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1
Tummel, Kurt (Kurt K. ). "Investigation of model micro-scale reconnecting plasma modes." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44822.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.Includes bibliographical references (leaf 27).
We numerically and analytically investigate the linear complex mode frequencies of model micro-reconnecting plasma modes which have transverse wavelengths of the order of the electron skin depth c/lwpe. This model mode, which can have finite wavelength parallel to the magnetic field, is found in the limit of a straight and uniform magnetic field in the presence of temperature gradients. The theory of the related micro-reconnecting modes has been previously developed in view of explaining the observation of macroscopic instabilities which are not predicted by the drift tearing mode theory [2]. These micro-reconnecting modes are radially localized by magnetic shear and lead to the formation of microscopic magnetic islands. We derive the model dispersion equation, which closely follows the derivation of the micro-reconnecting mode dispersion equation [1], under relevant conditions using the drift kinetic approximation. We also consider the dispersion relation in the fluid limit [1]. We examine the solutions of the resulting dispersion relations and confirm the driving effect of the electron temperature gradient, and the stabilizing effect of a density gradient.
by Kurt Tummel.
S.B.
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Callan, M. A. "Trapping modes." Thesis, University of Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303739.
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Wei, Li. "Localisation optique : modes d'Anderson localisés et modes évanescents d'interface." Caen, 2010. http://www.theses.fr/2010CAEN2046.
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L'objectif premier de ce travail est consacré à l'étude théorique de la localisation optique. Les modes localisés d'Anderson des ondes optiques et les modes évanescents d'interface sont principalement étudiés. La méthode « Finite-Difference-Time-Domain » (FDTD) et celle de la fonction de Green sont utilisées pour les expériences numériques. Les propriétés dynamiques des états optiques "necklace" du régime de localisation d'Anderson dans des milieux aléatoires ont été analysées, et une image dynamique physique a été construite de manière à comprendre un incident d'impulsion dans le milieu aléatoire lorsque la localisation d'Anderson intervient. A l'interface des différents matériaux, les effets des modes optiques évanescents sur les propriétés spatiales et temporelles, comme le gain de cohérence temporelle, la super-résolution spatiale, etc, de l'image d’une lame mince d’un matériau de type « main-gauche » (LHM) ont été discutés en détail. De plus, la réfraction négative des matériaux « SNM » (single-negative-refractive-index material), pour lesquels seuls les modes évanescents existent, a été traitée. La condition de l'existence de réfraction négative dans les matériaux « SNM » a été précisée. Bien que cette conclusion soit obtenue pour des matériaux « SNM », les résultats sont suffisamment généraux pour être considérés comme corrects pour tous les milieux dispersifs linéaires. L'indice effectif de réfraction de phase d’une lame « non-LHM » mais présentant une réfraction négative a été également abordé. Ce travail devrait nous aider à mieux comprendre la localisation optique, et nous donner une nouvelle voie pour concevoir de nouveaux dispositifs optiquesThe primary objective of this work is devoted to the theoretical investigation of optical localization. Anderson localized modes of optical wave and optical interface evanescent modes are mainly investigated. Throughout the dissertation, the Finite-Difference-Time-Domain (FDTD) method and the Green's function method are used for the numerical experiments. In this work, the dynamical properties of the optical necklace states of Anderson localization regime in random media system have been investigated, and a dynamical physical picture have been constructed to understand a pulse incident into the random media system when Anderson localization occurs. For the optical interface evanescent modes which is localized at the interface of different materials, their effect on the temporal and spatial properties of the image of left-hand-material (LHM) slab, such as temporal coherence gain, spatial super-resolution, etc. , have been detailed discussed. In addition, the negative refraction in the SNM (single-negative-refractive-index material), in which only evanescent modes can exist, have been investigated. And the condition of the existence of negative refraction in the SNM has been demonstrated. Although this conclusion is focused on the presentation of SNM, the results are general enough and are expected to be correct for any linear dispersive media. Besides these, the effective phase refractive index for the non-LHM negative refractive slab has been also investigated. This study work could help us to understand further of the optical localization, and give us a new way to design new optical devices
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Pau, Michael Kristian. "Model-Based Output-Only Identication of Coupled Thermoacoustic Modes." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224166.
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A model-based output-only method for identifying from time-series data the parameters that determine the dynamics of a stochastically forced thermoacoustic oscillator has previously been implemented in the case of a single standing thermoacoustic mode. This thesis presents an extension of the method in question to two coupled standing modes at the same frequency. An appropriate thermoacoustic model, as used in the previous works, is presented wherein the dynamics and probability distributions of the coupled thermoacoustic oscillator are described by a Langevin equation and its corresponding Fokker-Planck equation. The system identification method consists of fitting the analytical drift and diffusion coefficients to values that are estimated numerically by extrapolating the finite-time Kramers-Moyal coefficients to the short-time limit. This method is shown to be functional for the case of coupled standing modes but areas of improvement remain, in particular concerning computational efficiency. An alternative method of system identification based on iterative finite element solutions of the adjoint Fokker-Planck equation is shown to be unsuitable for coupled standing modes without significant further optimisation in the finite element step. Finally, an exploratory investigation into the system identification of coupled rotating modes at the same frequency is conducted. It is found that the transition probabilities in this case display unusual behavior that is unknown at this stage to be physically correct or due to error.
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Siddiqui, Nadeem Hasan. "Nested logit models for motorized and non-motorized modes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ48474.pdf.
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Siddiqui, Nadeem Hasan Carleton University Dissertation Engineering Civil and Environmental. "Nested logit models for motorized and non-motorized modes." Ottawa, 1999.
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Lu, Peng. "Adaptive Control of Waveguide Modes in Two-Mode Fibers." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/65006.
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Few mode fibers and multimode fibers (MMFs) are traditionally regarded as unsuitable for important applications such as communications and sensing. A major challenge in using MMFs for aforementioned applications is how to precisely control the waveguide modes propagating within MMFs. In this thesis, we experimentally demonstrate a generic method for controlling the linearly polarized (LP) modes within a two-mode fiber (TMF). Our method is based on adaptive optics (AO), where one utilizes proper feedback signals to shape the wavefront of the input beam in order to achieve the desired LP mode composition.
In the first part of this thesis, we demonstrate the feasibility of AO-based mode control by using the correlation between the experimentally measured field distribution and the desired mode profiles as feedback for wavefront optimization. Selectively excitation of pure LP modes or their combinations at the distal end of a TMF are shown. Furthermore, we demonstrate that selective mode excitation in the TMF can be achieved by using only 5×5 independent phase blocks.
Afterwards, we extend our AO-based mode control method to more practical scenarios, where feedback signals are provided by all-fiber devices such as a directional fiber coupler or fiber Bragg gratings (FBGs). Using the coupling ratio of a directional coupler as feedback, we demonstrate adaptive control of LP modes at the two output ports of the directional coupler. With feedback determined by the relative magnitude of optical power reflected by a FBG and the transmitted power, selective excitations of the LP01 and the LP11 modes are experimentally shown.
As the final component of this thesis, we experimentally combine the AO-based mode control with time-division-multiplexing. By choosing reflected pulses with appropriate arrival time for mode control, we can selectively excite the LP11 mode at different FBG locations within the TMF, based on the ratio of optical signals reflected by FBGs in the TMF and the transmitted signal. Using two lasers set at the two FBG peak reflection wavelengths associated with the LP01 and the LP11 modes, we can accomplish AO-based mode control within a TMF by using only the reflection signals from the FBG. By using the ratio of the reflected signals of two lasers as feedback, we demonstrate selective excitation of almost pure LP01 or LP11 mode at the FBG location within the TMF.
The method developed in this thesis is generic and can be extended to many other applications using appropriately chosen feedback signals. It is possible to generalize the AO-based mode control method to MMF as well. This method may find important applications in MMF-based communication, sensing and imaging et. al. in the future.Ph. D.
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Podgorny, Zachary Z. "Modes and Monikers." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306863829.
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Ngolele, Claude-Alexis. "Temporalité : modes d'accès." Université de Provence. Faculté des lettres et sciences humaines (1969-2011), 2008. http://www.theses.fr/2008AIX1A118.
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Mettre au jour les modes d'accès à la temporalité requiert que soit déterminé au préalable ce qu'est le temps. Car dans notre projet la temporalité est saisie à partir du temps comme précisément, l'appropriation de son déploiement par l'esprit humain. La première partie du traité répond à ce préalable à travers notre intérêt pour le Cronos homérique, les apories de Zénon, le mouvement aristotélicien ou la procession plotinienne. On a cherché à travers leurs approches, au-delà de la nature du temps, la trace de sa saisie comme expérience assumée ou vécue par le sujet. Faute d'une telle trace, nous avons ouvert la question aux différentes déterminations de l'existence humaine, à travers les approches psychologiques et sociales. De cette ouverture il ressort l'éclatement des modes d'accès et de déploiement, ce qui nous privent d'une donation privilégiée de la temporalité. Notre réponse à cette question des voies d'accès à la temporalité a consisté à investir les déterminations d'une existence accomplie et intégrale du sujet (pensant et agissant comme lieu où tous ces modes trouvent un écho. L'appréhension heideggérienne de la notion de souci, qui inscrit les temporalités psychologique et sociale comme genre d'être du Dasein existant, comporte toute la quintessence de notre conclusion.
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Yan, Zhang. "Control and observation of electric machines by sliding modes." Columbus, Ohio : Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1039227737.
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Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xv, 156 p.; also includes graphics (some col.). Includes abstract and vita. Co-advisors: Vadim I. Utkin, Giorgio Rizzoni, Dept. of Electrical Engineering. Includes bibliographical references (p. 153-156).
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Foster, David H. "Fabry-Perot and Whispering Gallery Modes In Realistic Resonator Models." Thesis, view abstract or download file of text, 2006. http://wwwlib.umi.com/cr/uoregon/fullcit?p3211216.
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Thesis (Ph. D.)--University of Oregon, 2006.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 204-213). Also available for download via the World Wide Web; free to University of Oregon users.
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Hussain, A. R. Q. "Model calculations of gap and local modes in alkali halides." Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373469.
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Roelofse, Emmalinde. "M3 strategic decision-making under uncertainty : modes, models, & momentum." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3909.
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The M3 theory contributes to new knowledge through original research and advanced scholarship by introducing a descriptive framework for strategic decision-making in uncertain and changing environments. Aided by the introduction of a Social Realism epistemology into management literature it is differentiated its ability to present complex strategic positions as essentialist (via modes), relative (via models), and dynamic (via momentum) to plot the dynamic trajectory of innovation emergence, change, adaptation and transformation over time. At a fundamental level, the M3 theory identifies a consistent set of rules that decision-makers intentionally or unintentionally engage with or ignore to take strategic positions based on four integrated yet polarized pairs of modes: systematic (+S) vs. responsive (+R) strategies, and conforming (+C), vs. differentiating (+D) strategies. Systematic strategies (+S) is the mode dedicated to increasingly sophisticated rational cognitive processes; these processes plan, purposefully compartmentalize, and regulate emotions. Responsive strategies (+R) conversely, is the mode dedicated to increasingly sensitized intuitive processes; these processes are reflective, associative, action-orientated and emotionally expressive. The second pair of modes intersects with the two aforementioned modes with conforming strategies (+C) moving towards convergence by adapting or conveying socially perceived superior norms; these processes include the exploitation of existing power. In contrast, differentiating strategies (+D) represents the mode dedicated to diverging from traditional norms with empowerment for exploration. These processes include novelty-seeking, sabotage, risk-taking, experimentation, play, flexibility, discovery, and higher levels of innovation. Finally, the dynamic (momentum) component informs how strategic modes and models under uncertainty improve and adjust in sophistication under the pressure and demands of the four drives (+L). The M3 theory is informed by three distinct but interrelated and simultaneous empirical streams of data: (i) field data from five ethnographic case studies, with research participant feedback loops; (ii) the mapping of 200+ peer reviewed decision-making models; and (iii) prototyping the principles in the construction of the emergent M3 theory.
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Rafele, Antonio. "À rebours : motifs du regard et de l'expérience des modes de vie." Paris 5, 2008. http://www.theses.fr/2008PA05H070.
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La mode est un regard qui se produit à partir de l'expérience de certains processus historiques : le développement de la métropole et des médias du XIXéme siècle. La naissance de ce regard est donc liée au pouvoir social acquis par la métropole et par les différents médias, qui, dans l'ensemble, constituent un groupe homogène d'images historiques parce qu'ils sont unis par une accélération du temps. L'accélération du temps ôte aux choses leur linéarité et leur durée. L'attention se déplace continuellement sur leur naissance et sur leur mort. Une continuelle construction et destruction de choses est exhibée et vécue. La splendeur et la caducité constituent, en même temps, le mécanisme et le but de la vie ; par contrecoup, cette dernière devient une succession d'instants vécus ou morts. Immersion, sortie et retour posthume constituent le processus à la fois experiencielle et mnémonique qui caractérise le rapport avec les choses. Les différentes choses du monde devront être alors perçues comme des illusions ou des accoutumances qui absorbent et occupent le temps du moi, mais seulement pour une période donnée. La vie s'accomplit non pas en tant qu'expérience vitale mais comme expérience de mort. C'est précisément dans ce sens-là, que la mode, en tant que grand mécanisme ludique de création et de destruction d'accoutumances, devient l'image clé à la fois pour l'expérience et pour le regard qui se produit sur celle-ciFashion and lifestyle are a gaze produced by the experience of determined historical processes : development of metropolis and media in 19th century. The birth of this gaze is connected to the social power accumulated by metropolitain cities and various medias. Their homogeneous structure of historical images is determined by the phenomenon of time acceleration that removes the linearity and duration of the things. Attention is instead focused on their birth and death. Things are under a continuous construction and destruction, experienced and exhibited. Splendour and nullity constitute, at the same time, the mechanism and the goal of life which by-effect becomes a simple succession of instants, dead or alive. Immersion, exit and posthumous return constitute the alltogether existential and mnemonic process caracterizing our ralation to things. Therefore, different things can only be perceived as short time illusions and habituations. Life achieves itself not as vital experience but as experience of death. It is precisely in this means that lifestyle, defined as ludic mechanism of creation and destruction of habituations, becomes the key-image for the experience and the gaze directed on itself
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Santamaría, Sotillo Beatriz, and Shuang Ni. "Entry Modes of Starbucks." Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-857.
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Topic:When an MNC seeks to enter a foreign country, it must choose the most appropriate entry mode for that specific market, such as exporting, licensing, a turnkey project, franchising, joint ventures or wholly-owned subsidiaries. There are many factors which affect the choice of entry modes. Influential factors contributing to the entry mode decision can have different degrees of impact for each particular country. As a consequence, an MNC has to use different entry modes in order to adapt to the specific situations it faces in its international expansion strategy.
Research Problem: Our research problem is to find the answer to two specific research questions while investigating in a particular MNC: Starbucks. The relevant questions are: (1.) What factors affected Starbucks’ entry mode decisions? (2.) Which entry mode strategies did Starbucks use foreign markets and why?
Method: We collected data through a qualitative method. We regarded that a qualitative research method would provide us the necessary data to understand entry mode decisions. We collected data through literature, books, journals, and Internet resources. We have decided to focus our qualitative research on exploring Starbucks’ entry mode decision in some specific markets. In particular, we have concentrated on Spain, New Zealand and the United Kingdom.
Conclusions: The choice of entry mode is a critical decision made by MNCs. The choice is influenced by several factors; we have divided these into internal and external factors. We have found both groups are important in the decisions made by Starbucks. However, the degree of influence is different in each case. Moreover, it is possible that some influential factors in the choice of entry mode can differ by case. Finally, we have found external factors have been critical in affecting Starbucks’ choice of entry modes. Starbucks has sought to adapt to those external factors and local needs and requirements by using different entry modes.
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Mamboukou, Michel Nzikou. "The Earth's Slichter modes." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Physics and Astronomy, c2013, 2013. http://hdl.handle.net/10133/3387.
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Numerical methods have been used to predict the eigenperiods and eigenfunctions of the
Earth’s Slichter modes, known as the Slichter triplets. In order to test the validity of our
method, we have also computed the frequencies and displacement eigenfunctions of some of
the inertial modes of the Earth’s fluid core. We use a Galerkin method to integrate the Three
Potential Description (3PD) for a neutrally, stratified and rotating fluid core of a modified
Preliminary Reference Earth Model (PREM). Moreover, the same mathematical tool is used
for the computation of the frequencies and displacement amplitudes of the Slichter modes.
In the Galerkin formulation of the 3PD, using the divergence theorem, we make use of the
natural character of the boundary conditions to reduce the order of derivatives from second
to first. To compute the frequencies of the Slichter modes, we solve simultaneously the
equations of the inner core motion and the dynamics of the fluid core as described above.
The results are compared to those in previous studies and it is shown that in the case of the
inertial modes they agree well, which proves the validity of the approach. For the Slichter
modes, however, it is shown that the results are significantly different from previous work
for a similar Earth model. We have also plotted the displacement eigenfunctions for the
motion of the fluid in the fluid core during the Slichter oscillations. It is shown that the
pattern of motion is consistent with the motion of the inner core, which serves as a second test of the validity of our results.x, 105 leaves : ill. ; 29 cm
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Beau, Anne-Sophie Schweitzer Sylvie. "Grand Bazar, modes d'emploi." [S.l.] : [s.n.], 2001. http://theses.univ-lyon2.fr/sdx/theses/lyon2/2001/beau_as.
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Tran, Dinh Hai. "Atmospheric model and data analysis in terms of empirical normal modes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0024/NQ50323.pdf.
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Acuña, Vicente. "Models and algorithms for metabolic networks: elementary modes and precursor sets." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00850705.
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In this PhD, we present some algorithms and complexity results for two general problems that arise in the analysis of a metabolic network: the search for elementary modes of a network and the search for minimal precursors sets. Elementary modes is a common tool in the study of the cellular characteristic of a metabolic network. An elementary mode can be seen as a minimal set of reactions that can work in steady state independently of the rest of the network. It has therefore served as a mathematical model for the possible metabolic pathways of a cell. Their computation is not trivial and poses computational challenges. We show that some problems, like checking consistency of a network, finding one elementary mode or checking that a set of reactions constitutes a cut are easy problems, giving polynomial algorithms based on LP formulations. We also prove the hardness of central problems like finding a minimum size elementary mode, finding an elementary mode containing two given reactions, counting the number of elementary modes or finding a minimum reaction cut. On the enumeration problem, we show that enumerating all reactions containing one given reaction cannot be done in polynomial total time unless P=NP. This result provides some idea about the complexity of enumerating all the elementary modes. The search for precursor sets is motivated by discovering which external metabolites are sufficient to allow the production of a given set of target metabolites. In contrast with previous proposals, we present a new approach which is the first to formally consider the use of cycles in the way to produce the target. We present a polynomial algorithm to decide whether a set is a precursor set of a given target. We also show that, given a target set, finding a minimal precursor set is easy but finding a precursor set of minimum size is NP-hard. We further show that finding a solution with minimum size internal supply is NP-hard. We give a simple characterisation of precursors sets by the existence of hyperpaths between the solutions and the target. If we consider the enumeration of all the minimal precursor sets of a given target, we find that this problem cannot be solved in polynomial total time unless P=NP. Despite this result, we present two algorithms that have good performance for medium-size networks.
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Tran, Dinh Hai 1966. "Atmospheric model and data analysis in terms of empirical normal modes." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35504.
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The Empirical Orthogonal Function (EOF) analysis technique has proven to be one of the most powerful methods to analyze data in meteorology and many other fields. However, this method is statistical only and has no physical basis. Brunet (1994) has introduced Held's (1985) concept of conservation of wave activity and orthogonal functions into the EOF analysis and called it the "Empirical Normal Mode" (ENM) analysis technique. This new method uses both statistical concepts from the classical EOF analysis method and a dynamical constraint from the generalized Eliassen-Palm theorem to ensure that the functions that we obtained are orthogonal to each other and are the solutions of linearized dynamical equations.In this thesis, we use the ENM analysis to analyze data from both a (2D) shallow water model integration and from 3-D atmospheric observations, with an emphasis on stratospheric sudden warming events.
For the shallow water model case, the results of the ENM analysis are evaluated by testing against the theoretical (numerical) normal mode solutions provided by Longuet-Higgins (1968). It is shown that the ENM analysis can recover the spatial structures and the frequencies of the normal modes with a great degree of accuracy if the temporal record is sufficiently long. The average errors in the periods for 2000 and 100 day time series are found to be 1% and 4.6%, respectively. From the eigenvalues (percentage of the total variance) and sharp frequency peaks associated with normal modes, the ENM analysis shows that the model generates only a few modes with monochromatic frequencies. The method can be used to test a new or modified shallow water model integration or to study other Hough modes generated by different kinds of forcings.
Having shown the value of the ENM technique in a barotropic context, we advance further by performing an ENM analysis on an 11 year atmospheric data set. In this study, we focus on stratospheric warming events. The winter (DJF) data set is partitioned into warming and non-warming periods in order to characterize the flow differences between the regimes. The stratospheric quasi-potential vorticity or wave activity structure in the warming period is found to be much stronger, as expected, than in the non-warming periods. The ENM analysis clearly shows the tropospheric difference between the two periods, e.g., a higher wave activity in the main tropospheric structure as well as in the tropospheric polar regions in the warming periods. The analysis also reveals that there is a higher level of stratospheric wave activity during the warming periods in the second normal mode of zonal wave number 1 but the tropospheric structures of the quasi-potential vorticity are the same as during non-warming periods. This suggests that there is/are (a) mechanism(s) associated with the stratospheric warming other than the upward wave propagation. All the common features of the stratospheric warming event are captured by the first two normal modes of zonal wave numbers 1 and 2, such as wave-mean flow interaction leading to the deceleration of the zonal mean wind, the polar vortex being displaced by the northward movement of the Aleutian High, as well as wave amplitude enhancement/reduction during the growing/decaying stages.
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NETO, ELVIDIO GAVASSONI. "APPLICATION OF NONLINEAR VIBRATION MODES TO CONCEPTUAL MODELS OF OFFSHORE STRUCTURES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21272@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Estruturas offshore têm demandado, em função do aumento da profundidade da lâminha de água e da severidade do ambiente, análises de vibração cada vez mais confiáveis. Em face de oscilações com grandes deslocamentos, torna-se imprescindível uma análise não linear dessas estruturas. Métodos numéricos como os elementos finitos constituem-se numa tarefa computacionalmente custosa, uma vez que os acoplamentos modais tornam necessários modelos com muitos graus de liberdade. Isso dificulta as análises paramétricas e prolonga os ciclos de projeto para estruturas offshore. Uma alternativa a esses problemas é o uso de modelos de ordem reduzida. Os modos normais não lineares têm-se mostrado uma ferramenta eficiente na derivação de modelos de ordem reduzida para análises de vibrações não lineares. Isso ocorre porque um número menor de modos não lineares, em relação aos modelos com modos lineares, é necessário para se obter o mesmo nível de precisão num modelo reduzido. Esse trabalho utiliza modelos de ordem reduzida, obtidos por meio de análise modal não linear, para o estudo de vibração de modelos simplificados de estruturas offshore. Três exemplos de aplicação são utilizados: pêndulo invertido, torre articulada e plataforma spar. Além dos métodos baseado no procedimento de Galerkin e o assintótico, um procedimento numérico alternativo é proposto para obtenção dos modos, podendo ser utilizado para construção dos modos essencialmente não lineares. As vibrações livres e forçadas são estudadas. A estabilidade das soluções é analisada utilizando-se a teoria de Floquet, diagramas de bifurcação e de Mathieu e seções de Poincaré. As seções de Poincaré são também utilizadas para identificar a multiplicidade dos modos não lineares e a existência de multimodos. Os resultados são comparados com a solução obtida da integração numérica do sistema original de equações, mostrando uma boa precisão dos modelos reduzidos.
The increasing water depth and the ocean adverse environment demand more accurate vibration analysis of offshore structures. Due to large amplitude oscillations, a nonlinear vibration analysis becomes necessary. Numerical methods such as finite element constitute a computationally expensive task when applied to these problems, since the occurrence of modal coupling demands a high number of degrees-of-freedom. A feasible possibility to overcome these difficulties is the use of low order models. The nonlinear normal modes have been shown to be an effective tool in the derivation of reduced order models in nonlinear dynamics. In the use of nonlinear modal analysis fewer modes are required to achieve a given level of accuracy in comparison to the use of linear modes. This work uses the nonlinear normal modes to derive low dimensional models to study the vibration of simplified models of offshore structures. Three examples are considered: an inverted pendulum, an articulated tower and a spar platform. Both free and forced vibrations are studied. The asymptotic and Galerkin-based methods are used to derive the normal modes. In addition, an alternative numerical procedure to construct such modes is proposed, which can be used to derive coupled modes. The solution stability is determined by the use of the Floquet theory, bifurcation and Mathieu diagrams, and Poincaré sections. The Poincaré sections are also used to investigate the multiplicity of modes and multimodes. The results obtained from the numerical integration of the original system are favourably compared with those of the reduced order models, showing the accuracy of the reduced models.
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Ma, Leixin. "Using superposition of undamped modes to model non-orthogonally damped systems." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111714.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 76-78).
In many structural vibration problems non-orthogonal damping leads to coupling between modes, rendering simple normal mode superposition solutions not sufficiently accurate. The flow-induced vibration of drilling and production risers used in the offshore petroleum industry is an example of such a structure. The uneven distribution of hydrodynamic damping often results in non-orthogonal damping. The most common solution technique, pioneered by Lord Rayleigh, is to construct the solution as a simple superposition of normal modes, achieved by simply ignoring the off-diagonal terms introduced by the modal damping matrix. This approach is often not sufficiently accurate when used to predict the fatigue damage rate of marine risers exposed to common ocean currents. In many cases an accurate solution may be constructed by using complex modes which include the coupling created by the non-orthogonal damping. Though accurate the complex mode approach is computationally not very efficient. This problem is made more severe by the inherent non-linear nature of flow-induced vibration, in which the magnitude of the periodic excitation from vortex shedding is dependent on the displacement response amplitude. For each riser design it is common to make thousands of fatigue life predictions corresponding to widely varying ocean current profiles. Therefore, the numerical techniques used to make the predictions need to be both efficient and accurate. Simple normal mode superposition is efficient but often not sufficiently accurate due to the influence of non-orthogonal damping. Mode superposition using complex modes is accurate but much less numerically efficient. The goal of this research was to develop an analysis method with the efficiency of simple normal modes and the accuracy of complex modes. A solution using undamped normal modes is presented with realistic examples. A linear, tensioned, homogeneous beam under various damping distributions is chosen as a numerical example. Based on the pseudo force iteration method, a frequency domain, corrected normal mode superposition is formulated. The computed response is compared to that computed from direct numerical integration and complex mode superposition. Comparisons show that the corrected undamped normal mode superposition solution is accurate and very efficient.
by Leixin Ma.
S.M.
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Rauchenstein, Werner J. "A 3D Theodorsen-based rotor blade flutter model using normal modes." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FRauchenstein.pdf.
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Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, September 2002.Thesis advisor(s): E. Roberts Wood, Mark A. Couch. Includes bibliographical references (p. 55-56). Also available online.
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Acuna, Vicente. "Models and algorithms for metabolic networks : elementary modes and precursor sets." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10082/document.
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In this PhD, we present some algorithms and complexity results for two general problems that arise in the analysis of a metabolic network: the search for elementary modes of a network and the search for minimal precursors sets. Elementary modes is a common tool in the study of the cellular characteristic of a metabolic network. An elementary mode can be seen as a minimal set of reactions that can work in steady state independently of the rest of the network. It has therefore served as a mathematical model for the possible metabolic pathways of a cell. Their computation is not trivial and poses computational challenges. We show that some problems, like checking consistency of a network, finding one elementary mode or checking that a set of reactions constitutes a cut are easy problems, giving polynomial algorithms based on LP formulations. We also prove the hardness of central problems like finding a minimum size elementary mode, finding an elementary mode containing two given reactions, counting the number of elementary modes or finding a minimum reaction cut. On the enumeration problem, we show that enumerating all reactions containing one given reaction cannot be done in polynomial total time unless P=NP. This result provides some idea about the complexity of enumerating all the elementary modes. The search for precursor sets is motivated by discovering which external metabolites are sufficient to allow the production of a given set of target metabolites. In contrast with previous proposals, we present a new approach which is the first to formally consider the use of cycles in the way to produce the target. We present a polynomial algorithm to decide whether a set is a precursor set of a given target. We also show that, given a target set, finding a minimal precursor set is easy but finding a precursor set of minimum size is NP-hard. We further show that finding a solution with minimum size internal supply is NP-hard. We give a simple characterisation of precursors sets by the existence of hyperpaths between the solutions and the target. If we consider the enumeration of all the minimal precursor sets of a given target, we find that this problem cannot be solved in polynomial total time unless P=NP. Despite this result, we present two algorithms that have good performance for medium-size networks
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Lang, Gérald. "Du mode d'existence des modes managériales : étude d'un cas de reengineering." Palaiseau, Ecole polytechnique, 1999. http://www.theses.fr/1999EPXX0053.
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Les modes managériales se succèdent (cercles de qualité, qualité totale, reengineering, etc. ). Les théoriciens du phénomène (Abrahamson, Kieser) étudient leur invention, leur rhétorique, leur diffusion et leur déclin. Ils analysent leur marche. Reste à comprendre leur mode opératoire dans le changement des entreprises, leur mode d'existence. Quel rôle exact les modes jouent-elles dans la dynamique organisationnelle ? La thèse s'efforce de répondre à cette question. La méthode adoptée a été celle de l'étude de cas. Une mode a été choisie, celle du reengineering, et une entreprise exemplaire a été retenue. Eloignée a priori du phénomène de mode, elle a adopte un programme international de changement inspire du reengineering. Le chercheur a été observateur-participant durant deux ans. La thèse a conduit a une série de résultats. La mode managériale se présente à l'entreprise en deux temps : la décision de l'adopter ou non, et la mise en œuvre. Lors de l'adoption, deux dimensions jouent : l'application d'un test de compatibilité entre la rhétorique de la mode et la culture de l'entreprise et le moment de l'adoption de la mode (défini comme l'intersection entre la trajectoire propre à la mode et la trajectoire propre à l'entreprise). Lors de la phase de mise en œuvre, une fois la mode adoptée, plusieurs facteurs jouent un rôle : les techniques propres à la mode. Et leur articulation avec les idées d'expérience forgées dans l'entreprise. Pour que cette articulation soit possible, il faut que les techniques aient un certain caractère d'ouverture, d'indétermination. En pratique, l'articulation s'opère dans des dispositifs organisationnels adaptes. Dans la dynamique des modes managériales, les consultants jouent un rôle déterminant par leur capacité à opérer sur différents registres, à ouvrir le jeu politique, à mettre en place l'articulation entre techniques externes et idées d'expérience.
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Sun, Yifan. "Theory of mode-locked lasers based on non-conventional cavity modes." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASP003.
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Cette thèse de doctorat porte principalement sur la dynamique et la robustesse d’un nouveau concept de verrouillage de mode dans les nanolasers semi-conducteurs ultracompacts. Un tel nanolaser présente des modes ermites-gaussiens créés par une cavité photonique harmonique pour confiner la lumière. Cela permet de mapper la cavité optique en oscillateur harmonique de mécanique quantique, avec des fréquences propres régulièrement espacées, une condition essentielle pour le verrouillage de mode. La période de verrouillage de mode est contrôlée par la conception du potentiel photonique, et non par la longueur de la cavité. Les régimes non linéaires possibles sont décrits par l’équation de Gross-Pitaevskii avec un potentiel parabolique et des termes non linéaires décrivant le gain et l’absorption. Pour étudier ces comportements dynamiques, des simulations numériques directes sont principalement mises en œuvre. Tout d’abord, la compétition de mode pour le gain entre les modes ermites et gaussiens en l’absence d’absorption saturable est étudiée. Deuxièmement, on prévoit que le verrouillage des modes se produira avec une saturation instantanée du gain et de l’absorption sur un large éventail de paramètres, correspondant à l’émergence d’une soliton dissipative. Troisièmement, dans le régime de saturation non instantanée du gain et de l’absorption, différents comportements dynamiques du nanolaser sont obtenus en faisant varier le gain et l’absorption. Ces différents régimes, y compris la commutation Q, le verrouillage de mode à commutation Q et le verrouillage de mode CW, sont décrits en détail. L’influence du facteur Henry sur le verrouillage de mode est également abordée. Quatrièmement, la robustesse du verrouillage de mode des modes ermite et gaussien au désordre de la cavité harmonique est étudiée en détail, y compris l’effet de la non-parabolicité du potentiel et les erreurs aléatoires dans la forme du potentielThis PhD thesis mainly addresses the dynamics and the robustness of a novel concept of mode locking in ultracompact semiconductor nanolasers. Such a nanolaser exhibits Hermite-Gaussian modes created by a harmonic photonic cavity to confine light. This maps the optical cavity into quantum mechanical harmonic oscillator, with evenly spaced eigenfrequencies, an essential requirement for mode locking. The possible nonlinear regimes are described by the Gross-Pitaevskii equation with a parabolic potential and nonlinear terms describing gain and absorption. To investigate these dynamical behaviors, direct numerical simulations are mainly implemented. Continuation calculations are also performed using pde2path.First, the mode competition for gain among Hermite-Gaussian modes in the absence of saturable absorption is investigated and shown to be very different from usual resonators.Second, mode locking is predicted to occur with instantaneous saturation of gain and absorption over a broad range of parameters, corresponding to the emergence of dissipative soliton and multisoliton solutions. The mode locking period is controlled by the design of the photonic potential, and not by the cavity length. The dissipative soliton is well described by the coherent state of a quantum mechanical oscillator, namely a Gaussian envelope oscillating without deformation.Third, in the regime of noninstantaneous gain and absorption saturation, different dynamical behaviors of the nanolaser are obtained by varying the gain and the absorption. These different regimes, including Q-switching, Q-switched mode locking, and CW mode locking, are described in detail, illustrating the rich physics of this nonlinear system. The influence of the Henry factor on the mode locking is also discussed. Moreover, similar dynamical behaviors using spatially separated gain and absorber sections inside the cavity are obtained.Fourth, the robustness of mode locking of the Hermite-Gaussian modes to the disorder of the harmonic cavity is investigated in details. It includes the effect of non-parabolicity of the potential and the random errors in the shape of the potential
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Baxter, Bradley. "Control of a microgrid in islanded mode and Grid-connected modes." Thesis, Baxter, Bradley (2014) Control of a microgrid in islanded mode and Grid-connected modes. Other thesis, Murdoch University, 2014. https://researchrepository.murdoch.edu.au/id/eprint/25566/.
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Microgrids are small electrical power distribution networks that can be connected to a main utility power grid, or can operate in disconnected or islanded mode. They offer a potential solution to the world’s reliance on fossil fuel sourced electrical energy generation. They can improve energy security and reliability for customers connected to the microgrid. Microgrids usually incorporate distributed energy sources, including renewable sources. Many of the renewable sources are interfaced with power electronics which must be able to operate in conjunction with traditional forms of generation such as synchronous generators. Control of power electronic interfaced energy sources can pose challenges for coordinated control of the microgrid as a whole. The control systems main function is to ensure supply to critical loads is maintained, particularly when in islanded mode. This study investigated several strategies for control and management of a microgrid, including taking over voltage and frequency control in islanded mode.
The distributed nature of energy sources that usually makes up a microgrid favours a control system with minimal communication infrastructure and that for the most part operates autonomously in both a grid connected and islanded mode. The current study investigated the general concepts for control of both centralised and decentralised configurations of a microgrid and the problems associated with each. In-depth investigations and simulations were carried out on two decentralised control strategies, a pure droop control method and an angle-frequency droop control method.
The pure droop controller had the ability to autonomously perform equal power sharing and maintain stability in islanded mode of operation, but resulted in permanent steady state frequency offset. The angle-frequency droop also operated autonomously but with improved power sharing and frequency regulation.
The investigation used the MATLAB® environment to perform calculations and carry out simulations of the proposed systems over a range of grid connected and islanded mode scenarios. Performance measures such as power sharing accuracy, disturbance transient behaviour and islanded-grid connection transition were used to assess the suitability of each control scheme.
The P-f droop control has been widely reported on and has been proven to work over a range of conditions. The angle-frequency droop is a new proposal to improve the performance of a microgrid in islanded mode. Results demonstrated that both methods of control performed well in islanded mode. The angle-frequency droop had a slight increase in power sharing accuracy and superior frequency regulation. However it would appear that several design flaws may need addressing before the angle-frequency droop can be implemented as a truly decentralised topology.
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Balucan, Phillip James 1977. "Model reduction of a set of elastic, nested gimbals by component mode selection criteria and static correction modes." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/17520.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 112-113).
Model reduction techniques provide for a computationally inexpensive method for solving elastic dynamic problems with complex structures. The elastic nested gimbal problem is a problem which requires model reduction techniques as a means to reduce the dynamic equations. This is done using two methods: one technique employs mode ranking criteria to select modes which influence the dynamics of the problem the most. The second involves the use of static correction modes along with vibration modes to simulate the dynamics of this nested gimbal model. A model of the structure is described in terms of a lumped-parameter finite element model. This mathematical model of the physical system serves as the ha.sis for developing model reduction techniques for the nested gimbal problem. A truth model based on given initial conditions is used to compare the accuracy of the model reduced problem. A number of model reduction theories are described and applied to the gimbal simulation. The equations for the mode ranking techniques and the static and vibration mode analysis are developed as well as a quantitative error measure. Comparisons are made with the truth model using the mode ranking criteria base on the momentum coefficients and the frequency cutoff criteria. Test cases are also run using the static correction modes with vibration modes and static correction modes with the ranked vibration modes using momentum coefficients. The use of various static modes is discussed during the implementation of the static correction mode method. Applying the model reduction theories to a set of elastic, nested gimbals, the mode ranking criteria provides better results based on the error measure than the frequency cutoff criteria when the simulation is run using less than twenty-five modes. Using static modes along with ranked modes to represent the elastic dynamics of the problem does not provide better results than using the unranked vibration modes with the static modes. Modeling the dynamics using static correction modes with the unranked vibration modes provides the best results while using the lea.st number of modes. It is advantageous to take into account the given conditions applied to the system when reducing the model of a complex dynamic problem.
by Phillip James Balucan.
S.M.
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ElRif, Paul. "An examination of matched acquisition and recall modes versus mismatched acquisition and recall modes /." Thesis, Connect to Dissertations & Theses @ Tufts University, 1999.
Find full textAbstract:
Thesis (Ph.D.)--Tufts University, 1999.Adviser: Salvatore Soraci. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 174-183). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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De, Martino Danilo. "String inflationary models with non-monotonic slow-roll and detectable tensor modes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8391/.
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The first chapter of this work has the aim to provide a brief overview of the history of our Universe, in the context of string theory and considering inflation as its possible application to cosmological problems. We then discuss type IIB string compactifications, introducing the study of the inflaton, a scalar field candidated to describe the inflation theory. The Large Volume Scenario (LVS) is studied in the second chapter paying particular attention to the stabilisation of the Kähler moduli which are four-dimensional gravitationally coupled scalar fields which parameterise the size of the extra dimensions. Moduli stabilisation is the process through which these particles acquire a mass and can become promising inflaton candidates. The third chapter is devoted to the study of Fibre Inflation which is an interesting inflationary model derived within the context of LVS compactifications. The fourth chapter tries to extend the zone of slow-roll of the scalar potential by taking larger values of the field φ. Everything is done with the purpose of studying in detail deviations of the cosmological observables, which can better reproduce current experimental data. Finally, we present a slight modification of Fibre Inflation based on a different compactification manifold. This new model produces larger tensor modes with a spectral index in good agreement with the date released in February 2015 by the Planck satellite.
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Hägg, Gustav, Niklas Jonsson, and Josefine Björk. "Entry Modes - A banking perspective." Thesis, Halmstad University, School of Business and Engineering (SET), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1787.
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In the European Union the borders are being wiped out and this is creating new business markets for companies that before never had dreamt of going international. Today we see it as natural that companies act world-wide to gain success and increase the growth and profit. They need to do this to be competitive on the ever changing market that we have nowadays. One of the most important things to have in mind when thinking of expanding to other countries is which entry mode to choose. There are several ways of entering a market and if you do it right you might be very successful, but if you do not spend time on this decision the internationalization process can become very short and the company can lose a lot of capital. With this thesis we want to investigate how two large Scandinavian banks made their presence into the Baltic market in the mid 90’s, which kind of entry modes they went for and if one of them made a wiser choice than the other. In the thesis we have also gone in to the factors that have been of high importance when making the decision on why they chose the Baltic market and also which kind of entry mode. Our main findings after having made this thesis is that it was the profit and growth potential that was the main driving force for establishing on the Baltic market, but also the short distance and the low costs of going in on the market. The choice of entry mode differs between the two banks and that was expected since they have different strategies when going international. And even the know-how of the market in question and resources of the company have been important factors.
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Gentile, Martin James. "Exciton polariton modes in nanostructures." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/21872.
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In this thesis, original theoretical and numerical investigations into the interaction of light with excitonic nanostructures are presented, in a bid to demonstrate that excitonic nanostructures are viable alternatives to the use of plasmonic nanostructures where electric field enhancement and confinement are sought. In particular, the field enhancement and confinement around excitonic nanostructures on resonance is shown to be comparable if not in excess of that around noble metal nanoparticles such as gold and silver. These excitonic modes, when set in the context of a core-shell geometry, are shown to offer tunability through nanoparticle design and through the index of the environment. In addition, hybrid `hyperbolic' and `plexcitonic' modes are shown to offer similar properties in metallic-excitonic nanostructures. Altogether, these excitonic and hybrid excitonic modes are shown to have potential in nanophotonic applications.
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Gray, John T., of Western Sydney Nepean University, and Faculty of Business. "Organising modes of law firms." THESIS_FBT_XXX_Gray_J.xml, 1998. http://handle.uws.edu.au:8081/1959.7/292.
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This thesis examines why law firms are organised as they are. It develops a theoretical framework of reflexive archetype theory which is constructed from structuring theory (Ranson, Hinings and Greenwood 1980), archetype theory (Hinings and Greenwood 1988), and circuits of power theory (Clegg 1989). It emphasises the reflexivity and integration of the process of organising within law firms. Empirical data are collected from fifteen Sydney law firms and interpreted within reflexive archetype theory. These data confirm the reflexivity and integration of elements within law firms that are theoretically postulated. A research agenda is developed and the contributions of the thesis to the field of organisational analysis are enumerated.Doctor of Philosophy (PhD)
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Carter, Alexander Joel. "Two fluid viscoresistive ballooning modes." Thesis, University of York, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534928.
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Gogala, Marko. "Active modes of the translocon." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-180555.
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All proteins are synthesized in the cytoplasm. However some proteins function outside of cells, in the cell membrane, in the endoplasmic reticulum or one of the connected vesicular systems and need to be sorted and accordingly transported. Consequently, the secretory pathway, a highly conserved protein targeting, translocation and membrane insertion system has evolved to cope with this task. The central actor in the secretory pathway is the heterotrimeric Sec61αβγ protein complex also known as the translocon. This protein complex has been shown to act as a transmembrane channel facilitating protein translocation into the lumen of the endoplasmic reticulum, a starting point in protein secretion. The complex also contains a lateral opening, termed ‘lateral gate’ through which proteins have been suggested to insert into the membrane of the endoplasmic reticulum. The mechanics of translocon opening for protein secretion or membrane insertion has been a matter of debate.
The results presented here show secondary structure level resolution cryo-electron microscopic structures of the translocon in complex with stalled ribosome-nascent chain complexes carrying substrates with propensity for either secretion or membrane insertion as well as ribosome-bound inactive translocon molecules. The observed differences in secondary structure suggest a model for translocon activity in protein sorting.
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Sessford, Joanna Ruth. "Failure Modes of Organic Devices." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502300.
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Research into Organic Electronics has increased dramatically over the past 20 years. Organic Electronics cannot compete with single crystal silicon for speed and circuit complexity, but it can be regarded as a competitor because of its potential to produce very large area circuits at low process temperatures and low cost. Potential applications for conjugated polymer devices include photovoltaic cells (low cost solar panel), optical amplifiers, memory, displays (in conjunction with e-paper and large area LCD's) and radio frequency (RFID). Many of these devices will use Thin Film Transistors (TFTs). TFT characteristics are therefore discussed with 'an emphasis on the hysteresis observed; the results observed indicate that one ofthe causes ofhysteresis is ion movement. A number of different current-voltage equations have been derived for the drain current channel. It is important to develop these equations to determine the effect of treating the real variation in the concentration of carriers, normal to the interface. In addition, how this large variation in the density of carriers gives rise to an enhancement of carrier mobility at the interface is approached, has been examined. It has been shown that for devices fabricated using PTAA; the most appropriate equation is that which assumes the exponential distribution of states depends on electron concentration. MOS capacitors are important test structures; they are useful because of the light they shed on electrical instability in organic devices, MOS capacitors characteristics have therefore been discussed before the hysteresis they display has been examined. The following mechanisms of hysteresis in MOS capacitors have been examined: carrier hopping, carrier percolation, gate leakage current, ion movement in the semiconductor and instability in the gate dielectric. The main causes of instability appear to be oxygen ions in the semiconductor and in the gate dielectric. The hysteresis observed in Schottky diodes has also been examined; contributing factors appear to include ion movement and diffusion. Values for Meyer Neldels energy for ; . Schottky diodes fabricated using Lisicon (undoped) have been calculated to be 5.0.10-21 ; this value increases when dopant is added; this is expected as doping introduces more states and at high levels of doping leads to Fermi level pinning. As Organic Electronics is growing rapidly into an industry, it is vital to have aroadmap; to allow equipment manufacturers and semiconductor technologists to plan targets for the future, this piece of work provides a roadmap for Organic Electronics. One of the major potential uses of Organic Electronics is believed to be in the area of auto hI/rf tags, for example, the replacement of the barcode, the roadmap therefore concentrates on this area; it has been predicted that by the year 2030 full barcode replacement will be available at an economic cost.
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Duan, Yuting. "Trapped modes and acoustic resonances." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/12860.
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The scattering of waves by a finite thin plate in a two-dimensional wave guide and an array of finite thin plates, in the presence of subsonic mean flow, are formulated using a mode matching technique. The influence of mean flow on trapped modes in the vicinity of a finite thin plate in a two-dimensional wave guide is then investigated by putting the amplitude of the forcing term to zero in the scattering problem. The conditions for complex resonances are found, and numerical results are computed. The influence of mean flow on Rayleigh-Bloch modes is investigated by using a similar methodology. The condition for embedded trapped modes to exist is introduced next, and then numerical results for embedded trapped modes without mean flow are presented. Complex resonances without mean flow are then found by fixing the geometry of the waveguide. The influence of mean flow on complex resonances and embedded trapped modes is investigated subsequently. In addition, the investigation of scattering coefficients is discussed when the frequency of an incident wave is near the real part of the frequency of complex resonances or embedded trapped modes. Embedded trapped modes near an indentation in a strip wave guide, which may correspond to a two-dimensional acoustic wave guide or a channel of uniform water depth in water waves, are also found. Modes are sought which are either symmetric or anti-symmetric about the centreline of the guide and the centre of the indentation. In each case, a simple approximate solution is found numerically. Full solutions are then found by using a Galerkin approach in which the singularity near the indentation edge is modelled by choosing proper special functions. The final part of the thesis is devoted to spinning modes (Rayleigh-Bloch modes) in a cylindrical waveguide in the presence of radial fins. A mode matching technique is used to obtain the potential, and the coefficients in the expansion are found numerically by using an efficient Galerkin procedure. In addition, an existence proof for modes symmetric about the centre of the guide and the centre of the section with radial fins is given by applying a variational approach. The connection between Rayleigh-Bloch modes and trapped modes is discussed thereafter, and numerical results for a number of geometric configurations are presented.
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Giammatteo, Massimiliano. "Quasinormal modes of black holes." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397532.
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Mansuripur, Masud, Miroslav Kolesik, and Per Jakobsen. "Leaky modes of dielectric cavities." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622709.
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In the absence of external excitation, light trapped within a dielectric medium generally decays by leaking out-and also by getting absorbed within the medium. We analyze the leaky modes of a parallel-plate slab, a solid glass sphere, and a solid glass cylinder, by examining those solutions of Maxwell's equations (for dispersive as well as non-dispersive media) which admit of a complex-valued oscillation frequency. Under certain circumstances, these leaky modes constitute a complete set into which an arbitrary distribution of the electromagnetic field residing inside a dielectric body can be expanded. We provide completeness proofs, and also present results of numerical calculations that illustrate the relationship between the leaky modes and the resonances of dielectric cavities formed by a simple parallel-plate slab, a glass sphere, and a glass cylinder.
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Marga, Philippe. "Psychose et modes de suppléance." Paris 13, 1997. http://www.theses.fr/1997PA131004.
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Ce travail de recherche se propose d'examiner le problème de l'entrée dans la psychose et tout particulièrement les modes de suppléance, c'est à dire les stratégies que le sujet peut mettre en place pour retarder ou éviter l'entrée dans la psychose. L'étude du délire dans sa fonction freudienne d'auto-guérison permet de ne pas les confondre. Apres le repérage préliminaire des concepts utilises, nous avons effectue une recherche sur l'historique de la folie pour en arriver a l'approche de Freud et aux prolongements que Lacan a pu proposer. La crise psychotique y est examin2e ce qui donne corps a une clinique différentielle des psychoses. Les modes de suppléances sont articules aux trois registres lacaniens que sont le réel, le symbolique et l'imaginaire, en précisant qu'ils sont susceptibles de se combiner ou de se présenter en alternance dans le processus qui retient notre intérêt. Le premier mode de suppléance examine concerne la fonction de l'écrit a partir de l'œuvre de j. Joyce, de t. Bernhard, d'a. Artaud et de quelques écrits recueillis dans un cadre clinique. Les conduites addictives sont examinées pour leur valeur de suppléance et sont suivies par l'étude des conduites psychopathiques. Les conduites passionnelles trouvent leur place dans cette étude ainsi que le problème du transsexualisme et la fonction du phénomène psychosomatique. Le phénomène de sublimation pulsionnelle est étudie afin de voir s'il peut se mettre en place dans la structure psychotique. Le concept de sinthome, que l'on distingue de celui de symptôme, est retenu pour qualifier le processus qui semble être à l’ origine des modes de suppléance, et il parait s'articuler avec ce que Lacan repère comme la constitution de l'ego. La stabilisation et le problème du déclenchement sont appréhendes au regard de la fonction de l'autre dans la psychose, fonction qui diffère selon les modalités de décompensationThe object of this work is to approach the problem of the entering into the psychosis and more particularly the strategies used by the subject in order to put back or avoid that one : "les modes de supleance". The study of delirium in his fonction of self-recovery according to s. Freud allow to no fuse theses ones. After having located, in first, all the concepts used, we have made an historical search on the madness in order to explain the approach of s. Freud and after the extensions proposed by j. Lacan. The psychotic crisis is examined and suggest a differential clinic of the psychosis. "les modes de suppleances" are connected to the three registers of j. Lacan which are "le reel, le symbolique et l'imaginaire" these ones may appear combined or be presents alternatively. The first "mode de suppleance" examined is the fonction of the writing in the works of j. Joyce, t. Bernhard, a. Arthaud and some writings collected as part of clinic context. The addictive behaviours are examined for their value of suppleance. After we have studied the psychopatics behaviours, the pationnels behaviours, the problem of the transexual relations and the fonctions of the psychosomatics phenomena. The phenomenon of pulsionnal sublimation is studied in order to see he can put oneself in the psychotic structure. The concept of "sinthome" different from the one of symptom is used to qualify the processus who seem be at the origin of "les modes de suppleance". The stabilisation and the problem of the entering into the psychosis are analysed relatively to the functions of the "autre" in the psychosis, that one different according to the modalities of begining of the crisis
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Tourneux, François-Pierre. "Modes de représentation des paysages." Besançon, 2000. http://www.theses.fr/2000BESA1019.
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Trois modes de représentation des paysages sont successivement abordés, relatifs à la consommation par l'image, aux évolutions de composants du paysage visible, et à la caractérisation de contextes d'implantation d'habitats. La première approche repose sur le recueil et l'analyse systématique de collections d'images du paysage français, ouvrant sur des typologies des paysages valorisés, projetées dans l'espace national. Les contrastes régionaux apparaissent estompés par la répétition de modèles, qui composent un filtre de représentation, distinct du filtre perceptif. Une nouvelle lecture de ces filtres est proposée, séparant l'image et les points de vue sur l'image, conférant aux représentations le statut de modes de reconnaissance et de mémoire. Une seconde approche passe par l'analyse diachronique de représentations de l'occupation du sol, suivant le modèle Corine Land-Cover en Franche-Comté. . .
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PIASTRA, ELEONORE. "Esthesioneuroblastome : modes de revelation inhabituels." Lille 2, 1994. http://www.theses.fr/1994LIL2M155.
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Despagnet, Emmanuelle. "Phosphinocarbènes : modes de stabilisation, coordination." Toulouse 3, 2002. http://www.theses.fr/2002TOU30073.
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Pritz, Jakub. "Electromagnetic modes in cylindrical structures." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002634.
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Gray, John T. "Organising modes of law firms." Thesis, Campbelltown, N.S.W. : University of Western Sydney, Macarthur, Faculty of Business, 1998. http://handle.uws.edu.au:8081/1959.7/292.
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This thesis examines why law firms are organised as they are. It develops a theoretical framework of reflexive archetype theory which is constructed from structuring theory (Ranson, Hinings and Greenwood 1980), archetype theory (Hinings and Greenwood 1988), and circuits of power theory (Clegg 1989). It emphasises the reflexivity and integration of the process of organising within law firms. Empirical data are collected from fifteen Sydney law firms and interpreted within reflexive archetype theory. These data confirm the reflexivity and integration of elements within law firms that are theoretically postulated. A research agenda is developed and the contributions of the thesis to the field of organisational analysis are enumerated.
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Gray, John T. "Organising modes of law firms /." Campbelltown, N.S.W. : University of Western Sydney, Macarthur, Faculty of Business, 1998. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030523.113551/index.html.
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Egalon, Claudio Oliveira. "Injection efficiency of bound modes." W&M ScholarWorks, 1990. https://scholarworks.wm.edu/etd/1539623796.
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Previous work on efficiency of light injection into the core of a fiber from a thin film and a bulk distribution of sources in the cladding, have made use of the fields of a weakly guiding fiber. This approximation simplifies the analysis of the power efficiency by introducing universal values for the eigenvalues of different fibers with same {dollar}V{dollar}-number, but can not predict accurately the behavior of the injected light into a fiber with arbitrary differences in indices of refraction. We have used the exact field solution in the expressions of the power efficiency, {dollar}P\sb{lcub}\rm eff{rcub}{dollar}, and analyzed its behavior as a function of the remaining parameters. Although more complicated and harder to interpret, our formulas allow us to analyze the power injection efficiency of fibers with arbitrary differences in the indices of refraction. The results obtained are relevant for the design of more efficient optical fiber distributed sensors. The conclusions follow.;We have confirmed weakly guiding results obtained previously. However, we have found that the {dollar}P\sb{lcub}\rm eff{rcub}{dollar} does not always increase with the {dollar}V{dollar}-number but with the difference in the indices of refraction, {dollar}n\sb{lcub}\rm core{rcub} -n\sb{lcub}\rm clad{rcub}{dollar}.;For fixed {dollar}a/\lambda{dollar}, indices of refraction, {dollar}n\sb{lcub}\rm core{rcub}{dollar} and {dollar}n\sb{lcub}\rm clad{rcub}{dollar} and normalized inner and outer radius, {dollar}R\sb{lcub}\rm in{rcub}{dollar} and {dollar}R\sb{lcub}\rm out{rcub}{dollar}, the {dollar}P\sb{lcub}\rm eff{rcub}{dollar} is independent of core radius, {dollar}a{dollar}, and the wavelength, {dollar}\lambda{dollar}. This applies for any uniform cylindrical distribution of cladding sources. This result suggests that {dollar}a/\lambda, R\sb{lcub}\rm in{rcub}{dollar} and {dollar}R\sb{lcub}\rm out{rcub}{dollar} are independent variables.;For the bulk distribution we have found that {dollar}P\sb{lcub}\rm eff{rcub}{dollar} increases with the wavelength, {dollar}\lambda{dollar}, and decreases with the fiber core radius, {dollar}a{dollar}, i.e., it decreases with the {dollar}V{dollar}-number. However, for the thin film, the {dollar}P\sb{lcub}\rm eff{rcub}{dollar} remains almost constant with the wavelength, {dollar}\lambda{dollar}, and fiber core radius, {dollar}a{dollar}.
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Austin, Caroline G. "Perpetual modes of absence = presence." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/99824/1/Caroline_Austin_Thesis.pdf.
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This practice-led research investigates how technologically mediated space facilitates or impedes connection with those remote. The decision to foreground practice as the primary methodology aims to create a nuanced and detailed definition of the experience to emerge through creative practice that is as individual and idiosyncratic as the experience itself. Beginning with an examination of the context surrounding technologically mediated space, the research examines the processes of signification and the strengths and limitations of language to embody the experience of connection. It provides an analysis of collective and personal narratives using phenomenological methods that question the what, how and where of connection in technologically mediated spaces. From this analysis a critical mode has been developed that expands on the definition of connection, suggesting a future scenario in which a mode of absence that presence is engaged with and moved between.
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Moalla, Emna. "La distance et le choix du mode d'entrée sur les marchés étrangers : une analyse des entreprises françaises." Thesis, Lyon 3, 2013. http://www.theses.fr/2013LYO30073.
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Cette recherche étudie l’impact de la distance sur le choix du mode d’entrée à l’étranger. La revue de la littérature révèle l’intérêt accordé au concept de distance et plus précisément aux dimensions psychique et culturelle de la distance. Toutefois, ce concept fait objet de controverses concernant sa conceptualisation et son opérationnalisation. Les études antérieures ont tenté d’expliquer le choix du mode d’entrée par la distance culturelle. Les résultats s’avèrent hétérogènes et peu concluants. Ce travail tente d’apporter des réponses et d’éclaircir l’ambiguïté identifiée dans la littérature en adoptant une approche multidimensionnelle de la distance. Fondée sur la grille d’analyse proposée par Ghemawat (2001), cette recherche développe des hypothèses relatives aux différentes dimensions de la distance (distances culturelle, administrative, géographique, économique). Ces hypothèses sont testées sur un échantillon de 203 opérations de rapprochement effectuées par des entreprises françaises avec des partenaires localisés dans le monde entier. Les résultats de l’étude empirique montrent que la distance nationale influence le choix du mode de rapprochement (coopération versus fusion-acquisition). Ils révèlent que, dans le cas des entreprises françaises, les dimensions administrative et économique jouent un rôle prépondérant lors du choix du mode de rapprochement à l’étranger, contrairement aux distances culturelle et géographiqueThis research examines the impact of distance on the choice of foreign market entry modes. The literature review highlights the interest given to the concept of distance and more specifically to psychic and cultural dimensions of distance. Nonetheless, this concept is controversial regarding its conceptualization and operationalization. Previous studies have sought to explain the choice of entry mode mainly by cultural distance. The results are heterogeneous and inconclusive. This research attempts to provide answers and clarification to the ambiguity identified in the literature by adopting a multidimensional approach to distance. Based on the framework proposed by Ghemawat (2001), this study develops several hypotheses concerning the different dimensions of distance (cultural, administrative, geographic and economic distances). These hypotheses are tested on a sample of 203 interfirm linkages conducted by French companies with partners located around the world. The results of the empirical study show that the national distance influences the choice of alliance mode (cooperation versus merger-acquisition). In the case of French companies, the findings indicate that administrative and economic dimensions play an essential role in the choice of foreign market alliance mode, contrary to cultural and geographic distances
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Liu, Duixian. "Some relationships between characteristic modes and Inagaki modes for use in scattering and radiation problems." Connect to resource, 1986. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1144430762.
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