a second-order optimization method is employed to design pulses. Experiments and simulations show that OBUR pulses can provide more uniform spectra in the designed offset range and come up with advantages in CPMG experiments.</p> / Doctor of Philosophy (PhD)

The static and dynamic response of lattice materials is investigated to disclose and control the connection between microstructure and effective behavior. The analytical methods developed in the thesis aim at providing a new understanding of material instabilities and strain localizations as well as effective tools for controlling wave propagation in lattice structures. The time-harmonic dynamics of arbitrary beam lattices, deforming flexurally and axially in a plane, is formulated analytically to analyze the influence of the mechanical parameters on the dispersion properties of the spectrum of Floquet-Bloch waves. Several forms of dynamic localizations are shown to occur for in-plane wave propagation of grid-like elastic lattices. It is demonstrated that lattices of rods, despite being `simple' structures, can exhibit a completely different channeled response depending on the characteristics of the forcing source (i.e. frequency and direction) as well as on the slenderness of the elastic links. It is also shown how the lattice parameters can be tuned to attain specific dispersion properties, such as flat bands and sharp Dirac cones. In the research field of material instabilities, a key result proposed in this thesis is the development of both static and dynamic homogenization methods capable of accounting for second-order effects in the macroscopic response of prestressed lattices. These methods, the former based on an incremental strain-energy equivalence and the latter based on the asymptotic analysis of lattice waves, allow the identification of the incremental constitutive operator capturing the macroscopic incremental response of arbitrary lattice configurations. The homogenization framework has allowed the systematic analysis of prestress-induced phenomena on the incremental response of both the lattice structure and its `effective' elastic solid, which in turn has enabled the identification of the complex interplay between microstructure, prestress, loss of ellipticity (shear band formation) and short-wavelength bifurcations. Potential new applications for the control of wave propagation are also shown to be possible by leveraging the inclusion of second-order terms in the incremental dynamics. In particular, the tunability of the prestress state in a square lattice structure has been exploited to obtain dynamic interfaces with designable transmission properties. The interface can be introduced in a material domain by selectively prestressing the desired set of ligaments and the prestress level can be tuned to achieve total reflection, negative refraction, and wave channeling. The obtained results open new possibilities for the realization of engineered materials endowed with a desired constitutive response, as well as to enable the identification of novel dynamic material instabilities.

Dans cette thèse, nous avons répondu à certaines questions ouverts dans le domaine de la dynamique hors équilibre des systèmes quantiques unidimensionnels fermés. Durant ces dernières années, les avancées dans les techniques expérimentales ont revitalisé la recherche théorique en physique de la matière condensée et dans l'optique quantique. Nous avons traité trois sujets différents et en utilisant des techniques à la fois numériques et analytiques. Dans le cadre des techniques numériques, nous avons utilisé des méthodes de diagonalisation exacte, l'algorithme du groupe de renormalisation de la matrice densité en fonction du temps (t-DMRG) et l'algorithme de Lanczos. Au début, nous avons étudié la dynamique quantique adiabatique d'un système quantique près d'un point critique. Nous avons démontré que la présence d'un potentiel de confinement modifie fortement les propriétés d'échelle de la dynamique des observables en proximité du point critique quantique. La densité d'excitations moyenne et l'excès d'énergie, après le croisement du point critique, suivent une loi algébrique en fonction de la vitesse de la trempe avec un exposant qui dépend des propriétés spatio-temporelles du potentiel. Ensuite, nous avons étudié le comportement de bosons ultra-froids dans un réseau optique incliné. En commençant par l'hamiltonien de Bose-Hubbard, dans la limite de Hard-Core bosons, nous avons développé une théorie hydrodynamique qui reproduit exactement l'évolution temporelle d'une partie des observables du système. En particulier, nous avons observé qu'une partie de bosons reste piégée, et oscille avec une fréquence qui dépend de la pente du potentiel, au contraire, une autre partie est expulsée hors de la rampe. Nous avons également analysé la dynamique du modèle de Bose-Hubbard en utilisant l'algorithme t-DMRG et l'algorithme de Lanczos. De cette façon, nous avons mis en évidence le rôle de la non-intégrabilité du modèle dans son comportement dynamique. Enfin, nous avons abordé le problème de la thermalisation dans un système quantique étendu. À partir de considérations générales, nous avons introduit la notion de profil de température hors équilibre dans une chaîne des bosons à coeur dure. Nous avons analysé la dynamique du profil de temperature et, notamment, ses propriétés d'échelle / In this thesis we have addressed some open questions on the out-of-equilibrium dynamics of closed one-dimensional quantum systems. In recent years, advances in experimental techniques have revitalized the theoretical research in condensed matter physics and quantum optics. We have treated three different subjects using both numerical and analytical techniques. As far as the numerical techniques are concerned, we have used essentially exact diagonalization methods, the adaptive time-dependent density-matrix renormalization-group algorithm (t-DMRG) and the Lanczos algorithm. At first, we studied the adiabatic quantum dynamics of a quantum system close to a critical point. We have demonstrated that the presence of a confining potential strongly affects the scaling properties of the dynamical observables near the quantum critical point. The mean excitation density and the energy excess, after the crossing of the critical point, follow an algebraic law as a function of the sweeping rate with an exponent that depends on the space-time properties of the potential. After that, we have studied the behavior of ultra-cold bosons in a tilted optical lattice. Starting with the Bose-Hubbard Hamiltonian, in the limit of Hard-Core bosons, we have developed a hydrodynamic theory that exactly reproduces the temporal evolution of some of the observables of the system. In particular, it was observed that part of the boson density remains trapped, and oscillates with a frequency that depends on the slope of the potential, whereas the remaining packet part is expelled out of the ramp. We have also analyzed the dynamics of the Bose-Hubbard model using the tDMRG algorithm and the Lanczos algorithm. In this way we have highlighted the role of the non-integrability of the model on its dynamical behavior. Finally, we have addressed the issue of thermalization in an extended quantum system. Starting from quite general considerations, we have introduced the notion of out-of-equilibrium temperature profile in a chain of Hard-Core bosons. We have analyzed the dynamics of the temperature profile and especially its scaling properties

Le transport des ondes joue un rôle majeur dans les systèmes de communication comme le Wifi ou les fibres optiques. Les principaux problèmes rencontrés dans ces systèmes concernent la protection contre les intrusions, la consommation d’énergie et le filtrage modal. Nous proposons différentes expériences micro-ondes mettant toutes en œuvre une mise en forme des ondes, pour traiter ces problèmes. Dans une cavité micro-ondes, des états de diffusion particuliers sont générés en s’appuyant uniquement sur des mesures de transmission et sur le formalisme du temps de retard de Wigner-Smith. Ces états sont capables d’éviter une région déterminée de la cavité, de se concentrer sur un point particulier, ou de suivre une trajectoire d’une particule classique. Le filtrage de mode est mis en œuvre dans un guide d’ondes aux frontières ondulées et en présence de pertes dépendant de la position. Le profil du guide est choisi de façon à ce que les deux modes de Bloch qui se propagent encerclent un point exceptionnel. Cette trajectoire s’accompagne d’une transition non-adiabatique entre les deux modes et d'un filtrage asymétrique de ces modes. La thèse présente également des travaux liés à la problématique des algorithmes de « recherche quantique », notamment l’algorithme de Grover. Cette recherche est mise en œuvre dans un réseau en nid d’abeilles de résonateurs micro-ondes couplés, bien décrits par un modèle de liaisons fortes (le système constitue un analogue micro-ondes du graphène). Une expérience de preuve de principe propose la recherche de deux résonateurs distincts reliés au réseau. La loi d’échelle attendue pour cet algorithme est expérimentalement obtenue dans une chaîne linéaire / Transport of waves plays an important role in modern communication systems like Wi-Fi or optical fibres. Typical problems in such systems concern security against possible intruders, energy consumption, time efficiency and the possibility of mode filtering. Microwave experiments are suited to study this kind of problems, because they offer a good control of the experimental parameters. Thus we can implement the method of wave shaping to investigate atypical transport phenomena, which address the mentioned problems. Wave front shaping solely based on the transmission together with the Wigner-Smith time delay formalism allows me to establish special scattering states in situ. These scattering states avoid a pre-selected region, focus on a specific spot or follow trajectories of classical particles, so called particle-like scattering states. Mode filtering is induced inside a waveguide with wavy boundaries and position dependent loss. The boundary profiles are chosen in such a way that the two propagating modes describe an encircling of an exceptional point in the Bloch picture. The asymmetric mode filtering is found due to the appearing non-adiabatic transitions. Another part of my work deals with Grover’s quantum search. I put such a search into practice in a two-dimensional graphene-lattice using coupled resonators, which form a tight-binding analogue. In this proof of principle experiment we search for different resonators attached to the graphene-lattice. Furthermore, the scaling behaviour of the quantum search is quantified for a linear chain of resonators

Master of Music / Department of Music, Theatre, and Dance / Gary C. Mortenson / This report is an analysis and exploration of the following works: Eugène Bozza’s Caprice, Vincent Persichetti’s The Hollow Men, Halsey Stevens’s Sonata for Trumpet and Piano, Alexander Arutunian’s Concerto for Trumpet, Ernest Bloch’s Proclamation, and Eric Ewazen’s Grand Valley Fanfare. The purpose of this report is to aid performance preparation of these pieces by providing thematic and formal analysis as well as identifying general unifying elements for each piece. Once identified, these patterns will help the performer communicate the broad musical ideas to the audience by finding a balance between the technical aspects and musical statements in each work.

Mechanics of structure genome (MSG) is a unified homogenization theory that provides constitutive modeling of three-dimensional (3D) continua, beams and plates. In present work, the author extends the MSG to study the buckling of structures such as stiffened and sandwich panels. Such structures are usually slender or flat and easily buckle under compressive loads or bending moments which may result in catastrophic failure.<div><br><div>Buckling studies of stiffened and sandwich panels are found to be scattered. Most of the existed theories employ unnecessary assumptions or only apply to certain types of structures. There are few unified approaches that are capable of studying the buckling of different kinds of structures altogether. The main improvements of current approach compared with other methods in the literature are avoiding unnecessary assumptions, the capability of predicting all possible buckling modes including the global and local buckling modes, and the potential in studying the buckling of various types of structures.<br></div><div><br></div><div>For global buckling that features small local rotations, MSG mathematically decouples the 3D geometrical nonlinear problem into a linear constitutive modeling using structure genome (SG) and a geometrical nonlinear problem defined in a macroscopic structure. As a result, the original structures are simplified as macroscopic structures such as beams, plates or continua with effective properties, and the global buckling modes are predicted on macroscopic structures. For local buckling that features finite local rotations, Green strain is introduced into the MSG theory to achieve geometrically nonlinear constitutive modeling. Newton’s method is used to solve the nonlinear equilibrium equations for fluctuating functions. To find the bifurcated fluctuating functions, the fluctuating functions are then perturbed under the Bloch-periodic boundary conditions. The bifurcation is found when the tangent stiffness associated with the perturbed fluctuating functions becomes singular. Moreover, the arc-length method is introduced to solve the nonlinear equilibrium equations for post-local-buckling predictions because of its robustness. The imperfection is included in the form of geometrical imperfection by superimposing the scaled buckling modes in linear perturbation analysis on mesh.<br></div><div><br></div><div>Extensive validation case studies are carried out to assess the accuracy of the MSG theory in global buckling analysis and post-global-buckling analysis, and assess the accuracy of the extended MSG theory in local buckling and post-local-buckling analysis. Results using MSG theory and extended MSG theory in buckling analysis are compared with direct numerical solutions such as 3D FEA results and results in literature. Parametric studies are performed to reveal the relative influence of selective geometric parameters on buckling behaviors. The extended MSG theory is also compared with representative volume element (RVE) analysis with Bloch-periodic boundary conditions using commercial finite element packages such as Abaqus to assess the efficiency and accuracy of the present approach.<br></div></div>