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Kpadonou, Dossou. "Shape and anisotropy optimization by an isogeometric-polar method." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV048/document.
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Nous nous intéressons dans cette thèse à l’optimisation conjointe de forme et d’anisotropie pour les structures surfaciques. Nous nous focalisons dans un premier temps sur l’analyse de ces structures minces modélisées par des coques. Le modèle utilisé pour décrire le comportement mécanique est celui de Naghdi communément utilisé pour les coques modérément épaisses et qui permet de prendre en compte l’effet transverse de déformation. La discrétisation par méthode éléments finis est réalisée avec des éléments Lagrange standards de classe C0. Nous considerons la simulation d’assemblage de coques en utilisant la méthode des éléments finis avec joint (mortier). Cette méthode est flexible, elle est adaptée à l’utilisation de maillages localement raffinés et/ou non-conformes, c'est-à-dire non coïncidents. La deuxième partie se consacre à la définition d’un paramétrage pour la conception optimale de champ d’anisotropie. Notre approche se base sur l’utilisation conjointe du formalisme polaire pour représenter le tenseur d’élasticité et le principe isogéométrique permettant de paramétrer les champs d’anisotropie par des fonctions de type B-splines. La dernière partie est dédiée à l’optimisation conjointe de forme et de propriétés matériaux. Le nombre de paramètres d’optimisation dans l’approche proposée est maîtrisée puisque les paramètres d’optimisation sontles coordonnées des points de contrôle. Nous considérons principalement pour l’optimisation un critère detype complianceThis thesis tackles the problem of the shape and anisotropy optimization of shell structures. The first part of this work focuses on the analysis of the shell model. The mechanical behavior of the structure is described using the Naghdi’s shell model which allows to take into account the transverse shear deformation. This model is typically used for shallow shells. We use a standard Lagrange C0 finite elements discretization and we numerically simulate the shell assemblings by means of the mortar technique. This approach enables the application of local refinements and the use of nonconforming mesh discretizations. The second part of this thesis aims at defining an effective parameterization for the optimal design of the shell’s distributed elastic properties. The method adopted is based on the joint use of a polar formalism to represent the elastic tensor and an isogeometric technique for the parameterization of the elastic tensor fields by CAD-based functions such as B-splines. The number of design variables thus only depends on the control points coordinates making the approach numerically manageable. The last part is devoted to the joint optimization of both the material properties and shape of the shell using the structure compliance as objective function
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Norin, Gustav. "Development of UPLC-MS/MS method for the determination of polar metabolites." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-69074.
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Trimethylamine-n-oxide (TMAO) is a metabolite found in plasma/serum in humans. Elevated levels of TMAO have been associated with several types of heart disease. It’s therefore of interest to make a simple analytical method to analyse TMAO and other metabolites that are degraded to TMAO, including betaine. In this study, the goal was to develop a method for the sample preparation and analysis of these compounds in human plasma. Sample preparation was performed with an Ostro 96-well method for sample clean-up. The analysis was performed by ultraperformance liquid chromatography – hydrophilic interaction liquid chromatography – tandem masspectrometry (UPLC-HILIC-MS/MS) in multiple reaction monitoring (MRM)-mode using electrospray ionization in positive mode (ESI+)-mode as the ion source. The analytes eluted under five minutes and were all baseline separated in the chromatogram. TMAO and betaine were quantified in quality control (QC) plasma samples using external calibration. Concentration of TMAO ranged from 132 ng/mL – 253 ng/mL and 1025-2084 ng/mL for betaine. Due to the lack of isotopically labelled standards for TMAO and betaine, valine-d8 was tested as an internal standard for the extraction; however, it was not a suitable option due to the low recovery obtained (5-34%) and the low response in ESI+. The recovery needs to be investigated further using isotopically labelled TMAO or betaine. Overall, the developed UPLC-HILIC-MS/MS method was found to be suitable for analysis of TMAO and betaine in human plasma. Further development and validation is required before application to samples from clinical studies.
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Türk, Serhat, and Kristoffer Müller. "Kinetic Art Table : Polar sand plotter." Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296307.
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CNC machines are used with plenty of different implementations, one of which is in this project where a polar CNC machine was used to draw mesmerizing patterns on a table with fine sand. This construction read G-code and converted it to polar coordinates. The capabilities of what the plotter could draw were tested, everything from ODE plots to custom-made patterns and drawings with the help of Sandify. Although the patterns were drawn properly with small errors the ODE was too difficult to draw because it required a smaller magnetic ball and an even more precise system than what was used. This machine also generated noise at roughly 33 dB when it was in use.CNC-maskiner används med massor av olika implementationer, en av dem är i det här projektet där en polar CNC maskin användes för att rita fascinerande mönster på ett bord fylld med fin sand. Denna konstruktion läste in G-kod och konverterade det till polära koordinater. Förmågan av vad maskinen kunde rita testades, allt från ODE grafer till specialtillverkade mönster och ritningar med hjälp av Sandify. Aven om de olika mönstren ritades ordentligt men med mindre små fel var ODE för svårt att rita på grund av att det krävde en mindre magnetisk kula och ännu mer noggrannhet jämfört med detta system. Denna maskin alstrade också ljud på cirka 33 dB under användning.
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Ahmadian, Mohammad Réza. "A general strategy for the optimal design of laminated composites by the polar-genetic method." Versailles-St Quentin en Yvelines, 2007. http://www.theses.fr/2007VERS0008.
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La thèse propose une formulation générale de la conception optimale des composites stratifiés, exprimée comme un problème d’optimisation avec contraintes en fonction de tous les paramètres constitutifs du stratifié et en utilisant la méthode polaire. Dans l’approche présentée il n’est pas nécessaire d’introduire d'hypothèses simplificatrices, que ce soit sur les critères de conception ou sur l’espace de recherche. D’autre part, une partie importante de ce travail concerne la production d’une nouvelle version de l’algorithme génétique BIANCA: il s’agit d’un algorithme génétique multi population, capable de résoudre des problèmes difficiles d’optimisation avec contraintes et multi objectif, dont les problèmes formulés pour la conception optimale des composites stratifiés. Dans la dernière partie, l’algorithme BIANCA est testé pour la résolution des problèmes formulés selon l’approche basée sur la méthode polaire; de nombreux cas d'intérêt sont traités en conception de composites stratifiés. Appliquée à une série étendue de cas d'exemple, la méthode polaire-génétique montre son efficacité et sa robustesseIn this thesis, we introduce a new global approach to the optimal design of laminated composites. This method uses the polar representation of plane tensors and the design of laminates is formulated as a constrained optimization problem without any pre-defined simplifying hypothesis. The design variables are all the constitutive parameters of the laminate. The first part of the thesis concerns the creation of a suitable genetic algorithm, BIANCA, able to handle any constrained/unconstrained and multi-objective optimization problems, and which is rich in its architecture and information representation. The genetic algorithm BIANCA is successfully applied to the resolution of optimal design problems for composite laminates, as they are formulated by our polar approach. Several practical cases are treated, and through an extended series of examples, we show the effectiveness and robustness of the polar-genetic method for the optimal design of composite laminates
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Horne, David. "A method to obtain dust and ice cloud optical depths over the cold polar surfaces of Mars /." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etd/view.cgi?acc_num=toledo1177653341.
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Dissertation (Ph.D.)--University of Toledo, 2007Typescript. Title on abstract page: A method to obtain thermal spectra of Martian dust storms over cold polar surfaces "Submitted as partial fulfillment of the requirements for The Doctor of Philosophy Degree in Physics." Bibliography: leaves 91-98.
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Horne, David J. "A Method to Obtain Dust and Ice Cloud Optical Depths over the Cold Polar Surfaces of Mars." University of Toledo / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1177653341.
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Li, Wei-Szu. "Using the C-vector method to derive the three-dimensional circulation pattern near the East Greenland Polar Front." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/38509.
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Approved for public release; distribution is unlimited.The C-vector method is used to determine the three-dimensional pseudo-vorticity field of the East Greenland Current by using a CTD data set acquired during the 1984 Northwind cruise. The value of the ageostrophic pseudo- vorticity, the total (geostrophic and ageostrophic) pseudo vorticity and the vertical component of the C-vector curl, Psi, can be calculated by the C-vector method. From these values the pseudo-vorticity can be investigated for the East Greenland Current. Additionally, the positive and the negative vertical motion at each level can be investigated from the Psi value. A two-cell structure with downward motion around the East Greenland Polar Front was found. The C-vector method also demonstrates that the vertical circulation induced by an anticyclonic gyre and the cross-coastal circulation generated by the surface wind can be depicted.
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Johnston, Stephen Jaye. "Molecular dynamics studies of a generalised multipole model of molecular asymmetry in apolar and polar liquid crystals." Thesis, Coventry University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369971.
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Alves, Aylton José. "Uma modelagem da máquina síncrona considerando o efeito da curvatura da sapata polar." Universidade Federal de Uberlândia, 2011. https://repositorio.ufu.br/handle/123456789/14278.
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This work develops a new mathematical model to the salient pole synchronous machines
(SPSM), based on the abc reference system. The model considers the distribution
and coil pitch factors of windings and develops a new function for the variable
air gap, generated by the curvature of the polar mass. As a result, the development
of the modeling takes into account the spatial harmonic components of: magneto
motive force MMF(θ)h, electromagnetic
ux density B(θ)h and variation function
of the air gap g(θ)h.
It is also proposed a new and simplied methodology using the locked rotor tests,
volt-ampere method, to obtain the constants of the synchronous machine design,
which allow the calculation of the modeling parameters and the terminals magnitudes
determination. It presents also contributions to traditional methods of obtaining
experimental inductances, using the locked rotor test. Yet it develops procedures
and makes the simulation of the main temporal magnitudes at the generator terminals
connected to the utility grid, electrical torque, speed, voltage and current.
The model is validated through the theoretical and experimental confrontation
of inductances, and also of the voltages and currents at the generator terminals
connected to the utility grid.Este trabalho desenvolve uma nova modelagem matemática para as máquinas síncronas de polos salientes (MSPS), baseada no sistema abc de referência. A modelagem considera os fatores de distribuição e de passo de bobina dos enrolamentos e desenvolve uma nova função para o entreferro variável, gerado pela curvatura da sapata polar. Como conseqüência o desenvolvimento da modelagem leva em consideração os componentes harmônicos espaciais de: força magneto motriz FMM(θ)h, densidade de uxo eletromagnético B(θ)h e da função de variação do entreferro g(θ)h. É também proposto uma nova e simplificada metodologia a partir dos testes de rotor bloqueado, método volt-ampere, para a obtenção das constantes de projeto da máquina síncrona que possibilitam os cálculos dos parâmetros da modelagem, bem como a determinação das grandezas terminais. Também apresenta contribuições aos métodos tradicionais de obtenção de indutâncias experimentais, a partir dos testes de rotor bloqueado. Ainda desenvolve os procedimentos e faz a simulação das principais grandezas temporais nos terminais do gerador conectado à rede da concessionária: torque elétrico, velocidade, corrente e tensão. A modelagem é convalidada através das confrontações teórico-experimental das indutâncias, e também dos resultados de correntes e tensões nos terminais do gerador conetado à rede da concessionária.
Doutor em Ciências
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Hubáček, David. "Měření posunů a přetvoření střešní konstrukce." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-414307.
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The thesis deals with the evaluation of displacements and deformation of the large span wooden roof structure of the aquapark hall in Brno - Kohoutovice. The task of this work is to compare and verify the applicability of the laser scanning method for the evaluation of displacements and deformation. The comparison was performed with regard to the polar method with quantities measured by the total station. As part of the work, two-stage measurements were performed on the basis of which a comparison of both methods was performed. The data obtained by the polar method were processed using LSM, the data from laser scanning were processed in an Excel spreadsheet. A comparison of the two methods shows that we have achieved a similar level of accuracy with the laser scanning method when compared to the polar method. It is therefore possible to use the laser scanning method to measure displacements and deformation.
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Klinčík, Radoslav. "Měření posunů a přetvoření střešní konstrukce sportovní haly." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-444252.
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Diploma thesis describes the measurement and evaluation of displacements and deformations of the wooden roof structure of the aquapark hall in Brno – Kohoutovice. Part of the work is devoted to the preparation and testing of used devices and tools. The main part of the work consists of performing one stage of measurement using the polar method and the laser scanning method. The polar method measurement is compared with the results of the polar method of the previous stage. The next part of the work deals with the comparison of the polar method and the laser scanning method measured in the last stage. The results achieved are interpreted in the final part of the work.
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Baladová, Vendula. "Zaměření fary a přilehlých hospodářských stavení v Čučicích." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390201.
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The diploma thesis deals with measurement of the interior of a parish building and its close surroundings in Čučice. Necessary steps for creating the thematic map and the building documentation are described in this thesis. First the preparatory work was made, which means that ground reconnaissance was made and required equipment and tools were chosen. In the next part the measurements, which include the construction of an auxiliary measuring network, the measurement of the detailed and control points, are described. After the measurement work, the office work followed, the coordinates and the heights of the auxiliary and detailed points were specified. The accuracy of the map according to ČSN 01 3410 was tested. Finally a thematic map in scale 1: 500 and the building drawings in scale 1:50: 1st floor plan, 2nd floor plan, longitudinal and cross-section were created.
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Staněk, Boleslav. "Měření přetvoření mostní konstrukce a železničního svršku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226600.
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This diploma thesis deals with the phases measuring deformation of the bridge construction and railway superstructure on the bridge over the river Dyje in Breclav and its surroundings. The main goal was to determine the longitudinal displacements of the rail web and the bridge structure. The object of this thesis was also transverse displacements which have been caused mainly due to temperature changes. The introduction describes the location. The following section discusses the methodology terrestrial deformation measurements and calibrations selected surveying devices. Furthermore, there is stated the processing of measurements and the calculations. In conclusion, the thesis evaluates the longitudinal and transverse displacements, which are shown in the annexes.
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Suchánek, Zbyněk. "Určení přetvoření železničního svršku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226602.
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The aim of this master thesis was to measure and evaluate shifts of rail strip and deck of the bridge in the 0,206 km route Zábřeh - Bludov across the river Moravská Sázava. The measurement was performed by classical geodetic methods. The result of the study was evaluation of the three periods of deformation measurements and numerical and graphical documentation. Shifts were caused especially by changes in temperature and operational effects.
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Marth, Wieland. "Hydrodynamic Diffuse Interface Models for Cell Morphology and Motility." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-204651.
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In this thesis, we study mathematical models that describe the morphology of a generalized biological cell in equilibrium or under the influence of external forces. Within these models, the cell is considered as a thermodynamic system, where streaming effects in the cell bulk and the surrounding are coupled with a Helfrich-type model for the cell membrane. The governing evolution equations for the cell given in a continuum formulation are derived using an energy variation approach. Such two-phase flow problems that combine streaming effects with a free boundary problem that accounts for bending and surface tension can be described effectively by a diffuse interface approach. An advantage of the diffuse interface approach is that models for e.g. different biophysical processes can easily be combined. That makes this method suitable to describe complex phenomena such as cell motility and multi-cell dynamics. Within the first model for cell motility, we combine a biological network for GTPases with the hydrodynamic Helfrich-type model. This model allows to account for cell motility driven by membrane protrusion as a result of actin polymerization. Within the second model, we moreover extend the Helfrich-type model by an active gel theory to account for the actin filaments in the cell bulk. Caused by contractile stress within the actin-myosin solution, a spontaneous symmetry breaking event occurs that lead to cell motility. In this thesis, we further study the dynamics of multiple cells which is of wide interest since it reveals rich non-linear behavior. To apply the diffuse interface framework, we introduce several phase field variables to account for several cells that are coupled by a local interaction potential. In a first application, we study white blood cell margination, a biological phenomenon that results from the complex relation between collisions, different mechanical properties and lift forces of red blood cells and white blood cells within the vascular system. Here, it is shown that inertial effects, which can become of relevance in various parts of the cardiovascular system, lead to a decreasing tendency for margination with increasing Reynolds number. Finally, we combine the active polar gel theory and the multi-cell approach that is capable of studying collective migration of cells. This hydrodynamic approach predicts that collective migration emerges spontaneously forming coherently-moving clusters as a result of the mutual alignment of the velocity vectors during inelastic collisions. We further observe that hydrodynamics heavily influence those systems. However, a complete suppression of the onset of collective migration cannot be confirmed. Moreover, we give a brief insight how such highly coupled systems can be treated numerically using finite elements and how the numerical costs can be limited using operator splitting approaches and problem parallelization with OPENMPDiese Dissertation beschäftigt sich mit mathematischen Modellen zur Beschreibung von Gleichgewichts- und dynamischen Zuständen von verallgemeinerten biologischen Zellen. Die Zellen werden dabei als thermodynamisches System aufgefasst, bei dem Strömungseffekte innerhalb und außerhalb der Zelle zusammen mit einem Helfrich-Modell für Zellmembranen kombiniert werden. Schließlich werden durch einen Energie-Variations-Ansatz die Evolutionsgleichungen für die Zelle hergeleitet. Es ergeben sie dabei Mehrphasen-Systeme, die Strömungseffekte mit einem freien Randwertproblem, das zusätzlich physikalischen Einflüssen wie Biegung und Oberflächenspannung unterliegt, vereinen. Um solche Probleme effizient zu lösen, wird in dieser Arbeit die Diffuse-Interface-Methode verwendet. Ein Vorteil dieser Methode ist, dass es sehr einfach möglich ist, Modelle, die verschiedenste Prozesse beschreiben, miteinander zu vereinen. Dies erlaubt es, komplexe biologische Phänomene, wie zum Beispiel Zellmotilität oder auch die kollektive Bewegung von Zellen, zu beschreiben. In den Modellen für Zellmotilität wird ein biologisches Netzwerk-Modell für GTPasen oder auch ein Active-Polar-Gel-Modell, das die Aktinfilamente im Inneren der Zellen als Flüssigkristall auffasst, mit dem Multi-Phasen-Modell kombiniert. Beide Modelle erlauben es, komplexe Vorgänge bei der selbst hervorgerufenen Bewegung von Zellen, wie das Vorantreiben der Zellmembran durch Aktinpolymerisierung oder auch die Kontraktionsbewegung des Zellkörpers durch kontraktile Spannungen innerhalb des Zytoskelets der Zelle, zu verstehen. Weiterhin ist die kollektive Bewegung von vielen Zellen von großem Interesse, da sich hier viele nichtlineare Phänomene zeigen. Um das Diffuse-Interface-Modell für eine Zelle auf die Beschreibung mehrerer Zellen zu übertragen, werden mehrere Phasenfelder eingeführt, die die Zellen jeweils kennzeichnen. Schließlich werden die Zellen durch ein lokales Abstoßungspotential gekoppelt. Das Modell wird angewendet, um White blood cell margination, das die Annäherung von Leukozyten an die Blutgefäßwand bezeichnet, zu verstehen. Dieser Prozess wird dabei bestimmt durch den komplexen Zusammenhang zwischen Kollisionen, den jeweiligen mechanischen Eigenschaften der Zellen, sowie deren Auftriebskraft innerhalb der Adern. Die Simulationen zeigen, dass diese Annäherung sich in bestimmten Gebieten des kardiovaskulären Systems stark vermindert, in denen die Blutströmung das Stokes-Regime verlässt. Schließlich wird das Active-Polar-Gel-Modell mit dem Modell für die kollektive Bewegung vom Zellen kombiniert. Dies macht es möglich, die kollektive Bewegung der Zellen und den Einfluss von Hydrodynamik auf diese Bewegung zu untersuchen. Es zeigt sich dabei, dass der Zustand der kollektiven gerichteten Bewegung sich spontan aus der Neuausrichtung der jeweiligen Zellen durch inelastische Kollisionen ergibt. Obwohl die Hydrodynamik einen großen Einfluss auf solche Systeme hat, deuten die Simulationen nicht daraufhin, dass Hydrodynamik die kollektive Bewegung vollständig unterdrückt. Weiterhin wird in dieser Arbeit gezeigt, wie die stark gekoppelten Systeme numerisch gelöst werden können mit Hilfe der Finiten-Elemente-Methode und wie die Effizienz der Methode gesteigert werden kann durch die Anwendung von Operator-Splitting-Techniken und Problemparallelisierung mittels OPENMP
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Chaloupka, Roman. "Vyhotovení mapových podkladů areálu Metra v Blansku - severní část." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-400159.
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The diploma thesis deals with the creation of map bases in the northern part of the Metra areal in Blansko in the form of a thematic map in a scale 1:250. Descriptive information for each element has been added to the map. The thesis describes in detail the process of creating a measuring network, detailed survey, calculations, testing accuracy and creation of a thematic map including descriptive information.
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Hui, Fei. "Visual Tracking of Deformation and Classification of Object Elasticity with Robotic Hand Probing." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36477.
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Performing tasks with a robotic hand often requires a complete knowledge of the manipulated object, including its properties (shape, rigidity, surface texture) and its location in the environment, in order to ensure safe and efficient manipulation. While well-established procedures exist for the manipulation of rigid objects, as well as several approaches for the manipulation of linear or planar deformable objects such as ropes or fabric, research addressing the characterization of deformable objects occupying a volume remains relatively limited. The fundamental objectives of this research are to track the deformation of non-rigid objects under robotic hand manipulation using RGB-D data, and to automatically classify deformable objects as either rigid, elastic, plastic, or elasto-plastic, based on the material they are made of, and to support recognition of the category of such objects through a robotic probing process in order to enhance manipulation capabilities. The goal is not to attempt to formally model the material of the object, but rather employ a data-driven approach to make decisions based on the observed properties of the object, capture implicitly its deformation behavior, and support adaptive control of a robotic hand for other research in the future. The proposed approach advantageously combines color image and point cloud processing techniques, and proposes a novel combination of the fast level set method with a log-polar mapping of the visual data to robustly detect and track the contour of a deformable object in a RGB-D data stream. Dynamic time warping is employed to characterize the object properties independently from the varying length of the detected contour as the object deforms. The research results demonstrate that a recognition rate over all categories of material of up to 98.3% is achieved based on the detected contour. When integrated in the control loop of a robotic hand, it can contribute to ensure stable grasp, and safe manipulation capability that will preserve the physical integrity of the object.
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Zhang, Huaijian. "Boundary Integral Techniques in Three Dimensions for Deep Water Waves." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306712208.
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Slabotinský, Filip. "Využití fotogrametrie v oboru znalectví ve stavebnictví a oceňování nemovitostí." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-233118.
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The task of this diploma thesis is to design and test the optimal procedures for taking photos to build a 3D model of a civic building using the programme PHOTOMODELER. Then to determine the specific dimensions of the civic building and compare them with the dimensions received with the help of the basic method of measurement in common building practice, i.e. the method of cross directions (using a tape or a telescopic measuring rod) and the geodetic method of measurement. After that to evaluate these measurements and make the conclusion concerning the accuracy or inaccuracy of measurements received with the help of the 3D model of the compiled programme PHOTOMODELER.
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Fatarova, Maria. "The metabolic consequences of gene knockout to pathway flux in trypanosomes." Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0025/document.
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Le contexte de ce projet de thèse était d’approfondir la compréhension du métabolisme de Trypanosoma brucei. Les trypanosomes utilisent différents types de sources de carbone, des hydrates de carbone ainsi que des acides aminés pour alimenter leurs besoins énergétiques et biosynthétiques (conditions imitant réellement l'environnement dans la mouche tse-tse). Les différences de thioesters d'acyl-CoA sont encore inconnues dans ces conditions. Une telle élucidation est essentielle pour comprendre les adaptations métaboliques de l'organisme au cours de son cycle de vie. Cet objectif pourrait être complété par une combinaison d'analyses sensibles de divers groupes de métabolites, de délétions dirigées de gènes ou de régulations négatives. Ces derniers développements intègrent un flux de travail complet d'analyse des flux métaboliques par 13C à l’état-instationnaire. Ce flux de travail combine les méthodes existantes pour la collecte d'échantillons, la métabolomique quantitative basée sur MS et l'analyse isotopique d'acides organiques, d'acides aminés, de composés phosphorylés en plus des thioesters d'acyl Coenzyme A (acyl-CoAs), qui représentent un point central entre le métabolisme central du carbone et les voies anaboliques. Ce flux de travail a d'abord été évalué et validé sur l'organisme modèle Escherichia coli et a fourni de nouvelles idées sur son fonctionnement métabolique. Par la suite, ce flux de travail a ensuite été exploité pour étudier le métabolisme de T. brucei, pour lequel les résultats préliminaires sont décrits et discutés dans cette thèseUnusual metabolism of protozoan parasite causing deadly sleeping sickness, Trypanosoma brucei, has been enigmatic for many years. In the past decades, targeted genetic perturbations combined with metabolic analysis have advanced the view on complex compartmentalized metabolism of this organism, but acyl-CoA metabolism on the crossroad between catabolic and anabolic pathways, remains largely uncharacterized. Present work aims at clarifying mitochondrial operation and topology of acyl-CoA network of T. brucei, as well as its interconnections with the rest of metabolism. This has required the development of a complete framework for investigation of acyl-CoA metabolism in T. brucei integrating isotope labeling experiments with metabolite quantification. Sensitive LC-MS method for identification and quantification of acyl-CoAs based on high-resolution mass spectrometry (HRMS) with LTQ-OrbiTrap has been established and applied to investigate acyl-CoA metabolism in the protozoan parasite, as well as in the model organism in systems and synthetic biology, Escherichia coli. Complete workflow from cell cultivation, measurement of extracellular fluxes and analysis of isotopic profile which is result of enzyme-specific incorporation of isotopic tracer allowed modelling of metabolic network and calculation of metabolic fluxes. The entire workflow has been biologically validated and has clarified the link between acyl-CoA and central carbon metabolism in E. coli. The proposed framework has been adapted to T. brucei, for which several sample collection methods have been evaluated thoroughly. It was possible to extract, identify and quantify main acyl-CoA species produced from glucose catabolism. This optimised setup for acyl-CoA analysis will allow collection of data for NMR-based analysis of metabolic end products as well as collection of intracellular metabolites from same sample
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Hammoudeh, Ismail. "Qualitative nichtlineare Zeitreihenanalyse mit Anwendung auf das Problem der Polbewegung." Phd thesis, [S.l. : s.n.], 2002. http://pub.ub.uni-potsdam.de/2003/0003/hammoud.pdf.
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Helweg, Christian. "Methods for determination of environmentally important physical- chemical properties of polar polycyclic organic material /." Roskilde : Roskilde University, Institute of Life Sciences and Chemistry, Risø National Laboratory, Department of Plant Biology and BiogeoChemistry, 1997. http://hdl.handle.net/1800/472.
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Schmitz, Matthias. "Entwicklung, Anwendung und Vergleich von Methoden zur Berechnung von Infrarotspektren einzelner Moleküle in polaren Lösungsmitteln." kostenfrei, 2004. http://nbn-resolving.de/urn/resolver.pl?urn=nbn:de:bvb:19-31600.
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Sedin, Jonas. "A comparison of Polar Code Constructions and Punctur-ing methods for AWGN and Fading channels." Thesis, KTH, Teknisk informationsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-212307.
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Today 5G and other wireless standards are being developed for the future of our society. The different use-cases of future wireless services are going to be ever-more demanding, whether it is vehicular communication or low-powered sensor networks. High-rate, ultra-reliable and low-power are future requirements that will also affect the coding schemes being used. A relatively recent coding scheme, called polar codes, has the potential to fulfill all of these requirements if the coding scheme applied is well-designed. In this thesis we will be focusing on practical algorithms for implementation of polar codes at medium-sized block-lengths. Polar codes are very different from other modern coding schemes. The code construction is rather unique in that they are dependent on the underlying channel, where the code construction can change with the Signal-to-Noise-Ratio of the AWGN channel. The puncturing of polar codes is also non-trivial compared to other coding schemes. Since the Polar Codes are dependent on the underlying channel, the fading channel performance is thus important to consider. In this thesis we aim to show through simulations how these different concepts affect the Block Error Rate (BLER) performance. Specifically, we compare how code constructions compare over the AWGN channel, how code construction affects the BLER performance with puncturing and how puncturing affects the performance over fading channels. We find that an appropriate code construction is very important for optimal performance over the AWGN channel with puncturing, in our case using Gaussian Approximation. We also find that different puncturing methods have vastly different performances for different rates over the AWGN and Rayleigh fading channel and that applying an interleaver is very important for optimal performance.Idag så utvecklas och standardiseras 5G och andra trådlösa standarder. De olika applikationerna av framtida trådlösa nätverk kommer att vara mer och mer krävande, allt från kommunikation mellan fordon till små energisnåla sensorer. Högre hastigheter, påliltlighet och energieffektivitet är krav som också kommer att påverka den kanalkodningen som används av standarden. En relativt ny typ av kanalkodning, polar codes, har all potential att kunna uppfylla de framtida kraven. I denna uppsats så kommer vi att undersöka praktiska algoritmer för implementation av polar codes för blocklängder i mediumstorlek. Polar codes är annorlunda från andra moderna kanalkodningar. Kodkonstruktionen är unik på så sätt att den är beroende av den underliggande kanalen som koden används över, där exempelvis kodkonstruktionen kan ändras med Signal-till-Brus-förhållandet (SNR) över Additiv-Vit-Gaussisk-Brus-kanalen (AWGN). Punktueringen av polar codes är också annorlunda jämfört med andra kanalkodningar. Eftersom polar codes är beroende av den underliggande kanalen, så är prestandan över fädande kanaler viktig att undersöka. I denna uppsats så visar vi genom simulationer hur de ovannämnda koncepten påverkade block-felfrekvensen (BLER). Specifikt så jämför vi hur kodkonstruktioner presterar över AWGN-kanalen, hur kodkonstruktion påverkar prestande med punktuering samt hur punktuering påverkar prestandan över fädande kanaler. I denna uppsats så observerar vi att kodkonstruktion är viktig för optimal prestanda över AWGN-kanalen, där vi använder Gaussian Approximation. Vi observerar också att olika punktueringsmetoder har omfattande olika prestanda över AWGN och fädande kanaler och att använda en interleaver är väldigt viktig för optimal prestanda över fädande kanaler.
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Molčan, Vladimír. "Určení prostorových vztahů jeřábové dráhy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-227104.
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The main theme of this master thesis is the design of technological process measurement and processing of measured data entered crane tracks to determine the geometric parameters of these crane tracks. Diploma thesis further describes the procedure for testing and possible rectification surveying equipment and instrumentation. The thesis is divided of 7 parts, contains 31 images, 4 graphs, 44 tables and 13 attachments. The theoretical part of this thesis contains information about several types of cranes, methods of measurement and processing, as well information on legal and technical regulations related to this topic of the thesis. The fourth and fifth parts of this thesis provides information on selected crane tracks on which the measurements were taken, the choice of methods of measurement, processing technique and the results obtained. The final part of the thesis includes evaluation of the results obtained, comparing methods of measurement, processing, evaluation and design of a technique of determining the geometric parameters of crane tracks.
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MORIN, PHILIPPE. "Couplage chromatographie en phase dioxyde de carbone supercritique-spectrometrie infrarouge a transformee de fourier." Paris 6, 1988. http://www.theses.fr/1988PA066684.
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Etude de l'effet d'un modificateur organique, polaire, du dioxyde de carbone sur les donnees spectrales infra-rouge. Dans un deuxieme temps, l'effet de la phase stationnaire constituee par un copolymere est analyse
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Russell, J. J. "Development of generic methods for the analysis and purification of polar compounds by high performance liquid chromatography." Thesis, University of the West of England, Bristol, 2016. http://eprints.uwe.ac.uk/28136/.
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Generic methods were developed using different columns for analysis and purification of hydrophilic compounds by hydrophilic interaction chromatography (HILIC). Mobile phases were investigated in detail, and across each column chemistry tested (BEH Amide, Atlantis bare silica, ZIC-HILIC and Cogent Hydride), salt-buffered mobile phase offered good to excellent peak shape for acids, bases and neutral solutes with a range of hydrophilicities. Additionally, cation exchange occurred on the bare silica column even when rubidium nitrate was added to the mobile phase, which should block all cation exchange sites. Measurement of mobile phase pH in hydroorganic solvent (ACN-water mixture with buffer) better represented the environment solutes experience on column than fully-aqueous pH measurement. The performance of HILIC with Charged Aerosol Detection (CAD) was evaluated with a hydrophilic acid, a hydrophobic base and a hydrophilic neutral solute; limits of detection and quantitation were 1-3 ng and 5-9 ng on column, respectively. This compared favourably to literature values for other universal detectors. HILIC-CAD was further investigated by flow injection analysis (FIA) using 29 solutes containing acids, bases and neutrals. HILIC and CAD had excellent compatibility: peak areas were double compared to reversed-phase conditions, response was reasonably uniform for 21 non-volatile solutes considering the solutes’ diversity. HILIC-CAD was viable for retention and detection of highly hydrophilic species without chromophores: salts, sugars and amino acids. Salts travelled down the column as independent cations and anions. Resolution of sugars and amino acids was challenging and was incomplete due to project time constraints. Generic methods were developed on an analytical system in the labs of the industrial collaborator and applied to purifications on wide-bore columns at scaled-up flow rates (21mm id, 20mL/min prep vs. 4.6mm id 1 mL / min analytical analytical). A standard prep system was capable of usable productivity using HILIC with 1mL injections (22 mg of crude purified per hour) and use of At-Column Dilution enhanced this around 10-fold with scope for 4mL injections (223 mg of crude purified per hour).
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Farhat, Ayman. "Calculs théoriques avec le couplage spin orbitales pour les molécules diatomiques YS, YN, ZrS, et ZrN." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10078/document.
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Cette thèse est consacrée à l'étude ab initio des structures électroniques des molécules diatomiques polaires YN, YS, ZrN, et ZrS. Cette étude est motivé par le manque d’informations dans la littérature sur la structure électronique de ces molécules, alors qu’elles ont clairement été identifiées dans le spectre de certaines étoiles. Des calculs théoriques sont ainsi nécessaire puisqu’ils peuvent fournir d'importantes informations quant aux propriétés des états électroniques fondamentaux et excités qui ne sont pas accessibles expérimentalement. Dans ce travail les calculs ab initio ont été effectués par la méthode du champ auto-cohérent de l'espace actif complet (CASSCF), suivie par l'interaction de configuration multiréférence (MRSDCI). La correction de Davidson, notée (MRSDCI+ Q), a ensuite été appliquée pour rendre compte de clusters ou agrégats quadruples non liés. Les calculs ont été effectués selon deux schémas. Dans le premier les effets spin-orbite ont été négligés alors que dans le second les effets spin orbite ont été inclus par la méthode des potentiels de noyau efficaces. Tous les calculs ont été effectués en utilisant le programme de calcul de chimie physique MOLPRO et en tirant parti de l’interface graphique Gabedit. Les courbes d'énergie potentielle ont été construites et des constantes spectroscopiques calculées, ainsi que les moments dipolaires électriques permanent, les champs électriques moléculaires intenses et les structures énergétiques de vibration-rotation. Nous avons détecté dans la molécule ZrS plusieurs niveaux vibrationnels dégénérés ceux-ci peuvent être utilisés pour rechercher les variantes possibles de la constante de structure fine α etdu rapport de masse μ de l’electron par rapport au proton dans trois étoiles de type S, du nomde Rand, les RCas, et χCyg. La comparaison des données expérimentales et théoriques pour la plupart des constantes calculées a montré une bonne précision pour nos prédictions avec une différence relative (en pourcentage) qui varie entre 0,1% et 10%. Ces résultats devraient ainsi mener à des études expérimentales plus poussées pour ces moléculesThis dissertation is dedicated to the ab initio study of the electronic structures of the polardiatomic molecules YN, YS, ZrN, and ZrS. The identification of these molecules in the spectraof stars as well as the lack in literature on the electronic structures of these molecules motivatedthe present study. Theoretical calculations are useful in this respect since they can provideimportant data for the properties of the ground and excited electronic states that are not availablefrom experimental means. In the present work the ab initio calculations were performed at thecomplete active space self-consistent field method (CASSCF) followed by multireference singleand double configuration interaction method (MRSDCI). The Davidson correction noted as(MRSDCI+Q) was then invoked in order to account for unlinked quadruple clusters. Thecalculations were performed on two stages in the first spin orbit effects were neglected while inthe second type of calculations spin orbit effects were included by the method of effective corepotentials. All of the calculations were done by using the computational physical chemistryprogram MOLPRO and by taking advantage of the graphical user interface Gabedit. In thepresent work potential energy curves were constructed and spectroscopic constants computed,along with permanent electric dipole moments, internal molecular electric fields, and vibrationalrotationalenergy structures. We detected in the ZrS molecule several degenerate vibrationalenergy levels which can be used to search for possible variations of the fine structure constant αand the electron to proton mass ratio μ in three S-type stars, named Rand, RCas, and χCyg. Acomparison with experimental and theoretical data for most of the calculated constantsdemonstrated a good accuracy for our predictions giving a percentage relative difference thatranged between 0.1% and 10%. Finally, we expect that the results of the present work shouldinvoke further experimental investigations for these molecules
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Minten, Johanna. "Development of methods for the analysis of polar compounds in environmental matrices using LC/UV and LC/MS /." Stockholm : Department of applied environmental science (ITM), Stockholm University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-29108.
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Diss. (sammanfattning) Stockholm : Stockholms universitet, 2009.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Submitted. Härtill 4 uppsatser.
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Medeiros, Bárbara da Silva. "Proposição de modelos de fluxo de potência polar intervalar mediante utilização de métodos de compensação." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/7902.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Nesta dissertação, duas novas estratégias são propostas para calcular o problema do fluxo de potência sujeito às incertezas nos parâmetros das linhas de transmissão e das cargas dos sistemas elétricos. No estudo de fluxo de potência tradicional, os parâmetros dos sistemas de potência são tratados como quantidades determinísticas. Entretanto, esses dados, como a impedância das linhas de transmissão e a potência aparente das cargas conectadas às barras, podem apresentar incertezas associadas à medição ou à variação ao longo do tempo. Técnicas baseadas em amostragem, como Monte Carlo, apresentam resultados excelentes, porém demandam elevado tempo de processamento computacional. Por isso, atualmente, técnicas soft-computing, que apresentam resultados confiáveis de maneira eficiente, sem necessitar de muitos recursos computacionais, têm sido pesquisadas. O objetivo deste trabalho é, neste sentido, adaptar metodologias existentes na literatura, que não são utilizadas, a princípio, para este fim, para a solução do fluxo de potência intervalar e avaliar se os resultados são confiáveis e eficientes. A adaptação é realizada considerando pequenas incertezas, como geralmente ocorre na realidade, resultando em métodos aproximados de análise de fluxo de potência intervalar. O primeiro método desenvolvido é baseado na técnica de montagem direta da matriz impedância de barras, sem recorrer à inversão da matriz admitância de barras. O segundo método é baseado no Teorema da Compensação, utilizado na análise de sensibilidade. O algoritmo é desenvolvido e testado em Matlab, considerando diferentes casos de incerteza, com os seguintes sistemastestes: brasileiro de 33 barras, IEEE de 57 barras e brasileiro de 107 barras. Os resultados são comparados com aqueles gerados pela simulação de Monte Carlo, a fim de validação. Em geral, os métodos apresentam desempenho satisfatório, pois resultados intervalares viáveis de tensão e fluxo de potência, assim como perdas nas linhas, são encontrados como esperado, sem a aplicação de técnicas existentes na literatura, como a matemática intervalar ou aritmética affine.
In this dissertation, two new strategies are proposed to calculate the problem of power flow subjected to uncertainties in the parameters of transmission lines and loads of electrical systems. In traditional power flow analisys, power system parameters are treated as deterministic quantities. However some data, such as the impedance of transmission lines and the apparent power of loads connected to buses, may present uncertainties associated with measurement or variation over time. Sampling techniques, such as Monte Carlo, present excellent results, but require a high processing time. Therefore, nowadays, soft-computing techniques, which present reliable results in an efficient manner, without the need of many computational resources, have been researched. In this sense, the objective of this work is to adapt existing methodologies in the literature, which are not used for this purpose, for the solution of interval power flow and to evaluate if the results are reliable and efficient. The adaptation is performed considering small uncertainties, as usually occurs in reality, resulting in approximate methods of interval power flow analysis. The first method developed is based on the technique of direct assembly of the bus impedance matrix, without resorting to the inversion of the bus admittance matrix. The second method is based on the Compensation Theorem, used in the sensitivity analysis. The algorithm is developed and tested in Matlab, considering different cases of uncertainty, with the following test systems: Brazilian 33-bus, IEEE 57-bus and Brazilian 107-bus. The results are compared with those generated by the Monte Carlo simulation for validation. In general, the methods present satisfactory performance, as viable intervals of voltage and power flow, as well as losses in the lines, are found as expected, without application of techniques existing in the literature, such as interval mathematics or arithmetic affine.
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Nasif, Ammar. "Hyphenated mass spectrometry methods for the direct characterisation and quantification of polar molecules in crude oil or modified crude oils." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/414109/.
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Crude oil is arguably one of the most complex organic mixture in nature. Therefore, crude oil characterisation requires the use of high resolution and high mass accuracy mass spectrometer such as FT-ICR MS; needed to resolve thousands of ions and assign their elemental formulae. Different heteroatom containing compounds classes are present in crude oil such as N1, S1 and O2 containing compounds. These compounds cause variety of different problems such as N containing compounds cause catalyst deactivation for processes such as hydrodesulfurisation. The choice of the ionisation technique and its polarity is critical to the type of compounds that are observed in a crude oil mass spectrum. Two main studies for crude oil samples are covered in this thesis. The first is crude oil-1, 2 and 3 characterisation using ESI and APPI. The second is structural elucidation of nitrogen containing compounds in crude oil-2. Positive ion ESI FT-ICR MS ionises basic molecules in crude oils. In the literature crude oil samples are dissolved using different ratios of toluene:methanol. The effect of using different solvent composition is often not regarded as important factor to consider. One of the reasons is the addition of ionisation enhancing additive such as formic acid, thought to normalise the ionisation response across different sample solvent composition. However, the solvent composition study data show that different toluene:methanol ratios play a critical role on the ionisation response of nitrogen containing compounds in different crude oils even with the addition of formic acid. Three different ratios were used which are toluene:methanol solvent ratios of 1:9, 3:7 and 6:4 with and without the addition of 0.1% formic acid for the analysis of crude oil-1, 2 and 3. The highest ionisation for N1 containing compounds are achieved through using toluene:methanol ratio of 1:9 with 0.1% formic acid. Further to this the increase of toluene content in the sample solvent decreased the ionisation of N1 containing compounds in the analysed crude oils even with the addition of formic acid. However, the rate of decrease in the ionisation of N1 containing compounds is more significant for crude oil-1 and 2 compared to crude oil-3. Thus, comparing nitrogen containing compounds among different crude oils should be undertaken using the solvent composition, toluene:methanol ratio of 1:9 with 0.1% formic acid. Another aspect for the solvent composition study is that multimer formation is not only concentration driven but as well sample solvent composition dependent. The data showed that multimer formation in N1 DBE versus carbon number plots are reduced with acid addition and methanol content increase in the sample solvent. The use of positive ion ESI allowed the ionisation of basic compounds in crude oil-1, 2 and 3. To ionise non-polar classes such as aromatics and thiophene containing compounds in crude oil-1, 2 and 3 positive ion APPI is used. Aromatics and thiophene were the most abundant ions in crude oil-1, 2 and 3 mass spectra. No significant difference in ion intensities for these ions were observed for crude oil-1, 2 and 3 mass spectra. However, the use of negative ion APPI showed major differences in the ions intensities of crude oil-1, 2 and 3 regarding HC, HC-R, N1, S1 and S1-R classes. Further, comparable data for the O2 class were obtained using negative ion ESI and APPI Orbitrap MS for crude oil-1, 2 and 3. Thus, negative ion APPI Orbitrap MS can be used to compare the O2 class relative abundance among different crude oils. Further to the characterisation study, structural elucidation of nitrogen containing compounds in crude oil-2 using positive ion ESI FT-ICR MS/MS was undertaken. Understanding the chemical structure might have applications in designing more effective catalysts for HDN process. At first a method development approach was undertaken to reduce the analysis time to 4.5 min and increase detection of low m/z low intensity fragment ions. This aim was achieved through increasing the ion accumulation time from 0.05 s to 5 s with averaging 40 spectra. Different N1 precursor ions were isolated at different DBE values and degree of alkylation. A collision energy of 60 V was required to observe characteristic fragment ions such as N expulsion for N1 precursor ion with DBE value of 13.5. While for N1 precursor ion at DBE value of 6.5 a CE 40 V was enough to observe characteristic fragment ions. However, different approach was used for N1 precursor ion with low DBE values, isolating the precursor ion with the lowest degree of alkylation. This approach was essential to observe N expulsion fragment ions for N1 precursor ion with DBE value of 6.5. The core aromatic structure for N1 precursor ions from DBE values of 3.5 to 10.5 were suggested. This suggestion was based on N expulsion fragment ion and the dealkylated fragment ion. Furthermore, N expulsion from the aromatic ring supports the postulation that the nitrogen in the various precursor ions discussed is pyridinic. This was further confirmed for N1 precursor ion with DBE value of 6.5 using a model compound, 2-butlyquinoline.
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Rodrigues, Chayenny Edna da Silva. "Efeitos na dinâmica da mesosfera no setor brasileiro durante eventos de aquecimento da estratosfera polar." Universidade Estadual da Paraíba, 2017. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2794.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this study, the winds obtained by meteor radar at São João do Cariri (7.4 S, 35 W) during 2005, 2006, 2007 and 2008 years, and at Cachoeira Paulista (22.7 S, 45.0 W) during 2002, 2003, 2004, 2005, 2006 and 2008, have been used to characterize the dynamics of the mesosphere region over the two sites during the sudden stratospheric warming events on polar stratosphere in the Northern Hemisphere. The wind measurements were subjected to a wavelet spectrum analysis to identify a presence of periodic oscillations. Wave amplitudes were obtained through harmonic analysis by least squares fitting and the 2-day wave momentum fluxes have been estimated from the wind perturbations. The values of the 2-day wave amplitudes and the respective zonal momentum fluxes observed over C. Paulista were higher in the 2003, 2004 and 2006 summers, and over S. J. do Cariri in 2006 summer, when events of SSW Major have occurred. The mean wind behavior it is indicative that the MLT region, during the summer, have been affected by 2-day wave, however, it was not possible to identify pattern associated with the effects of the SSW events on dynamic behavior of the MLT region over two sites. From analyzes, the 2-day wave intensification and their momentum fluxes during years in which SSWs were major, provide additional evidence to stratospheric jet instabilities, which is the main 2-day wave source mechanism in the summer hemisphere.
Nesta pesquisa, estimativas do campo de velocidade dos ventos obtidas por radar meteórico em São João do Cariri (7,4 S, 35 O), durante os anos de 2005, 2006, 2007 e 2008, e em Cachoeira Paulista (22,7 S, 45,0 O), durante os anos de 2002, 2003, 2004, 2005, 2006 e 2008, foram usadas para caracterizar a dinâmica da região da mesosfera sobre ambas as localidades durante eventos de aquecimento abrupto da estratosfera polar do hemisfério norte. As medidas de vento foram submetidas a análise de espectro de ondaletas para identificar a presença de oscilações periódicas. As amplitudes da s ondas foram obtidas através análise harmônica por ajuste de mínimos quadrados e os fluxos de momentum da onda de 2 dias foram estimados a partir das perturbações. Os valores das amplitudes da onda de 2 dias e dos respectivos fluxos de momentum zonais observados em C. Paulista foram maiores nos verões de 2003, 2004 e 2006, e em S. J. do Cariri em 2006, quando ocorreram eventos de SSW fortes. O comportamento do vento médio demostra que a dinâmica da região MLT durante o verão é impactada pela onda de 2 dias, contudo, não foi possível identificar padrão associado a efeitos dos eventos de SSW com o comportamento dinâmico da região MLT sobre as duas localidades, a partir dessas análises. A intensificação da onda de 2 dias e dos fluxos de momentum durante os anos em que ocorreram SSW fortes fornecem indícios de forçamento adicional para instabilidade do jato estratosférico, que é o principal mecanismo de excitação da onda no hemisfério de verão.
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BOUDH-HIR, MOHAMED ESSALAH. "Contribution a l'etude theorique de la structure et de la thermodynamique d'un fluide polaire au voisinage d'une surface." Paris 6, 1987. http://www.theses.fr/1987PA066040.
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Le profil position-orientation donne par les approximations type msa, lhnc. . . Est identique a celui des spheres dures. Il est montre que, meme dans ce cas, il existe des orientations privilegiees. Loin de la surface, seul le potentiel image classique subsiste. Au voisinage de celle-ci, le resultat est plus complique et ne peut etre prevu par la theorie classique. Il est montre aussi qu'un potentiel anisotrope faible ( equiv. A kt) suffit pour produire des effets observables sur le plan experimental. Deux approximations ont ete comparees: blip et l'inegalite de gibbs-bogolioubov. Enfin, etude des fonctions de correlation de paire: il est montre que, sur la surface et loin de celle-ci, ces fonctions sont decrites par les potentiels direct et image. Dans la region intermediaire, la solution est plus compliquee
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Waters, Lois Diane. "Relationships Between Hybrid Poplar Tree Extractives and Ground Water Contamination at a Phytoremediation Site." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31583.
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In 1997, a phytoremediation program began at a creosote-contaminated former railroad tie yard in Oneida, Tennessee with the planting of over 1000 hybrid poplar trees onsite. Creosote, a mixture of hazardous chemicals composed of 85% polycyclic aromatic hydrocarbons (PAH) had entered the site soil and ground water. After planting, a seasonal ground water testing program began that monitored the progress of remediation by measuring the concentration of the 10 predominant PAHs in the contaminant plume: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, and benzo(b)fluoranthene. The concentrations of these compounds steadily decreased over time, but the role the trees played in the remediation was unclear.
In order to gain a clearer understanding of the role the trees played in contaminant remediation, chemical analysis of tree tissue began. It was not known whether the trees were taking up PAH contaminants or their metabolites or if the rhizosphere zone created by the trees simply enhanced the ability of the site microflora to degrade the PAH. The objectives of this research were to (1) develop a suitable method for the chemical analysis of tree tissue collected from a field site, (2) determine if there were any chemicals not usually found in poplar trees that occurred in the trees growing over contamination, (3) determine if bud, bark, and twig tissue differed in their ability to predict ground water contamination, and (4) determine if a spatial correlation existed between the aromatic compounds in the tree tissue and the ground water total PAH plume.
Two types of tree tissue/ground water comparisons were performed: spatial distribution of isoeugenol concentration in tree tissue with spatial distribution of total PAH in ground water over the area of interest; and the spatial distribution of the quantity of aromatic compounds in tree tissue with the spatial distribution of total PAH concentration in ground water. Due to unit discrepancies between the quantities of interest, all comparisons were made on a percentile basis.
Initial tree sampling revealed that several compounds not usually present in poplar trees occurred only in those trees growing over contamination. In the first part of this study, the concentration of one of these chemicals, the substituted phenol isoeugenol, was compared with the concentration of total PAH in ground water from samples collected from February-March 2002. The bark tissue percentiles fell within 20 percentiles of ground water total PAH concentrations in 60% of the study area. The twig tissue showed slightly better agreement, with 67% of the study area differing from ground water by twenty percentiles or less.
The second comparison took place over three sampling events: March 2001, July 2001, and February-March 2002. The number of unique aromatic compounds in bark, bud, and twig tissue was compared with the total PAH concentration in ground water. Twig tissue aromatic compound content was the most accurate predictor of ground water contamination among the tissue types. After excluding those chemicals likely to be interferences from consideration, twig tissue aromatic content agreed with ground water total PAH concentration to within 20 percentiles over 2/3 or more of the study area during each sampling event, suggesting the potential uptake of PAHs or their microbial metabolites as a mechanism of phytoremediation at the site.
Master of Science
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Bergerbit, Cédric. "RAFT polymerization of ethylene for the synthesis of polar-apolar olefin block copolymers." Thesis, Lyon, 2019. https://n2t.net/ark:/47881/m6s181w9.
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La synthèse de copolymères à blocs, comprenant un bloc semi-cristallin de polyéthylène (PE) apolaire et un bloc polaire (poly(acétate de vinyle) (PAcV), poly(méthacrylate de méthyle) (PMAM), poly(oxide d’éthylène) (POE)) a été étudiée par polymérisation RAFT. L’étude préliminaire de l’homopolymérisation de l’éthylène en conditions relativement douces (T = 70 – 80 °C, P = 200 bar) a révélé que l’utilisation d’agents de transfert de chaîne (ATC) de type xanthates aromatiques conduit à une perte de fonctionnalité des extrémités de chaînes au cours de la polymérisation, conséquence directe de réactions de terminaison se produisant sur le radical intermédiaire. L’utilisation de dithiocarbamates aromatiques a permis de s’affranchir de ce mécanisme parasite et pour la première fois des chaînes de PE présentant une fonctionnalité de bout de chaîne proche de 100%. Des ATCs macromoléculaires polaires, obtenus avec les agents de transfert de chaînes identifiés au cours de l’étude préliminaire, ont ensuite été utilisés pour la synthèse de copolymères à blocs dans le carbonate de diméthyle (DMC), un solvant organique peu transférant. Le rôle clé de la thermodynamique du milieu de polymérisation (mélange DMC/éthylène supercritique à 200 bar) a alors été mis en évidence. En effet, les macro-ATCs sont insolubles dans un tel milieu, ce qui a conduit à la formation d’un mélange d’homopolymères. La diminution de la pression de polymérisation (P < 100 bar) a toutefois permis d’éviter ce phénomène et les copolymères PVAc-b-PE, PMMA-b-PE et PEO-b-PE attendus ont été obtenus. Des propriétés d’auto-assemblage ont été mises en évidence et des morphologies de type fibre ont été obtenues pour les copolymères PMMA-b-PE et PEO-b-PE synthétisés dans le DMC, permettant d’envisager un mécanisme de type auto-assemblage induit par la polymérisation (PISA). Le passage en milieu aqueux en utilisant le macro-ATC hydrosoluble PEO a permis l’observation de morphologies de type sphériques, vésicules ou encore ellipsoïdes selon le rapport molaire macro-ATC/amorceur utiliséThe synthesis of polar-apolar olefin block copolymers, combining a semi-crystalline polyethylene (PE) block and a polar block (poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), poly(ethylene oxide) (PEO)) was investigated by RAFT polymerization. A preliminary study on ethylene homopolymerization revealed parasite cross-termination reactions happening at the intermediate radical, resulting in the loss of chain-end fidelity when using aromatic xanthates as chain transfer agents (CTA) under relative mild conditions (T = 70 – 80 °C, P = 200 bar). The extent of cross-termination was greatly reduced with aromatic dithiocarbamates, and for the first time, PE chains with a high livingness were obtained. These first results were used to equip polar macromolecular CTAs (PVAc, PMMA, PEO), with selected aromatic xanthates and dithiocarbamates, that were further used for block copolymerization with ethylene in a low-transferring organic solvent (dimethyl carbonate, DMC). A critical influence of the ethylene pressure was evidenced as block polymerization at 200 bar could not be achieved due to solubility issues in the resulting supercritical DMC/ethylene mixture. This was circumvented by performing the block copolymerization below the supercritical point of the mixture (P < 100 bar) and well-defined PVAc-b-PE, PMMA-b-PE and PEO-b-PE copolymers were eventually obtained. The block copolymers were found to feature self-assembly properties and worm-like morphologies were observed for PMMA-b-PE and PEO-b-PE synthesized in DMC, hinting at a plausible polymerization-induced self-assembly (PISA) mechanism. The successful switch from DMC to water for the synthesis of PEO-b-PE copolymers enabled the observation of various particle morphologies: spheres, vesicles and ellipsoidal particles, depending on the initial macro-CTA:initiator molar ratio
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Beldon, Charlotte. "VHF radar studies of mesosphere and thermosphere." Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512294.
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Bonev, Boncho Peichev. "Towards a chemical toxonomy of comets : infrared spectroscopic methods for quantitative measurements of cometary water (with an independent chapter on Mars polar science) /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2005. http://www.ohiolink.edu/etd/view.cgi?toledo1133980701.
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Thesis (Ph. D.)--University of Toledo, 2005.Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Physics." Includes bibliographical references (leaves 295-304).
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Bonev, Boncho P. "Towards a Chemical Taxonomy of Comets: Infrared Spectroscopic Methods for Quantitative Measurements of Cometary Water (With an Independent Chapter on Mars Polar Science)." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1133980701.
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Wiklund, Susanne. "Spectroscopic data and multivariate analysis : tools to study genetic perturbations in poplar trees." Doctoral thesis, Umeå : Department of Chemistry, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1396.
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Gaimard, Patricia. "Fonctions de distribution de vitesses non-maxwelliennes dans le plasma ionosphérique et application à la mesure par diffusion incohérente." Phd thesis, Université Joseph Fourier (Grenoble), 1996. http://tel.archives-ouvertes.fr/tel-00724945.
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En période magnétiquement perturbée il est nécessaire de considérer une fonction de distribution des vitesses ioniques non-Maxwellienne, si l'on veut pouvoir estimer correctement les paramètres ionosphériques de l'ionosphère aurorale, mesurés par diffusion incohérente. Nous avons comparé deux modèles de fonction de distribution non-Maxwellienne : l'approximation polynomiale généralisée qui est une solution analytique de l'équation de Boltzmann et une distribution numérique basée sur une méthode Monte Carlo. Ces deux approches conduisent, pour les deux espèces ioniques 0+ et NO+, à des résultats semblables lors de champs électriques inférieurs à 100 m V lm. La fonction analytique a été introduite dans l'analyse des spectres EISCAT afin d'étudier l'ionosphère sous des champs électriques pouvant atteindre 100 m V /m. Cette nouvelle analyse a, dans un premier temps, été testée sur plusieurs jeux de simulations avec notamment des études de sensibilité aux modèles utilisés. Dans une seconde étape, nous avons étudié des spectres présentant des caractéristiques non-Maxwelliennes et avons ainsi déterminé la composition de l'ionosphère sous forts champs électriques. Enfin avec une dernière série de données réelles nous avons estimé quantitativement l'erreur commise lors d'une interprétation "Maxwellienne" de spectres non-Maxwelliens dans le cas d'une ionosphère composée d'ions moléculaires.
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Rosa, Paulo César Pires 1976. "Preparação, caracterização da fase estacionária C8, com grupo polar uréia embutido e aplicações na análise e no desenvolvimento e validação de métodos para determinação de fármacos." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250527.
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Orientador: Isabel Cristina Sales Fontes JardimTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Neste trabalho, desenvolveu-se uma nova fase estacionária (FE) (-NH-C(O)-NH-C8) capeada, contendo o grupo polar uréia inserido na cadeia alquila C8. Os estudos de análise elementar, espectroscopia infravermelho, ressonância magnética nuclear de C e Si confirmaram o sucesso da síntese da FE. A FE foi preparada e foi caracterizada cromatograficamente na separação de misturas testes e de diversas classes de fármacos, no desenvolvimento e validação de métodos para avaliação de misturas de estatinas em cápsulas, clobutinol e doxilamina em xarope e para determinação de impurezas e produtos de degradação dos fármacos alprazolam e cloxazolam. As colunas recheadas com a FE Si-C8-uréia proporcionaram boas separações, com eficiências entre 60.000 e 80.000 pratos m e picos simétricos, especialmente para compostos básicos. O comportamento da nova FE foi comparado com os das FE comerciais, obtendo desempenho semelhante na separação de misturas testes e de fármacos, como furoato de mometasona em creme, conservantes como os alquilparabenos, clonazepam e impurezas, valerato de betametasona, clioquinol e tolnaftato em creme, dropropizina em xarope, mistura de paracetamol, cafeína e ácido acetisalicílico em comprimidos e mistura de cefalexina, prilocaína e amitriptilina. A FE Si-C8-uréia apresentou boa aplicabilidade na separação de fármacos devido ao grupo uréia reduzir a interação dos compostos básicos com os silanóis residuais. Dessa forma, a nova FE possui potencialidade para ser empregada em laboratórios de pesquisa e controle de qualidade, especialmente na análise de compostos básicos
Abstract: In this work, it a new end-capped stationary phase (SP) containing a urea polar group inserted into the C8 alkil chain (-NH-C(O)-NH-C8) was prepared. Elementar analysis, infrared spectroscopy and C and Si nuclear magnetic ressonance allowed confirmation of the success of the synthesis of the SP. The new SP was chromatographically caracterizeded by the separation of test mixtures and of different types of pharmaceutical compounds, in the development and validation of methods for analysis of a mixture of statins in capsules, clobutinol hydrochloride and doxilamine in syrups and for determination of impurities and degradation products of the pharmaceutical compounds alprazolam and cloxazolam. Columns containing Si-C8-urea SP showed good separations, with efficiencies between 60 000 and 80 000 plates.m and symmetrical peaks, especially for basic compounds. The behavior of the new SP was compared with commercially available SP and the results showed similar behaviors for separation of test mixtures and of pharmaceutical compounds such as mometasone furoate in creams, preservatives like alkylparabens, clonazepam and impurities, bethametasone valerate, clioquinol and tolnaftate in creams, dropropizine in syrup, mixtures of acetaminophen, caffeine and aspirin in tablets and mixtures of cefalexin, prilocaine and amitriptiline. The Si-C8-urea SP showed good applicability for separation of pharmaceutical compounds due to the urea group reducing the interaction of basic analytes with the residual silanols. Thus, the new SP has the potencial to be employed in research and for quality control, especially for the analyses of basic pharmaceutical compounds
Doutorado
Quimica Analitica
Doutor em Ciências
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Rotschky, Gerit. "Spatial distribution of snow accumulation and snowpack properties in Dronning Maud Land, Antarctica : observational techniques and methods for surface mass-balance assessments of polar ice sheets = Räumliche Verteilung von Schneeakkumulation und Schneedeckeneigenschaften in Droning Maud Land, Antarktis : Observationstechniken und Methoden der Netto-Massenbilanzbestimmung polarer Eisschilde /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2007. http://www.loc.gov/catdir/toc/fy0804/2007462672.html.
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Gentile, Chiara. "Metodo del gradiente coniugato per problemi ai minimi quadrati non lineari." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12187/.
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In questo elaborato vengono prese in considerazione tre versioni del metodo del gradiente coniugato proposte per
l'ottimizzazione di funzioni non quadratiche con l'obiettivo di analizzare il loro utilizzo come metodi di regolarizzazione per problemi ai minimi quadrati non lineari mal condizionati. In particolare le tre versioni
prese in esame sono: il metodo di Fletcher-Reeves, il metodo di Polak-Polyak-Ribiére e una versione ibrida dei due. Dai risultati numerici è stato possibile osservare che i metodi in questione sono metodi di regolarizzazione iterativi e producono risultati competitivi con i metodi
di solito utilizzati in questo contesto (Lavenberg-Marquard, Gauss-Newton).
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Himmelsbach, Jennifer Nicole. "Aqueous ammonia soaking (AAS) as a biomass pretreatment method pilot-scale study with switchgrass, bench-scale use with poplar, and methane potential from anaerobic digestion of pretreated switchgrass /." [Ames, Iowa : Iowa State University], 2009.
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Rotschky, Gerit. "Spatial distribution of snow accumulation and snowpack properties in Dronning Maud Land, Antarctica observational techniques and methods for surface mass balance assessments of polar ice sheets = Räumliche Verteilung von Schneeakkumulation und Schneedeckeneigenschaften in Dronning Maud Land, Antarktis /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=98347785X.
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Zbránek, Jakub. "Měření horizontálních a vertikálních posunů gabionové zdi." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226754.
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The main subject of this diploma thesis is monitoring of horizontal and vertical displacements of the supporting wall in village Smědčice. The thesis describes the whole production process, from construction of the reference net and the net of observed points to the final review. There are also displayed main theoretical basis. Final outputs of the thesis are charts, graphical sketches, tables and final word summary.
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Zubík, Tomáš. "Vyhotovení mapových podkladů areálu Metra v Blansku - jižní část." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-400183.
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The diploma thesis deals with planimetric and altimetry determination of the area Metro company in Blansko , its southern part. The content of the thesis is a detailed description of the schedule, survey section, calculations, graphic processing in the GEOSTORE V6® program, description information connection. The result is a printed 1: 250 scale maps in the S-JTSK coordinate system and the Bpv elevation system.
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Grosset, Lucas. "Observations extragalactiques avec optique adaptative : polarisation dans les noyaux actifs de Galaxie et étude des super amas d'étoiles." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEO004/document.
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Malgré l’existence de modèles précis, notre connaissance des structures à petite échelle des galaxies est toujours limitée par le manque de preuves observationnelles. Les progrès instrumentaux ont permis d’atteindre une haute résolution angulaire à l’aide des nouvelles générations de télescopes, mais celle-ci est restreinte à un faible nombre de cibles extragalactiques à causes des besoins de l’Optique Adaptative (OA). En effet, afin de permettre une mesure efficace du front d’onde, l’OA requiert une source brillante et ponctuelle proche de la cible scientifique, typiquement en dessous de 30 . La partie principale de cette thèse porte sur l’analyse de la dizaine de parsecs centrale des Galaxies à Noyaux Actifs (NAG) à l’aide de différentes techniques observationnelles et numériques. Nous avons dans ce contexte développé un code de transfert radiatif nous permettant d’analyser les données polarimétriques. La seconde partie de ce travail est dédiée à l’analyse d’images en proche infrarouges de galaxies à flambée d’étoiles afin de contraindre les paramètres décrivant les super amas stellaires, jeunes cocons de poussière très massifs abritant une formation d’étoiles très soutenue, à l’aide de données obtenues avec l’instrument CANARY, démonstrateur de nouvelles technologies d’OADespite having strong theoretical models, the current limitation in our understanding of the small-scale structures of galaxies is linked to the lack of observational evidences. Many powerful telescopes and instruments have been developed in the last decades, however one of these strongest tools, namely Adaptive Optics (AO), can only be used on a very limited number of targets. Indeed, for AO to be efficient, a bright star is required close to the scientific target, typically under 30 . This is mandatory for the AO systems to be able to measure the atmospheric turbulence and this condition is rarely satisfied for extended extragalactic targets such as galaxies. The main part of this thesis work consisted in going deeper in the analysis of the inner tens of parsecs of Active Nuclei (AGN) by combining different techniques to obtain and to interpret new data. In this context, we developed a new radiative transfer code to analyse the polarimetric data. A second part of my work was dedicated to a high angular resolution study of Super Star Clusters (SSC) in a new system, thanks to data obtained with the AO demonstrator CANARY instrument
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Perombelon, Brice Désiré Jude. "Prioritising indigenous representations of geopower : the case of Tulita, Northwest Territories, Canada." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:71e14c26-d00a-4320-a385-df74715c45c8.
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Recent calls from progressive, subaltern and postcolonial geopoliticians to move geopolitical scholarship away from its Western ontological bases have argued that more ethnographic studies centred on peripheral and dispossessed geographies need to be undertaken in order to integrate peripheralised agents and agencies in dominant ontologies of geopolitics. This thesis follows these calls. Through empirical data collected during a period of five months of fieldwork undertaken between October 2014 and March 2015, it investigates the ways through which an Indigenous community of the Canadian Arctic, Tulita (located in the Northwest Territories' Sahtu region) represents geopower. It suggests a semiotic reading of these representations in order to take the agency of other-than/more-than-human beings into account. In doing so, it identifies the ontological bases through which geopolitics can be indigenised. Drawing from Dene animist ontologies, it indeed introduces the notion of a place-contingent speculative geopolitics. Two overarching argumentative lines are pursued. First, this thesis contends that geopower operates through metamorphic refashionings of the material forms of, and signs associated with, space and place. Second, it infers from this that through this transformational process, geopower is able to create the conditions for alienating but also transcending experiences and meanings of place to emerge. It argues that this movement between conflictual and progressive understandings is dialectical in nature. In addition to its conceptual suggestions, this thesis makes three empirical contributions. First, it confirms that settler geopolitical narratives of sovereignty assertion in the North cannot be disentangled from capitalist and industrial political-economic processes. Second, it shows that these processes, and the geopolitical visions that subtend them, are materialised in space via the extension of the urban fabric into Indigenous lands. Third, it demonstrates that by assembling space ontologically in particular ways, geopower establishes (and entrenches) a geopolitical distinction between living/sovereign (or governmentalised) spaces and nonliving/bare spaces (or spaces of nothingness).
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Bonan, Bertrand. "Assimilation de données pour l'initialisation et l'estimation de paramètres d'un modèle d'évolution de calotte polaire." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00930097.
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L'évolution des calottes polaires est régie à la fois par une dynamique d'écoulement complexe et par des mécanismes tel le glissement à la base, la température de la glace ou le bilan de masse en surface. De plus, de nombreuses boucles de rétroactions sont constatées entre les différents phénomènes impliquées. Tout ceci rend la modélisation de cette évolution complexe. Malgré tout, un certain nombre de modèles ont été développés dans cette optique. Ceux-ci font tous intervenir des paramètres influents qui dans certains cas sont peu ou pas connus. Ils nécessitent donc d'être correctement spécifiés. L'assimilation de données peut permettre une meilleure estimation de ces paramètres grâce à l'utilisation d'observations qui sont peu nombreuses en glaciologie. Dans cette thèse, nous nous intéressons à la mise en place de systèmes d'assimilation performants pour deux problèmes inverses concernant l'évolution des calottes polaires. Pour mieux nous concentrer sur ce point, nous avons travaillé avec un modèle d'évolution de calotte simplifié (appelé Winnie) qui, cependant, représente bien la plupart des processus complexes de la dynamique de la glace, et permet de travailler à différentes échelles de temps. Dans un premier temps, nous mettons en place une approche 4D-Var pour la reconstruction de l'évolution d'un paramètre climatique influant sur l'évolution d'une calotte sur une échelle de temps typique de 20 000 ans. Elle nécessite notamment l'écriture du code adjoint du modèle. Dans un second temps, nous nous intéressons au problème du spin-up. Ce problème de calibration du modèle pour des simulations à échelle de temps courtes (pas plus de 100 ans) consiste plus particulièrement en la reconstruction conjointe de l'état initial, de la topographie du socle rocheux et des paramètres de glissement basal. Nous développons ici une approche filtre de Kalman d'ensemble pour résoudre ce problème.