Dissertations / Theses: 'Rotational systems'

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Tran, Quan Duc. "Tricyclic Steiner Triple Systems with 1-Rotational Subsystems." Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etd/2102.

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A Steiner triple system of order v, denoted STS(v), is said to be tricyclic if it admits an automorphism whose disjoint cyclic decomposition consists of three cycles. In this thesis we give necessary and sufficient conditions for the existence of a tricyclic STS(v) when one of the cycles is of length one. In this case, the STS(v) will contain a subsystem which admits an automorphism consisting of a fixed point and a single cycle. The subsystem is said to be 1-rotational.

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2

Horton, Bryan. "Rotational motion of pendula systems for wave energy extraction." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25873.

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3

Sinclair, Andrew James. "Generalization of rotational mechanics and application to aerospace systems." Texas A&M University, 2002. http://hdl.handle.net/1969.1/2274.

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This dissertation addresses the generalization of rigid-body attitude kinematics, dynamics, and control to higher dimensions. A new result is developed that demonstrates the kinematic relationship between the angular velocity in N-dimensions and the derivative of the principal-rotation parameters. A new minimum-parameter description of N-dimensional orientation is directly related to the principal-rotation parameters. The mapping of arbitrary dynamical systems into N-dimensional rotations and the merits of new quasi velocities associated with the rotational motion are studied. A Lagrangian viewpoint is used to investigate the rotational dynamics of N-dimensional rigid bodies through Poincar??e??s equations. The N-dimensional, orthogonal angularvelocity components are considered as quasi velocities, creating the Hamel coefficients. Introducing a new numerical relative tensor provides a new expression for these coefficients. This allows the development of a new vector form of the generalized Euler rotational equations. An N-dimensional rigid body is defined as a system whose configuration can be completely described by an N??N proper orthogonal matrix. This matrix can be related to an N??N skew-symmetric orientation matrix. These Cayley orientation variables and the angular-velocity matrix in N-dimensions provide a new connectionbetween general mechanical-system motion and abstract higher-dimensional rigidbody rotation. The resulting representation is named the Cayley form. Several applications of this form are presented, including relating the combined attitude and orbital motion of a spacecraft to a four-dimensional rotational motion. A second example involves the attitude motion of a satellite containing three momentum wheels, which is also related to the rotation of a four-dimensional body. The control of systems using the Cayley form is also covered. The wealth of work on three-dimensional attitude control and the ability to apply the Cayley form motivates the idea of generalizing some of the three-dimensional results to Ndimensions. Some investigations for extending Lyapunov and optimal control results to N-dimensional rotations are presented, and the application of these results to dynamical systems is discussed. Finally, the nonlinearity of the Cayley form is investigated through computing the nonlinearity index for an elastic spherical pendulum. It is shown that whereas the Cayley form is mildly nonlinear, it is much less nonlinear than traditional spherical coordinates.

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Akin, Faith W., Owen D. Murnane, Stephanie M. Byrd, and J. K. Kelly. "A Comparison of the Subjective Visual Vertical across Rotational Chair Systems and Off-Axis Rotation Protocols." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/2466.

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5

Clunas, Scott. "The synthesis of chiral Câ†3-symmetric systems." Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310643.

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Chapter one is an overall introduction reviewing the applications of compounds possessing rotational symmetry, in particular their role as asymmetric reagents/catalysts in various reactions. The attempted syntheses of two different types of C₃-symmetric homochiral triols are described in chapter two. Unfunctionalised and functionalised triamides were synthesised from the corresponding amine and 1,3,5-benzenetricarbonyl trichloride. Unfunctionalised N-substituted 1,3,5-triazacychlohexanes (triazines) were synthesised from the corresponding amine and formaldehyde, however reactions between chiral amino alcohols and formaldehyde failed to give the desired trihydroxy triazines. Chapter three describes the syntheses of a range of unfunctionalised chiral C₃-symmetric compounds, as well as a review of C₃-symmetric systems as host molecules. The successful synthesis of a range of unfunctionalised triethrs was carried out by reacting 1,3,5-tris(bromomehyl)mesitylene with some selected terpenes and other alcohols. Their role as host molecules was investigated, however they failed to bind with any of the various metals that were used. Their asymmetric induction capabilities were also tested when one of the triethers was used as a catalyst in the Et₂Zn/aldehyde reaction. The desired alcohol was indeed isolated, however it was found by ¹H nmr of the Mosher's ester to be a reacemic mixture. In chapter four the synthesis of the unfunctionalised triethers that was described in chapter three was extended to the synthesis of C₃-symmetric triethers containing functional groups. A range of tridentate ligands were synthesised containing either amino, ester, keto or hydroxyl terminal groups. In addition to these, trihydroxy ligands containing amino linkages in place of ethereal linkages were also synthesised. From these compounds three of the trihydroxy ligands were used in complexation reactions with Sn, Ti, Si, Ni, and Cu. The reactions using Si, Ni and Cu failed to give the desired complexes. However, strong evidence was obtained for the existence of the desired Sn and Ti complexes. Once again using the Et₂Zn/aldehyde reaction preliminary asymmetric induction studies were carried out using one of the Ti complexes. The reaction showed some selectivity in favour of the R enantiomer. Chapter four also describes the syntheses of some hexadentate ligands, in particular the synthesis of a chiral C₃-symmetric hexol, a C₃-symmetric ligand containing three β keto-ester groups, and also a 1,3-diketo derivative.

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6

Cowan, John D. "A billiard model for a gas of particles with rotation /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2004.

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Thesis (Ph.D.)--Tufts University, 2004.
Adviser: Boris Hasselblatt. Submitted to the Dept. of Mathematics. Includes bibliographical references (leaves 61-62). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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7

Szczesny, Spencer E. 1981. "Design of compliant mechanisms for attenuation of unidirectional vibrations in rotational systems." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/27880.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 146-148).
The purpose of this research was to generate the knowledge required to design compliant mechanisms that (1) attenuate undesired small-motion angular vibrations in rotational power transmission systems and (2) preserve the desired transmission of large-motion torque/angle inputs. This thesis investigates the design of vibration attenuating compliant mechanisms that are directly integrated into the load path of rotational systems. These devices enable designers to attenuate the amplitude of undesirable vibrations while simultaneously optimizing the transmission of torque inputs. The design, modeling, fabrication and experimental validation of two Compliant Vibration Attenuator (CVA) concepts will be presented. The first device, the Small Amplitude Vibration Isolator (SAVI), is a non-linear compliant device that isolates a resonating or non-resonating rotational system from vibrations by acting as a mechanical lowpass filter. The second device, the Damping Vibration Link (DVL) utilizes compliance and damping to attenuate undesired vibrations due to resonance. A linear lumped parameter model was created in Matlab® to simulate the static and dynamic characteristics of rotational power transmission systems. This model enables one to determine the dynamic characteristics of a system for a given set of inputs, thereby making it possible to (1) understand the requirements for the CVA and (2) ascertain the effect of the CVA on the system. Finite-element simulations were conducted to verify an empirical, parametric model that describes the performance of a SAVI as a function of its stiffness parameters.
(cont.) Proof-of-concept prototypes were tested to verify performance predictions and to determine the practical issues related to implementation. The thesis concludes with a case study which demonstrates the effectiveness of a SAVI when integrated into the steering system of a light-duty pickup truck. The SAVI was shown to offer a 60% reduction in vibration amplitude by trading off 7 ms of delay in steering wheel-vehicle response.
by Spencer E. Szczesny.
S.M.

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8

Kravchenko, Anatoliy G. "Overcoming the rotational antagonism of corn following wheat in high residue cropping systems." Diss., Connect to online resource - MSU authorized users, 2006.

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Thesis (M. S.)--Michigan State University. Dept. of Crop and Soil Sciences, 2006.
Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references (p. 94-99). Also issued in print.

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9

Huysamen, Kirsten Christina. "Validation of an assessment tool for mental fatigue applied to rotational shift work." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013551.

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Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.

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Cakar, F. selcen. "A Study Of Precoding Schemes For Ofdm Systems." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609916/index.pdf.

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We examine the effect of precoding on OFDM systems. The precoding operation, which is also known as constellation rotation, leads to a gain in diversity order for fading channels. In this thesis, we examine the effect of precoding for different receivers such as Maximum Likelihood (ML), Minimum Mean Squared Error (MMSE), and Zero Forcing (ZF) receivers. The diversity gain due to precoding comes at no cost of bandwidth expansion or power increase. Therefore it is an attractive and practical alternative. We also examine the precoding gain, when some reduction of rate is tolerable and compare the performance of rate reduced system with the uncoded system with the system which is coded by rateless unitary precoders, and with the hard-decision decoded BCH coded coded system.

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Najdecka, Anna. "Rotating dynamics of pendula systems for energy harvesting from ambient vibrations." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201961.

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This thesis has been motivated by the idea of harvesting the energy from ambient vibrations via nonlinear dynamics of the parametric pendulum. It aims to cover those aspects of the pendulum dynamics, which are relevant for energy extraction purposes and have not been addressed in previous studies. A simple system like parametric pendulum can experience variety of responses. One of them is rotary motion, which is characterised by significantly higher kinetic energy than oscillations and thus has a potential of delivering more energy, when subjected to the parametric excitation. Initially, a preliminary study on the dynamics of parametric pendulum has been conducted. This involved comparison of oscillatory and rotary responses with a view to application in energy harvesting, numerical continuation of rotary solutions and developing a control method for initiating and maintaining the desired response. As a next step, different forcing configurations have been considered, including pendulum excited along a tilted axis and a combined excitation, where pendulum additionally performs rocking action. The influence of the forcing arrangement on the lower limit of stability of rotary motion has been examined. The vibrations which can be observed in the environment are rarely perfectly harmonic. To provide more realistic results, the response of the pendulum under noisy excitation has been studied. Different types of noise have been considered and their influence on the pendulum rotation examined. One of the major energy sources, which could be utilised are the oscillating ocean surfaces. Therefore, a stochastic model of the sea wave has been constructed and the response of the pendulum system studied under parametric excitation by a wave profile. Finally, taking into account the imbalanced forces which rotating pendulum exerts on the supporting base, the model has been extended to a system of two pendulums. Synchronization in such a system was studied. The influence of the synchronization mode on the rotation of the pendulums and on the stability of supporting structure was considered. All of the numerical results presented in this thesis have been verified experimentally to ensure good correspondence.

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Holt, Jennifer A. "THz Systems: Spectroscopy and Simulation." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417536443.

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13

Thompson, Roger Clifton. "A perturbation approach to control of rotational/translational maneuvers of flexible space vehicles." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/45682.

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An open loop control law is applied to a flexible spacecraft that admits translational, as well as rotational and flexural motion. The translational degrees of freedom are coupled to the rotation and deformation through the active controls applied to the structure. The objective of any maneuver is to control the attitude of the craft as well as to dissipate any vibrations of the structure.

Depending on the type of maneuver specified, the equations of motion may be divided into two distinct optimal control problems. Singleâ axis rotational maneuvers (with small flexural deformations) constitute a strictly linear problem. The solution of the resulting two Q point boundary value problem is accomplished through the use of matrix exponential functions. Maneuvers which involve the translational degrees of freedom, are described by nonlinear equations. The solution method presented is a algorithm that generates successive approximations similar to quasiâ linearization. A perturbed linear optimal control problem is solved for each approximation. Examples are presented which illustrate the effectiveness of the solution methods for both types of maneuvers.

>
Master of Science

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Yao, Suqin. "Computer-Aided Manufacturing Planning (CAMP)of Mass Customization for Non-rotational Part Production." Link to electronic dissertation, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-1216103-153523/.

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Dissertation (Ph.D.) -- Worcester Polytechnic Institute.
Keywords: Computer aided manufacturing planning; Object-oriented systems analysis (OSA); Feature; manufacturing resource capability; setup planning; multi-part fixture Includes bibliographical references (p.146-154).

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Langer, Franz Dieter. "Kinematic and rotational dynamics of multi-linkage systems and the control of a planar two-link system in the air /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487266011224129.

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Miller, Lucas S. Kerley Monty Stephen. "Increasing land and forage utilization by Missouri cow/calf operations using silvopasture practices." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4593.

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Thesis (M.S.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed Aug. 27, 2007). Includes bibliographical references.

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Williams, Kenneth A. "A rotational arm connection point design for a C-130 aircraft standardized sensor platform." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4703.

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Thesis (M.S.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains viii, 77 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 58-59).

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Spigelman, Tracy H. "COORDINATION OF SWIMBENCH FREESTYLE IN ELITE AND NON-ELITE SWIMMERS: A DYNAMICAL SYSTEM APPROACH." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/691.

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Elite swimmers can be distinguished from novice swimmers by freestyle stroke technique. Elite swimmers move through multiple coordination modes, increases in stroke lengths, stroke rates, and body roll allowing for a more symmetrical stroke and increased speed compared with novice swimmer during 100m freestyle. Coaches strive to improve swimmers’ performance by providing feedback about stroke technique, mostly from the pool deck where view of the full stroke cycle is obstructed by the water. Tools to assess swimming are often expensive and require extra training, which does not provide a pragmatic solution. A dryland rotational swimbench would provide a means to evaluate freestyle swimming. The aim of the present study is to evaluate the sensory motor system of elite and novice level swimmers by comparing kinematic, coordinative structures and spatial-temporal characteristics of freestyle stroke on a dryland swimbench with a rotational component. Thirty elite and novice collegiate and masters swimmers were instrumented with reflective markers bilaterally on the upper extremity and torso. A series of four ten second trials of freestyle sprint swimming were performed on the swimbench. Repeated measures were used for statistical analysis for comparison between and within groups. Bonferroni corrections were used as post-hoc analysis. Results indicated no significant difference between elite and novice swimmers’ sensory-motor system, kinematics or spatio-temporal systems on a rotational swimbench. Similarities could be accounted for by swimmers perceiving a novel task due to differences in sensory feedback, and mechanical limitations of the bench. It is noteworthy that catch-up/opposition coordination are more common than superposition which provides support for the swimbench providing a more similar representation to in water swimming.

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Butdee, Suthep. "Development of a hybrid intelligent process planning system for rotational parts." Thesis, Queensland University of Technology, 1997.

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20

Hewes, Dominic [Verfasser]. "Frequency Stability in Sustainable Power Systems: Effects of Reduced Rotational Inertia on Frequency Stability in the European Transmission System / Dominic Hewes." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219469866/34.

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Bobga, Benkam Benedict. "Bicyclic Mixed Triple Systems." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etd/1043.

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In the study of triple systems, one question faced is that of finding for what order a decomposition exists. We state and prove a necessary and sufficient condition for the existence of a bicyclic mixed triple system based on the three possible partial orientations of the 3-cycle with twice as many arcs as edges. We also explore the existence of rotational and reverse mixed triple systems. Our principal proof technique applied is the difference method. Finally, this work contains a result on packing of complete mixed graphs on v vertices, Mv, with isomorphic copies of two of the mixed triples and a possible leave structure.

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22

Urbina, Iglesias Laura Sofia. "Guidance and robust control methods for the approach phase between two orbital vehicles with coupling between translational and rotational motions." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30086/document.

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Les techniques liées au vol en formation et aux opérations de proximité de satellites autonomes font partie des technologies opérationnelles spatiales les plus marquantes et les plus ambitieuses de ces dernières années. En particulier, cela nécessite la complète maitrise des phases de rendez-vous proche et de survol par un satellite actif avec un satellite, une station ou un débris passif. Le développement de systèmes GNC (Guidage Navigation Contrôle) associés performants et sûrs repose sur la connaissance d'un modèle dynamique réalisant un bon compromis entre faible complexité et prise en compte suffisante des principales caractéristiques dynamiques et cinématiques de ce type de systèmes. La première partie de cette thèse est consacrée au développement d'une modélisation unifiée de la dynamique relative couplée entre un satellite coopératif chasseur et un satellite cible non coopérative. En effet, lorsque deux satellites sont proches l'un de l'autre, ils ne peuvent plus être traités comme des masses ponctuelles, car leur forme et leur taille affectent le mouvement relatif entre les points de masse décentralisés, conduisant à un couplage des mouvements de translation et de rotation. Ce développement est abordé de manière progressive: le mouvement de translation relatif non linéaire est décrit sous hypothèses képlériennes dans le repère orbital de la cible ainsi que le modèle linéarisé associé. Ensuite, le modèle non linéaire d'attitude relative est présenté au moyen des paramètres d'Euler-Rodrigues. Enfin, le formalisme des quaternions duaux est utilisé afin d'obtenir le modèle relatif couplé en translation et en attitude. La phase de modélisation du mouvement relatif linéaire de translation a ainsi permis de mettre en évidence certaines transformations de coordonnées conduisant à une caractérisation intéressante des trajectoires périodiques du chasseur et ainsi de proposer un premier type de loi de contrôle de guidage pour la phase d'approche et de survol. Dans l'ensemble de notre travail, nous considérons un chasseur équipé de propulseurs chimiques et l'hypothèse classique des poussées impulsionnelles. Ce type de systèmes dynamiques conciliant dynamique continue et contrôle impulsionnel se définit naturellement comme une classe particulière de systèmes dynamiques hybrides. Plusieurs lois de contrôle hybrides sont alors proposées afin de stabiliser le chasseur sur une trajectoire de référence périodique proche de la cible. Les propriétés de stabilité et de convergence de ces différentes lois sont analysées et de nombreuses simulations numériques montrent les forces et les faiblesses de chaque contrôleur en termes d'indices de performance comme le temps de convergence, la consommation ainsi que des contraintes de sécurité. Dans un second temps, des contraintes opérationnelles supplémentaires (contraintes de visibilité par exemple) sont prises en considération en imposant une direction d'approche rectiligne (glideslope) au chasseur. Cette trajectoire impose au satellite chasseur de suivre une droite dans n'importe quelle direction du repère local reliant l'emplacement courant du chasseur à sa destination finale. Sous l'hypothèse de propulsion impulsionnelle, les résultats existant dans la littérature pour ce type d'approche ont été généralisés aux orbites elliptiques en identifiant une nouvelle formulation du problème comprenant des degrés de liberté utiles qui permettent de minimiser la consommation de carburant tout en contrôlant l'excursion de la trajectoire libre en dehors de la droite de glideslope en la confinant dans un couloir d'approche défini par l'utilisateur. La synthèse des lois de guidage ainsi obtenues repose sur la résolution de problèmes d'optimisation SDP dans le cas général ou linéaire pour les cas plus simples d'approche standards du type V-bar ou R-bar
The techniques related to formation flying and proximity operations of autonomous satellites belong to the most significant and challenging operational space technologies of the last years. In particular, they require full mastery of the close-range rendezvous and observation phases by an active satellite with a passive satellite, station or debris. The development of efficient and safe associated GNC systems relies on the knowledge of a dynamic model that achieves a good trade-off between low complexity and sufficient inclusion of the main dynamic and kinematic characteristics of this type of systems.The first part of this thesis is devoted to the development of a unified modeling of the relative coupled dynamics between a cooperative chaser satellite and a non-cooperative target satellite. Indeed, when two satellites are close to each other, they can no longer be treated as point masses because their shape and size affect the relative motion between the decentralized points, leading to a translational-attitude motions coupling. This development is addressed in a progressive way: the relative nonlinear translational motion is described under Keplerian assumptions in the target's orbital reference frame, as well as the associated linearized model. Then, the nonlinear relative attitude model is presented by means of the Euler-Rodrigues parameters. Finally, the dual quaternion formalism is used to obtain the relative translational and attitude coupled model. The modeling phase concerning the linear relative translational motion has allowed us to highlight certain coordinates transformations leading to an interesting characterization of the chaser's periodic trajectories and thus, to propose a first type of control law for the close-phase rendezvous and observation phases.All along this work, we consider a chaser satellite equipped with chemical thrusters under the classical hypothesis of impulsive thrusts. This type of dynamic systems gathering continuous dynamics and impulsive control naturally belongs to a particular class of dynamical hybrid systems. Several hybrid control laws are then proposed in order to stabilize the chaser on a periodic reference trajectory close to the target. The stability and convergence properties of these different laws are analysed and several numerical simulations show the strengths and weaknesses of each controller in terms of performance indices such as convergence time, consumption and safety constraints. In a second step, additional operational constraints (line-of-sight constraints for example) are taken into account by imposing a rectilinear (glideslope) direction to the chaser. This trajectory requires the chaser satellite to follow a straight line in any direction of the local reference frame and connecting the current location of the chaser to its final destination. Under the impulsive propulsion assumptions, the results in the literature for this type of approach have been generalized to elliptic orbits by identifying a new formulation of the problem including useful degrees of freedom, which allow minimizing the fuel consumption while controlling the humps of the trajectory outside the glideslope line by enclosing it in a user-defined approach corridor. Guidance laws are therefore synthetized via the solution of an SDP optimisation problem in the general case and via a linear programming when considering standard cases like the V-bar or R-bar approaches

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Vega, Gregorio Robles. "SIMULATION OF HORSE-FENCE CONTACT AND INTERACTION AFFECTING ROTATIONAL FALLS IN THE SPORT OF EVENTING." UKnowledge, 2017. http://uknowledge.uky.edu/me_etds/98.

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Rotational falls, or somersault falls, have led to serious and fatal injuries during the cross-country phase of Eventing competitions. Research to improve the safety of the sport began in 2000 after five fatal injuries occurred in the 1999 Eventing season. These efforts led to safety devices such as air jackets, improved helmets, and frangible/deformable fences. The focus of this thesis is to develop a more complete understanding of the horse-fence interaction as the approach motion transitions to a rotational fall. To achieve this, a large distribution of inertial properties was compiled through the development of a cylinder-based inertia approximation and a citizen science effort to gather equine geometrical measurements through a survey distributed by the United States Eventing Association (USEA). Furthermore, fundamental kinematic properties of the horse and rider were gathered from the literature. These distributions were used to conduct a Monte Carlo analysis to examine if the approach conditions of the horse and rider would result in a transition to a rotational fall upon horse-fence contact. Through the analysis the sensitivity of the main control parameters was explored to determine the dominant variables in the transition.

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Hoglund, James R. "An expert system for off-line analysis of rotating equipment." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/46041.

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The analysis of rotating equipment difficulties is currently accomplished by a specialist in rotating equipment examining the signs and symptoms of the equipment, applying his expert judgement, and determining the cause of the machine's difficulty. This thesis covers the development of an off-line expert system that can be used to emulate the expert's ability to interpret the signs and symptoms of the machine, including suggestions of possible further actions to take for repairing the problem or refining the proof for the proposed cause the difficulty. An editor has also been built which will allow an expert to keep the information used by the system current with the state of the art for rotating machinery diagnostics. This thesis documents the development of the PC-based Turbo Prolog expert shell and external knowledge-base editor. The use of the system editor is illustrated by loading current diagnostic table information into a knowledge base. Then the expert program's operation is illustrated by applying the editor-formed database in a typical session. The expert shell and knowledge base can operate as a stand-alone unit for field application. Resident experts in machinery diagnostics can build and update databases for distribution to users in the company to assure full uniform utilization of the current and most correct knowledge.

Master of Science

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Sheehe, Suzanne Marie Lanier. "Heat Release Studies by pure Rotational Coherent Anti-Stokes Raman Scattering Spectroscopy in Plasma Assisted Combustion Systems excited by nanosecond Discharges." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1401377491.

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Bisht, Saurabh. "Methods for Structural Health Monitoring and Damage Detection of Civil and Mechanical Systems." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33672.

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In the field of structural engineering it is of vital importance that the condition of an ageing structure is monitored to detect damages that could possibly lead to failure of the structure. Over the past few years various methods for monitoring the condition of structures have been proposed. With respect to civil and mechanical structures several methods make use of modal parameters such as, natural frequency, damping ratio and mode shapes. In the present work four methods for modal parameter estimation and two methods for have been evaluated for their application to multi degree of freedom structures. The methods evaluated for modal parameter estimation are: Wavelet transform, Hilbert-Huang transform, parametric system identification and peak picking. Through various numerical simulations the effectiveness of these methods is studied. It is found that the simple peak-picking method performs the best and is able to identify modal parameters most accurately in all the simulation cases that were considered in this study. The identified modal parameters are then used for locating the damage. Herein the flexibility and the rotational flexibility approaches are evaluated for damage detection. The approach based on the rotational flexibility is found to be more effective.
Master of Science

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Walker, Richard John. "Behaviour of nanocolloidal particles on mica : investigations using atomic force microscopy." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4633.

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In this thesis we used atomic force microscopy (AFM) to investigate systematically the behaviour of both electrostatically stabilised silica and sterically stabilised polystyrene (PS) colloidal systems on freshly cleaved mica substrates. For the silica colloidal nanoparticles we explored the effect of colloidal suspension concentration, particle size, and different application techniques on both the adsorption behaviour and subsequent structuring of the particles. For the PS colloidal nanoparticles we explored concentration effects and experimented with both dip-coating and droplet application techniques. We showed that silica nanoparticles adsorbed onto mica via irreversible adsorption that possessed lateral mobility due to the weak attraction between the nanoparticles and the substrate, facilitating subsequent capillary structuring of the nanoparticles during drying. We associated the effects of volume fraction with Debye screening, and kinetics effects with particle size and volume fraction. We also successfully imaged a partially dried film and showed the role of convective/capillary forces in the structuring of the nanoparticles. Studies with variations in particle size generated a number of different topography structures; with dewetting phenomena observed for 10 nm nanoparticles and the formation of crystalline structures for 100 nm nanoparticles. Spin coating techniques were used to produce even larger crystalline structures of nanoparticles. Size dependent ordering occurred for low concentration samples due to the polydispersity of the colloidal suspension. We showed that acceleration can affect interparticle spacing. We also studied the role of rotational speed on the crystallinity of the particle configurations and showed how fine tuning of rotational speed can generate large scale monolayer crystalline formations of nanoparticles.

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Bäck, David. "Neural Network Gaze Tracking using Web Camera." Thesis, Linköping University, Department of Biomedical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5579.

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Gaze tracking means to detect and follow the direction in which a person looks. This can be used in for instance human-computer interaction. Most existing systems illuminate the eye with IR-light, possibly damaging the eye. The motivation of this thesis is to develop a truly non-intrusive gaze tracking system, using only a digital camera, e.g. a web camera.

The approach is to detect and track different facial features, using varying image analysis techniques. These features will serve as inputs to a neural net, which will be trained with a set of predetermined gaze tracking series. The output is coordinates on the screen.

The evaluation is done with a measure of accuracy and the result is an average angular deviation of two to four degrees, depending on the quality of the image sequence. To get better and more robust results, a higher image quality from the digital camera is needed.

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Sousa, João Miguel Gomes de. "Monte Carlo studies of phase transitions and adsorption : application to n-6 Lennard-Jones, C60 and zeolite systems." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13897.

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Doutoramento em Física
The solid-fluid transition properties of the n - 6 Lennard-Jones system are studied by means of extensive free energy calculations. Different values of the parameter n which regulates the steepness of the short-range repulsive interaction are investigated. Furthermore, the free energies of the n < 12 systems are calculated using the n = 12 system as a reference. The method relies on a generalization of the multiple histogram method that combines independent canonical ensemble simulations performed with different Hamiltonians and computes the free energy difference between them. The phase behavior of the fullerene C60 solid is studied by performing NPT simulations using atomistic models which treat each carbon in the molecule as a separate interaction site with additional bond charges. In particular, the transition from an orientationally frozen phase at low temperatures to one where the molecules are freely rotating at higher temperatures is studied as a function of applied pressure. The adsorption of molecular hydrogen in the zeolite NaA is investigated by means of grand-canonical Monte Carlo, in a wide range of temperatures and imposed gas pressures, and results are compared with available experimental data. A potential model is used that comprises three main interactions: van der Waals, Coulomb and induced polarization by the permanent electric field in the zeolite.
Neste trabalho, as propriedades da transição sólido-fluido do sistema de Lennard-Jones n - 6 são determinadas recorrendo a cálculos intensivos de energias livres. Vários valores do parâmetro n que regula a intensidade da interacção repulsiva do potencial são investigados. As energias livres dos sistemas com n < 12 são calculadas usando o sistema com n = 12 como referência, recorrendo a uma generalização do método dos histogramas que permite combinar simulações canónicas independentes realizadas com diferentes Hamiltonianos e calcular diferenças de energia livre entre elas. O comportamento de fases do sistema de fulerenos C60 é investigado a partir de simulações de Monte Carlo NPT e utilizando uma classe de potenciais atomísticos que consideram cada átomo da molécula como um centro de interacção distinto. Adicionalmente, podem incluir cargas parciais localizadas nas ligações interatómicas. Em particular, a transição de uma fase com ordem orientacional para uma fase rotacionalmente livre, que acontece com o aumento da temperatura, é estudada em função da pressão. A adsorção de hidrogénio no zeólito NaA é simulada numa gama alargada de temperaturas e pressões recorrendo ao algoritmo de Monte Carlo no ensemble macrocanónico. Os resultados são comparados com dados experimentais. É utilizado um potencial que incluiu termos de van der Waals, Coulomb e de polarização induzida devido à presença de um campo eléctrico permanente no zeólito.

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Odendaal, Morné. "Wireless rotational process monitoring system." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1347.

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The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.

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Sounness, Marcus Neil. "Alternative grazing systems and pasture types for the South West of Western Australia : a bio-economic analysis." University of Western Australia. School of Agricultural and Resource Economics, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0054.

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Alternative grazing systems and pasture types for wool production in the south west of Western Australia were analysed using bio-economic modelling techniques in order to determine their relative productivity and profitability. After reviewing the experimental and modelling literature on perennial pastures and grazing systems, seven case studies of farmers were conducted in order to investigate the practical application of innovative grazing systems and use of perennial pastures. Together these case studies provided information for identifying relevant variables and for calibrating the modelling work which followed. The core of the work lies in a bio-economic model for investigating the comparative value of the three grazing systems and two pasture families mentioned above. A baseline scenario using currently available and reliable scientific data provides baseline results, after which a number of sensitivity analyses provide further insights using variations of four key parameters: persistence, heterogeneity, water soluble carbohydrates, and increased losses. Results show that perennial pastures are in the studied region more profitable than annual pastures. Under current baseline conditions, continuous grazing with perennial pastures is the most profitable enterprise, but this superiority is not robust under parameter variations defined by other scenarios. The more robust solution in terms of enterprise profitability is cell grazing with perennial pastures. The results indicate that intensive grazing systems such as cell grazing have the potential to substantially increase the profitability of grazing operations on perennial pasture. This result is an encouraging one in light of its implications for water uptake and salinity control. It means that economics and land care can go hand in hand, rather than be competitive. It is to be noted that it is the choice of the grazing system in combination with the pasture species, rather then the pasture species itself, that allows for such complementarity between economics and sustainable land use. This research shows that if farmers adopt practices such as cell grazing they may be able to increase the area that they can profitably plant to perennial pasture thus reducing the impacts of dryland salinity. This finding is consistent with the findings of the case studies where the farmers perceived that, provided grazing was planned, increasing the intensity of their grazing management and the perenniallity of their pastures would result in an increase in the profitability of their grazing operation. As a result this research helps to bridge a gap which has existed in this area of research, between the results of scientific research and those reported in practice.

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Flynn, Angela Elizabeth. "Rotational dynamics in the solar system." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420310.

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Baroud, Charles Naim. "Transitions from three- to two-dimensional turbulence in a rotating system." Access restricted to users with UT Austin EID UMI Company copy, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035939.

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Tang, Xiaoqing. "Knowledge based inspection planning system for rotational components." Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243932.

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35

Halde, Caroline. "Organic rotational no-till system adapted for Manitoba, Canada." ACSESS-Alliance of Crop, Soil, and Environmental Science Societies, 2013. http://hdl.handle.net/1993/23848.

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In the northern Great Plains of Canada, there has been limited research conducted on reduced-tillage grain production systems managed organically. The objective was to adapt an organic rotational no-till system to the growing conditions of Manitoba, and to test its agronomic performance. A set of four experiments were conducted between 2010 and 2012, in Carman, MB, Canada. Mulches with hairy vetch (Vicia villosa Roth) showed the most promising results, producing the highest mulch biomass and organic no-till spring wheat (Triticum aestivum L.) yield. Organic flax (Linum usitatissimum L.) yield was significantly higher in no-till than in the two tillage treatments. Reduced content of soil nitrate-N and perennial weeds limited crop productivity after 4 yr under organic continuous no-till. In conclusion, the successful adaptation of the organic rotational no-till system to the growing conditions of Manitoba eliminated the need for tillage for a period of 1.5 to 2 yr.

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36

Toh, Tzern Tzuin. "A gravitational torque energy harvesting system for rotational motion." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6404.

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This thesis describes a novel, single point-of-attachment, gravitational torque energy harvesting system powered from rotational motion. The primary aim of such a system is to scavenge energy from a continuously rotating host in order to power a wireless sensor node. In this thesis, a wireless tachometer was prototyped. Most published work on motion-driven energy harvesters has used ambient vibrations in the environment as the energy source. However, none of the reported devices have been designed to harvest energy directly from continuous ambient rotation. There are important applications such as tire pressure sensing and condition monitoring of machinery where the host structure experiences continuous rotation. In this work, it is shown that in many applications, a rotational energy harvester can offer significant improvements in power density over its vibration-driven counterparts. A prototype single point-of-attachment rotational energy harvester was conceived using a simple direct-current generator. The rotational source was coupled to the stator and an offset mass was anchored on the rotor to create a counteractive gravitational torque. This produces a relative angular speed between rotor and stator which causes power to be generated. Power transfer from the generator to a load was maximised by enforcing an input impedance match between the generator’s armature resistance and the input impedance of a boost converter which in this case, functioned as a resistance emulator. Energy storage and output voltage regulation were implemented using supercapacitors and a wide-input buck regulator respectively. When excess power was generated, it was stored in the supercapacitors and during low source rotation speeds, i.e. insufficient harvested power, the supercapacitors will discharge to maintain operation of the interface electronics. A detailed optimisation procedure of a boost converter was conducted in Matlab in order to minimise the power loss, resulting in a maximum voltage gain of 11.1 and measured circuit efficiency of 96 %. A state-space control model of the harvester electronics was developed in the analogue domain using classical control techniques and this showed the system to be closed-loop stable. A final prototype of the rotational energy harvesting system was built and this comprised an input impedance controller, wireless transmitter and tachometer. The entire system has a measured end-to-end efficiency which peaked at 58 % from a source rotation of 1400 RPM with the generator producing 1.45 W under matched load conditions.

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Almazan, Morales Alhely. "Impact of unrecognized knowledge-gatekeepers and lack of job rotation in product development process of growing organizations." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/105304.

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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, 2015.
Cataloged from PDF version of thesis. Page 87 blank.
Includes bibliographical references (pages 67-68).
In technology oriented organizations like those enclosed in the Automotive Industry, effective communication and collaboration are core competencies that, when properly managed, generate a constant flow of information and ideas that can keep activated the innovation process inside the organization. The complex architecture of the communication systems and their close relationship with the organizational structure have been previously studied to help organizations improve their communication and overcome their own unique challenges. In this thesis, I review the communication system of a Product Development Organization (PDO) along with the influence that the organizational structure has in the communication process complexity. I explain how the opportune identification of the key individuals in the communication system that serve as gatekeepers of the technological information is critical to the success of product development processes and innovation progress. Finally, a survey in an automotive PDO was conducted with the aim to understand how the communication system currently works and integrate the technological gatekeeper concept as a strategy to reinforce the transfer of technological information that increases effectiveness of execution along with innovation.
by Alhely Almazan Morales.
S.M. in Engineering and Management

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38

Ruffino, Paulo Regis Caron. "Rotation numbers for stochastic dynamical systems." Thesis, University of Warwick, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308575.

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Rosso, Roberto Silvio Ubertino. "STEP compliant CAD/CAPP/CAM system for rotational asymmetric parts." Thesis, Loughborough University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421919.

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Anderson, Jeremiah P. "State-space modeling, system identification and control of a 4th order rotational mechanical system." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FAnderson.pdf.

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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2009.
Thesis Advisor(s): Yun, Xiaoping. Second Reader: Julian, Alex. "December 2009." Description based on title screen as viewed on January 26, 2010. Author(s) subject terms: System identification, state-space, pole placement, full state feedback, observer. Includes bibliographical references (p. 91). Also available in print.

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Typrin, Marcello. "IMTS (Intelligent Monitoring and Trending System) : a PC-based monitoring, evaluation and trending system for rotating machinery /." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12302008-063435/.

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42

Ozsuer, Erhan. "Development Of A Web-based Manufacturing Application System For Rotational Parts." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1059930/index.pdf.

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Developing process plans and part programs rapidly and correctly for CNC machine tools plays a vital role in manufacturing. This study is concerned with the development of a web-enabled virtual design and manufacturing application system for rotational parts. The object oriented methodology is used in the application development. Windows Distributed interNet Application (DNA) architecture which describes a framework of building software technologies in an integrated web and client-server model of computing, is employed in the system. The entire system was modeled with Unified Modeling Language (UML), which is an industry-standard visual modeling notation to express software development architectures. Feature-based design approach, being a practical way of linking the design with manufacturing, is implemented in the rotational part design. Users have to be registered in order to use the system. With the supplied web site, users can easily register to system. After registration, the user obtains a password and a unique username. Upon the user authentication, the user session starts. A typical user session involves new or past project selection, material selection, part sketching, blank size definition and cutting parameters determination. After all the steps are completed, process plan and part-program, which are required to manufacture the part on Denford Mirac CNC Turning Machine are generated and displayed on the web site and then saved to the database. The application enables the users to see past projects and to generate new process plan and part programs for different cutting parameters. The process plan, part program and the 2D wire frame drawing of the corresponding part are demonstrated on the web site for the chosen projects.

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Moore, M. P. "Development of a Prolog vibration expert system for rotational machinery management." Thesis, Cranfield University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237556.

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Sabri, Abderrahmane. "Regimes oscillatoires et couplage vibro-rotatif d'un systeme dynamique a periodicite spatio-temporelle." Toulouse 3, 1986. http://www.theses.fr/1986TOU30199.

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L'objet de cette etude est la determination qualitative et quantitative des regimes oscillatoires et vibro-rotatifs d'un systeme dynamique conservatif ou faiblement amorti, modelises par l'equation du pendule excite periodiquement. L'analyse qualitative est basee essentiellement sur l'etablissement de la distribution des singularites dans le plan de phase de la recurrence associee, pour les regimes oscillatoires, et sur un cylindre de phase particulier pour les regimes vibro-rotatifs. La connaissance des proprietes quantitatives a permis de construire les expressions analytiques approchees de plusieurs solutions stationnaires oscillatoires et vibrorotatives ainsi que leurs solutions voisines. Ces solutions permettent de determiner les regimes importants pour les applications techniques

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Brooks, Michael. "Muon-spin rotation studies of correlated inorganic systems." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443599.

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46

Piper, Allison. "Root Length Affects Soluble Carbon and Phosphorus in a Rotational Cropping System." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/PiperA2005.pdf.

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Jones, Mark. "Determining the Rotational and Orbital Velocities of Objects in the Solar System." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/honors/585.

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Astronomers have been observing the night sky for many centuries to establish a better understanding for our universe and solar system. As part of their observations, astronomers characterize celestial bodies by fundamental properties such as mass, motion, and composition in order to provide further insight about the objects in question. As technology and science have evolved, the methods for measuring these properties have become more precise and accurate. One such methodology is known as spectroscopy, and it is a signiﬁcant tool for observational astronomy. In this paper, we shall describe how we used astronomical spectroscopy to determine orbital and rotational velocities for various objects in our solar system. This method was implemented speciﬁcally using the facilities of the Harry D. Powell Observatory on the campus of East Tennessee State University.

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48

Keane, James Tuttle, and James Tuttle Keane. "Tidal-Rotational Dynamics of Solar System Worlds, From the Moon to Pluto." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625474.

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The spins of planetary bodies are not stagnant; they evolve in response to both external and internal forces. One way a planet's spin can change is through true polar wander. True polar wander is the reorientation of a planetary body with respect to its angular momentum vector, and occurs when mass is redistributed within the body, changing its principal axes of inertia. True polar wander can literally reshape a world, and has important implications for a variety of processes—from the long-term stability of polar volatiles in the permanently shadowed regions of airless worlds like the Moon and Mercury, to the global tectonic patterns of icy worlds like Pluto. In this dissertation, we investigate three specific instances of planetary true polar wander, and their associated consequences. In Chapter 2 we investigate the classic problem of the Moon's dynamical figure. By considering the effects of a fossil figure supported by an elastic lithosphere, and the contribution of impact basins to the figure, we find that the lunar figure is consistent with the Moon's lithosphere freezing in when the Moon was much closer to the Earth, on a low eccentricity synchronous orbit. The South Pole-Aitken impact basin is the single largest perturbation to the Moon’s figure and resulted in tens of degrees of true polar wander after its formation. In Chapter 3 we continue our analyses of the lunar figure in light of the discovery of a lunar ”volatile" paleopole, preserved in the distribution of hydrogen near the Moon's poles. We find that the formation and evolution of the Procellarum KREEP Terrain significantly altered the Moon’s orientation, implying that some fraction of the Moon’s polar volatiles are ancient—predating the geologic activity within the Procellarum region. In Chapter 4 we investigate how the formation of the giant, basin-filling glacier, Sputnik Planitia reoriented Pluto. This reorientation is recorded in both the present- day location of Sputnik Planitia (near the Pluto-Charon tidal axis), and the tectonic record of Pluto. This reorientation likely reflects a coupling between Pluto’s volatile cycles and rotational dynamics, and may be active on other worlds with comparably large, mobile volatile reservoirs. Finally, in Chapter 5 we consider the broader context of these studies, and touch on future investigations of true polar wander on Mercury, Venus, Mars, Vesta, Ceres, and other worlds in our solar system.

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Eccles, Mark Richard. "Linear Jahn-Teller systems with troughs." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311773.

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Zhang, Hui. "The investigation of correlator systems utilizing object and frequency space filters." Thesis, Abertay University, 2000. https://rke.abertay.ac.uk/en/studentTheses/5afbbda6-0d84-471b-bfcd-f3717c905233.

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The aim of this research is to develop real-time object recognition systems which are robust and have good discrimination. An important aspect of this work is the development of a rotationally invariant optical correlator. Optical correlation systems are investigated for the purpose of high speed, high discriminant and distortion invariant pattern recognition. A photorefractive joint transform correlator (JTC) using Bismuth Silicon Oxide (BSO) as a non-linear recording medium and a liquid crystal television as a spatial light modulator is implemented. The underlying physics is considered, some specific techniques to improve the operation are proposed. The properties of photorefractive BSO are investigated for use as the dynamic holographic recording medium in information processing systems. The moving grating technique is used for edge-enhanced image reconstruction and for making the correlation peak sharper. The object and frequency space filtering methods are presented to improve the correlation performance, the discrimination, and to realise distortion invariant pattern recognition. Circular harmonic matched filters and phase-only filters with different expansion orders are involved in the photorefractive JTC for real-time rotationally invariant pattern recognition. These filters can also be used to track an object with different orientations. The coherent triple joint transform correlator employs a third beam to modify the Fourier spectrum and hence improves the correlation performance. In the incoherent triple JTC, the wavelet transform is used in the Fourier domain to achieve a high signalto-noise ratio, noise robustness as well as discrimination. Several wavelet functions are also used, after processing, in the conventional JTC for high-speed image feature extraction. The wavelet transform functions can also be used in the JTC with circular harmonic filters to improve the output quality of rotation invariant pattern recognition.

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Dissertations / Theses on the topic 'Rotational systems'

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