Made available in DSpace on 2017-07-10T17:36:49Z (GMT). No. of bitstreams: 1 2013_Lorena_Maia_Noreto.pdf: 1204258 bytes, checksum: 13d5a3e9e5a92c9d8ebf5436c3142a61 (MD5) Previous issue date: 2013-03-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to determine the growing degree-days sum and the relationship between the period length from sowing to physiological maturity and sowing dates of thirteen wheat cultivars, in the Palotina PR and Cascavel - PR. The data on wheat crop were colected by the Cooperativa Central de Pesquisa Agrícola (COODETEC) and correspond to the harvests of 2006 to 2011. The treatments consisted of 13 wheat cultivars, 3 sowing dates for Cascavel and 4 sowing dates for Palotina. The data used for the analysis were: Total elapsed days from sowing to the silking and to physiological maturity, and of the silking to physiological maturity, along with the growing degree-days sum for these periods, beyond grains yield and hectoliter weight. The results indicate that the average length of sowing to silking was 64 days for Palotina and 71 days for Cascavel. For the period from silking to physiological maturity the average length was 56 days for Palotina and 54 days for Cascavel. The increase in length of time from sowing to silking in cultivars sowed in May 25th (JD 145) was due to the decrease in air temperature. The average of growing degree-days sum between the period from sowing to physiological maturity was 1487, for both locations. The cultivars that stood out presenting a shorter period of silking to physiological maturity and high productivity were the cultivars CD 114, CD 120 and CD 124 for Palotina and CD 114, CD 120, CD 121, CD 122, CD 124 and Onix for Cascavel / O trabalho teve como objetivo determinar o acúmulo de graus-dia e a relação entre a duração do período da semeadura a maturação fisiológica e as datas de semeadura de treze cultivares de trigo, nos municípios de Palotina - PR e Cascavel PR. Os dados referentes a cultura do trigo foram cedidos pela Cooperativa Central de Pesquisa Agrícola (COODETEC) correspondente as safras agrícolas de 2006 a 2011. Os tratamentos foram constituídos de 13 cultivares de trigo, 3 datas de semeadura para Cascavel e 4 datas de semeadura para Palotina. Os dados utilizados para a análise foram: totais de dias transcorridos da semeadura ao espigamento e a maturação fisiológica e do espigamento a maturação fisiológica, juntamente com o acúmulo de graus-dia para estes períodos, além do rendimento de grãos e peso hectolitro. Os resultados indicam que a duração média do período da semeadura ao espigamento foi de 64 dias para Palotina e 71 dias para Cascavel. Para o período do espigamento a maturação fisiológica a duração média foi de 56 dias para Palotina e 54 dias para Cascavel. O aumento na duração do período da semeadura ao espigamento para cultivares semeados em 25 de Maio (DJ 145) ocorreu em virtude da diminuição da temperatura do ar. O acúmulo médio de graus-dia entre o período da semeadura a maturação fisiológica foi de 1487 para as duas localidades. Os cultivares que destacaram-se, apresentando um menor período do espigamento a maturação fisiológica e com boa produtividade foram os cultivares CD 114, CD 120 e CD 124 para Palotina e CD 114, CD 120, CD 121, CD 122, CD 124 e Onix para Cascavel

A numerical method for computing three-dimensional Stokes flow driven by a doubly-periodic array of regularized forces is presented. In the non-periodic direction either a free boundary or a homogeneous Dirichlet condition is enforced. The method consists of finding a regularized Green's function in Fourier space analytically. Then only an inverse fast Fourier transform (inverse FFT) has to be computed. Accuracy is verified by comparing numerical results to a solution that is independent of the method. In an Ewald splitting, the FFT method can be used to compute the smooth component of the flow, which allows for a splitting parameter as small as a few grid cells. This selection makes the sum in physical space converge extremely fast. Numerical examples demonstrate that fact. Since the forces are regularized, in some cases splitting is not even needed, depending on the relative sizes of the numerical parameters. The method is applied to model the flow created by carpets of nodal cilia based on cilium shape. / acase@tulane.edu

The stochastic Galerkin and collocation methods are used to solve an advection-diusion equation with uncertain and spatially varying viscosity. We investigate well-posedness, monotonicity and stability for the extended system resulting from the Galerkin projection of the advection-diusion equation onto the stochastic basis functions. High-order summationby- parts operators and weak imposition of boundary conditions are used to prove stability of the semi-discrete system. It is essential that the eigenvalues of the resulting viscosity matrix of the stochastic Galerkin system are positive and we investigate conditions for this to hold. When the viscosity matrix is diagonalizable, stochastic Galerkin and stochastic collocation are similar in terms of computational cost, and for some cases the accuracy is higher for stochastic Galerkin provided that monotonicity requirements are met. We also investigate the total spatial operator of the semi-discretized system and its impact on the convergence to steadystate

Partial differential equations (PDEs) are used to model various phenomena in nature and society, ranging from the motion of fluids and electromagnetic waves to the stock market and traffic jams. There are many methods for numerically approximating solutions to PDEs. Some of the most commonly used ones are the finite volume method, the finite element method, and the finite difference method. All methods have their strengths and weaknesses, and it is the problem at hand that determines which method that is suitable. In this thesis, we focus on the finite difference method which is conceptually easy to understand, has high-order accuracy, and can be efficiently implemented in computer software. We use the finite difference method on summation-by-parts (SBP) form, together with a weak implementation of the boundary conditions called the simultaneous approximation term (SAT). Together, SBP and SAT provide a technique for overcoming most of the drawbacks of the finite difference method. The SBP-SAT technique can be used to derive energy stable schemes for any linearly well-posed initial boundary value problem. The stability is not restricted by the order of accuracy, as long as the numerical scheme can be written in SBP form. The weak boundary conditions can be extended to interfaces which are used either in domain decomposition for geometric flexibility, or for coupling of different physics models. The contributions in this thesis are twofold. The first part, papers I-IV, develops stable boundary and interface procedures for computational fluid dynamics problems, in particular for problems related to the Navier-Stokes equations and conjugate heat transfer. The second part, papers V-VI, utilizes duality to construct numerical schemes which are not only energy stable, but also dual consistent. Dual consistency alone ensures superconvergence of linear integral functionals from the solutions of SBP-SAT discretizations. By simultaneously considering well-posedness of the primal and dual problems, new advanced boundary conditions can be derived. The new duality based boundary conditions are imposed by SATs, which by construction of the continuous boundary conditions ensure energy stability, dual consistency, and functional superconvergence of the SBP-SAT schemes.

When seen through a stereoscope, a Gabor pattern (a Gaussian enveloped sinusoid) that is masked by visual noise is more readily detectable when it appears in front of or behind the noise than when it is embedded in the noise itself. The enhanced visibility brought about by stereo cues is referred to as binocular unmasking. In this work, we investigated whether binocular unmasking may also occur with visual objects more complex than simple Gabor patterns, and with tasks more demanding than detection. Specifically, we examined the effects of binocular unmasking in the detection, categorization, and identification of noise masked images of natural objects. We observed the occurrence of binocular unmasking in all three tasks. However, the size of this effect was greater for detection performance than for categorization or identification performance; the latter two benefited to the same extent by the availability of stereoscopic cues. We argue that these results suggest that low level stereoscopic depth cues may play a helpful role, not only in simple detection tasks with psychophysical stimuli, but also in the perception of complex stimuli depicting natural objects.

When seen through a stereoscope, a Gabor pattern (a Gaussian enveloped sinusoid) that is masked by visual noise is more readily detectable when it appears in front of or behind the noise than when it is embedded in the noise itself. The enhanced visibility brought about by stereo cues is referred to as binocular unmasking. In this work, we investigated whether binocular unmasking may also occur with visual objects more complex than simple Gabor patterns, and with tasks more demanding than detection. Specifically, we examined the effects of binocular unmasking in the detection, categorization, and identification of noise masked images of natural objects. We observed the occurrence of binocular unmasking in all three tasks. However, the size of this effect was greater for detection performance than for categorization or identification performance; the latter two benefited to the same extent by the availability of stereoscopic cues. We argue that these results suggest that low level stereoscopic depth cues may play a helpful role, not only in simple detection tasks with psychophysical stimuli, but also in the perception of complex stimuli depicting natural objects.

Adverse childhood events have been identified as a risk factor for developing chronic pain conditions in adulthood. However, previous studies have inconsistently supported the link between adverse childhood events and hypersensitivity to laboratory-induced pain. Therefore, this study intended to investigate the effects of adverse childhood events on temporal summation of second pain (TSSP). A group of 38 healthy and pain-free college students participated in laboratory pain tests after being screened for childhood trauma history. Half of participants (47.5% female) were positive for childhood trauma and the other half (63.2% female) reported no adverse childhood event. The laboratory pain tests measured TSSP using 10 thermal pulses per trial over four consecutive trials. The trauma group showed a tendency of greater sensitization within TSSP trials and lack of habituation over repeated TSSP trials. In sum, adverse childhood events predisposed adults to enhanced TSSP, which is potentially linked to an increased likelihood to develop chronic pain problems.

This thesis deals with the numerical solution of ordinary differential equations (ODEs) using finite difference (FD) methods. In particular, boundary summation equation (BSE) preconditioning for FD approximations for ODEs with constant coefficients on locally refined meshes is studied. Firstly, the BSE for FD approximations of ODEs with constant coefficients is derived on a locally refined mesh. Secondly, the obtained linear system of equations are solved by the iterative method GMRES. Then, the arithmetic complexity and convergence rate of the iterative solution of the BSE formulation are discussed. Finally, numerical experiments are performed to compare the new approach with the FD approach. The results show that the BSE formulation has low arithmetic complexity and the convergence rate of the iterative solvers is fast and independent of the number of grid points.

In this thesis, the numerical solution of time-dependent partial differential equations (PDE) is studied. In particular high-order finite difference methods on Summation-by-parts (SBP) form are analysed and applied to model problems as well as the PDEs governing aerodynamics. The SBP property together with an implementation of boundary conditions called SAT (Simultaneous Approximation Term), yields stability by energy estimates. The first derivative SBP operators were originally derived for Cartesian grids. Since aerodynamic computations are the ultimate goal, the scheme must also be stable on curvilinear grids. We prove that stability on curvilinear grids is only achieved for a subclass of the SBP operators. Furthermore, aerodynamics often requires addition of artificial dissipation and we derive an SBP version. With the SBP-SAT technique it is possible to split the computational domain into a multi-block structure which simplifies grid generation and more complex geometries can be resolved. To resolve extremely complex geometries an unstructured discretisation method must be used. Hence, we have studied a finite volume approximation of the Laplacian. It can be shown to be on SBP form and a new boundary treatment is derived. Based on the Laplacian scheme, we also derive an SBP artificial dissipation for finite volume schemes. We derive a new set of boundary conditions that leads to an energy estimate for the linearised three-dimensional Navier-Stokes equations. The new boundary conditions will be used to construct a stable SBP-SAT discretisation. To obtain an energy estimate for the discrete equation, it is necessary to discretise all the second derivatives by using the first derivative approximation twice. According to previous theory that would imply a degradation of formal accuracy but we present a proof that this is not the case.

The investigation of the dynamics of chemical reactions, both from the theoretical and experimental side, has drawn an increasing interest since Ahmed H. Zewail was awarded the 1999 Nobel Prize in Chemistry for his work on femtochemistry. On the experimental side, new techniques such as femtosecond lasers and attosecond lasers enable laser control of chemical reactions. Numerical simulations serve as a valuable complement to experimental techniques, not only for validation of experimental results, but also for simulation of processes that cannot be investigated through experiments. With increasing computer capacity, more and more physical phenomena fall within the range of what is possible to simulate. Also, the development of new, efficient numerical methods further increases the possibilities. The focus of this thesis is twofold; numerical methods for chemical reactions including dissociative states and methods that can deal with coexistence of spatial regions with very different physical properties. Dissociative chemical reactions are reactions where molecules break up into smaller components. The dissociation can occur spontaneously, e.g. by radioactive decay, or be induced by adding energy to the system, e.g. in terms of a laser field. Quantities of interest can for instance be the reaction probabilities of possible chemical reactions. This thesis discusses a boundary treatment model based on the perfectly matched layer (PML) approach to accurately describe dynamics of chemical reactions including dissociative states. The limitations of the method are investigated and errors introduced by the PML are quantified. The ability of a numerical method to adapt to different scales is important in the study of more complex chemical systems. One application of interest is long-range molecules, where the atoms are affected by chemical attractive forces that lead to fast movement in the region where they are close to each other and exhibits a relative motion of the atoms that is very slow in the long-range region. A numerical method that allows for spatial adaptivity is presented, based on the summation-by-parts-simultaneous approximation term (SBP-SAT) methodology. The accuracy and the robustness of the numerical method are investigated. / eSSENCE