Flow control is a key factor in optimizing the performance of any vehicle moving through fluids. Particularly, in aerodynamics there are many potential benefits for implementing synthetic jets to achieve aircraft designs with less moving parts, uper- maneuverability, and separation control for fuel economy. Piezoelectric synthetic jets are of special interest because of their lightweight and low power consumption. Numerous publications on such jets are available. Actuator properties and boundary conditions relevant to this particular application however are often overlooked. The focus of this project is to numerically model synthetic jets in quiescent air to study the influence of cavity geometry and boundary conditions of the piezoelectric diaphragm on jet velocity. Numerical simulation is performed for two synthetic jet cavities of different height and orifice diameter. The numerical modeling utilizes a turbulent RNG κ – ε model and a moving boundary condition with two oscillating deflection profiles, parabolic and logarithmic, applied to the diaphragm. The actuators modeled are typical Bimorph and Thunder piezoelectric actuators. The initial conditions for the actuators are obtained experimentally resulting in 0.396mm and 0.07mm respectively when driven with a sinusoidal wave input at 1524 V/m and 4064 V/m. Although the velocity boundary numerical model gave overall better results than the current moving-boundary numerical model, the moving-boundary model is more accurate since it better approximates the movement of the diaphragm. From an optimizing viewpoint the moving boundary is more suitable to attempt to optimize the design because displacement magnitude of the diaphragm can be measured directly from experiments. For the higher displacement Bimorph actuator, a logarithmic profile matches the experimental results, whereas the parabolic profile provided better results for the relatively small displacement Thunder actuator. It is thus hypothesized that both tested actuators, Bimorph and Thunder, oscillate according to the specified logarithmic and parabolic profile respectively. Cavity height was briefly investigated for the Bimorph actuator. Results show that cavity height did not make a difference in the centerline velocity for the numerical model. The model fails to consider the important effect of the dynamic coupling of the actuator displacement and the pressure that develops inside the cavity. The pressure values obtained are comparable to the theoretical blocking pressure for the Bimorph in the cavity. The results of this study show that jet formation and development has unique characteristics for each actuator and cavity configuration. The smaller orifice cavity configuration produced a faster, longer, thinner jet with larger vortices than the bigger orifice. During max expulsion, t = 0.25T, and max ingestion, t = 0.75T, a low-pressure area localized at the corners of the orifice, inlet and exit respectively, were observed. All cavity configurations passed all three known jet formation criterions that include, Lo/Do>1, Re > 50, and Re/S2 > 0.16.

Atmospheric mass is transported in and out of the stratospheric polar cap region by a wave-driven meridional circulation. Using composites of polar cap pressure anomalies, defined as deviations from the average annual cycle, it is shown that this stratospheric mass flux is accompanied by a similar mass flux near the surface. This 'tropospheric amplification' of the stratospheric signal is introduced as a new way to quantify stratosphere-troposphere coupling. Regression analysis is used to create a vertical profile of atmospheric pressure during a tropospheric amplification event, and the regression slope profile is used as a tool to quantify the amplification. Using data from 5 reanalysis datasets and 11 climate models, it is shown that high-top models, with a model lid of above 1 hPa, are significantly better at reproducing tropospheric amplification than low-top models, due to having more detailed parameterisations of stratospheric processes. However, the regression slope profiles of all models, bar one, are significantly different to the profile of reanalysis data at a 95% confidence level. Tropospheric amplification is also investigated in historical and future simulations from these models, and it is concluded that there is not expected to be a large change in the phenomenon over the next 100 years. The processes needed to reproduce tropospheric amplification can be identified by comparing idealised models of different complexity. A simple dry-core model is not able to reproduce tropospheric amplification, while a model with a comprehensive radiation scheme does produce the basic regression slope profile under certain configurations. The associations between pressure change and mass flux are further investigated using primitive equations. It is found that vertical and horizontal contributions to mass flux act to mostly cancel each other out, leaving a poorly-conditioned residual, and that the horizontal mass flux across the polar cap boundary has both geostrophic and ageostrophic components.

NMR is a powerful analytical spectroscopic tool used to perform detailed studies of structure and dynamics of molecules in solution. However, despite NMR's excellent spectral sensitivity, most NMR methods suffer from low detection sensitivity. This low detection sensitivity results largely from extremely small (Boltzmann) nuclear spin polarization at thermal equilibrium--in even the strongest of magnets. This dissertation focuses on selected research areas that maybe used to combat the limitations presented by NMR and measure weak spectral responses with atomic-scale precision. In particular, these methods involve the use of laser-polarized xenon, liquid crystals, and polarization transfer (cross-polarization) techniques to enhance NMR sensitivity and/or measure weak interactions. The potential use of these tools to study host-guest interactions is of particular interest. In certain systems the sensitivity problem of conventional NMR/MRI can be overcome by applying optical pumping (OP) methods to enhance nuclear spin polarization. For instance, OP of noble gases (such as xenon) is employed to dramatically increase their nuclear spin polarization by transferring angular momentum of laser light to electronic and then nuclear spins. Next, cryptophane complexes are ideal choices for fundamental studies of prototypical host-guest interactions. Of general interest when studying host-guest interactions is how (1) physical confinement at the nanoscale and (2) interactions between guest and host may affect the properties, dynamics, interactions, and/or reactivity of a trapped molecule and the host/guest complex as a whole. As a more specific example, we are interested in probing host-guest dynamic coupling, which refers to the relative motion of the guest within the host, determined by the relative sizes and geometries--as well as the interactions involved. With the development of new NMR methods and techniques, we hope to gain insight into mechanisms that underlie complex formation by probing the structures, dynamics and energetic contributions involved in ligand binding, where molecular contributions such as: orientational and motional freedom of the guest; and structure, dynamics, and ordering of the host can influence the behavior of inclusion complexes.

At the royal institute of technology (KTH) in the department of applied process metallurgy, a novel modelling approach has been developed which allows a dynamic coupling between the commercial thermodynamic software Thermo-Calc and the commercial computational fluid dynamic (CFD) software Ansys Fluent, only referred to as Fluent in the study. The dynamic coupling approach is used to provide numerical CFD-models with thermodynamic data for the thermo-physical properties and for the fluid-fluid chemical reactions occurring in metallurgical processes. The main assumption forthe dynamic coupling approach is the existence of local equilibrium in each computational cell. By assuming local equilibrium in each computational cell it is possible to use thermodynamic data from thermodynamic databases instead of kinetic data to numerically simulate chemical reactions. The dynamic coupling approach has been used by previous studies to numerically simulate chemical reactions in metallurgical processes with good results. In order to validate the dynamic coupling approach further, experimental data is required regarding surface reactions. In this study, a graphiteand metallurgical coke oxidation experimental setup was suggested in order to provide the needed experimental data. With the experimental data, the ability of the dynamic couplings approach to numerically predict the outcome of surface reactions can be tested.By reviewing the literature, the main experimental apparatus suggested for the oxidationexperiments was a thermo-gravimetric analyzer (TGA). The TGA can provide experimental data regarding the reaction rate, kinetic parameters and mass loss as a function of both temperature and time. An experimental setup and procedure were also suggested.In order to test the ability of Fluent to numerically predict the outcome of surface reactions, without any implementation of thermodynamic data from Thermo-Calc, a benchmarking has been conducted. Fluent is benchmarked against graphite oxidation experiments conducted by Kim and No from the Korean advanced institute of science and technology (KAIST). The experimental graphite oxidation rates were compared with the numerically calculated graphite oxidation rates obtained from Fluent. A good match between the experimental graphite oxidation rates and the numerically calculated graphite oxidation rates were obtained. A parameter study was also conducted in order to study the effect of mass diffusion, gas flow rate and the kinetic parameters on the numerically calculated graphite oxidation rate. The results of the parameter study were partially supported by previous graphite oxidation studies. Thus, Fluent proved to be a sufficient numerical tool for numerically predicting the outcome of surface reactions regarding graphite oxidation at zero burn-off degree.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ. / Science, Faculty of / Computer Science, Department of / Graduate

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A premissa pelo uso racional da Ãgua tem demandado informaÃÃes em escalas de espaÃo e tempo cada vez menores. Neste estudo investiga-se a sensibilidade da simulaÃÃo climÃtica de um downscaling dinÃmico de precipitaÃÃo (1971-2000) acoplado a um modelo chuva-vazÃo e sua aplicaÃÃo na operaÃÃo de um reservatÃrio hÃdrico na regiÃo semi-Ãrida do Estado do CearÃ. Foi dada uma Ãnfase a escala intrasazonal (abaixo de um mÃs) em anos de contrastess climÃticos classificados como de La NiÃa, El NiÃo e Normais ocorridos no Oceano PacÃfico Tropical. Foram usados o modelo de circulaÃÃo geral da atmosfera ECHAM4.5, e o modelo regional, denominado de Modelo Regional Espectral (MRE), versÃo 97, do National Centers for Atmospheric Prediction- NCEP. O MRE foi aninhado aos dados simulados pelo ECHAM4.5 tendo como condiÃÃo de contorno a Temperatura da SuperfÃcie do Mar observada no perÃodo de janeiro a junho de 1971-2000. Para a estimativa de vazÃo foi usado o modelo SMAP. Entre os principais resultados citam-se: apÃs a correÃÃo pela tÃcnica das Probability Density Functions (PDFs), os dados simulados pelo MRE, conseguiram capturar melhor a variabilidade diÃria da precipitaÃÃo no posto fluviomÃtrico de Iguatu, mÃdia entre 01 de janeiro e 30 de junho. A explicaÃÃo da variÃncia antes da correÃÃo foi de menos de 5%, passando a em torno de 40% apÃs as correÃÃes pelas PDFs. As simulaÃÃes de vazÃo, analisadas pela explicaÃÃo da variÃncia, coeficiente de correlaÃÃo ao quadrado, mostraram que hà um ganho de explicaÃÃo desta variÃncia de duas ou mais vezes, quando se compara esta explicaÃÃo em relaÃÃo à precipitaÃÃo. Este ganho foi observado tanto para perÃodos diÃrios, pentadais e quinzenais e para todo o perÃodo (1971-2000). Mais de 70% do sinal das anomalias pentadais de vazÃo foram bem simulados. SimulaÃÃes de volume de um reservatÃrio hipotÃtico (com as caracterÃsticas do AÃude OrÃs), com volume inicial V0=0,25k (capacidade mÃxima - 1940 hm3), 0,50k e 0,75k, mostraram que hà potencial do uso dessa informaÃÃo de precipitaÃÃo em cascata com o modelo chuva-vazÃo, em particular para os anos classificados como Normais. A explicaÃÃo da variÃncia entre os volumes simulados e observados diÃrios, para os meses de janeiro a junho, para estes anos Normais tiveram resultados mais expressivos. Esta ficou torno ou mais de 80%. Em sÃntese, os resultados evidenciaram o potencial de uso da simulaÃÃo acoplada da modelagem dinÃmica atmosfÃrica com a modelagem hidrolÃgica associada à operaÃÃo do reservatÃrio. / The premiss for the rational use of water has demanded information on smaller space and time scales. This study investigates the sensitivity of climate simulation of a dynamic downscaling of precipitation (1971-2000) coupled to a rain-flow model and its application to the operation of a water reservoir in the semi-arid region of Cearà State. Emphasis was given to intra seasonal scale (smaller than a month) in years of climatic contrasts classified with La NiÃa, El NiÃo and Normals (averaged) in the Tropical Pacific Ocean. We used atmospheric general circulation model ECHAM4.5, and the Regional Spectral Model (RMS), version 97 of National Center for Atmospheric Prediction-NCEP. The RSM was nested with data simulated by ECHAM4.5, taking as boundary condition the sea surface temperature observed in the period January to June 1971-2000. For estimating streamflow we rate used the SMAP model. Results show that after the technique of Probability Density Functions (PDFs) correction, the simulation by RSM, best captured daily variability of precipitation at fluviometric post of Iguatu, average, from 01 January to 30 June. The explaned variance before the correction was less than 5%, rising to around 40% after the correction by PDFs. The simulations of streamflow, analyzed by the explaned variance, square of correlation coefficient, shows that there is a two or more gain of explaned this variance, as compared with explanation to streamflow in relation to rainfall. This gain is observed for all periods (daily and accumulated five and fifteen days), and for the entire period (1971-2000). More than 70% pentads anomalies of stramflow were well simulated. Simulations of volume of a hypothetical reservoir (with the characteristics of the OrÃs Dam) with initial volum V0 = 0.25k ( maxim capacity - 1940 hm3), 0.50k and 0.75k, showed that there is the potential use of that cascade information of precipitation with rain-flow model, in particular for averaged years classified. The explanation of the variance between simulated and observed daily volumes for the months of January to June, for these years Normal results was more expressive. This was about 80%. In summary, the results showed the potential for use of coupled simulation model between atmospheric modeling water associated with the reservoir operation.

Les travaux décrits dans ce document abordent le problème du couplage dynamique homme-système haptique. Nous proposons une étude de ce couplage basée sur l'hypothèse d'un système hybride temporaire. Selon cette hypothèse, le système formé lors du couplage peut être considéré comme un système dynamique dont les deux parties ne peuvent pas être séparées. Ce sujet est pluridisciplinaire, se situant à l'intersection des sciences cognitives, de l'automatique et de l'haptique. La première partie du document comporte un état de l'art sur l'analyse du couplage dans ces trois domaines, une description de la problématique et de la méthode à utiliser pour notre étude ainsi qu'une proposition des typologies du geste. Lors de cette étude du couplage, nous nous intéressons à un groupe de gestes particuliers, notamment le geste périodique et le geste passif dans une situation de simulation haptique ainsi qu'aux modèles d'interaction capables de les générer. La méthode générale, consiste à définir des approches pour la modélisation du couplage main-système haptique pour ensuite réaliser une analyse du système couplé à partir d'une acquisition des données du système lors du couplage et en utilisant des méthodes d'identification de paramètres issus de l'automatique pour caractériser les modèles. La dernière partie, décrit la mise en place du dispositif pour l'analyse expérimentale du couplage en situation de simulation avec une interaction haptique. Ce dispositif permet l'acquisition des données du geste pour l'analyse. Nous présentons également, l'étude réalisée sur le simulateur haptique afin d'établir l'équivalence entre les paramètres virtuels introduits et issus du simulateur et des paramètres physiques réels. Ensuite, nous décrivons l'analyse expérimentale des différentes situations de couplage proposées. Les expériences effectuées lors de cette étude ont été réalisées sur la plateforme temps réel ERGON_X, conçue par l'ACROE/ICA. Les résultats de ces expériences ont permis de quantifier les modèles du geste et d'observer ses composantes, selon les modèles établis. Mots clés : haptique, interface haptique, interfaces homme-machine, simulation temps réel, couplage homme-objet, geste, modélisation physique, identification de paramètres. / The work described in this document deals with the problem of human-haptic system dynamic coupling. We propose a study of this kind of coupling based on the hypothesis of a temporary hybrid system. Under this hypothesis, the system formed during the coupling can be considered as a dynamic system in which the two parties that compose it cannot be separated. This is multidisciplinary topic, situated at the intersection of cognitive science, automation and haptics. The first part of the document includes a state of the art on the analysis of coupling in these three areas, the description of the problem and the methodology for the study as well as a proposal of gesture typology. In this study of coupling, we are interested in a particular group of actions, such as periodic movement and passive gesture in a situation of haptic simulation and also, in the interaction models able to generate them. The general method is to define the approaches for modeling the hand-haptic device coupling and then perform an analysis of the coupled system by acquiring system data during the coupling and using parameter identification methods to characterize the models. The final section describes the implementation of the device for the experimental analysis of coupling during simulation with a haptic interaction. This device allows data acquisition for gesture analysis. We also present the study of the haptic simulator to establish the equivalence between virtual parameters introduced to and returned by the simulator and real physical parameters. Then, we describe the experimental analysis of different proposed coupling situations. The experiments performed for this study were performed using the real-time platform ERGON_X, designed by ACROE / ICA. The results of these experiments were used to quantify gesture models and to observe its components, according to established models. Keywords: haptic, haptic interface, human-machine interfaces, real-time simulation, human-object coupling, gesture, physical modeling, parameter identification.

Made available in DSpace on 2016-03-15T19:38:07Z (GMT). No. of bitstreams: 1 Ivan Gonzalez.pdf: 604401 bytes, checksum: 1652d5996de760edf38fd1a3bb2e64e4 (MD5) Previous issue date: 2006-09-18 / A variant of Kuramoto's model for phase oscillators with dynamic coupling is studied. The coupling weight is adjusted by the phase difference resulting in a connection which is strengthened for synchronized oscillators and weakened for non-synchronized oscillators. Equilibrium solutions and their stabilities are presents and it is shown the occurrence of saddle-node and Hopf bifurcations. It is shown that networks formed by such oscillators can be used for detecting image border. / Uma variante do modelo de Kuramoto para osciladores de fase com acoplamento dinâmico é estudada. A intensidade do acoplamento é ajustada pela diferença de fases dos osciladores, de forma que a conexão é reforçada para osciladores sincronizados e enfraquecida para osciladores não sincronizados. As soluções de equilíbrio e suas estabilidades são apresentadas, e mostra-se que o sistema apresenta bifurcações sela-nó e de Hopf. Mostra-se que redes formadas com esses osciladores podem ser usadas para extrair o contorno de figuras.