Дисертації з теми "Dispersion functions"
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Alves, Claudia Marins. "Stochastic models for the treatment of dispersion in the atmosphere." Laboratório Nacional de Computação Científica, 2006. http://www.lncc.br/tdmc/tde_busca/arquivo.php?codArquivo=135.
Повний текст джерелаModelos Lagrangianos estocásticos constituem ferramenta muito utilizada no estudo da dispersão de substâncias passivas na Camada Limite Atmosférica. Sua aplicação consiste em calcular a trajetória de milhares de partículas, que simulam numericamente a dispersão de uma substância em suspensão na atmosfera. Nesta tese, são apresentados e discutidos os conceitos básicos relacionados à Modelagem Lagrangiana Estocástica de Partículas, bem como suas principais características e sua implementação computacional, para o estudo da dispersão de partículas na atmosfera. Numa experimentação computacional, comparam-se os resultados obtidos com dados observacionais provenientes do experimento TRACT, realizado na Europa em 1992. Os dados de entrada necessários ao modelo de dispersão são extraídos de simulações do modelo de previsão numérica do tempo RAMS. A dispersão sobre o Estado do Rio de Janeiro é também testada em um segundo experimento.
Tjulin, Anders. "Waves in space plasmas : Lower hybrid cavities and simple-pole distribution functions." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3527.
Повний текст джерелаDreiling, Jennifer [Verfasser]. "Crustal structures in southern Madagascar and Sri Lanka in the context of Gondwana’s assembly and break-up : A study based on surface wave dispersion and receiver functions / Jennifer Dreiling." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/121203175X/34.
Повний текст джерелаGoncalves, Juliana Bittencourt. "EMPREGO DE UM MODELO DE DISPERSÃO TURBULENTO NO ESTUDO DA UNIVERSALIDADE DA TAXA DE DISSIPAÇÃO DA ENERGIA." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/10254.
Повний текст джерелаThis study employed different autocorrelation functions and Maclaurin series expansions in the derivation of expressions describing the dissipation rate of turbulent kinetic energy. These expressions have the same functional form, but are described in terms of different numerical coefficients. The values obtained for the numerical coefficients were used in a Lagrangian stochastic dispersion model to simulate the dispersion of contaminants in the Planetary Boundary Layer (PBL). The simulation results were compared with concentration data observed in the Copenhagen experiment. The good performance of the parameterization and analysis through statistical indices showed that the mathematical relationships that describe the turbulent dissipation rate present an uncertainty. The analysis developed in this study indicates that there is no a universal functional form describing the dissipation rate of turbulent energy.
Neste estudo foram empregadas diferentes funções de autocorrelação e expansões em série de Maclaurin na derivação de expressões que descrevem a taxa de dissipação da energia cinética turbulenta. Estas expressões apresentam a mesma forma funcional, porém são descritas em termos de diferentes coeficientes numéricos. Os valores obtidos para os coeficientes numéricos foram empregados em um modelo de dispersão estocástico Lagrangiano para simular a dispersão de contaminantes na Camada Limite Planetária (CLP). Os resultados das simulações foram comparados com dados de concentração do experimento de Copenhagen. O bom desempenho da parametrização e a análise através de índices estatísticos permitiram concluir que as relações matemáticas que descrevem a taxa de dissipação da turbulenta, apresentam uma incerteza. A análise desenvolvida nesse estudo permite concluir que não existe uma forma funcional universal descrevendo a taxa de dissipação de energia turbulenta.
Gibbons, Luke J. "Nanocomposite Dispersion: Quantifying the Structure-Function Relationship." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77214.
Повний текст джерелаPh. D.
Johnson, Erin R. "A density-functional theory including dispersion interactions." Thesis, Kingston, Ont. : [s.n.], 2007. http://hdl.handle.net/1974/926.
Повний текст джерелаAlison, John Michael. "A dielectric study of lossy materials over the frequency range four to eighty-two gigahertz." Thesis, King's College London (University of London), 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263831.
Повний текст джерелаMididoddi, Rajiv. "Investigation on material dispersion as a function of pressure and temperature for sensor design." ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,109.
Повний текст джерелаTitle from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Electrical Engineering."--Thesis t.p. Vita. Includes bibliographical references.
Nisa, Khoirin. "On multivariate dispersion analysis." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2025.
Повний текст джерелаThis thesis examines the multivariate dispersion of normal stable Tweedie (NST) models. Three generalize variance estimators of some NST models are discussed. Then within the framework of natural exponential family, two characterizations of normal Poisson model, which is a special case of NST models with discrete component, are shown : first by variance function and then by generalized variance function. The latter provides a solution to a particular Monge-Ampere equation problem. Finally, to illustrate the application of generalized variance of normal stable Tweedie models, examples from real data are provided
Pilemalm, Robert. "Dispersion forces in a four-component density functional theory framework." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18487.
Повний текст джерелаThe main purpose of this thesis is to implement the Gauss--Legendre quadrature for the dispersion coefficient. This has been done and can be now be made with different number of points. The calculations with this implementation has shown that the relativistic impact on helium, neon, argon and krypton is largest for krypton, that has the highest charge of its nucleus. It was also seen that the polarizability of neon as a function of the imaginary angular frequency decreases monotonically from a static value.
Valencia, Germán Ayala. "Propriedades físicas de filmes à base de biopolímeros reforçados com laponita." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-31072017-094541/.
Повний текст джерелаThe environmental problems caused by packaging based on non-biodegradable synthetic materials have lead to a significant increase in studies about biopolymer films. However, these films have limited physicochemical properties due mainly to its sensitivity to ambient relative humidity. Among the alternatives studied to improve the physicochemical properties of these materials is the use of nanoparticles, especially the montmorillonite, which has problems of dispersion in water. Another nanoparticle no so much studied in films based on biopolymers is laponite, which is a synthetic nanoparticle. Thus, this these aims to development and characterize films based on biopolymers (collagen, gelatin and cassava starch), with a nanoparticle (laponite). The effects of biopolymer and laponite concentrations were studied, as well as, the film production method (casting and spreading), besides the quality of laponite dispersion and its relationship with the physicochemical properties of the films were investigated, with special interest on the surface properties. The films were produced by the dehydration of filmogenic-forming solutions (FFS), with 2, 4 or 8 g of biopolymer/100 g FFS; 25 or 30 g glycerol/100g of biopolymer; and 0, 1.5, 3, 4.5 and 6 g of laponite/100g of biopolymer. The laponite was dispersed in water using ultraturrax, at 20,000 rpm, for 30 minutes. The laponite particles in water had sizes smaller than 50 nm. There was not effect of biopolymer concentration and film production method (casting or spreading) on the surface and physicochemical properties studied in the nanocomposite films. X-ray analysis and Fourier transform infrared spectroscopy revealed that laponite platelets were exfoliated and/or intercalated in the films, and that there were no formed chemical bonds between laponite platelets and the biopolymers studied. The presence of laponite increased the surface irregularity of the films, especially in those produced with collagen and cassava starch. Other properties in the nanocomposite films, such density, moisture content, color, opacity, thermal properties, mechanical properties, water solubility, water contact angle, sorption isotherms and water vapor permeability were not altered by the presence of laponite.
Kazemi, Noj. "Circuit analysis of a parallel plate waveguide." Thesis, KTH, Elektroteknisk teori och konstruktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-222617.
Повний текст джерелаM°alet med detta arbete var att modellera en fyr-portars v°agledare somen simpel elektrisk krets, genom att f¨orst b¨orja med en tv°a-portars sedantre-portars -v°agledare. Detta arbete var baserat p°a Nathan Marcuvitz bokWaveguide handbook, d¨arav s¨oktes det en analytisk l¨osning f¨or kretsparametrarna.F¨or att kunna f°a en analytisk l¨osning, studerades tre metoder;Variationsmetoden, Integralsekvationsmetoden samt den Statiskametoden.Av dessa tre metoder valdes den sistn¨amnda, p°a grund av dess styrka medatt f¨orenkla randvillkoren. M°alet att modellera en fyr-portars samt en treportarsv°agledare var alldeles f¨or komplicerat. Detta ledde till att m°alet¨andrades till att f¨ors¨oka f°a en h¨ogre precision p°a den befintliga kretsmodellenf¨or en tv°a portars v°agledare, genom att l¨osa ut flera termer till kretsparametern.Detta gjordes d°a Marcuvitz endast hanterade de tv°a f¨orstamoderna korrekt, samt att det inte framgick ifall kretsmodellen ¨ar stabil f¨orh¨ogre ordningar av Taylor serier. I slut¨andan l¨ostes en kretsmodel f¨or env°agledare med en iris som hanterar de f¨orsta 16 moderna korrekt. Genomatt kolla p°a de dispersiva egenskaperna f¨or kretsen, kunde en j¨amf¨orelse medsimuleringsprogrammet CST Microwave Studio ske, d¨ar slutsatsen blev attkretsmodellen gav goda resultat upp till 2b/ < 1. Det visade ¨aven sig attprecisionen var ungef¨ar densamma som den kretsmodell som°aterfinns i Waveguidehandbook, men det kan n¨amnas att precisionen ¨ar minimalt b¨attref¨or den kretsmodell som togs fram i detta arbete. En sak som uppt¨acktes underdetta arbete var att restriktionen som n¨amns i Waveguide handbook f¨orfallet n¨ar gapet f¨or irisen ¨ar centrerad st¨ammer inte, den b¨or vara 2b/ < 1.Dessutom visade det sig att kretsmodellen fortfarande var stabil f¨or h¨ogreordningar av Taylorserier, i detta fall upp till den 16:e ordningen.
Dobson, Benjamin Pirnie. "Dispersions of graphene for use as thermal and functional fluids." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12570/.
Повний текст джерелаPatra, Abhirup. "Surface properties, adsorption, and phase transitions with a dispersion-corrected density functional." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/516784.
Повний текст джерелаPh.D.
Understanding the “incomprehensible” world of materials is the biggest challenge to the materials science community. To access the properties of the materials and to utilize them for positive changes in the world are of great interest. Often scientists use approximate theories to get legitimate answers to the problems. Density functional theory (DFT) has emerged as one of the successful and powerful predictive methods in this regard. The accuracy of DFT relies on the approximate form of the exchange-correlation (EXC) functional. The most complicated form of this functional can be as accurate as more complicated and computationally robust method like Quantum Monte Carlo (QMC), Random Phase Approximation (RPA). Two newest meta-GGAs, SCAN and SCAN+rVV10 are among those functionals. Instantaneous charge fluctuation between any two objects gives rise to the van der Waals (vdW) interactions (often termed as dispersion interactions). It is a purely correlation effect of the interacting electrons and thus non-local in nature. Despite its small magnitude it plays a very important role in many systems such as weakly bound rare-gas dimers, molecular crystals, and molecule-surface interaction. The traditional semi-local functionals can not describe the non-local of vdW interactions; only short- and intermediate-range of the vdW are accounted for in these functionals. In this thesis we investigate the effect of the weak vdW interactions in surface properties, rare-gas dimers and how it can be captured seamlessly within the semi-local density functional approximation. We have used summed-up vdW series within the spherical-shell approximation to develop a new vdW correction to the meta-GGA-MS2 functional. This method has been utilized to calculate binding energy and equilibrium binding distance of different homo- and hetero-dimers and we found that this method systematically improves the MGGA-MS2 results with a very good agreement with the experimental data. The binding energy curves are plotted using this MGGA-MS2, MGGA-MS2-vdW and two other popular vdW-corrected functionals PBE-D2, vdW-DF2. From these plots it is clear that our summed-up vdW series captures the long-range part of the binding energy curve via C6, C8, and, C10 coefficients. The clean metallic surface properties such as surface energy, work functions are important and often play a crucial role in many catalytic reactions. The weak dispersion interactions present between the surfaces has significant effect on these properties. We used LDA, PBE, PBSEsol, SCAN and SCAN+rVV10 to compute the clean metallic surface properties. The SCAN+rVV10 seamlessly captures different ranges of the vdW interactions at the surface and predicts very accurate values of surface energy ( ) , and work function (𝞥) and inter-layer relaxations (𝞭%). Our conclusion is adding non-local vdW correction to a good semi-local density functional such as SCAN is necessary in order to predict the weak attractive vdW forces at the metallic surface. The SCAN+rVV10 has also been employed to study the hydrogen evolution reaction (HER) on 1T-MoS2. We have chosen as a descriptor differential Gibbs free energy (𝚫 GH ) to understand the underlying mechanism of this catalytic reaction. Density functional theory calculations agree with the experimental findings. In the case of layered materials like 1T-MoS2, vdW interactions play an important role in hydrogen binding, that SCAN+rVV10 calculation was able to describe precisely. We have also used SCAN and SCAN+rVV10 functionals to understand bonding of CO on (111) metal surfaces, where many approximations to DFT fail to predict correct adsorption site and adsorption energy. In this case SCAN and SCAN+rVV10 do not show systematic improvements compared to LDA or PBE, rather, both SCAN and SCAN+rVV10 overbind CO more compared to PBE but less compared to the LDA. This overbinding of CO is associated with the incorrect charge transfer from metal to molecule and presumably comes from the density-driven self-interaction error of the functionals. In this thesis we assessed different semi-local functionals to investigate molecule surface systems of 𝞹-conjugated molecules (thiophene, pyridine) adsorbed on Cu(111), Cu(110), Cu(100) surfaces. We find the binding mechanism of these molecules on the metallic surface is mediated by short and intermediate range vdW interactions. Calculated values of binding energies and adsorbed geometries imply that this kind of adsorption falls in the weak chemisorption regime. Structural phase transitions due to applied pressure are very important in materials science. However, pressure induced structural phase transition in early lanthanide elements such as Ce are considered as abnormal first order phase transition. The Ce 𝝰-to-𝝲 isostructural phase transition is one of them. The volume collapse and change of magnetic properties associated with this transition are mediated by the localized f-electron. Semi-local density functionals like LDA, GGA delocalize this f-electron due to the inherent self-interaction error (SIE) of these functionals. We have tested the SCAN functional for this particular problem, and, it was found that the spin-orbit coupling calculations with SCAN not only predicts the correct magnetic ordering of the two phases, but also gives a correct minima for the high-pressure 𝝰-Ce phase and a shoulder for the low-pressure 𝝲-Ce phase.
Temple University--Theses
Moor, Lilian Piecha. "Proposta de uma nova função de autocorrelação para o estudo do meandro do vento horizontal." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/3935.
Повний текст джерелаIn this study is propose a new mathematical expression to describe the observed meandering autocorrelation functions in low-wind speed. The analysis utilizes a large number of the data to show that the new proposed theoretical function reproduces the experimental behavior of the fit curves, well as the negative lobes that characterizing the autocorrelation function for meandering condition. Furthermore, the good agreement of the measured autocorrelation curves with the proposed algebraic autocorrelation function allows to calculate the magnitudes of the meandering period and of the loop parameter. In adition, the parameters founded in this study can be used to simulate the dispersion of contaminant during low wind episodes. The results agree with the values presented and discussed in the literature.
O presente estudo propõe uma nova expressão matemática para descrever as funções de autocorrelação observadas sob condições de meandro do vento horizontal. A análise utiliza um grande número de dados para demonstrar que a função proposta reproduz o comportamento da curva experimental, bem como os lóbulos negativo que caracterizam a função de autocorrelação para a situação de meandro. Além disso, a boa concordância entre as curvas de autocorrelação observadas e a nova função de autocorrelação algébrica, proposta neste trabalho, permitiu realizar o cálculo de grandezas físicas como o parâmetro de oscilação e o período de meandro. Um resultado adicional, foi empregar os valores médios encontrados para os parâmetros do meandro na simulação da dispersão de contaminante durante episódios de vento fraco. Os resultados encontrados estão de acordo com os valores apresentados e discutidos na literatura.
Carpentier, Florence. "Modélisations de la dispersion du pollen et estimation à partir de marqueurs génétiques." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20101.
Повний текст джерелаPollen dispersal is a major component of gene flow in plants. It determines to genetic diversity and spatial genetic structure.Studying it at the scale of a single reproduction event enables to understand the impact of current changes (fragmentation, anthropization ...) and to propose conservation practices.Two types of methods, based on microsatellite markers, estimate pollen dispersal functions : (i) direct methods (e.g. mating model) based on paternity assignment require exhaustif sampling (position and genotype of individuals in the study plot, genotypes of seeds harvested on mothers); (ii) indirect methods (e.g. TwoGener), require a weaker sampling (seeds genotypes, genotypes and positions of their mothers) and summarize data through genetic indices.We propose a statistical formalization of both types of methods and show that they rely on different dispersal functions : the direct methods estimate a potential forward function (pollen transfer from the father), whereas the indirect methods estimate an integrative backward one (from fecondation to father existence). We exhibit the link between forward and backward functions, assumptions leading to their equivalence and constrains affecting the backward functions.Finally, we develop an Approximate Bayesian Computation method, which enable (i) a forward estimation, (ii) with credibility intervals, (iii) from a non exhaustive dataset and partial information (e.g. positions without genotypes) and (iv) the use of different dispersal models
Hermann, Jan. "Towards unified density-functional model of van der Waals interactions." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18706.
Повний текст джерелаThe ubiquitous long-range van der Waals interactions play a central role in nearly all biological and modern synthetic materials. Yet the most widely used theoretical method for calculating material properties, the density functional theory (DFT) in semilocal approximation, largely neglects these interactions, which motivated the development of many different vdW models. The work in this thesis paves way towards a unified vdW model that combines best elements from the different classes of the vdW models. To this end, we developed a unified theoretical framework based on the range-separated adiabatic-connection fluctuation--dissipation theorem that encompasses most existing vdW models. We analyze the MBD correlated wave function on the prototypical case of π–π interactions in supramolecular complexes and find that these interactions are largely driven by delocalized collective charge fluctuations. To identify a balanced short-range density functional to accompany the long-range vdW model, we present a comprehensive study of the interplay between the short-range and long-range energy contributions in eight semilocal functionals and three vdW models on a wide range of systems. The binding-energy profiles of many of the DFT+vdW combinations differ both quantitatively and qualitatively, and some of the qualitative differences are independent of the choice of the vdW model. Finally, we investigate the performance of the Vydrov—Van Voorhis polarizability functional across the periodic table, identify systematic underestimation of the polarizabilities and vdW C₆ coefficients for s- and d-block elements, and develop an orbital-dependent generalization of this functional to resolve the issue.
Gunasinghe, Rosi Najeela. "Structural and electronic properties of boron nano structures: A dispersion-corrected density functional study." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2012. http://digitalcommons.auctr.edu/dissertations/341.
Повний текст джерелаEdwards, Angela Celeste. "Probing the Hydrogen Bonding Interaction at the Gas-Surface Interface using Dispersion Corrected Density Functional Theory." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71784.
Повний текст джерелаMaster of Science
Kim, Jeong-Han. "Optical display of the Airy function and transient wave propagation in a dispersive medium." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02132009-172038/.
Повний текст джерелаOthman, Rahimah. "Production of functional pharmaceutical nano/micro-particles by solvent displacement method using advanced micro-engineered dispersion devices." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/22905.
Повний текст джерелаForsythe, Martin Blood Zwirner. "Advances in Ab Initio Modeling of the Many-Body Effects of Dispersion Interactions in Functional Organic Materials." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:26718708.
Повний текст джерелаPhysics
Lucena, Rodrigo Ferreira de. "Avaliações e testes dos métodos MASW e ReMi por meio do tratamento de dados empíricos e sintéticos em um programa de processamento e inversão desenvolvido em MATLAB e sua implicação em um problema geológico na Bacia de Taubaté." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/44/44138/tde-17062016-135652/.
Повний текст джерелаThe surface wave methods to Rayleigh waves were used as the center of this Doctoral work. Initially, the Rayleigh waves were modeled, what enabled the study of the sensitivity of dispersion curves about different sets of physical parameters representing several layer models, wherein it could be observed parameters with higher and lower sensitivity and also some effects caused by low Poisson ratios. Moreover, in the data inversion step the Rayleigh modeling was used for the construction of the object function, that aggregate to the least-squares method, by Levenberg-Marquardt, allowed the implementation of a local search algorithm responsible for data inversion of the surface waves. By reason of being a local search procedure, the data inversion algorithm was complemented with a pre-inversion step wherein an initial model was generated so that the inversion procedure was faster and efficient. Seeking a more efficiency of the inversion procedure, mainly to layer models with velocities inversion, it was implemented a post-inversion algorithm based in a trial and error procedure minimizing the values of the relative Root Mean Squared Error (rRMSE) of the data inversion. More than 50 layer models were used to test the data modeling, pre-inversion, inversion and post-inversion allowing the precise fit of the mathematical and physical parameters present in the several scripts implemented in Matlab. Before to invert the field-acquired data, they need to be treated in the data processing step, whose main aim is the extraction of the dispersion curve caused due the surface waves. For this, three processing methodologies with different mathematical approaches were implemented, also in Matlab. These methodologies were tested and evaluated with synthetic and real data and it was possible to find their strengths and weaknesses, as well as the limitations caused by discretization of the field data. Lastly, the data processing, pre-inversion, inversion and post-inversion steps were unified to form a complete data treatment program of surface waves (Rayleigh). It was used to real data originated by study of a geological problem in the Bacia de Taubaté wherein it was possible to map the geologic contacts along of the seismic acquisition points. The results were compared to an existing initial model based in geomorphological observations of the study area, geological map and global and local geologic information of the tectonic movements in the region. The geophysical The surface wave methods to Rayleigh waves were used as the center of this Doctoral work. Initially, the Rayleigh waves were modeled, what enabled the study of the sensitivity of dispersion curves about different sets of physical parameters representing several layer models, wherein it could be observed parameters with higher and lower sensitivity and also some effects caused by low Poisson ratios. Moreover, in the data inversion step the Rayleigh modeling was used for the construction of the object function, that aggregate to the least-squares method, by Levenberg-Marquardt, allowed the implementation of a local search algorithm responsible for data inversion of the surface waves. By reason of being a local search procedure, the data inversion algorithm was complemented with a pre-inversion step wherein an initial model was generated so that the inversion procedure was faster and efficient. Seeking a more efficiency of the inversion procedure, mainly to layer models with velocities inversion, it was implemented a post-inversion algorithm based in a trial and error procedure minimizing the values of the relative Root Mean Squared Error (rRMSE) of the data inversion. More than 50 layer models were used to test the data modeling, pre-inversion, inversion and post-inversion allowing the precise fit of the mathematical and physical parameters present in the several scripts implemented in Matlab. Before to invert the field-acquired data, they need to be treated in the data processing step, whose main aim is the extraction of the dispersion curve caused due the surface waves. For this, three processing methodologies with different mathematical approaches were implemented, also in Matlab. These methodologies were tested and evaluated with synthetic and real data and it was possible to find their strengths and weaknesses, as well as the limitations caused by discretization of the field data. Lastly, the data processing, pre-inversion, inversion and post-inversion steps were unified to form a complete data treatment program of surface waves (Rayleigh). It was used to real data originated by study of a geological problem in the Bacia de Taubaté wherein it was possible to map the geologic contacts along of the seismic acquisition points. The results were compared to an existing initial model based in geomorphological observations of the study area, geological map and global and local geologic information of the tectonic movements in the region. The geophysical information associated with geological information allowed the generation of an analytical profile of the study region with two geological interpretation confirming the suspect of neotectonic movements in the region wherein the geological contacts between the quaternary and tertiary deposits were identified and they agreed with the initial model of a hemi-graben with dip to Southeast.
Barbosa, Itamar Magno. "Estudo das dispersões metrológicas em redes neurais artificiais do tipo Multilayer Perceptrons através da aplicação em curvas de calibração." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-12082010-113757/.
Повний текст джерелаThe present study investigates metrological dispersions in fitting partially or totally unknown functions. An alternative method is the application of a multilayer perceptron neural network used here to fit functions. The fitting functions are calibration curves from calibration indications of measurement systems or instruments. These curves hold metrological properties and establish a link between elements of Metrological theory and elements of Computing Intelligence theory: the Multilayer Perceptrons. An external balance of aerodynamic forces and moments and an electronic tongue applied in the measurement of cation concentrations were the measurement systems used to apply the concepts of this alternative methodology. This thesis proposes improvements in the accuracy of fitting calibration curves considering the following factors: influence quantities, uncertainties about target values, tendency of hidden or not solved systematic errors and metrological performance functions. The measurement quality indicator or the laboratory metrological competence indicator is established by uncertainty values and the calibration curve is the starting point for the calculation of these values. The establishment of this curve is one of the difficulties in assessing uncertainties and the curve itself is an uncertainty source. Therefore, a careful and meticulous methodology is necessary in curve approximation, which explains the strategic importance of this work. Metrological dispersions have connotation of uncertainty in measurements and are the basis for calculating their numerical values, the performance functions can represent metrological dispersions and the opposite is also true: the standard uncertainty can be a performance function. Making a synthesis, this thesis demonstrates how computing intelligence theory takes into account the metrological theory and vice versa, in the elements of these theories that were discussed in the present study.
Campos, Vanessa Ellen Wendt [UNESP]. "O efeito da fragmentação na diversidade específica e funcional de primatas no Brasil." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/141536.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
As florestas tropicais representam um dos biomas mais ameaçados pelas ações antrópicas no mundo. Os primatas representam 40% da biomassa de vertebrados frugívoros nas florestas tropicais, mas mais da metade das espécies estão ameaçadas de extinção. Tendo em vista a importância dos primatas no funcionamento dos ecossistemas devido a sua função de dispersores de sementes, é de extrema relevância entender como a fragmentação das florestas tropicais afetam as comunidades de primatas e suas funções. Portanto, nossos objetivos são: 1) analisar a relação entre diversidade funcional e filogenética de primatas e como esses índices são influenciados pela riqueza; 2) determinar o efeito da fragmentação das florestas tropicais na riqueza específica e funcional dos primatas; 3) determinar quais características funcionais são perdidas com a fragmentação, na Amazônia e na Mata Atlântica brasileira. Para isso, montamos bancos de dados de ocorrência dos primatas e de suas características funcionais ligadas à dispersão de sementes para gerar os índices de diversidade funcional (FD), regularidade funcional (FEve) e divergência funcional (FDiv) e relacioná-los com métricas da paisagem: área do fragmento, isolamento médio entre os fragmentos, distância em relação à zona urbana, distância à floresta contínua, conectividade funcional e porcentagem de cobertura vegetal no entorno do fragmento. A diversidade funcional dos primatas é fortemente correlacionada com a diversidade filogenética (R2= 0.94 e p<0.001). A redução da área dos fragmentos e da conectividade funcional, assim como o aumento do isolamento médio entre os remanescentes florestais diminuem a diversidade (FD), a regularidade (FEve) e a divergência funcional (FDiv) dos primatas. As espécies de primatas de grande porte que possuem grandes áreas de vida e que dispersam grandes sementes são as espécies mais prejudicadas pela fragmentação. Nosso trabalho permitiu ressaltar que além da perda de riqueza específica de primatas, a fragmentação nas florestas tropicais também afeta o serviço de dispersão de sementes, o que, consequentemente, pode alterar a estrutura das comunidades vegetais.
Tropical forests are the most threatened biome by human activities worldwide. Primates represent almost 40% of the frugivore vertebrate biomass in tropical forests and more than half of their species are threatened by extinction. Given the importance of primates as seed dispersers for the ecosystem functioning, it is extremely important to understand how the fragmentation of tropical forests affects primate communities and the functions they provide. Therefore, this project aims at: 1) analyzing the relationship between primate functional and phylogenetic diversities and how those indices are influenced by species richness; 2) determining the influence of forest fragmentation on primate species richness and functional diversity; 3) determining which functional traits are lost with habitat fragmentation, in Amazonian and Atlantic Forests of Brazil. To do this, we built a database of primates’ occurrence and their functional traits related to seed dispersal to compute indices of functional diversity (FD), functional evenness (Feve) and functional divergence (FDiv). Then, we related these indices to landscape metrics: patch size, average isolation between patches, distance to the nearest urban area, distance to the nearest continuous forest, functional connectivity and percentage of forest cover surrounding the fragment. Functional diversity is strongly correlated with phylogenetic diversity (R2= 0.94 e p<0.001). The decrease of fragment areas and functional connectivity, and the increase of average isolation between forest remnants, reduce primate functional diversity (FD), regularity (FEve) and divergence (FDiv). Large primates with large home ranges that disperse large seeds are the most affected by fragmentation. Our results enable highlighting that beyond the loss of primate species richness, the fragmentation of tropical forests also affect seed dispersal service, which consequently may alter the structure of plant communities.
FAPESP: 2014/14739-0
CNPq: 830816/1999-2
Kerber, Torsten. "Dispersionskorrekturen von DFT für Festkörperprobleme." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16634.
Повний текст джерелаIn this work, the long-range dispersion correction for density functional theory is extended to periodic boundary conditions. The influence of the dispersion correction on energy and structural parameters is shown for graphite. The calculated values of the interlayer distance and the interaction energy are in good agreement with experimental ones. By a series of cluster calculations it is shown, that the dispersion correction converges very slowly with respect to the system size. The accurate description of the dispersion interaction between graphite layers requires the usage of PBE+D method applying periodic boundary conditions or embedded cluster models. For structural parameters, the PBE+D methods compares well with the accurate but computationally very demanding [MP2:PBE+CCSD(T)] method. However, the calculated reaction energies differ remarkably. The newly developed, efficient [PBE+D + MP2 + CCSD(T)] method extends the PBE+D energy by two correction terms. The first one, the MP2 correction, rectifies the over stabilization of polar structures (PBE) by a MP2 calculation at the basis set limit. The second term verifies the MP2 correction by a CCSD(T) calculation for a small cluster model. The [PBE+D + MP2 + CCSD(T)] method is applied for the reaction of C4H8 hydro carbons witr the zeolite Ferrierite. Within the pore of a zeolite, pi complexes, butyl cations and surface alkoxides are identified as minima on the potential energy surface. The isomerization of butenes is compared to the rearrangement of linear butyl cations in the gas phase. In both cases, the rate determining step is the formation of the tertial butyl cation from a methyl bridged cation. The CCSD(T) method is for the determination of accurate energy profiles required.
Grossman, Esther Florence. "Comparing B3LYP and its dispersion-corrected form to B97-D3 for studying adsorption and vibrational spectra in nitrogen reduction." Ohio University Honors Tutorial College / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors155628790845.
Повний текст джерелаBovo, Alex Augusto de Abreu. "Diversidade e riqueza funcional de assembleias de aves na Mata Atlântica." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-19042016-111324/.
Повний текст джерелаBird assemblages composition suffer alteration according to landscape changes. The substitution of forest by others land uses can affect the group of functions, and consequently, the ecological process played by birds. This dissertation had two main goals: 1) to identify landscape metrics which has relation with functional diversity and richness of bird assemblages; and 2) to identify morphological changes in fruit-eater bird assemblage and discuss the potentials impacts on the seed dispersal process. To reach this, a database was created using literature data, with 48 bird assemblages of Atlantic Forest remnants from 33 studies. From the most central point of each fragment, was created a focal landscape of 2000 meters buffer, the land use was classified in \'forest\' or \'non-forest\' and metrics was calculated. The index of bird assemblages used were composition and functional diversity and richness, calculated using morphological and habitat traits. Linear regression and mixed models were used to investigate relationships between landscape metrics and i) functional diversity and richness of forest birds (obj. 1) and ii) functional diversity, species richness and morphological traits of fruit-eater birds (obj. 2). The results showed that fragment area and core area were the most important traits to preserve the functions in bird assemblage, demonstrating the importance of big blocks of forest. To morphological changes, the decreasing on forest over was related to decreases on values of: body mass, hand-wing index and bill width. The reduction of these values can promote the dispersal of smaller seeds, reduction on dispersal of plants with big seed and decreases of area cover by seed rain.
Vilamiu, Raphael Gustavo d'Almeida. "Generalização da decomposição por EMD para grafos e sua aplicação à dispersão geográfica da dengue." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306715.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica
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Resumo: Nesta tese, desenvolvemos uma técnica para gerar grafos à partir de conjuntos de séries temporais considerando a correlação entre estas e uma extensão do Método de Decomposição Empírica (EMD) para grafos (GEMD). Tal trabalho se justifica pelo fato de que uma grande gama de sinais formados por conjuntos de séries temporais não possuem uma localização bem definida em nenhum espaço n-dimensional. Desta forma, as relações entre as séries temporais só são satisfatoriamente representadas com o uso de grafos. Contudo, o desenvolvimento do GEMD é dependente do uso de algum método de interpolação em grafos. Tais métodos são escassos e não produzem propriedades satisfatórias para o uso no GEMD. Para esta finalidade, estendemos a interpolação por Funções de Base Radial (RBF) em Grafos (GRBF), onde a norma euclidiana no cálculo da matriz de interpolação por RBF é substituída pela norma induzida pelo grafo. Testes numéricos sugerem que a extensão possui boas propriedades de convergência e uma técnica é desenvolvida para garantir a existência e unicidade da solução. Finalmente, aplicamos o GEMD em um conjunto de dados de incidência de Dengue Hemorrágica na Tailândia. Os modos intrínsecos encontrados desta forma não apresentam nenhuma onda viajante emanando de nenhuma das províncias, contrastando com o resultado utilizando o EMD original [5]. Além disso, os períodos médios dos modos intrínsecos de [5] são claramente distintos dos encontrados pela decomposição por GEMD
Abstract: In this thesis, we developed a technique to generate a graph from a set of temporal series, which are then decomposed trough an extension of the Empirical Mode Decomposition (EMD) on Graphs (GEMD) created by us. This procedure is justified by the fact that a huge amount of signals cannot be properly localized on an n-dimensional space which can only be properly represented by a graph. The development of the GEMD is dependent on some graph interpolation method. Such methods are scarce in the literature and do not have the necessary properties to accomplish the GEMD decomposition. For this goal, we extend the Radial Basis Functions (RBF) interpolation to graphs (GRBF), where the euclidean norm used in the calculation of the RBF interpolation matrix is substituted by a graph induced norm. Numerical tests suggests that GRBF have good convergence properties and we present a technique which guarantees the existence and uniqueness of the solution. We finally apply the GEMD decomposition to a data set of Dengue Hemorrhagic Fever incidence in Thailand. The intrinsic modes found in this way do not show any traveling wave emanating from any of the provinces, contrasting with the results found using the original EMD [5]. Moreover, the mean period for the intrinsic modes in [5] are clearly diverse of those found by GEMD decomposition
Doutorado
Doutor em Matemática Aplicada
Yang, Qianqian. "Novel analytical and numerical methods for solving fractional dynamical systems." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/35750/1/Qianqian_Yang_Thesis.pdf.
Повний текст джерелаKooshapur, Sheema [Verfasser], Michael [Akademischer Betreuer] [Gutachter] Manhart, and Insa [Gutachter] Neuweiler. "Modelling dispersion on the pore scale based on the velocity distribution function / Sheema Kooshapur ; Gutachter: Insa Neuweiler, Michael Manhart ; Betreuer: Michael Manhart." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1118722388/34.
Повний текст джерелаRaoult, Cécile. "Modélisation numérique non-linéaire et dispersive des vagues en zone côtière." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1150/document.
Повний текст джерелаIn this work, a potential flow model based on the Euler-Zakharov equations was developed with the objective of simulating the propagation of irregular and multidirectional sea states from deep water conditions to the coast over variable bathymetry. A highly accurate representation of nonlinear and dispersive effects for bidimensional (2DH) nearshore and coastal domains on the order of kilometers is targeted.The preexisting 1DH version of the model, resolving the Laplace Boundary Value problem using a combination of high-order finite difference schemes in the horizontal direction and a spectral approach in the vertical direction, was improved and validated. The generation of incident waves through the implementation of specific Dirichlet and Neumann boundary conditions was studied in detail. In practice, these conditions were used in combination witha relaxation zone to improve the stability of the model.The linear dispersion relation of the model was derived analytically for the flat bottom case. Its analysis showed that the accuracy of the representation of dispersive effects improves significantly by increasing the vertical resolution (i.e. the maximum degree of the Chebyshev polynomial basis used to project the potential in the vertical). A convergence study conducted for moderate to highly nonlinear solitary waves confirmed the exponential convergence in the vertical dimension owing to the spectral approach, and the algebraic convergence in time and in space (horizontal dimension) with orders of about 4 (or higher) in agreement with the numerical schemes used.The capability of the model to represent nonlinear effects induced by variable bathymetry, such as the transfer of energy between harmonic components, as well as the accurate representation of dispersive properties, were demonstrated with comparisons to several experimental data sets. A visco-potential flow formulation was also implemented to take into account viscous effects induced by bulk viscosity and bottom friction. This formulation was validated inthe limit of small viscosity for mild slope bathymetries.To represent 2DH wave fields in complex nearshore domains, the model was extended using an unstructured discretization (scattered nodes) in the horizontal plane. The horizontal derivatives were estimated using the RBF-FD (Radial Basis Function - Finite Difference) method, while the spectral approach in the vertical remained unchanged. A series of sensitivity tests were conducted to evaluate numerically the robustness of the RBF-FD method, including a comparison of a variety of RBFs with or without shape factors and augmented polynomials. The 2DH version of the model was used to simulate two wave basin experiments, validating the approach and demonstrating the applicability of this method for 3D wave propagation, including nonlinear effects. As an initial attempt to improve the computational efficiency ofthe model for running simulations of large spatial domains, the code was adapted to use a parallelized direct linear solver
Morais, Douglas Souza Figueiredo. "Estudo da crosta no sudoeste do cráton amazônico utilizando técnicas sismológicas /." Rio Claro, 2018. http://hdl.handle.net/11449/182036.
Повний текст джерелаResumo: Técnicas sismológicas como Função do Receptor, Análise de Dispersão de Ondas de Superfície, Correlação de ruídos sísmicos e razão espectral H/V são cada vez mais estudadas e utilizadas para o conhecimento geológico da crosta. Sendo possível determinar a composição crustal média e os principais contatos obtidos por fortes contrastes de impedância tais como limite crosta superior e inferior, assim como, limite crosta inferior e manto superior (descontinuidade de Moho). O conhecimento da velocidade de percurso das ondas de um sismo registrados através de uma estação sismográfica fornecem informações, como: o tempo de percurso, relação Vp/Vs e outros. A região de Pontes e Lacerda/MT está localizada no Sudoeste do Cráton Amazônico e o levantamento dos dados se deram em fases distintas com implantação de sismômetros alinhados em direção perpendicular (NE-SW) às principais estruturas da Faixa Móvel Aguapeí (NNW-SSE). Além da coleta de dados dessas estações temporárias foram compilados dados de sismos para a estação fixa PTLB, esta estação faz parte das estações sismológicas coordenadas pela UNB (Universidade Nacional de Brasília) e pela USP (Universidade de São Paulo). A espessura média encontrada na crosta para a região variou pouco para as diferentes técnicas abordadas, sendo que, para a técnica de Função do Receptor (estação fixa PTLB) foi obtido valor de aproximadamente 44 Km de espessura e, para as estações temporárias (S01 ao S10) valor médio de 42 km. Já a seção sísmica gerad... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Seismic techniques such as receiver function, surface wave dispersion, seismic noise correlation and H / V spectral ratio are increasingly studied and used for geological knowledge of the crust. It is possible to determine the average crustal composition and the main contacts obtained by strong impedance contrasts as upper and lower crust boundary, as well as, lower crust limit and upper mantle (Moho discontinuity). The knowledge of the speed of travel of the waves of an earthquake recorded through a seismographic station provides information, such as: the travel time, Vp / Vs ratio and others. The region of Pontes e Lacerda / MT is located in the Southwest of the Amazonian craton and the data were taken in different phases with the implantation of seismometers aligned in a perpendicular direction (NE-SW direction) to the main structures of the Faixa Móvel Aguapeí (direction NNW- SSE). In addition to collecting data from these temporary stations, earthquake data were collected for the PTLB fixed station. The average thickness found in the crust for the region did not vary much for the different techniques, and for the Receiver Function (PTLB fixed station), a value of approximately 44 Km of thickness was obtained and for the temporary stations (S01 to S10) average value of 42 km. The seismic section generated by the correlation of the signals for all short-time temporary stations brought the signals coherence in 4s, 5s and later coherence ranging from 9.5 to 11 seconds. This ... (Complete abstract click electronic access below)
Doutor
Favre-Bac, Lisa. "Rôle de corridor écologique des fossés pour la dispersion des espèces végétales dans les paysages agricoles." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S053/document.
Повний текст джерелаThe establishment of ecological networks is considered as one of the solutions to mitigate the negative effects of fragmentation on biodiversity. In agricultural landscapes, non-crop linear elements may form large networks, and constitute refuge habitats and/or dispersal corridors for plant species. The objective of this study is to understand which role may a dense drainage ditch network play for the maintenance and dispersal of plant species in an intensive agricultural landscape located in northern France. In addition, we also investigated the impact of landscape characteristics, network connectivity and plant species life-history traits on propagule dispersal within the ditch network. Our results indicate that ditches are indeed ecological corridors for plant species. By focusing more specifically on hydrochorous species, we demonstrated that they essentially depend on ditch network composition and connectivity and on elements immediately adjacent to the banks. The network also drives patterns of gene flow for two ditch bank plant species. Finally, our results also indicate that species’ response to ditch network connectivity depends on a combination of dispersal traits, and that connectivity reduction leads to functional convergence of those traits at the metacommunity scale. Together, these results provide a better understanding of the corridor role of ditches for plant species, in order to include these features into ecological network planning in agricultural landscapes
Greim, Dominik [Verfasser], and Jürgen [Akademischer Betreuer] Senker. "Disorder in solids probed by NMR chemical shielding using semi empirical dispersion corrected density functional theory / Dominik Greim ; Betreuer: Jürgen Senker." Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1223023354/34.
Повний текст джерелаEmin, Azad [Verfasser]. "Dispersive mixing of oil in plasticized starch by extrusion processing to design functional foods / Azad Emin." München : Verlag Dr. Hut, 2013. http://d-nb.info/1042307571/34.
Повний текст джерелаEmin, M. Azad [Verfasser]. "Dispersive mixing of oil in plasticized starch by extrusion processing to design functional foods / Azad Emin." München : Verlag Dr. Hut, 2013. http://d-nb.info/1042307571/34.
Повний текст джерелаSilva, Danylo Alves da. "Implementação de uma correção de dispersão empírica aos métodos semiempíricos RM1 (Recife Model 1) e PM6 (Parametric method 6)." Pós-Graduação em Química, 2017. https://ri.ufs.br/handle/riufs/6653.
Повний текст джерелаIn the present study, the implementation and parameterization of the dispersion correction functions, denominated DM1 and DM2, was carried out to the quantum semiempirical methods RM1 and PM6, in the program Mopac2007. The aim of this study is to improve the description of weak interactions by the methods above mentioned with the addition of na energy correction. The DM1 methodology contains 7 parameters while the DM2 model presents 13 parameters for the correction function. Unlike previous work, the correction was used to adjust not only the energy, but also the geometric parameters. The parameterization was performed using a training set composed by 10 structures from S22 database and 24 structures from S66 database. The results show that RM1-DM1 and RM1- DM2 improved the total response function when compared to RM1, the RM1- DM1 is better at describing the geometries of the complexes on the other hand, the RM1-DM2 is more efficient in reproducing the dispersion energy. The PM6- DM1 and PM6-DM2 methods, for the test set, had a smaller response function than PM7 and PM6 and their extensions with correction of dispersion forces. The best response function for PM6-DM1 and PM6-DM2 is related to the description of the geometries of the complexes, with the dispersion energy being slightly higher than that obtained by the PM6-DH2 method. The semiempirical methods discussed here, together with the theory of density functional, with the most popular B3LYP functional, were used to calculate the geometry of cyclodextrin/guest complexes. The results obtained, with semiempirical methods, showed that AM1, PM3, PM6-DM1 and PM6-DM2 presented the lowest values of RMSD and variability for a set of 43 cyclodextrins. The DFT methodology was used to calculate the geometry of a set of 9 cyclodextrins/guest complexes, the result was compared to semiempirical methods. The best DFT result was obtained with the 6-31G base, it is similar to obtained by the RM1 method. For this set, the methods AM1, PM6-DM1 and PM6-DM2 presented the best results in the description of the geometries.
No presente estudo foi realizada a implementação e parametrização das funções de correção de dispersão, denominadas DM1 e DM2, aos métodos semiempíricos quânticos RM1 e PM6, no programa Mopac2007. O estudo tem o como finalidade melhorar a descrição de interações fracas pelos métodos supracitados com a adição de uma correção de energia. A metodologia DM1 contém 7 parâmetros enquanto, o modelo DM2 apresenta 13 parâmetros para a função de correção. Diferente de trabalhos anteriores a correção foi usada para ajustar, não somente, a energia, mas também parâmetros geométricos. A parametrização foi executada usando um conjunto treinamento que usa 10 estruturas do banco de dados S22 e 24 estruturas do banco de dados S66. Os parâmetros obtidos através do conjunto treinamento foram aplicados ao conjunto teste, o qual é formado pelas 54 estruturas que não fizeram parte do conjunto treinamento. Os resultados mostram que RM1-DM1 e RM1-DM2 melhoraram a função resposta total quando comparado ao RM1, sendo o RM1-DM1 melhor em descrever as geometrias dos complexos e RM1-DM2 mais eficiente em reproduzir a energia de dispersão. Os métodos PM6-DM1 e PM6-DM2 para o conjunto teste apresentaram uma função resposta menor do que o PM7 e PM6 e suas extensões com correção das forças de dispersão. A melhor função resposta para PM6-DM1 e PM6-DM2 está relacionada a descrição das geometrias dos complexos, sendo a energia de dispersão um pouco maior do que a obtida pelo método PM6-DH2. Os métodos semiempíricos, aqui abordados, junto com a teoria do funcional da densidade, com o funcional mais popular B3LYP, foram usados para calcular a geometria de complexos ciclodextrina/convidado. Os resultados obtidos com os métodos semiempíricos mostraram que os métodos AM1, PM3, PM6-DM1 e PM6-DM2 apresentam os menores valores de RMSD e variabilidade para um conjunto de 43 ciclodextrinas. A metodologia DFT foi usada para calcular a geometria para um conjunto de 9 complexos ciclodextrinas/convidado, o resultado foi comparado aos métodos semiempíricos. O melhor resultado DFT foi obtido com a base 6-31G, esse é semelhante ao obtido pelo método RM1. Para esse conjunto os métodos AM1, PM6-DM1 e PM6-DM2 apresentaram os melhores resultados na descrição das geometrias.
São Cristóvão, SE
Hutridurga, Ramaiah Harsha. "HOMOGÉNÉISATION ET DISPERSION POUR DES ÉCOULEMENTS COMPLEXES EN MILIEU POREUX ET APPLICATIONS." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00866253.
Повний текст джерелаChoi, Yeonsik. "Novel functional polymeric nanomaterials for energy harvesting applications." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/282877.
Повний текст джерелаVeit, Max David. "Designing a machine learning potential for molecular simulation of liquid alkanes." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/290295.
Повний текст джерелаGunasinghe, Rosi. "Electronic and Magnetic Properties of Carbon-based and Boron-based Nano Materials." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2017. http://digitalcommons.auctr.edu/cauetds/64.
Повний текст джерелаShukla, Ushma. "Dispersion épizoochore des graines par les ongulés sauvages dans des paysages changeants : le cerf élaphe comme étude de cas." Thesis, Orléans, 2020. http://www.theses.fr/2020ORLE3060.
Повний текст джерелаEpizoochory is one mode of plant dispersal, where seeds are conveyed externally on animals. It mostly concerns forbs and graminoids, shrubs and trees relying more on endozoochory or abiotic vectors. Epizoochory is considered a strong biotic filter that shapes local plant assemblages from the regional pool of species. Abundant populations of large-bodied ungulates and their home range movements provide frequent ‘mobile links’ among habitat patches. For my thesis, I was interested in assessing the role of wild ungulates, especially red deer, in epizoochorous seed dispersal. I addressed 1) the role of ungulates in structuring local plant communities with respect to dispersal-related plant traits, 2) the effect of landscape composition on movement decisions made by individual red deer on subsequent seed dispersal kernels, and 3) the complementarity of ungulate-mediated dispersal modes and their overall influence on local plant communities. I used a combination of empirical field data and ecological modeling to address these questions. I found that zoochory presents a weak signal in structuring plant communities compared to other abiotic factors, but that dispersal-enabling traits were good predictors. I demonstrated the importance of accounting for home ranging behavior in range-resident ungulates in the seed dispersal kernel, which prevents from over-estimating dispersal distances. Moreover, I underlined how considering the total seed load dispersed by individual red deer is crucial and reveals the complementarity of dispersal modes in the total dispersal kernel. Finally, I highlighted the underrated role of ungulates in spreading invasives as a real threat to biodiversity
Casas, Grasiela. "Padrões de diversidade de aves e rede de interação mutualística ave-planta em mosaico floresta-campo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/141942.
Повний текст джерелаClassic studies on taxonomic diversity, though essential, do not consider the functional differences between species in a community. Studies using functional traits and functional diversity are filling this gap. Understanding the structure and dynamics of mutualistic interactions is also essential for biodiversity studies and allows the investigation of ecological and evolutionary mechanisms. However, most networks published are small in the number of species and interactions, and they are likely to be under-sampled. In addition, studies have demonstrated that many network metrics are sensitive to both sampling effort and network size. The aims of this thesis were: 1) to investigate bird taxonomic diversity (TD), functional diversity (FD), and patterns of trait convergence (TCAP: Trait Convergence Assembly Patterns) across forest-grassland transitions; 2) to analyse the structure of seed-dispersal networks between plants and birds using the metrics of nestedness, modularity, connectance and degree distribution; 3) to develop a statistical framework to assess sampling sufficiency for some of the most widely used metrics in network ecology, based on methods of bootstrap resampling. Bird species composition indicated species turnover between forest, forest edge and grassland. Regarding TD, only forest and edges differed. FD was significantly different between grassland and forest, and between grassland and edges. TD and FD responded differently to environmental change from forest to grassland, since they may capture different processes of community assembly along such transitions. Trait-convergence assembly patterns indicated niche mechanisms underlying assembly of bird communities, linked to changes in habitat structure across forest-edge-grassland transitions acting as ecological filters. Seed dispersal mutualistic networks apparently show a common assembly process regardless differences in sampling methodology or continents where the 19 networks were sampled. Using bootstrap resampling we found that sampling sufficiency can be reached at different sample sizes (number of interaction events) for the same dataset, depending on the metric of interest.
Sauer, Elmar [Verfasser], and Joachim [Akademischer Betreuer] Groß. "A new dispersion contribution based on the PCP-SAFT equation of state in the framework of classical density functional theory / Elmar Sauer ; Betreuer: Joachim Groß." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1195798415/34.
Повний текст джерелаAlves, Claudia Marins. "Modelos estocásticos para tratamento da dispersão de material particulado na atmosfera." Laboratório Nacional de Computação Científica, 2006. https://tede.lncc.br/handle/tede/62.
Повний текст джерелаLagrangian stochastic models are a largely used tool in the study of passive substances dispersion inside the Atmospheric Boundary Layer. Its application is related to the trajectory computation of thousands of particles, that numerically simulate the dispersion of suspense substances in the atmosphere. In this study, the basic concepts related to the Lagrangian stochastic modelling are presented and discussed together with its main characteristics and its computational implementation, to the study of particles dispersion in the atmosphere. In a computational experiment, the obtained results are compared with observational data from the TRACT experiment, that took place in Europe in 1992. The input data needed for the dispersion model are extracted from simulations with the numerical weather forecast model RAMS. Dispersion over Rio de Janeiro region is also tested in a second experiment.
Modelos Lagrangianos estocásticos constituem ferramenta muito utilizada no estudo da dispersão de substâncias passivas na Camada Limite Atmosférica. Sua aplicação consiste em calcular a trajetória de milhares de partículas, que simulam numericamente a dispersão de uma substância em suspensão na atmosfera. Nesta tese, são apresentados e discutidos os conceitos básicos relacionados à Modelagem Lagrangiana Estocástica de Partículas, bem como suas principais características e sua implementação computacional, para o estudo da dispersão de partículas na atmosfera. Numa experimentação computacional, comparam-se os resultados obtidos com dados observacionais provenientes do experimento TRACT, realizado na Europa em 1992. Os dados de entrada necessários ao modelo de dispersão são extraídos de simulações do modelo de previsão numérica do tempo RAMS. A dispersão sobre o Estado do Rio de Janeiro é também testada em um segundo experimento.
Crabot, Julie. "Continuité écologique, fragmentation et dynamique spatio-temporelle des communautés en rivières intermittentes." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1319.
Повний текст джерелаEcology aims at understanding how species and individuals are distributed in space and time. Progress has been recently made in spatial analyses of communities but structuring mechanisms are often considered as static or stable over time. This could affect the understanding of the role of deterministic (such as the influence of local environmental factors) and stochastic processes (such as random fluctuations of mortality rates) in maintaining ecosystems, especially for dynamic ecosystems regularly exposed to drastic changes of environmental conditions. My objective in this thesis was to improve knowledge on spatial and temporal structures of communities in dynamic ecosystems, based on the study of intermittent rivers, experiencing interruption of flow and/ or loss of surface water. The Chapter 3 contributed to improve a statistical tool routinely used in spatial analyses of community. Mantel tests, measuring the correlation between two distance matrices and its significance, are frequently used to study to which extent environmental filtering and dispersal structure metacommunities. We showed that Moran Spectral Randomization allowed us to correct the overestimation of the correlation between distance matrices when they presented spatial autocorrelation. Our results suggest that community analyses based on those tests may have overestimated the structuring role of environmental filtering and that our method will allow future analyses to avoid this bias. In addition, Mantel tests being used in other domains such as genetics, the improvement suggested here will have larger outcomes than community ecology. In Chapter 4, I showed that spatial and temporal distributions of drying event influenced community dynamics in intermittent rivers. The influence of the spatial pattern of disturbances, defined here as an extreme change of environmental conditions, had been previously tested with simulations and mesocosms but not in situ. Upstream-drying river basins harboured more dissimilar communities compared to downstream-drying basins. Upstream drying events may restrain recolonization for aquatic dispersers and lead to a lesser homogenisation of communities. Frequency and duration of drying events also influenced the temporal dynamics of communities and generally led to a higher temporal variability of taxonomic and functional compositions; this relationship was, however, dependent on the spatial drying pattern. By comparing French rivers that have been exposed to drying for centuries and Czech rivers recently exposed to flow intermittence caused by anthropic disturbances, I showed that aquatic communities responded differently to intermittence (Chapter 5). Measuring spatial and temporal beta diversity highlighted the higher variability of communities induced by drying in Czech rivers from both taxonomic and functional perspectives. In addition, a higher sensitivity of resilient taxa to increasing flow intermittence was found in Chapter 5 for non-natural intermittent rivers and this suggests that the increase of drying duration and drying length induced by climate change might jeopardize the recovery of community of these ecosystems after drying in near future
Emin, M. Azad [Verfasser], and H. P. [Akademischer Betreuer] Schuchmann. "Dispersive mixing of oil in plasticized starch by extrusion processing to design functional foods / M. Azad Emin. Betreuer: H. P. Schuchmann." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1044349573/34.
Повний текст джерелаVálková, Hana. "Modelování v perfusním MR zobrazování." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220837.
Повний текст джерелаTuma, Christian. "A QM/QM hybrid method for MP2/Plane-Wave-DFT studies of extended systems." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=983810583.
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