Luminosity-velocity diagrams for 12 spiral galaxies in the Virgo cluster are presented. Optical rotation curves obtained for the innermost portions of eight galaxies, complemented with velocity data from the literature, are coupled with luminosity growth curves to investigate the distance indication capabilities of the initial linear branch (ILB) feature and to delve into the physical basis for the T-F relation. Luminosity growth curves are obtained from Gunn r CCD images. The ILB feature is found to have a substantially larger dispersion in slope (~0.9) (and consequently, zero point) than previously thought. Plotting the magnitude and velocity of the final point in the ILB for all the galaxies in our sample yields a tight correlation (essentially an "inner T-F relation"), with the caveat that two galaxies are rejected from the fit (one is foreground, the other is a member of a binary pair). Ramifications of this relation are briefly discussed. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The muon is a useful probe of magnetic fields in superconductors, but knowing the field seen by the muon is often of limited value until we know where the muon is in the crystal lattice. In this thesis I employ two independent theoretical methods to search for candidate muon sites: the potential energy field method, which seeks the minimum of the electrostatic potential of the μ⁺, and the magnetic dipolar field method, which compares the calculated magnetic field (due to the host electronic, atomic or nuclear dipolar fields) with the observed local fields at the muon. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

La RMN des solides est un outil analytique puissant, qui permet notamment de caractériser les catalyseurs, les polymères ou les macromolécules biologiques. Ce travail de thèse a porté sur le développement de nouvelles méthodes RMN des solides, capables de réintroduire les couplages dipolaires dans les conditions de rotation à l'angle magique. Ces techniques permettent d'obtenir des informations sur les proximités atomiques et de faciliter l'attribution des spectres RMN pour des échantillons solides. Nous avons tout d'abord introduit des séquences de recouplage homonucléaires double-quantum robustes, compatibles avec les haut champs et les vitesses de rotation élevées. Ces séquences ont notamment d'attribuer les spectres 19F de fluorures inorganiques à haut champ et à des fréquences de rotation supérieures à 60 kHz. Ces méthodes de recouplage homonucléaires ont aussi été mises à profit pour les noyaux 1H, 13C et 31P. De plus, la symétrie et le supercyclage proposés ont pu être utilisés pour détecter des corrélations homonucléaires entre noyaux quadripolaires, tels que l'aluminium-27. Notre étude de la RMN des noyaux quadripolaires a aussi porté sur le recouplage hétéronucléaire entre noyaux quadripolaires et noyaux de spin-1/2. En particulier, nous avons introduit une technique de corrélation 1H-13C filtrée 14N, permettant d'analyser les acides aminés en abondance naturelle isotopique. / Solid state NMR as a powerful analysis tool is extensively used in many fields such as catalysis science, polymer materials, and biological molecules. This thesis work mainly describes the development of new NMR methods to recover dipolar coupling of rotating solids and their applications for spectral assignment and structural investigation by solid state NMR. First, a new broadband homo-nuclear Double Quantum (DQ) dipolar recoupling sequence which can be used at high field and ultra-fast magic-angle spinning was introduced. To improve the spectral resolution, 1H homonuclear decoupling technique were applied during the acquisition time, t2 and indirect evolution time, t1. Then, a comparison between different symmetry sequences with and without composite pulses which also can be used at ultra fast spinning for DQ coherence excitation was discussed. Moreover, these homonuclear DQ dipolar recoupling sequences were the employed for the unambiguous assignment of 19F spectra of inorganic fluorides at high field (18.8 T) and ultra-fast magic-angle spinning (65 kHZ). To expand DQ dipolar recoupling methods on half-integer quadrupolar nuclei, a low radiofrequency (RF) pulse sequence with block cycling to selectively excite homo-nuclear DQ coherence of central transition (CT) was proposed. Last, a scheme for rapid analysis of natural abundance amino acid by high-resolution 14N filtered high resolution 1H-13C correlation was designed in the NMR of rotating solid.

The motion of bacteria in the environment is relevant to several fields. At very small scales and with simple helical shapes, we are able to describe experimentally and mathematically the motion of solid spirals falling freely within a liquid pool. Using these shapes we intend to mimic the motion of bacteria called Spirochetes. We seek to experimentally investigate the linear and the rotational motion of such shapes. A better understanding of the dynamics of this process will be practical not only on engineering and physics, but the bioscience and environmental as well. In the following pages, we explore the role of the shape on the motion of passive solid helixes in different liquids. We fabricate three solid helical shapes and drop them under gravity in water, glycerol and a mixture of 30% glycerol in water. That generated rotation due to helical angle in water. However, we observe the rotation disappear in glycerol. The movement of the solid helical shapes is imaged using a high-speed video camera. Then, the images are analyzed using the supplied software and a computer. Using these simultaneous measurements, we examine the terminal velocity of solid helical shapes. Using this information we computed the drag coefficient and the drag force. We obtain the helical angular velocity and the torque applied to the solid. The results of this study will allow us to more accurately predict the motion of solid helical shape. This analysis will also shed light onto biological questions of bacteria movement.

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No description available.

No description available.

Higher turbine inlet temperatures (TIT) are required for higher overall efficiency of gas turbine engines. Due to the constant push towards achieving high TIT, the heat load on high pressure turbine components has been increasing with time. Gas turbine airfoils are equipped with several sophisticated cooling technologies which protect them from harsh external environment and increase their operating life and reduce the maintenance cost. The turbine airfoils are coated with thermal barrier coatings (TBCs) and the external surface is protected by film cooling. The internals of gas turbine blades are cooled by relatively colder air bled off from the compressor discharge. Gas turbine internals can be divided into three broad segments – Leading edge section, (2) mid-chord section and (3) trailing edge section. The leading edge of the airfoil is subjected to extreme heat loads due to hot main gas stagnation and high turbulence intensity of the combustor exit gases. The leading edge is typically cooled by jet impingement which cross-over the rib turbulators in the feed chamber. The mid-chord section of the turbine airfoils have serpentine passages connected via. 180° bends, and they feature turbulence promotors which enhance the heat exchange rates between the coolant and the internal walls of the airfoil. The trailing edge section is typically cooled by array of pin fins. On one hand, the coolant routed through the internal passages of turbine airfoil help maintain the airfoil temperatures within safe limits of operation, the cooled air comes at a cost of loss of high pressure air from the compressor section. The aim of this study is to develop internal cooling concepts which have high thermal hydraulic performance, i.e. to gain high levels heat transfer enhancement due to cooling concepts at lower pumping power requirements. Experimental and numerical studies have been carried out and new rib turbulator designs such as Criss-Cross pattern, compound channels featuring uniquely organized ribs and dimples, novel jet impingement hole shapes have been developed which have high thermal-hydraulic performance. Further, gas turbine blades rotate at high rotational speeds. The internal flow routed thought the serpentine passages are subjected to Coriolis and centrifugal buoyancy forces. The combined effects of these forces results in enhancement and reduction in heat transfer on the pressure side and suction side internal walls. This leads to non-uniformity in the heat transfer enhancement which leads to non-uniform cooling and increase in the sites of high and low internal wall temperatures. Development of cooling concepts which have high thermal hydraulic performance under non-rotating conditions is important, however, under rotation, the heat transfer characteristics of the internal passages is significantly different in an unfavorable way. So the aim of the turbine cooling research is to have concepts which provide highly efficient and uniform cooling. The negative effects of rotation has been addressed in this study and new orientation of two-pass cooling channels has been presented which utilizes the rotational energy in favor of heat transfer enhancement on both pressure and suction side internal walls. Present study has led to several new cooling concepts which are efficient under both stationary and rotating conditions. / Ph. D. / Higher turbine inlet temperatures lead to higher overall efficiency of gas turbines. Hence, the high pressure stages of turbine sections, which are downstream of the combustor section, have significant thermal load. The turbine inlet temperatures can be as high as 1700°C and turbine airfoil material melting point temperature is around 1000°C. In order to protect the blade for the harsh environment, relatively colder air (~700°C) bled off from the compressor discharge is routed through the internal cooling passages of turbine airfoils. The coolant bled from the compressor section contributes the reduction in the performance of the engine. Hence, the aim of the turbine cooling research is to achieve high rates of heat transfer at relatively lower pumping power requirements. In order to enhance the heat transfer rates from between the hot internal walls of airfoil and the coolant, turbulence promotors are typically installed in the mid-section of the airfoil which features serpentine passages interconnected by 180° bends. Present study is focused on development of highly efficient concepts for internal flows in turbine airfoils. The other aspect of internal cooling research is focused on characterization of heat transfer under rotating conditions. Coriolis force and centrifugal buoyancy forces lead to non-uniform cooling and the heat transfer rates are significantly different under rotating conditions compared to non-rotating conditions. Present study utilizes detailed measurements of heat transfer coefficients under rotating conditions for the development of cooling designs for two-pass ribbed channels where rotational effects can be used in favor of heat transfer enhancement, leading to enhanced and more uniform cooling of internal walls.

Title: Pedagogy of yoga with regard to population health: a focus on rotational positions and their contribution to physiotherapy. Objectives: The aim of the thesis is to briefly summarize the general knowledge of the positive influence of yoga on the human musculoskeletal apparatus, and then to focus on the description of the rotation movements, consdiering both terms of yoga practice and the anatomical- kinesiological (physiotherapeutic) point of view. Three selected yoga positions will be examined; Bharadvádžásana, Maríčjásana and Parivrtta trikonasana, based on literature dealing with the practice of yoga asanas. In the practical section, the discrepancies between theory and practice will be evaluated, as well as the quality of yoga provided during the lessons in relation to population health. These discrepancies will be assessed from the perspective of a physiotherapist. Methods: It is a descriptive theoretical-empirical type of research. The methods used to collect data were - search research, observation, interview. Results: Discrepancies between the theoretical description in the literature and practice have been present. It was also confirmed that the rotational positions were part of all the attended yoga lessons. The assumption that the lecturers know the health of their trainees has not...

Poor audit quality has historically led to huge consequences for the society. A low audit quality is often related to a low auditor independence, which can be caused by the auditor's incentive to maximize personal gain. In attempts to strengthen the auditor independence and thereby the audit quality, several audit regulations have been issued, where the mandatory audit rotation has been the subject to intensive debate. Although the previous research on audit rotation and audit quality is extensive, few studies investigate the contingency aspects of the relationship more specifically firm visibility. The purpose of the study is to explain how audit firm rotation and audit partner rotation relate to audit quality and how this relationship is contingent on firm visibility. The study is conducted quantitatively using a positivistic deductive approach. Hypotheses are developed from existing theories and literature in the area. These are later tested by translating concepts into measurable variables. Audit quality has been measured through the proxy variable discretionary accruals which was estimated by two variants of the modified Jones model. The sample consisted out of 58 large-cap firms listed on the Stockholm OMX stock exchange, constituting a total of 580 firm years. The results of this study suggest that neither audit partner rotation nor audit firm rotation has an influence on audit quality. Furthermore, these relationships are not found to be contingent on firm visibility. The study’s findings contribute to existing debate on mandatory audit rotation. However, the results need to be interpreted with certain caution as we cannot be certain that discretionary accruals measured audit quality as it was intended to do.