Дисертації з теми "Collective rotation"
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1
Jenkins, Ian. "Collective nuclear rotation in '1'3'4Nd and '1'3'7Nd." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314529.
2
Barbier, Rémi. "Algèbre quantique Uqp(u2) et application à la dynamique collective de rotation dans les noyaux." Lyon 1, 1995. http://www.theses.fr/1995LYO10198.
Анотація:
Ce travail de these s'integre dans l'etude des nouvelles symetries en physique. Il se compose de trois parties. La premiere porte principalement sur l'etude de l'algebre quantique u#q#p(u#2). Plus precisement, nous developpons sa structure d'algebre de hopf et portons un interet particulier sur sa structure de coproduit. Les bases d'une theorie de la representation de u#q#p(u#2) sont introduites, d'une part, en construisant ses representations irreductibles de dimension finie et, d'autre part, en calculant ses coefficients de clebsch et gordan par la methode de l'operateur de projection extremal. Nous completons notre etude par la construction de quelques realisations en termes de bosons deformes des algebres quantiques u#q#p(u#2), u#q2(su#2) et u#q#p(u#1#,#1). La deuxieme partie est consacree a la construction d'un nouveau modele phenomenologique de rotateur non rigide se basant sur l'algebre quantique u#q#p(u#2). L'energie de rotation et les probabilites de transition reduites e2 sont obtenues en fonction des deux parametres de deformation de l'algebre quantique. Nous montrons comment et, dans quelle mesure, l'utilisation de la double deformation de l'algebre u#q#p(u#2) permet de generaliser le modele du rotateur en symetrie u#q(su#2). Nous introduisons egalement un nouveau modele de l'oscillateur anharmonique sur la base de cette algebre quantique. Nous montrons que les systemes physiques du rotateur non rigide et de l'oscillateur anharmonique peuvent etre couples par l'intermediaire des parametres de deformation de u#q#p(u#2). Un spectre de ro-vibration est obtenu sous la forme d'un developpement a la dunham de l'energie. L'objet de notre troisieme partie est l'application de notre modele de rotateur a la dynamique collective de rotation dans les noyaux super-deformes des regions de masse a 130 - 150 et a 190 et des isomeres de fission dans les actinides et les terres rares. Dans ce but, nous ajustons les parametres libres de notre modele ainsi que, a titre de comparaison, ceux de quatre autres modeles. Une analyse comparative est menee sur les energies de transition issues de l'ajustement et sur les valeurs des parametres. Nous calculons a partir des expressions des energies de rotation les moments d'inertie dynamiques. Une comparaison des resultats obtenus pour differents modeles permet de mettre en evidence le role des parametres de deformation de l'algebre quantique u#q#p(u#2)
3
Radjaï, Farhang. "Dynamique des rotations et frottement collectif dans les systèmes granulaires." Paris 11, 1995. http://www.theses.fr/1995PA112471.
Анотація:
L'unilateralite geometrique et la loi de frottement de coulomb constituent les aspects les plus generiques des interactions entre particules dans les systemes granulaires. Ces lois sont non-regulieres en ce sens que les variables conjuguees impliquees appartiennent a un ensemble continu des valeurs acceptables qui ne peut pas etre represente comme une fonction mathematique. Nous avons montre que ce caractere non-regulier entraine des correlations non-triviales, meme lorsqu'il s'agit des systemes a geometrie simple. Ces correlations apparaissent a la fois dans le temps, par une auto-organisation des variables dynamiques, et dans l'espace, par la formation des domaines de tailles intermediaires entre celle des particules et celle du systeme. Ces domaines sont lies a la mobilisation progressive de la force de frottement dans le systeme et aux modes de rotation collectifs. Les roulements ont pour effet majeur d'introduire un coefficient de frottement macroscopique inferieur au coefficient de frottement entre particules et une inertie effective plus grande que la masse totale du systeme. Celle-ci prend toute son importance dans la limite quasi-statique. Dans le contexte du desordre geometrique, les forces de contact s'organisent, quelque soit la composition du systeme en tailles des particules, pour definir une distribution statistique en loi de puissance pour les faibles et en decroissance exponentielle pour les fortes forces de contact. Pour ces etudes nous avons realise a la fois des simulations fondees sur les lois de contacts non-regulieres, des experiences en laboratoire et une analyse theorique detaillee
4
Selkowitz, Anthony R. "Mental rotation and a drawing based training regiment." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1139.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Psychology
5
Guyomar, Tristan. "Roles of acto-myosin cortex dynamics in organoid self-organisation." Electronic Thesis or Diss., Strasbourg, 2023. http://www.theses.fr/2023STRAJ100.
Анотація:
Dans cette thèse, nous étudions les organoïdes, mini-organes auto-assemblés issus de quelques cellules souches, qui offrent une perspective unique pour étudier l'organogenèse. Notre recherche relie les formes et les mouvements collectifs des organoïdes à la dynamique hors équilibre du cortex d’acto-myosine. À l'interface entre la physique et la biologie, nous concevons des expériences pour quantifier les propriétés cellulaires et tissulaires et nous intégrons ces mesures dans des modèles physiques révélant les règles d’auto-organisation des organoïdes. En utilisant des cystes MDCK, un modèle organotypique, nous explorons (i) le rôle des asymétries corticales sur la forme des cellules et du cyste, (ii) comment les protéines de jonction serrée influent sur la morphologie et la mécanique du cyste, et (iii) l'émergence de la rotation collective spontanée en 3D de doublets cellulaires due à la rupture de symétrie de la dynamique d’acto-myosine. Notre travail établit un lien entre l'auto-organisation des organoïdes et la dynamique d’acto-myosine, révélant comment les propriétés hors équilibre dirigent la morphogenèseIn this PhD study, we investigate organoids—self-assembled mini-organs derived from a few stem cells, offering a unique perspective on organogenesis. Our research links organoid shapes and collective motions to the out-of-equilibrium dynamics of the acto-myosin cortex. At the interface between Physics and Biology, we design experiments to quantify cellular and tissue properties and use theoretical physics to integrate measurements into models revealing the self-organization of organoids. Using MDCK cysts, an organotypic model, we explore (i) the role of cortical asymmetries on cell shape and cyst structure, (ii) how tight junction proteins influence cyst morphology and mechanics, and (iii) the emergence of spontaneous 3D collective rotation of cell doublets due to symmetry breaking of acto-myosin dynamics. Our work highlights the intricate link between organoid self-organisation and acto-myosin dynamics further revealing how out-of-equilibrium properties drive morphogenesis
6
Rogers, Rodney O. "Finding paths in the rotation graph of binary trees." Doctoral diss., University of Central Florida, 1996. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/2300.
Анотація:
University of Central Florida College of Arts and Sciences ThesisA binary tree coding scheme is a bijection mapping a set of binary trees to a set of integer tuples called codewords. One problem considered in the literature is that of listing the codewords for n-node binary trees, such that successive codewords represent trees differing by a single rotation, a standard operation for rebalancing binary search trees. Then, the codeword sequence corresponds to an Hamiltonian path in the rotation graph Rn of binary trees, where each node is labelled with an n-node binary tree, and an edge connects two nodes when their trees differ by a single rotation. A related problem is finding a shortest path between two nodes in Rn, which reduces to the problem of transforming one binary tree into another using a minimum number of rotations. Yet a third problem is determining properties of the rotation graph. Our work addresses these three problems.
Ph.D.
Doctorate;
Department of Computer Science
Arts and Sciences
Computer Science
247 p.
xi, 247 leaves, bound : ill. ; 28 cm.
7
Diaz, Derek Daniel. "Accidental Inversion During 3D Rotation With 2-Dof Input Devices." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2075.
Анотація:
This dissertation focuses on a human operator's ability to perform rotational control of a three-dimensional object using two-degrees of freedom (DOF) interface devices. Although input devices designed specifically for 3D interaction exist, devices traditionally used for two-dimensional user interaction, such as a mouse or joystick, have become ubiquitous to computer tasks. This research examines a particular human-computer interaction issue that arises from stimulus-response compatibility between three-dimensional stimuli spaces and 2-DOF response sets. The focal point of this research is a phenomenon referred to here as accidental inversion. Accidental inversions occur when an operator erroneously moves a three-dimensional object in a direction opposite than was intended. Thus, the effect of accidental inversion results from a mismatch between the operator's intended and actual input. A key assumption in diagnosing the causal factors involved in the accidental inversion effect is contribution from both internal (i.e., having to do with the individual) and external (i.e., having to do with the environment) influences. Three experiments were conducted to study accidental inversion. The first examined population stereotype, a measure of a target population's natural response tendencies to particular stimuli for a particular task. Results indicated a strong population stereotype for horizontal rotations (i.e., yaw) and weak stereotype for vertical rotations (i.e., pitch). This effect was mediated by whether the task was in the context of flight or ground-based movement. The second experiment analyzed the subjective preference for two opposite input-response (I-R) mappings (i.e., how the system responds to different input into the controlling device) for a task requiring control over vertical rotation. Results indicated that subjective preferences for I-R mappings were not heavily polarized. The third experiment also focused on vertical rotational control and examined how subjective preference for a particular I-R mapping affected performance. Furthermore, this experiment also examined performance when interference was introduced in the form of a temporary interruption where the participant had to conduct the task using an opposite I-R mapping. Results indicated that, upon being interrupted with the opposite I-R mapping, the group who used the mapping they subjectively preferred did worse than the group who used the mapping they did not prefer. This research has implications for the design of human-machine systems requiring human-in-the-loop three-dimensional rotational control. Some human-machine systems can have significant consequences from even a single mistake caused by a human-operator accidentally providing the wrong input. Findings from this research lead to two primary recommendations to the design of human-machine systems: a) an easily accessible and clearly indicated method to select input-response mapping which is provided before beginning the actual task, b) be informed of the current input-response mapping in use.Ph.D.
Department of Psychology
Sciences
Psychology PhD
8
Fatolitis, Philip. "Initial Validation of Novel Performance-Based Measures: Mental Rotation and Psychomotor Ability." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6223.
Анотація:
Given the high-risk nature of military flight operations and the significant resources required to train U.S. Naval Aviation personnel, continual improvement is required in the selection process. In addition to general commissioning requirements and aeromedical standards, the U.S. Navy utilizes the Aviation Selection Test Battery (ASTB) to select commissioned aviation students. Although the ASTB has been a good predictor of aviation student performance in training, it was proposed that incremental improvement could be gained with the introduction of novel, computer administered performance-based measures: Block Rotation (BRT) and a Navy-developed Compensatory Tracking task. This work constituted an initial validation of the BRT, an interactive virtual analog of Shepard-Metzler's (1971) Mental Rotation task that was developed with the intention of quantifying mental rotation and psychomotor ability. For Compensatory Tracking, this work sought to determine if data gathered concord with results in extant literature, confirming the validity of the task. Data from the BRT were examined to determine task reliability and to formulate relevant quantitative/predictive performance human models. Results showed that the BRT performance is a valid spatial ability predictor whose output can be modeled, and that Compensatory Tracking task data concord with the psychometric properties of tracking tasks that have been previously presented in the literature.Ph.D.
Doctorate
Psychology
Sciences
9
Hauschild, Karl. "Collective rotational behaviour in the A-130 region : #gamma#-ray spectroscopic studies of '1'3'2,'1'3'4Pr and '1'3'3Ce." Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284170.
10
Sleiti, Ahmad Khalaf. "EFFECT OF CORIOLIS AND CENTRIFUGAL FORCES ON TURBULENCE AND TRANSPORT AT HIGH ROTATION AND BUOYANCY NUMBERS." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4408.
Анотація:
This study attempts to understand one of the most fundamental and challenging problems in fluid flow and heat transfer for rotating machines. The study focuses on gas turbines and electric generators for high temperature and high energy density applications, respectively, both which employ rotating cooling channels so that materials do not fail under high temperature and high stress environment. Prediction of fluid flow and heat transfer inside internal cooling channels that rotate at high rotation number and high density ratio similar to those that are existing in turbine blades and generator rotors is the main focus of this study. Both smooth-wall and rib-roughened channels are considered here. Rotation, buoyancy, bends, ribs and boundary conditions affect the flow inside theses channels. Ribs are introduced inside internal cooling channel in order to enhance the heat transfer rate. The use of ribs causes rapid increase in the supply pressure, which is already limited in a turbine or a generator and requires high cost for manufacturing. Hence careful optimization is needed to justify the use of ribs. Increasing rotation number (Ro) is another approach to increase heat transfer rate to values that are comparable to those achieved by introduction of ribs. One objective of this research is to study and compare theses two approaches in order to decide the optimum range of application and a possible replacement of the high-cost and complex ribs by increasing Ro. A fully computational approach is employed in this study. On the basis of comparison between two-equation (k-[epsilon] and k-[omega]) and RSM turbulence models, against limited available experimental data, it is concluded that the two-equation turbulence models cannot predict the anisotropic turbulent flow field and heat transfer correctly, while RSM showed improved prediction. For the near wall region, two approaches with standard wall functions and enhanced near wall treatment were investigated. The enhanced near wall approach showed superior results to the standard wall functions approach. Thus RSM with enhanced near wall treatment is validated against available experimental data (which are primarily at low rotation and buoyancy numbers). The model was then used for cases with high Ro (as much as 1.29) and high-density ratios (DR) (up to 0.4). Particular attention is given to how turbulence intensity, Reynolds stresses and transport are affected by Coriolis and buoyancy/centrifugal forces caused by high levels of Ro and DR. Variations of flow total pressure along the rotating channel are also predicted. The results obtained are explained in view of physical interpretation of Coriolis and centrifugal forces. Investigation of channels with smooth and with rib-roughened walls that are rotating about an orthogonal axis showed that increasing Ro always enhances turbulence and the heat transfer rate, while at high Ro, increasing DR although causes higher turbulence activity but does not necessarily increase Nu and in some locations even decreases Nu. The increasing thermal boundary layer thickness near walls is the possible reason for this behavior of Nu. The heat transfer enhancement for smooth-wall cases correlates linearly with Ro (with other parameters are kept constant) and hence it is possible to derive linear correlation for the increase in Nu as a function of Ro. Investigation of channels with rib-roughened walls that rotate about orthogonal axis showed that 4-side-average Nur correlates with Ro linearly, where a linear correlation for Nur/Nus as a function of Ro is derived. It is also observed that the heat transfer rate on smooth-wall channel can be enhanced rapidly by increasing Ro to values that are comparable to the enhancement due to the introduction of ribs inside internal cooling channels. This observation suggests that ribs may be unnecessary in high-speed machines, and has tremendous implications for possible cost savings in these machines. In square channels that rotate about parallel axis, the heat transfer rate enhances with Ro on three surfaces of the square channel and decreases on the inner surface (that is the one closest to the axis of rotation). However, the four-sides average Nu increases with Ro. Increasing wall heat flux at high Ro does not necessarily increase Nu on walls although higher turbulence activity is observed. This study examines the rich interplay of physics under the simultaneous actions of Coriolis and centrifugal/buoyancy forces in one of the most challenging internal flow configurations. Several important conclusions are reached from this computational study that may have far-reaching implications on how turbine blades and generator rotors are currently designed. Since the computation study in not validated for high Ro cases, these important results call for a experimental investigation.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical, Materials and Aerospace Engineering
11
Deloncle, Isabelle. "Excitations collectives a basse energie : etude microscopique de la rotation, de la vibration et de leur couplage dans les noyaux pair-pairs." Paris 6, 1989. http://www.theses.fr/1989PA066137.
Анотація:
Le hamiltonien collectif de bohr le plus general, pour la dynamique quadrupolaire, a ete construit de facon purement microscopique au travers d'une approximation a l'approche adiabatique de hartree-fock dependant du temps. L'objectif de ce travail est, partant d'une interaction effective a deux corps (type skyrme), d'obtenir une description quantitative des proprietes collectives de basse energie dans les noyaux moyens et lourds. Dans ce contexte, le terme basse energie se refere aux regimes dynamiques ou le mouvement collectif est adiabatique compare aux modes associes aux degres de liberte individuels. Travaillant sur la solution du probleme nucleaire a n corps considere, nous faisons les hypotheses suivantes: existence d'un champ moyen a tout instant (les correlations d'appariement sont introduites de facon simplifiee a partir d'une force de seniorite); existence de quelques variables collectives contenant toute la dependance en temps; l'adiabacite du mouvement collectif. L'ensemble de ce travail constitue donc une expression microscopique du modele unifie de bohr et mottelson. Les spectres de basse energie ainsi calcules pour quatre noyaux transitionnels (#7#4ge, #7#6se, #1#1#0cd, #1#8#6pt) montrent un excellent accord avec les donnees experimentales
12
Creuly, Catherine. "Selection d'une collection industrielle de streptocoques mesophiles et thermophiles en vue de leurs utilisations en rotation dans les ferments lactiques." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2D206.
Анотація:
Cette etude a contribue a creer une collection de streptocoques lactiques: st. Lactis subsp. Cremoris, st. Lactis subsp. Lactis, st. Lactis subsp. Diacetylactis (bacteries mesophiles) et st. Thermophilus. Onze souches de st. Cremoris appartenant a la collection existante ont ete selectionnees parmi 67 bacteries mesophiles apres des tests de lysotypie (sur 59 phages) et de lysogenie (par action de la mitomycine). Les memes tests ont ete realises sur 30 st. Thermophilus et 19 serums phagiques. Mais ces souches semblent posseder des systemes de restriction-modification puissants et sont donc moins sensibles aux phages. Le peu de phages recoltes n'ont pas permis d'etablir des groupes de lysotypie significatifs et les souches testees ne sont pas lysogenes. Afin d'ameliorer la collection, 554 bacteries mesophiles ont ete isolees; identifiees et leur pouvoir acidifiant determine
13
Creuly, Catherine. "Sélection d'une collection industrielle de Streptocoques mésophiles et thermophiles en vue de leurs utilisations en rotation dans les ferments lactiques." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376041207.
14
Gonzalez, Luis O. "Analysis of high speed radially rotating high-temperature heat pipes." Honors in the Major Thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1030.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Engineering and Computer Science
Mechanical Engineering
15
Traas, Adam Michael. "Effects of a treatment using computer generation of isometric and orthographic projections on middle school students' spatial ability." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4563.
Анотація:
The primary focus of this study examines the effectiveness of the CRIOSAT (Computerized Rotational Isometric and Orthographic Spatial) spatial ability treatment on a random sample of middle school students' (n=137) spatial ability as measured by the Purdue Spatial Visualization Test: Rotations Test (PSVT-ROT) (Guay, 1977). The secondary focus of this study investigates the relationships between mathematical achievement, problem solving preferences, and spatial ability. The secondary focus was tested on a subsample (n=41), with the problem solving preferences measured via the Mathematical Processing Instrument (MPI) (Suwarsono, 1982). Findings indicated no significant gains in spatial ability scores after students' use of the CRIOSAT treatment; while some increases in spatial ability took place in males. Significant positive correlation was identified between mathematics achievement and spatial ability; while conversely, a significant negative correlation was found between mathematics achievement and level of visual problem solving used by students.ID: 028916877; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.Ed.)--University of Central Florida, 2010.; Includes bibliographical references (p. 148-161).
M.Ed.
Masters
Department of Teaching and Learning Principles
Education
16
Phelan, Michael. "THE DESIGN, CONSTRUCTION, AND VALIDATION OF NOVEL ROTATING WALL VESSEL BIOREACTORS." Master's thesis, Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/488702.
Анотація:
BioengineeringM.S.
The rotating wall vessel (RWV) bioreactor is a well-established cell culture device for the simulation of microgravity for suspension cells and the generation of spheroids and organoids. The key to the success of these systems is the generation of a delicately maintained fluid dynamics system which induces a solid body rotation capable of suspending cells and other particles in a gentle, low-shear environment. Despite the unique capabilities of these systems, the inherently delicate nature of their fluid dynamics makes the RWV prone to multiple failure modes. One of the most frequently occurring, difficult to avoid, and deleterious modes of failure is the formation of bubbles. The appearance of even a small bubble in an RWV disrupts the crucial laminar flow shells present in the RWV, inducing a high-shear environment incapable of maintaining microgravity or producing true spheroids. The difficulty of eliminating bubbles from the RWV substantially increases the learning curve and subsequent barrier-to-entry for the use of this technology. The objective of this study is to create a novel RWV design capable of eliminating the bubble formation failure mode and to demonstrate the design’s efficacy. The tested hypothesis is: “The addition of a channel capable of segregating bubbles from the fluid body of the RWV will protect its crucial fluid dynamics system while enabling the growth of consistently sized and properly formed cell spheroids, improving ease of use of the RWV and decreasing experimental failure.”
Temple University--Theses
17
Amrani, Foued. "Génération et intéraction d'un grand nombre de solitons dans les lasers à fibre : universalité des comportements collectifs." Angers, 2011. http://www.theses.fr/2011ANGE0077.
Анотація:
Le travail de cette thése comprend deux volets. Le premier concerne l’étude des interactions d’un grand nombre de solitons dans un laser, et le deuxiéme est la réalisation d 'un laser a fibre monomode de forte puissance, 10 Watts. La puissance mise en jeu dans I’expérience a permis de générer des “paquets” contenant quelques centaines d’impulsions suffisamment proches les unes des autres pour interagir. De ce fait, nous avons observé expérimentalement, dans un laser a fibre en anneau verrouillé en phase par la rotation non linéaire de la polarisation, des états ou les impulsions subissent des mouvements désordonnés, d’autres où le mouvement est collectif. Ces comportements collectifs sont analogues a ceux que I’on observe dans les états de la matiére. Nous avons présenté une classification phénoménologique de ces comportements collectifs : “gaz” de solitons ; “flux supersonique de gaz” de solitons ; “liquide” de solitons ; “polycristal ” de solitons ; “cristal” de solitons. Un laser a fibre en forme de huit verrouillé en phase par une boucle non linéaiie amplificatrice a été réalisé. Il nous a permis d'observer des comportements collectifs de solitons similaires a ceux obtenus dans Ie laser en anneau verrouillé en phase par la rotation non linéaire de la polarisation. II semble donc que l'on puisse attribuer a ces phénomènes un caractere universel, dans Ie sens où ils ne dépendraient pas d’un mécanisme particulier de verrouillage de modes, mais uniquement des interactions entre solitons. Le deuxiéme volet a consisté a réaliser un laser a fibre de puissance dopée Yb/Er avec un amplificateur qui délivre 10 W de puissance moyenne en sortie. Avec une telle puissance, un protocole strict a été mis en place pour assurer un fonctionnement sûr. En régime continu dans une cavité en anneau unidirectionnelle entièrement fibrée, une puissance de 8 W à la sortie du laser a été atteinte, ce qui constitue à notre connaissance un record pour un laser monomode fonctionnant en continu à 1550 nm. En régime multi-impulsionnel, le verrouillage de modes repose sur la rotation non linéaire de la polarisation. Nous avons obtenu expérimentalement une dynamique fascinante qui associe deux états de solitions en même temps : le verrouillage de modes harmonique de cristaux de solitions. Dans le cas du verrouillage de modes harmonique, le motif de base est une impulsion par période. Dans notre cas, le motif de base est un cristal. Des nouveaux records au niveau du nombre de solitions ont été obtenus, 900 pour l'état cristal impulsions et 2500 impulsions avec le régime harmonique de cristauxThe work of this thesis consists of two axes. The first concerns the study of interactions of a large number of solitons in fiber laser and the second is the realization of high-power single-mode fiber laser. We observed experimentally different states in a ring fiber laser mode-locked by nonlinear rotation of polarization, where the pulses are under disordered movements, others where the movement is collective. We have identified 5 different states. We point out an analogy with the states of the matter and propose for the first time a classification of dissipative soliton complexes : soliton gas, supersonic soliton gas flow, soliton liquid, soliton pottery stat and soliton crystal. We have investigated multiple-soliton pattern formations in a figure-of-eight fiber laser passively mode-locked through non linear amplifying loop mirror. We have obtained a variety of soliton patterns and states that were previously observed in double-clad fiber lasers passively mode-locked through nonlinear polarization rotation. Our results tend to demonstrate, for the first time, the universality of such soliton states. Indeed, the patterns do not depend on the precise mode locking mechanism. A high power passively mode-locked fitter laser exploiting the nonlinear polarization rotation with an amplifier that delivers 10 W at the output was set up. In multi pulsing regime, we obtained experimentally a fascinating dynamic that combines two states of solitons at the same time, the harmonic mode locking of soliton crystals, when the basic pattern is a crystal. New records in the number of solitons have been obtained for the crystal state 900 pulses and 2. 500 pulses with harmonic mode locking
18
McCole, Dlugosz Erin Theresa. "DEVELOPMENT AND APPLICATIONS OF FILAMENT-ASSISTED IMPULSIVE VIBRATIONAL AND ROTATIONAL RAMAN SPECTROSCOPIES." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/400871.
Анотація:
ChemistryPh.D.
This dissertation details the development and applications of two innovative types of optical filament-based impulsive Raman spectroscopy: filament-assisted Raman spectroscopy (FAIRS) and spectral-to-temporal amplitude mapping polarization spectroscopy (STAMPS). These techniques provide complimentary vibrational and rotational information on molecular systems of interest. Both are powerful due to their impulsive nature which allows for rapid measurement of entire Raman spectra. However, each type of spectroscopy utilizes the filament in a different manner. The recently reported vibrational technique, referred to as filament-assisted impulsive Raman spectroscopy, employs the pulse shortening and continuum generation of filamentation to impulsively excite a massive vibrational coherence in a molecular system for simultaneous measurement of all the Raman-active modes. In the first half of this dissertation, FAIRS is further developed and applied to a plethora of signature molecules. Radioactive decay signature molecules, including nitrogen oxides, ozone, and ions are detected via FAIR spectroscopy. Concurrent generation and detection of ozone, ionic, and excited-state molecules through filamentation is reported for the first time. Production of these species through the strong field chemistry of filamentation and their subsequent filament-driven excitation is a mark of sensitivity of FAIRS. Spatial studies of combustion species in a natural gas flame are also presented. FAIRS monitors the Raman signal intensities of known reactants and products as a function of vertical flame position. The appearance of combustion products as a function of flame height is also tracked. Spectral fringes overlapping the Raman-active modes are present in all measurements and enable more sensitive detection of low signal intensity species. The results described illustrate the potential of FAIRS for threat sensing applications. The rotational technique, referred to as spectral-to-temporal amplitude mapping polarization spectroscopy, temporally chirps the spectral content of the white-light continuum generated during filamentation to map the transient rotational rivals that are impulsively excited by a short pump pulse. In the second half of this dissertation, the initial development and testing, followed by the applications of STAMPS are described. STAMPS proves successful in mapping the rotational wavepacket rephasing of simple linear molecules, including nitrogen, oxygen, and carbon dioxide, as well as the more complicated asymmetric top molecules, ethylene and methanol. The application of STAMPS to the detection of nitrogen oxides and nitrous oxide, which are considered signatures of multiple threat substances and events, is demonstrated. A pressure study of nitrous oxide reveals dephasing effects as a function of time and pressure. These preliminary results also indicate the potential of STAMPS for hazard sensing applications.
Temple University--Theses
19
Clausen, Sally. "I never forget a face! : memory for faces and individual differences in spatial ability and gender." Honors in the Major Thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1394.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Psychology
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Holmes, Corinne Ashley. "IT’S THE JOURNEY, NOT THE DESTINATION: ARRAY STABILITY SUPPORTS FLEXIBLE SPATIAL MEMORY." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/432549.
Анотація:
PsychologyPh.D.
The ability to recall a spatial layout from multiple orientations – spatial flexibility – is a challenging cognitive process, especially when the global configuration cannot be viewed from a single vantage point, as spatial information must first be integrated before it can be flexibly recalled. The current study examined if experiencing the transition between multiple viewpoints enhances spatial flexibility for both non-integrated (Exp. 1) and integrated environments (Exp. 2), if the type of transition matters, and if action provides an additional advantage over passive visual flow. In Experiment 1, participants viewed an array of dollhouse furniture from four viewpoints that presented the global configuration from multiple orientations. In Experiment 2, the array was viewed piecemeal, from four viewpoints that presented the global configuration in partial chunks. The control condition presented the dollhouse as a series of static views, whereas in the remaining conditions, visual flow was continuous. Participants viewed the natural transition between viewpoints, and either passively experienced the transitions (i.e., by watching the dollhouse rotate or being rolled around it), or actively generated them (i.e., by rotating the dollhouse or walking around it). Across both experiments, continuous visual flow significantly enhanced spatial flexibility when paired with observer movement around the dollhouse, either active or passive. Furthermore, when participants had to integrate spatial information across discrete learning experiences (Exp. 2), active movement provided a significant advantage above passive experience. These findings suggest that array stability is key to flexible spatial memory, with action providing an additional boost to spatial integration.
Temple University--Theses
21
Pond, Jarrad W. T. "Perturbation analysis of fluctuations in the universe on large scales, including decaying solutions and rotational velocities." Honors in the Major Thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1309.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Physics
22
Tucker, Brandon Raye. "Reducing the incidence of ventilator-associated pneumonia with selected positional strategies." Honors in the Major Thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1512.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Nursing
Nursing
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Blanchet, Célia. "Étude des facteurs de l’instabilité dans les groupes : quels effets sur le système de mémoire transactive et les performances collectives ?" Thesis, Rennes 2, 2015. http://www.theses.fr/2015REN20029/document.
Анотація:
Cette thèse a pour objectif d’examiner les effets de certains facteurs d’instabilité sur le développement du système de mémoire transactive et sur les performances groupales. Son originalité réside à la fois dans la manière d’appréhender l’instabilité dans les groupes et dans l’approche de psychologie sociale expérimentale proposée. L’analyse des différents facteurs d’instabilité et la tentative d’intégration ont permis d’étudier plus précisément l’impact de deux facteurs d’instabilité – le conflit lié à la tâche et le changement de membres dans le groupe – sur le système de mémoire transactive. Deuxpremières études examinent l’effet du conflit lié à la tâche et ses modes de régulation (épistémique vs. relationnelle). Si les résultats ne sont pas constants, ils affirment le rôle médiateur du système de mémoire transactive dans la relation conflit-performance et invitent à réfléchir aux effets de ce conflit, qui ne sont pas nécessairement néfastes. La troisième étudeporte sur le changement prévu ou imprévu de membres dans le groupe. Comme attendu, le changement prévu d’un membre bloque la construction du système de mémoire transactive, limitant ainsi la performance groupale. Cette étude apporte un regard nouveau sur les recherches liées au turnover et invite à prolonger les travaux sur les effets de ce phénomène sur l’efficacité des équipes. Un travail d’élaboration d’un outil d’observation de la mémoire transactive à partir d’indicateurs langagiers est également présenté. Les perspectives futures et implications pratiques des résultats de cette thèse pour le travail d’équipe sont discutées, en encourageant notamment le développement de recherches en situation de simulationThe aim of this thesis is to examine the effects of several factors of instability on the development of transactive memory systems and on team performance. Its originality is due to the way in which we consider the instability in teams and our experimental social psychology approach. The analysis of different factors of instability and the attempt at integrating them enabled us to further study the impact of two factors of instability – task conflict and turnover – on transactive memorysystems. The first two studies examine the effect of task conflict and the ways in which it is regulated (epistemic vs relational). The results are inconsistent, but reveal that transactive memory mediates the effects of task conflict on team performance. In addition, the results lead us to consider the effects of task conflict, which are not necessarily harmful. The third study is about unexpected or expected turnover in groups. As anticipated, expected turnover impedes building atransactive memory system, thereby decreasing collective performance. This study provides a new perspective on previousresearch concerning turnover and proposes the continuation of this research on the effects of this phenomenon on the efficacy of teams. The development of an observational tool to measure transactive memory using language indicators is also presented. The future perspectives and practical implications of the results are discussed, including promoting thedevelopment of simulation studies
24
Podal, Pavel. "Studium vlastností katalyzátoru na bázi MnOx s využitím RRDE." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219064.
Анотація:
This master thesis deals with qualifications of the catalytic materials for positive electrode low-temperature fuel cells. The teoretical part focuses on the physical and chemical properties of low-temperature fuel cells. There are described methods of hydrodynamic RDE and RRDE. RRDE study utilizes methods linear and cyclic voltammetry for qualifying performance of catalytic materials and presentation of results. The practical part describes the preparation various types of carbon materials. There are monitored the oxygen reduction using RRDE. Catalytic materials are evaluated: CV, stability, kinetic parameters, creation of intermediate H2O2 and kinetics of electrode reactions.
25
Rezgui, Cyrine. "Etude du potentiel d'introduction de la culture du pois d'hiver dans les successions culturales en Normandie : conséquences sur les communautés microbiennes du sol et les flux d'azote Impacts of the winter pea crop (instead of rapeseed) on soil microbial communities, nitrogen balance and wheat yield Quantification et analyse des exsudats racinaires de pois, de blé et de colza : mise au point d’une méthodologie de collecte des exsudats racinaires N rhizodeposition quantification and root exudates characterization of pea (Pisum Sativum L.), rapeseed (Brassica napus L.) and wheat (Triticum aestivum L.) under controlled conditions Linking soil microbial community to C and N dynamics during crop residues decomposition." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR047.
Анотація:
La transition agroécologique vise la triple performance agronomique, écologique et sociétale des exploitations agricoles. Un certain nombre de pratiques agricoles permet d’envisager la construction et le développement de systèmes de culture répondant à ces contraintes. Les légumineuses, par leur capacité à fixer l’azote atmosphérique, sont une alternative intéressante aux intrants azotés. Outre l’absence de fertilisation lors de leur culture, elles fournissent de l’azote à la culture suivante. Il existe cependant un manque de références sur certaines légumineuses à graines et notamment la culture du pois d’hiver. En effet, si des données acquises dans différentes régions françaises sont disponibles, aucune référence n’a été publiée pour la Normandie où la culture du pois d’hiver connaît un récent regain d’intérêt. Cette thèse propose d’évaluer, sur une période de deux ans, l’effet du remplacement du colza par le pois d’hiver en tête de rotation en réalisant une analyse comparative de ces deux successions (pois d’hiver-blé et colza-blé). L’objectif était d’évaluer l’effet de ce changement de tête de rotation (pois d’hiver vs colza) sur l’état biologique du sol et les flux d’azote à différentes échelles spatiotemporelles. Les résultats ont révélé une forte variabilité spatio-temporelle dans la réponse des communautés microbiennes du sol, et mis en évidence l’importance du contexte pédoclimatique dans le déterminisme de l’abondance et de l’activité des communautés microbiennes du sol. Ils ont montré par ailleurs, l’effet positif du pois d’hiver sur la disponibilité de l’azote minéral au cours du cycle cultural et pour les cultures suivantes, ici le blé puis l’orge. Les apports d’azote minéral dans le sol lié à la contribution des parties racinaires via la rhizodéposition et à la dégradation des résidus de culture après récolte ont été évalués au cours de ce travail de thèse. En effet, si la rhizodéposition s’est révélée plus importante sous pois d’hiver, elle n’a pas eu d’impact significatif sur les communautés microbiennes rhizosphériques. Contrairement à ces observations, la dégradation des résidus de culture a significativement modifié la composition des communautés bactériennes en lien avec leur composition biochimique initiale. La succession culturale incluant le pois a enrichi le sol en azote minéral mais des risques de perte d’azote par lixiviation de l’ordre de 23 kg N. ha-1 ont été estimés. Ces constats soulignent l’importance d’adapter la conduite des systèmes de culture incluant le pois d’hiver, en limitant les pertes d’azote par lixiviation et en maximisant son utilisation par les cultures suivantes. Les résultats de ces travaux ont confirmé la diminution des quantités d’engrais azoté utilisées dans la succession contenant le pois, sans préjudice de productivité, ni pour le pois, ni pour la culture suivante, ici, le blé. Finalement, introduire le pois d’hiver dans la rotation de culture en région Normandie, semble permettre de répondre à la problématique d’augmentation du coût des intrants, et aux enjeux de transition agroécologique et d’autonomie protéique régionaleThe agroecological transition targets triple agronomic, ecological, and societal performance of farms. Some new agricultural practices had emerged to develop a new cropping system to respond to these constraints. Legumes constitute an interesting alternative. Indeed, legumes are advantageous for soils due to their symbiotic relationship with nitrogen-fixing bacteria. The presence of compatible rhizobia combined to nitrogen-limited conditions promotes symbiosis which is the most efficient way for legumes to acquire more nitrogen. Compared with non-nodulated plants, symbiosis provides a competitive advantage by increasing soil nitrogen pool. However, some grain legumes, notably winter pea, are rarely studied, especially in the Normandy region where no reference has been published for this crop. The objective of this study is to compare two crop successions for a period of two years (winter pea-wheat and rapeseed-wheat), in order to assess the effect of replacing rapeseed by winter pea at the head of the rotation .We evaluated the effect of these two crops (winter pea vs rapeseed) on the biological state of the soil and nitrogen fluxes at different spatio-temporal scales. The results showed a significant spatio-temporal effect on the response of soil microbial communities and highlighted the importance of the pedoclimatic context in determining the abundance and activity of soil microbial communities. A positive effect of winter pea has been demonstrated on the availability of mineral nitrogen during the crop cycle and for following crops (wheat and barley). The supply of nitrogen to the soil is linked to the rhizodeposition of nitrogen via plants roots and the degradation of crop residues after harvest. Our results showed that winter pea exhibited the greatest amount of nitrogen rhizodeposition. However, rhizodeposition did not have a significant impact on rhizospheric microbial communities. Contrary to these observations, the degradation of crop residues significantly modified the composition of bacterial communities linked to their initial biochemical composition. Crop succession including winter pea enriched the soil with mineral nitrogen but simulation with STICS software revealed a nitrogen leaching around of 23 kg N. ha-1 during the cropping cycle. These findings underline the importance of adapting an adequate crop management system, including winter pea, to limit nitrogen losses. The results showed also that wheat yields after winter pea without the use of nitrogen fertilizers were equivalent to those obtained after rapeseed. However, rapeseed required significant nitrogen fertilization. Including winter pea in crop rotation in Normandy region may be a key to enhance productivity, to respond to the challenges of agroecological transition, regional protein autonomy, and to reduce environmental and economic costs, by reducing notably, the costs of fertilizers production and uses
26
Wang, Xiaofeng. "Exotic collective excitations at high spin triaxial rotation and octupole condensation /." 2007. http://etd.nd.edu/ETD-db/theses/available/etd-12132007-005645/.
Анотація:
Thesis (Ph. D.)--University of Notre Dame, 2007.Thesis directed by Umesh Garg and Robert V. F. Janssens for the Department of Physics. "December 2007." Includes bibliographical references (leaves 274-285).
27
"Détermination des paramètres de rotation de Mars à partir de mesures de poursuite Doppler : Théorie et Simulations." Université catholique de Louvain, 2003. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-12152003-123413/.