The gas transfer process across the air-water interface in a buoyant-convective environment has been investigated by Direct Numerical Simulation (DNS) to gain improved understanding of the mechanisms that control the process. The process is controlled by a combination of molecular diffusion and turbulent transport by natural convection. The convection when a water surface is cooled is combination of the Rayleigh-B´enard convection and the Rayleigh-Taylor instability. It is therefore necessary to accurately resolve the flow field as well as the molecular diffusion and the turbulent transport which contribute to the total flux. One of the challenges from a numerical point of view is to handle the very different levels of diffusion when solving the convection-diffusion equation. The temperature diffusion in water is relatively high whereas the molecular diffusion for most environmentally important gases is very low. This low molecular diffusion leads to steep gradients in the gas concentration, especially near the interface. Resolving the steep gradients is the limiting factor for an accurate resolution of the gas concentration field. Therefore a detailed study has been carried out to find the limits of an accurate resolution of the transport for a low diffusivity scalar. This problem of diffusive scalar transport was studied in numerous 1D, 2D and 3D numerical simulations. A fifth-order weighted non-oscillatory scheme (WENO) was deployed to solve the convection of the scalars, in this case gas concentration and temperature. The WENO-scheme was modified and tested in 1D scalar transport to work on non-uniform meshes. To solve the 2D and 3D velocity field the incompressible Navier-Stokes equations were solved on a staggered mesh. The convective terms were solved using a fourth-order accurate kinetic energy conserving discretization while the diffusive terms were solved using a fourth-order central method. The diffusive terms were discretized using a fourth-order central finite difference method for the second derivative. For the time-integration of the velocity field a second-order Adams-Bashworth method was employed. The Boussinesq approximation was employed to model the buoyancy due to temperature differences in the water. A linear relationship between temperature and density was assumed. A mesh sensitivity study found that the velocity field is fully resolved on a relatively coarse mesh as the level of turbulence is relatively low. However a finer mesh for the gas concentration field is required to fully capture the steep gradients that occur because of its low diffusivity. A combined dual meshing approach was used where the velocity field was solved on a coarser mesh and the scalar field (gas concentration and temperature) was solved on an overlaying finer submesh. The velocities were interpolated by a second-order method onto the finer sub-mesh. A mesh sensitivity study identified a minimum mesh size required for an accurate solution of the scalar field for a range of Schmidt numbers from Sc = 20 to Sc = 500. Initially the Rayleigh-B´enard convection leads to very fine plumes of cold liquid of high gas concentration that penetrate the deeper regions. High concentration areas remain in fine tubes that are fed from the surface. The temperature however diffuses much stronger and faster over time and the results show that temperature alone is not a good identifier for detailed high concentration areas when the gas transfer is investigated experimentally. For large timescales the temperature field becomes much more homogeneous whereas the concentration field stays more heterogeneous. However, the temperature can be used to estimate the overall transfer velocity KL. If the temperature behaves like a passive scalar a relation between Schmidt or Prandtl number and KL is evident. A qualitative comparison of the numerical results from this work to existing experiments was also carried out. Laser Induced Fluorescence (LIF) images of the oxygen concentration field and Schlieren photography has been compared to the results from the 3D simulations, which were found to be in good agreement. A detailed quantitative analysis of the process was carried out. A study of the horizontally averaged convective and diffusive mass flux enabled the calculation of transfer velocity KL at the interface. With KL known the renewal rate r for the so called surface renewal model could be determined. It was found that the renewal rates are higher than in experiments in a grid stirred tank. The horizontally averaged mean and fluctuating concentration profiles were analysed and from that the boundary layer thickness could be accurately monitored over time. A lot of this new DNS data obtained in this research might be inaccessible in experiments and reveal previously unknown details of the gas transfer at the air water interface.

This study attempts to determine a relative age of the Wahianoa moraines, Mt Ruapehu using three relative age dating techniques: Lichenometry, Schmidt hammer and Boulder roundness. There were three study areas used, termed the Wahianoa ‘A’, ‘B’ and ‘C’ moraines. Upon determining a relative age for these moraines, their timing of their formation was placed within New Zealand’s glacial timescale. This is the first study of its kind conducted on Mt Ruapehu and has left the door open for more research in this field. The species of lichens measured on the Wahianoa moraines were Rhizocarpon subgenus, which the largest diameters were measured using callipers. A total of 606 lichens were measured in the Wahianoa Valley and were processed using the growth curve and size frequency methods. A lichenometric growth curve was constructed from lichens growing in the Ohakune cemetery. The dates derived from both methods placed the formation of the Wahianoa moraines during the Little Ice Age. An L-type Schmidt hammer was used on the boulders in the Wahianoa Valley. A total of 280 measurements were taken off the boulders on the Wahianoa moraines. The results of this method, when compared to Winkler’s (2005) study in the South Island placed the formation of the Wahianoa moraines pre-Little Ice Age. Although no definitive ages could be derived from this comparison due to differences in lithology between the two studies, it provided an idea as to where the formation of these moraines could belong. This is the first time that the Boulder roundness method has been used in New Zealand, having only been developed by Kirkbride (2005). This method was used to determine which of the ridges in the Wahianoa Valley were older. It was found that the Wahianoa ‘A’ moraines were the oldest in the valley followed by Wahianoa ‘B’ and ‘C’ respectively. A climate reconstruction was also conducted for the Wahianoa Valley to see what conditions may have been in existence during the formation of the Wahianoa moraines. The paleo-ELA for the Wahianoa Glacier was estimated using the Accumulation-Area Ratio (AAR), Terminus to Headwall Ratio (THAR), Maximum Elevation of the Lateral Moraines (MELM) and Extrapolation methods. The current ELA was estimated using the AAR, THAR and Extrapolation methods. The difference between these estimates was used to determine what temperature decrease would have caused the formation of the Wahianoa moraines. The average paleo-ELA was found to be c. 1715m, while the current ELA was found to be 2475m which lead to a 4.5°C decrease. This temperature decrease correlates well with that of the Last Glacial Maximum. This study found significant differences in relative age of the Wahianoa moraines. There are a number of factors that can affect the growth of lichens such as micro-environmentalconditions and the fact that a growth curve was constructed off site. Factors such aspetrography can affect the Schmidt hammer results and the Boulder roundness measurements. In addition, precipitation can affect the ELA values which can then cause the wrong placement within a glacial event. Further research lies in the use of the Schmidt hammer on a known age surface such as the Mangatepopo moraines which will aide in a better correlation of relative age. Also, further research using climate reconstructions on Mt Ruapehu and the effect of precipitation will also aide in a better correlation with a glacial event.

This dissertation investigates characteristics of the vertical distributions of mass flux observed in field and laboratory experiments. Thirty vertical mass flux profiles were measured during a field experiment in Jericoacoara, Brazil from October to November, 2008. These data were supplemented with 621 profiles gathered from an extensive review of the aeolian literature. From the field experiment, the analysis of the grain-size statistics for the flux caught in each trap shows that a reverse in grain-size trends occurs at an inflection zone located 0.05 ? 0.15 m above the bed. Below this inflection, mean grain-size decreases steeply with elevation in the near bed region dominated by reptation and saltation modes of transport. Above the inflection there is a coarsening of grain size with elevation; as saltation becomes the dominant transport mode. These results indicate that the coarsest grains are found close to and farthest from the bed. Using a data set comprising 274 vertical flux profiles, the performance of the exponential, power and logarithmic functions were tested to see which provided the best fit to the vertical flux distributions. The exponential function performed best 88% of the time. The average r2 value for the grouped exponential, logarithmic, and power function fits are 0.98, 0.85 and 0.91, respectively. The populations of the exponent coefficients, representing the relative rate of decrease with height above the surface, or slope of the vertical mass flux profiles, are statistically different in wind tunnels and field experiments. The slopes of the vertical flux profiles observed in wind tunnel experiments are steeper compared to field environments, which infers that saltation is suppressed in wind tunnels. These differences are magnified in wind tunnels with small working cross section areas, and in wind tunnel experiments that use extreme environmental conditions, such as very high shear velocities. The Rouse concentration model, widely used in water studies, was tested to see if it could replicate the observed vertical flux distributions and transport rates. A fall velocity (w0) equation for particles falling in air was derived using a grain size (d) dependency: w0 (in m/s) = 4.23d (in mm) + 0.1956 (r^2=0.88). The Rouse model performs poorly when the value of the beta (a form of the Schmidt number in the Rouse number exponent) is assumed to be unity. The values of beta were modeled using a relationship derived from a dependency of beta on the w0/u* ratio: beta = 3.2778(w0/u*) - 0.4133 (r^2=0.65). The values of beta ranged from 6.11 ? 17.83 for all the experiments. The Rouse profiles calculated using this approach predict very similar vertical distributions to the observed data and predicted 86% and 81% of the observed transport rate in field and wind tunnel experiments respectively. The Rouse approach is more physically meaningful than current approaches that use standard curve fitting functions to represent the vertical flux data but do not provide any explanatory power for the shape or magnitude of the profile.

Abstract The Copper Catalyzed Azide-Alkyne Cycloaddition (CuAAC) is a paradigm of ¡§click¡¨ chemistry which has been applied in different fields. To understand the interaction between organic azides and a copper surface, we use benzyl azide (Bn¡ÐN£\¡ÐN£]¡ÝN£^) as an adsorbate on Cu(111) under ultrahigh vacuum conditions. The thermal reaction process was explored by a combination of temperature-programmed desorption (TPD), reflection absorption infrared spectroscopy (RAIRS), and X-ray photoemission spectroscopy (XPS) techniques. The TPD profiles show a multilayer desorption peak at 190K, two peaks for N2 , and H2 from 270K to 390K. At 345K, peak of desorption product (m/z=103) represents phenyl cyanide (PhCN) or phenyl isocyanide (PhNC). RAIR and XP spectra demonstrate that at 190K benzyl azide on Cu(111) readily adopt the imine intermediate formalism involving N£\¡ÐN£] scission and phenyl group shift from carbon to nitrogen. The mechanism is analogous to the organic reaction of Schmidt rearrangement. To heat the surface to 250K, the CH2 group of the imine intermediate undergoes C¡ÐH bond scission to produce a surface isocyanide intermediate, (M=C=N¡ÐPh). Therefore the final desorption product is phenyl isocyanide at ~350K. Intriguingly, the thermal chemistry of benzyl azide involves both imine and isocyanide intermediacy, despite the fact that azido species usually generate nitrene or imido complexes under thermal conditions.

There has always been a desire to apply technology to human endeavors to increase a person's capabilities and reduce the numbers or skill level required of the people involved, or replace the people altogether. Three fundamental areas are investigated where technology can enable the reduction or removal of humans in complex tasks. The fi rst area of research is the rapid calibration of multiple camera systems when cameras share an overlapping fi eld of view allowing for 3D computer vision applications. A simple method for the rapid calibration of such systems is introduced. The second area of research is the autonomous exploration of hallways or other urbancanyon environments in the absence of a global positions system (GPS) using only an inertial motion unit (IMU) and a monocular camera. Desired paths that generate accurate vehicle state estimates for simple ground vehicles are identi fied and the bene fits of integrated estimation and control are investigated. It is demonstrated that considering estimation accuracy is essential to produce efficient guidance and control. The Schmidt-Kalman filter is applied to the vision-aided inertial navigation system in a novel manner, reducing the state vector size signi ficantly. The final area of research is a decentralized swarm based approach to source localization using a high fidelity environment model to directly provide vehicle updates. The approach is an extension of a standard quadratic model that provides linear updates. The new approach leverages information from the higher-order terms of the environment model showing dramatic improvement over the standard method.

n the problem of time delay estimation (TDE), the desired source signals of interest are correlated and with a specific spectral distribution. In such cases, the convergence speed using the conventional approaches, viz., time domain adaptive constrained and unconstrained LMS TDE algorithms, becomes slowly and the performance of TDE will be degraded, dramatically. In fact, the convergence rate depends highly on the distribution of spectral density of the desired signal sources. Also, the performance of TDE is affected by the background noises, accordingly. To circumvent the problem described above, in this thesis, a transformed domain adaptive constrained filtering scheme, refers to the constrained adaptive DCT-LMS algorithm, for TDE is devised. We show that this new proposed constrained algorithm, with the so-called direct delay estimation formula, for non-integer TDE does perform better than the conventional time domain adaptive constrained and unconstrained LMS TDE algorithms and the unconstrained adaptive DCT-LMS TDE algorithm. Finally, to further reduce the spread of eigenvalue in the unconstrained adaptive DCT-LMS algorithm, the Gram-Schmidt orthogonalizer approach realizing by the adaptive Escalator is investigated. It indicates that bias of TDE will occur without using the constraint of weight vector. That is, it could not be used to alleviate the effect due to background noises.

Das Ziel dieser Diplomarbeit ist ein Modell für die Plattendeformationen unter Beachtung großer Verzerrungen sowie die Implementierung einer entsprechenden FE-Simulation. Durch Einsetzen der Kirchhoff-Hypothese in die nichtlineare statische dreidimensionale Elastizitätstheorie wird die Gesamtenergie einer deformierten Platte einzig und allein durch die Verschiebungen ihrer Mittelfläche beschrieben. Minimieren dieser Energie führt auf ein nichtlineares Variationsproblem, welches mit Hilfe des Newton-Verfahrens und der Finiten-Elemente-Methode numerisch gelöst werden kann. Dafür werden die Formeln des Energiefunktionals sowie der notwendigen zwei Linearisierungen angegeben. Mit der weiteren Annahme, dass sich die Normale der Mittelfläche nicht ändert, wird eine FE-Implementierung mit bilinearen Elementfunktionen in der Plattenebene und bikubischen Elementfunktionen, vom Bogner-Fox-Schmidt-Element, in Dickenrichtung hergeleitet. / The aim of this thesis is a model for the plate deformations, under consideration of large strains, and the implementation of a suitable FE simulation. Starting from nonlinear static 3D elasticity theory and introducing the Kirchhoff assumptions, the total energy of a deformed plate is described solely by the displacements of its midsurface. Minimizing this energy leads to a nonlinear variational problem, which can be solved numerically, using Newton's method and the finite element method. For this purpose, the formulae of the energy functional and its necessary two linearizations are provided. With the further assumption that the normal of the midsurface does not change, an FE implementation is derived, with bilinear element functions in the in-plane-direction and bicubic element functions, from the Bogner-Fox-Schmidt-element, in the out-of-plane-direction.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in German." Includes bibliographical references (p. 176-193).

Techn. Universiẗat, Diss., 2000--Dresden.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T21:15:22Z No. of bitstreams: 1 PauloDeMacedoCaldasNeto_TESE.pdf: 1612541 bytes, checksum: 01ea3633e7ca4d3521607ae167d6b964 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-18T19:52:14Z (GMT) No. of bitstreams: 1 PauloDeMacedoCaldasNeto_TESE.pdf: 1612541 bytes, checksum: 01ea3633e7ca4d3521607ae167d6b964 (MD5) / Made available in DSpace on 2017-04-18T19:52:14Z (GMT). No. of bitstreams: 1 PauloDeMacedoCaldasNeto_TESE.pdf: 1612541 bytes, checksum: 01ea3633e7ca4d3521607ae167d6b964 (MD5) Previous issue date: 2016-12-09 / A abordagem do discurso liter?rio e das suas rela??es com o discurso hist?rico parte de uma indaga??o voltada ao entendimento da mem?ria e do sujeito. Este, enquanto ser psicossocial, dotado da capacidade de perceber e de lembrar algo significativo, ir? contribuir para a forma??o de sua pr?pria mem?ria. Esta acabar? sendo preenchida pelas lembran?as de grupos sociais de que fez parte o sujeito, instituindo o que se chama de mem?ria coletiva. Em seguida, produzir-se-? uma reflex?o sobre o discurso hist?rico, tendo-se a Historiografia, vertente da Filosofia da Hist?ria respons?vel pela aprecia??o dos fatos que marcaram uma sociedade, como base para a an?lise liter?ria do objeto de estudo em quest?o ? a prosa de mem?rias de Augusto Frederico Schmidt. Este trabalho tem como primeiro foco a compreens?o dos alicerces da mem?ria individual do eu nos relatos memorial?sticos de O Galo Branco, As florestas e outros textos publicados, na categoria prosa, pelo escritor e homem de neg?cios Augusto Frederico Schmidt. Conhecido por sua intensa atua??o pol?tica no Governo JK, nos idos de 50 e 60 no Brasil, vamos nos deparar com um sujeito preocupado com o registro de sua vida e com as correspond?ncias existentes entre a sua obra art?stico-biogr?fica e os acontecimentos de uma ?poca. Alguns dos textos schmidtianos lembram cr?nicas, porque foram editados em jornais e possuem a brevidade, o lirismo, a poesia do momento, muito embora sigam al?m do registro circunstancial, alcan?ando a estrutura de uma narrativa longa e cheia de pontos autobiogr?ficos. Tivemos a preocupa??o aqui de apontar as fronteiras entre o memorial?stico, o historiogr?fico e o autobiogr?fico, principalmente ao estabelecermos liga??es te?ricas e anal?ticas para a explica??o est?tica das obras liter?rias em quest?o. Todo o mecanismo psicomotor da lembran?a, componente para a ativa??o da mem?ria, foi destacado. A seguir, abordamos a maneira pela qual se apresenta o discurso hist?rico no interior das narrativas reais de Schmidt e a representatividade da conex?o entre a mem?ria e a hist?ria no interior da prosa. / The approach of literary discourse and its relations with the historical speech starts from an inquiry focused on the understanding of memory and the subject.This, as a psychosocial being, endowed with the capacity to perceive and remember something meaningful, will contribute to the formation of his own memory. This will be filled by the memories of social groups of which the subject was part, instituting what is called collective memory. Afterwards, a reflection on the historical discourse will take place, with Historiography, a branch of the Philosophy of History responsible for the appreciation of the facts that marked a society, as a basis for the literary analysis of the object of study in question ? the Prose of memories of Augusto Frederico Schmidt. This work has as its primary focus the understanding of the foundations of individual memory I in memorialistic reports White Rooster, Forests and other published texts, in prose category, the writer and businessman Augusto Frederico Schmidt. Known for its intense political activity in the Government JK, the ides of 50 and 60 in Brazil, we will come across a worried man with the record of his life and the existing connections between his artistic and biographical work and the events of an era. Some of Schmidtian texts resemble chronic, because they were published in newspapers and have the brevity, lyricism, poetry of the moment, although follow beyond circumstantial record, reaching the structure of a long and full of autobiographical narrative points. This research points out to the boundaries between memorialistic, historiographical and autobiographical texts, especially when we establish theoretical and analytical links to the aesthetic explanation of literary works in question. All psychomotor mechanism of memory, component for activation of memory, has been highlighted. Then, we approach the way in which it presents the historical discourse within the actual narratives of Schmidt and the connection of representation between memory and history within the prose.