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Asymmetries in spiral galaxiesSchoenmakers, Remco Hubertus Maria, January 1999 (has links)
Thesis (Doctoral)--Rijksuniversiteit Groningen, 1999. / Includes bibliographical references (p. 153-155).
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Spiral dynamics : an expression of world viewsKotze, Ian Kincaid 17 October 2009 (has links)
Spiral dynamics as a theory offers an explanation of human values. The historical development of this theory with the original theoretician, Graves, not having written a seminal work, opens up possibilities of different understandings or interpretations. In this thesis the contributions of either Graves or Beck and Cowan (1996) to Spiral dynamics is not disputed. One of the goals in this thesis is to identify specific differences between Graves’s original descriptions and Beck and Cowan’s contributions. The focus will be on two main areas. First the difference between Graves’s original work and Beck and Cowan’s theory of Spiral dynamics. Second, the intricate relationship between Spiral dynamics and Existentialism will be explained. In the next chapter the theory of Spiral dynamics will be examined. This theory will be explained in terms of Graves’s original research, as well as the subsequent contribution by Beck and Cowan. Because of the complicated nature of the development and content of this theory, Spiral dynamics will form the exclusive content of Chapter 1. The theory of Existentialism will be dealt with on the following chapter. In order to understand Existentialism, it is necessary to highlight the context from which this theory developed. Therefore, the third chapter will briefly deal with the field of Phenomenology and how this field relates to Existentialism. The links between an understanding of the theory of Spiral dynamics and the theory of Existentialism will be discussed in Chapter 2. A discussion of the results will be presented in Chapter 3. The Lens questionnaire was used to show the application of the theory, Relevant Lens profiles will be shown in the Results chapter. The Lens psychometric instrument was developed to measure world views according to Graves’s original theory. In the development of this questionnaire, certain gaps in the understanding of the theory were identified. These shortcomings in the Spiral dynamics theory in terms of the precepts of the theory of Existentialism will also be addressed in this thesis. In Chapter 4 the previous chapters will be summarised, and a Conclusion will be presented. For the sake of practicality, the detailed descriptions of the Spiral according to Beck and Cowan are presented in Appendix 1. The detailed description of the research into the Lens is included in Appendix 2. For the sake of clarity the basic colours will be used to describe the different stages on the spiral. Graves described the stages as A-N, B-O, C-P, D-Q, E-R. F-S, G-T, H-U, but in this work the descriptions added by Beck and Cowan (1996) will be used. Therefore A-N will be referred to as Beige, B-O will be referred to as Purple, C-P will be referred to as Red, D-Q will be referred to as Blue, E-R will be referred to as Orange, F-S will be referred to as Green, G-T will be referred to as Yellow, and H-U will be referred to as Turquoise. / Thesis (DPhil)--University of Pretoria, 2009. / Psychology / unrestricted
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On the Existence and Stability of Rotating Wave Solutions to Lattice Dynamical SystemsBramburger, Jason January 2017 (has links)
Rotating wave solutions to evolution equations have been shown to govern many important biological and chemical processes. Much of the rigorous mathematical investigations of rotating waves rely on the model exhibiting a continuous Euclidean symmetry, which is only present in an idealized situation. Here we investigate the existence of rotationally propagating solutions in a discrete spatial setting, in which typical symmetry methods cannot be applied, thus presenting an unique perspective on rotating waves. Our goal in this thesis is to demonstrate the existence and potential stability of rotating wave solutions to a spatially discretized infinite systems of coupled differential equations. This goal is achieved by considering so-called Lambda-Omega systems, which have frequently been used to model typical oscillatory dynamics. Our work is broken into three major components: 1. An infinite system of coupled phase equations is investigated and we demonstrate that under some mild assumptions the system exhibits a phase-locked rotating wave solution. The phase system is derived from a limiting case of the original Lambda-Omega system, and therefore solutions of the phase equation will be useful in finding rotating wave solutions to the full Lambda-Omega system. 2. We examine the stability of the rotating wave solution found in the coupled phase equations. This is achieved by providing a link with an underlying graph-theoretic geometry endowed by the spatially discretized system. We use results from random walks on infinite graphs to provide a general stability theorem for coupled phase equations. 3. We use the rotating wave solution of the phase equations to extend to a rotating wave solution of the full Lambda-Omega system. This result is achieved using a non-standard Implicit Function Theorem, since we show that typical implicit function arguments cannot be applied to our present situation.
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Measurements of Drag Coefficients and Rotation Rates of Free-Falling HelixesAl-Omari, Abdulrhaman A. 05 1900 (has links)
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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Thermal behavior of spiral bevel gearsHandschuh, Robert Frederick January 1993 (has links)
No description available.
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The Spiro-Helical AntennaGhoreishian, Idine 11 September 1999 (has links)
A novel antenna made of a spiral wire wrapped into a larger helical shape is introduced. The geometry of this antenna, which is a doubly helical structure, is fully described by five independent parameters, including two radial dimensions, two pitch angles, and the number of turns. Radiation properties of this antenna are examined both theoretically and experimentally. The Numerical Electromagnetic Code (NEC-2) is used to obtain simulation results. A large number of cases with different radii, pitch angles, and number of turns are investigated. Results for far-field patterns, gain, axial ratio, and bandwidth are presented. The influence of parameters on radiation properties are examined. Several prototypes of the antenna were constructed and tested using an outdoor antenna range. Measured far-field patterns are presented over a wide range of frequencies. The measured and computed radiation patterns are in good agreement.
The results of this study indicate that the proposed antenna provides circular polarization and high gain over a wide frequency range. For example, when the number of turns is 10, a gain of 11-14 dB, a boresight axial ratio of less than 3 dB, and a half-power beamwidth of about 40 degrees are achieved over a 30% bandwidth. The side-lobe level for most cases examined is better than 10 dB below the main beam. A unique advantage of this antenna is its much smaller size compared with a conventional helical antenna made of straight wire shaped into a helix. Having about the same radiation characteristics, including gain, circular polarization, bandwidth, and side-lobe level, this new antenna occupies a volume more than 2.5 to 3 times smaller than the conventional helix. This reduction in size, which in turn may imply smaller weight and lower packaging and manufacturing costs, makes the proposed antenna very appealing to many communications and aerospace applications. / Master of Science
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A search for additional parameters in the infrared luminosity/21 cm line-width relation for spiral galaxies in clusters of galaxies.Cornell, Mark Edward. January 1989 (has links)
The relationship first pointed out by Tully and Fisher between the luminosity of spiral galaxies and their maximum rotation velocity, as measured by the 21 cm line-width, continues to be one of the best methods available to measure relative distances. At infrared wavelengths, the observational scatter about this relation is typically 0.35 to 0.50 magnitudes, permitting relative distance estimates with an accuracy of about 20 percent. The Malmquist bias in a magnitude-limited sample is 1.38σ ², and while the solution to the general problem is complex, it is clear that reducing the scatter about the Tully-Fisher relation by even a factor of two would make a large difference in our ability to determine the local velocity field from distances and velocities of individual galaxies. In this dissertation we discuss the scatter in the Tully-Fisher relation at infrared wavelengths, and look for ways to reduce that dispersion through the inclusion of additional observational parameters. The data for this study are derived from a CCD survey of 244 spiral galaxies in twenty clusters falling in the redshift range 3,000 to 11,000 km s⁻¹. From surface brightness profiles and elliptical aperture photometry, we obtained isophotal and total magnitudes at B, R, and I, isophotal diameters, mean and nuclear surface brightnesses, and a concentration parameter indicative of the bulge-to-disk ratio. These quantities were then combined with colors and HI-content measures taken from the literature in a search for correlations with Tully-Fisher residuals. None of the trial second-parameters resulted in a substantial decrease in the scatter about the fiducial Tully-Fisher relation. An examination of the properties of the cluster samples shows that many of the clusters exhibit considerable substructure. While it is possible that the implied depth effects are important to the scatter about the magnitude/line-width relation, calculated lower limits to the dispersion in depth turn out to be rather small.
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An unbiased study of the local velocity field using IRAS selected galaxiesStephenson, Lisa January 1999 (has links)
No description available.
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An analysis of the acquisition process of the Joint Fires Network/Tactical Exploitation System-NavyLeyland, Patricia E. 06 1900
Approved for public release, distribution is unlimited / There is a growing movement throughout the Department of Defense (DoD) towards the implementation of Network Centric Warfare (NCW). In an effort to transition to NCW, the Navy has fielded many different technologies. One system exploiting new technologies in the Intelligence, Surveillance, and Reconnaissance (ISR) domain is the Joint Fires Network/Tactical Exploitation System-Navy (JFN/TES-N), which was developed from the Army Tactical Exploitation System, (TES-A). This system was developed rapidly and uniquely for fleet deployment in accordance with the interim acquisition guidance signed by the Honorable Paul Wolfowitz. This guidance authorized Evolutionary Acquisition following a Spiral Development process in lieu of the "traditional" cold war process described in the DoD 5000 series publications. Assuming that (JFN/TES-N) will be viewed as a successful acquisition, several Navy personnel have stated that it may become the model for future C4I (and other) system acquisitions. This thesis seeks to help develop that model. The objectives of this thesis are: ʺ To examine whether the TES-N acquisition process is an appropriate model of Evolutionary Acquisition following a Spiral Development. ʺ To identify and make recommendations for changes or improvements to the TES-N acquisition program, so it can be used as a more appropriate model for Evolutionary Acquisition following a Spiral Development. This thesis concludes that Evolutionary Acquisition following a Spiral Development shown with the JFN/TES-N system is an acquisition policy that is appropriate for programs of the same size and scope, but larger more complex programs will not have as much success. Yet, in order for the JFN/TES-N program and future programs using Evolutionary Acquisition following a Spiral Development to succeed, changes have to be made in policies such as budgetary submissions, test and evaluation, policy, process, and training. / Ensign, United States Navy
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"Halos triaxiais e a razão axial de galáxias espirais" / Triaxial halos and the axis ratio of spiral galaxiesMachado, Rubens Eduardo Garcia 20 April 2006 (has links)
A triaxialidade dos halos das galáxias espirais foi estudada através das funções de distribuição de razões axiais aparentes dos seus discos. Utilizou-se uma amostra de galáxias limitada por magnitude (g<16). Foram selecionadas ~1600 galáxias espirais do SDSS (Sloan Digital Sky Survey), que foram classificadas morfologicamente por inspeção visual. Para evitar contaminações espúrias, removeram-se da amostra galáxias em interação, com companheiras próximas ou aproximadamente alinhadas com estrelas da Galáxia. As razões axiais das galáxias foram medidas individualmente e com critérios uniformes, ajustando-se isofotas elípticas a cada imagem no filtro r. Um algoritmo de Monte Carlo foi empregado para inferir a distribuição de razões axiais intrínsecas. O modelo de disco oblato é incapaz de reproduzir a observada falta de galáxias aparentemente circulares. A fração reduzida de galáxias aparentemente circulares, que se observa sistematicamente nas espirais de todos os sub-tipos morfológicos, é uma forte indicação de que os discos destas galáxias sejam intrinsecamente elípticos. O modelo triaxial mostrou-se mais estatisticamente significativo, além de ser capaz de prever a fração correta de galáxias quase circulares. Concluímos, portanto, que o modelo de disco não-circular descreve melhor as observações e que a razão dos eixos no plano do disco deve ser de p = 0,849 +/- 0,063. Empregando uma abordagem analítica simplificada, nós propusemos uma descrição da formação de halos escuros triaxiais no contexto de colisões de protogaláxias. Aproximando as protogaláxias por elipsóides homogêneos de Jacobi, notamos que a triaxialidade do objeto resultante de uma fusão depende da velocidade de colisão e calculamos a época em que estes encontros devem ter ocorrido, para gerar elipsóides com a triaxialidade em questão. Estimamos que neste cenário os discos das galáxias espirais tenham sido construídos a partir de aproximadamente z = 0,69 +/- 0,32. / The triaxiality of the halos of spiral galaxies was studied through the distribution function of the apparent axial ratios of their disks. We used a magnitude-limited sample of galaxies (g<16). We selected ~1600 spiral galaxies from the SDSS (Sloan Digital Sky Survey), which were morphologically classified by visual inspection. In order to avoid spurious contaminations, interacting galaxies were removed from the sample, as well as those with nearby companions or with foreground stars. The axial ratios of the galaxies were measured individually and with uniform criteria, by fitting elliptical isophotes to each r-filter image. A Monte Carlo algorithm was used to infer the distribution of intrinsic axial ratios. The oblate disk model is unable to account for the observed lack of apparently circular galaxies. The small fraction of apparently circular galaxies, which is systematically observed in spirals of all morphological subtypes, is as strong indication that the disks are indeed intrinsically elliptical. The triaxial model is more statistically significant and also, it is able to predict the correct fraction of nearly circular galaxies. We find, therefore, that the non-circular disk model provides a better description of the observations and that the axes on the plane of the disk should be in the ratio p = 0.849 +/- 0.063. By adopting a simplified analytical approach, we propose a description of the formation of triaxial dark halos in the context of collisions of protogalaxies. Assuming that the protogalaxies might be represented by homogeneous Jacobi ellipsoids, we noted that the triaxiality of the resulting object depends on the collision velocity. We also find the epoch at which such encounters would yield the required triaxiality. We estimate that in this scenario the disks of spiral galaxies would have been assembled at z = 0.69 +/- 0.32.
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