Dissertations / Theses on the topic 'Continuous maps'
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Byrne, Jesse William. "Multifractal Analysis of Parabolic Rational Maps." Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278398/.
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The investigation of the multifractal spectrum of the equilibrium measure for
a parabolic rational map with a Lipschitz continuous potential, φ, which satisfies
sup φ < P(φ)
x∈J(T)
is conducted. More specifically, the multifractal spectrum or spectrum of singularities, f(α) is studied.
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Huggins, Mark C. (Mark Christopher). "A Continuous, Nowhere-Differentiable Function with a Dense Set of Proper Local Extrema." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc500353/.
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In this paper, we use the following scheme to construct a continuous, nowhere-differentiable function 𝑓 which is the uniform limit of a sequence of sawtooth functions 𝑓ₙ : [0, 1] → [0, 1] with increasingly sharp teeth. Let 𝑋 = [0, 1] x [0, 1] and 𝐹(𝑋) be the Hausdorff metric space determined by 𝑋. We define contraction maps 𝑤₁ , 𝑤₂ , 𝑤₃ on 𝑋. These maps define a contraction map 𝑤 on 𝐹(𝑋) via 𝑤(𝐴) = 𝑤₁(𝐴) ⋃ 𝑤₂(𝐴) ⋃ 𝑤₃(𝐴). The iteration under 𝑤 of the diagonal in 𝑋 defines a sequence of graphs of continuous functions 𝑓ₙ. Since 𝑤 is a contraction map in the compact metric space 𝐹(𝑋), 𝑤 has a unique fixed point. Hence, these iterations converge to the fixed point-which turns out to be the graph of our continuous, nowhere-differentiable function 𝑓. Chapter 2 contains the background we will need to engage our task. Chapter 3 includes two results from the Baire Category Theorem. The first is the well known fact that the set of continuous, nowhere-differentiable functions on [0,1] is a residual set in 𝐶[0,1]. The second fact is that the set of continuous functions on [0,1] which have a dense set of proper local extrema is residual in 𝐶[0,1]. In the fourth and last chapter we actually construct our function and prove it is continuous, nowhere-differentiable and has a dense set of proper local extrema. Lastly we iterate the set {(0,0), (1,1)} under 𝑤 and plot its points. Any terms not defined in Chapters 2 through 4 may be found in [2,4]. The same applies to the basic properties of metric spaces which have not been explicitly stated. Throughout, we will let 𝒩 and 𝕽 denote the natural numbers and the real numbers, respectively.
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Islam, Md Shafiqul. "Absolutely continuous invariant measures for piecewise linear interval maps both expanding and contracting." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ54294.pdf.
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Aliakbarian, Meysam. "Derivation of continuous zoomable road network maps through utilization of Space-Scale-Cube." Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-153432.
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The process of performing cartographic generalization in an automatic way applied on geographic information is of highly interest in the field of cartography, both in academia and industry. Many research e↵orts have been done to implement di↵erent automatic generalization approaches. Being able to answer the research question on automatic generalization, another interesting question opens up: ”Is it possible to retrieve and visualize geographic information in any arbitrary scale?” This is the question in the field of vario-scale geoinformation. Potential research works should answer this question with solutions which provide valid and efficient representation of geoinformation in any on-demand scale. More brilliant solutions will also provide smooth transitions between these on-demand arbitrary scales. Space-Scale-Cube (Meijers and Van Oosterom 2011) is a reactive tree (Van Oosterom 1991) data structure which shows positive potential for achieving smooth automatic vario-scale generalization of area features. The topic of this research work is investigation of adaptation of this approach on an interesting class of geographic information: road networks datasets. Firstly theoretical background will be introduced and discussed and afterwards, implementing the adaptation would be described. This research work includes development of a hierarchical data structure based on road network datasets and the potential use of this data structure in vario-scale geoinformation retrieval and visualization.
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Al-Khal, Jawad Yusuf. "New examples of S-unimodal maps with a sigma-finite absolutely continuous invariant measure." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/2087.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Mathematics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Zhang, Cheng. "Continuous and quad-graph integrable models with a boundary : reflection maps and 3D-boundary consistency." Thesis, City University London, 2013. http://openaccess.city.ac.uk/3016/.
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This thesis is focusing on boundary problems for various classical integrable schemes. First, we consider the vector nonlinear Schrodinger (NLS) equation on the halfline. Using a Backlund transformation method which explores the folding symmetry of the system, classes of integrable boundary conditions (BCs) are derived. These BCs coincide with the linearizable BCs obtained using the unified transform method developed by Fokas. The notion of integrability is argued by constructing an explicit generating function for conserved quantities. Then, by adapting a mirror image technique, an inverse scattering method with an integrable boundary is constructed in order to obtain N-soliton solutions on the half-line, i.e. N-soliton reflections. An interesting phenomenon of transmission between different components of vector solitons before and after interacting with the boundary is demonstrated. Next, in light of the fact that the soliton-soliton interactions give rise to Yang-Baxter maps, we realize that the soliton-boundary interactions that are extracted from the N-soliton reflections can be translated into maps satisfying the set-theoretical counterpart of the quantum reflection equation. Solutions of the set-theoretical reflection equation are referred to as reflection maps. Both the Yang-Baxter maps and the reflection maps guarantee the factorization of the soliton-soliton and soliton-boundary interactions for vector NLS solitons on the half-line. Indeed, reflection maps represent a novel mathematical structure. Basic notions such as parametric reflection maps, their graphic representations and transfer maps are also introduced. As a natural extension, this object is studied in the context of quadrirational Yang-Baxter maps, and a classification of quadrirational reflection maps is obtained. Finally, boundaries are added to discrete integrable systems on quad-graphs. Triangle configurations are used to discretize quad-graphs with boundaries. Relations involving vertices of the triangles give rise to boundary equations that are used to described BCs. We introduce the notion of integrable BCs by giving a three-dimensional boundary consistency as a criterion for integrability. By exploring the correspondence between the quadrirational Yang-Baxter maps and the so-called ABS classification, we also show that quadrirational reflection maps can be used as a systematic tool to generate integrable boundary equations for the equations from the ABS classification.
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Mansouri, Asma. "Exponentiation of set-valued maps and applications." Thesis, Perpignan, 2020. http://www.theses.fr/2020PERP0002.
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Dans cette thèse, nous avons présenté notre contribution au calcul des points fixes pour des équations linéaires et non linéaires. nous avons introduit une nouvelle méthode pour calculer les points fixes d'une classe de fonctions itérées dans un temps fini, en calculant l'exponentiel des opérateurs linéaires multivalués. Afin d'illustrer notre approche et montrer que cette méthode peut donner des résultats rapides et précis pour les équations linéaires et non linéaires, nous avons choisi deux applications bien connues qui sont difficiles à manipuler par les techniques habituelles, pour le cas des équations linéaires. Premièrement, nous appliquons l'exponentiation des opérateurs linéaires à un filtre numérique afin d'obtenir une approximation fine de son comportement à un moment arbitraire. Deuxièmement, on considére un contrôleur PID. Afin d'obtenir une estimation fiable de sa fonction de contrôle, on applique l'exponentiation d'un faisceau d'opérateurs linéaires. Pour le cas des équations non linéaires, nous avons choisi un système dynamique non linéaire, plus précisément un contrôleur en boucle ouverte, et nous avons calculé le point fixe de son approximation linéaire. Notons que cette technique peut être appliquée dans un cadre plus général, pour toute fonction multivoque linéaire et non linéaire et que l'algorithme général est également introduit dans ce manuscritIn this thesis, we presented our contribution to the computation of fixed-points for both linear and nonlinear equations. We introduced a new method for computing fixed points of a class of iterated functions in a finite time, by exponentiating linear multivalued operators. In order to illustrate our approach and show that this method can give fast and accurate results for both linear and non linear equations, we have chosen two well-known applications which are difficult to handle by usual techniques, for linear equations case. First, we apply the exponentiation of linear operators to a digital filter in order to get a fine approximation of its behavior at an arbitrary time. Second, we consider a PID controller. In order to get a reliable estimate of its control function, we apply the exponentiation of a bundle of linear operators. For the non linear equations case, we have chosen a dynamic non linear system, more precisely, an open loop control command system, and we computed the fixed point of its linear approximation. Note that, this technique can be applied in a more general setting, for any multivalued linear and non linear map and that the general algorithm is also introduced in this manuscript
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Schnellmann, Daniel. "Viana maps and limit distributions of sums of point measures." Phd thesis, KTH, Matematik (Inst.), 2009. http://tel.archives-ouvertes.fr/tel-00694201.
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This thesis consists of five articles mainly devoted to problems in dynamical systems and ergodic theory. We consider non-uniformly hyperbolic two dimensional systems and limit distributions of point measures which are absolutely continuous with respect to the Lebesgue measure. Let $f_{a_0}(x)=a_0-x^2$ be a quadratic map where the parameter $a_0\in(1,2)$ is chosen such that the critical point $0$ is pre-periodic (but not periodic). In Papers A and B we study skew-products $(\th,x)\mapsto F(\th,x)=(g(\th),f_{a_0}(x)+\al s(\th))$, $(\th,x)\in S^1\times\real$. The functions $g:S^1\to S^1$ and $s:S^1\to[-1,1]$ are the base dynamics and the coupling functions, respectively, and $\al$ is a small, positive constant. Such quadratic skew-products are also called Viana maps. In Papers A and B we show for several choices of the base dynamics and the coupling function that the map $F$ has two positive Lyapunov exponents and for some cases we further show that $F$ admits also an absolutely continuous invariant probability measure. In Paper C we consider certain Bernoulli convolutions. By showing that a specific transversality property is satisfied, we deduce absolute continuity of the to these Bernoulli convolutions associated distributions. In Papers D and E we consider sequences of real numbers in the unit interval and study how they are distributed. The sequences in Paper D are given by the forward iterations of a point $x\in[0,1]$ under a piecewise expanding map $T_a:[0,1]\to[0,1]$ depending on a parameter $a$ contained in an interval $I$. Under the assumption that each $T_a$ admits a unique absolutely continuous invariant probability measure $\mu_a$ and that some technical conditions are satisfied, we show that the distribution of the forward orbit $T_a^j(x)$, $j\ge1$, is described by the distribution $\mu_a$ for Lebesgue almost every parameter $a\in I$. In Paper E we apply the ideas in Paper D to certain sequences which are equidistributed in the unit interval and give a geometrical proof of an old result by Koksma.
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Radwan, Mohsen Nada Ashraf. "Lightweight & Efficient Authentication for Continuous Static and Dynamic Patient Monitoring in Wireless Body Sensor Networks." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39938.
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The emergence of the Internet of Things (IoT) brought about the widespread of Body Sensor Networks (BSN) that continuously monitor patients using a collection of tiny-powered and lightweight bio-sensors offering convenience to both physicians and patients in the modern health care environment. Unfortunately, the deployment of bio-sensors in public hacker-prone settings means that they are vulnerable to various security threats exposing the security and privacy of patient information. This thesis presents an authentication scheme for each of two applications of medical sensor networks. The first is an ECC based authentication scheme suitable for a hospital-like setting whereby the patient is hooked up to sensors connected to a medical device such as an ECG monitor while the doctor needs real-time access to continuous sensor readings. The second protocol is a Chebyshev chaotic map-based authentication scheme suitable for deployment on wearable sensors allowing readings from the lightweight sensors connected to patients to be sent and stored on a trusted server while the patient is on the move. We formally and informally proved the security of both schemes. We also simulated both of them on AVISPA to prove their resistance to active and passive attacks. Moreover, we analyzed their performance to show their competitiveness against similar schemes and their suitability for deployment in each of the intended scenarios.
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Espinoza, Benjamin. "Whitney preserving maps." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2451.
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Thesis (Ph. D.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains vii, 60 p. : ill. Includes abstract. Includes bibliographical references (p. 59-60).
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NASCIMENTO, Edmar José do. "Mapas de Shannon-Kotel’nikov na distribuição quântica de chaves com variáveis contínuas." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/715.
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Protocolos para a distribuição quântica de chaves (DQC) permitem que duas partes (Alice e Bob) compartilhem uma chave secreta que pode ser usada para fins criptográficos. A segurança do protocolo é baseada em propriedades da mecânica quântica, ao invés de hipóteses computacionais. Na distribuição quântica de chaves com variáveis contínuas (DQCVC), a informação é codificada nas amplitudes de quadratura do campo eletromagnético quantizado. Quando implementado com variáveis contínuas, o aparato usado na DQC é consideravelmente mais simples que nas implementações convencionais com variáveis discretas, já que se pode utilizar a medição do tipo homódina, ao invés da detecção de fótons. Uma vez realizada a medida, ainda se faz necessária uma etapa de processamento clássico, denominada de reconciliação da informação, a fim de que Alice e Bob possam compartilhar uma cadeia comum de bits. Para que a DQCVC possa ser realizada em distâncias razoáveis (superiores a 30 km), o processo de reconciliação precisa ser feito com eficiências elevadas (superiores a 90%). Entretanto, eficiências dessa ordem para baixas SNRs (signal-to-noise ratio - razão sinal ruído) requerem o uso de códigos clássicos de comprimento bastante elevado e, assim, são difíceis de serem alcançadas. Nesta tese, se propõe o uso dos mapas de Shannon-Kotel’nikov na preparação dos estados quânticos que são usados na DQCVC. Com a utilização desses mapas, é possível aumentar a SNR entre Alice e Bob sem aumentar a variância da modulação de Alice. Dessa forma, o processo de reconciliação se torna mais simples, pois eficiências de reconciliação mais altas são mais facilmente alcançadas em SNRs maiores. Como contribuições desta tese têm-se: a proposição de um protocolo; a definição de um cenário de simulação e a análise do protocolo para dois tipos de mapas (a espiral uniforme de Arquimedes e as curvas geodésicas em um toro planar).
Quantum key distribution (QKD) protocols allow two parties, Alice and Bob, to share a secret key that may be used for cryptographic purposes. The security of QKD is based on quantum mechanics properties instead of computational assumptions. In continuous-variable quantum key distribution (CVQKD), the information is encoded in the quadrature amplitudes of the quantized electromagnetic field. When QKD is implemented with continuous variables, hardware components are much simpler than their discrete variables equivalents. This is mainly due to homodyne detection instead of photon detection. After measuring the transmitted states, it is still necessary to carry out a classical processing stage known as information reconciliation. This stage allows Alice and Bob to share a common sequence of bits. In order to deploy CVQKD over reasonable distances (over 30 km), reconciliation must be done at high efficiencies (over 90%). However, such high efficiencies for low SNRs (signal-to-noise ratio) require long length classical codes and are difficult to be reached. In this thesis, we propose to use Shannon-Kotel’nikov maps for preparing quantum states in CVQKD. By using these maps, it is possible to increase the SNR between Alice and Bob, without increasing Alice’s variance. Thus, reconciliation becomes easier because higher reconciliation efficiencies are more easily reached for higher SNRs. The contributions of this theses are: the proposal of a CVQKD protocol; the statement of a simulation scenario; the analysis of the proposed protocol for two kinds of maps (uniform Archimedes’ spiral and geodesic curves on a flat torus).
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Beane, Robbie Allen. "Inverse limits of permutation maps." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Beane_09007dcc804f93c9.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 9, 2008) Includes bibliographical references (p. 71-73).
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Hedin, Andreas. "CRAMO : Continuously Rendered Aerial Maps with Open Data." Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-85290.
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One issue with a lot of the free aerial satellite maps that exists is the actuality of the acquired images in terms of the acquisition date. A lot of times the images are a few years old and will not represent the current reality. This project will try and mitigate this by using free open data from the Copernicus directive supplied by the European Space Agency ESA and use that to create maps. By doing this the ability to have daily updated aerial satellite maps occurs and that could be really interesting for scientific and commercial purposes. To make this work an automated process was created that downloaded the images from Copernicus and processed them with GDAL to create the maps. The process deals with the issues of mosaicing, reprojection and unattended downloads amongst other things. In the results, there is a comparison between three different maps to give a comparison and an idea of how big of a map the process can handle in a reasonable time.
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Stone, Jennifer Williamson Heath Jo W. Smith Michel. "Non-metric continua that support Whitney maps." Auburn, Ala., 2007. http://hdl.handle.net/10415/1375.
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Tatjer, i. Montaña Joan Carles. "Invariant manifolds and bifurcations for one-dimensional and two-dimensional dissipative maps." Doctoral thesis, Universitat de Barcelona, 1990. http://hdl.handle.net/10803/2113.
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It is known that for the study of continuous dynamical systems the discret case plays an important role because, with it we can study the continuous one by using the Poincaré return map. In the discret case we can distinguish between conservative maps (or area preserving maps, in the case of flows living on a 3-dimensional manifold) and non conservative maps. Among the last ones, there are the dissipative maps. Two of the main subjects of the study of dissipative maps are: the existence or not of attracting periodic orbits and the possible existence of strange attractors -that is, attractors that are neither periodic orbits nor invariant curves, which are minimal and contain a dense orbit. Moreover, these attractors can have sensitive dependence on the initial conditions, or have an absolutely continuous invariant measure. On the other hand there exists a transition between these two behaviours: the so-called flip or period doubling bifurcation cascade. After the final of this cascade (in a suitable set of parameters), strange attractors can appear, and also more attracting periodic orbits.This doctoral dissertation is divided in four chapters:
In the first one we study the dynamics of the so called logistic map; more specifically, we study first fold and flip bifurcations of this family, giving analytical expressions of the parameter values for which they occur. In the second chapter, we consider the Hénon map with strong dissipation. In the third chapter we study the Newhouse phenomenon. To this end we prove a more complete version of the phenomenon than others proved before, in which we show the existence of generic saddle-node and flip bifurcations, for parameters close to the parameter of homoclinic tangency. In chapter four we study the behaviour of the codimension one and two bifurcations in one and two dimensional families of maps. To do this, we consider one-parameter families of diffeomorphisms, to study saddle-node and flip bifurcations, and two-parameter families of dissipative diffeomorphisms, to study cusps and codimension two flips.
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Willis, C. A. "Continuous mass flow rate and velocity measurements of pneumatically conveyed powder." Thesis, Nottingham Trent University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354922.
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Walsh, Maria. "Indentity-in-motion : the narrative duration of the dis/continuous film moment." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/361.
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The trajectorv of this thesis is set out like a journey upon which encounters are staged between two films. film theor), and philosophers. such as Slavoj Zizek. Gilles Deletize, and Maurice Merleau-Ponty. An encounter with a moment of image suspension. a cut to the blank screen- in Tacita Dean's film, Disappearance atSea (1996). motivates the beginning of this journey's narrative. My reading of this moment counters the way that suspended film moments have been discussed in terms of non-narrative in 1970s film theory and in the contemporary psychoanalýlic filin theory of Slavoj Zizek. Using Gilles Deleuze's notion of narrativization as a process of serialization. I argue that the supposedly non-narrative moment is coextensive with the spectator's dis/continuity in time as opposed to Slavoj Zizek's static suspension or film theory's distanciation. A performative text based on Disappearance at Sea, which I refer to as a 'montage text' and for which precedence is found in Roland Barthes' writing, acts as an interlude that runs in tandem to the main theoretical trajectory. The generativity of absence that emerges from these encounters, both theoretical and poetic. is heightened in the second half of the thesis by the appearance of another 'montage text' based on Chantal Akerrnan's News From Home (1976). In this text. I reconfigure the negativity of historical readings of absence in Neus From Home where it was related to the impossible question of a woman's desire. In my reconfiguration, absence. rather than suspending time. generates a temporalized space and a spatialized time in which the spectator performs the dis/continuity of narrative duration. In the theoretical trajectory of this movement, Gilles Deleuze is hybridized with aspects of Merleau-Ponty's phenomenology, my argument being that the sublime infinity of Deleuzian serialization requires a relation to embodiment in order for it to be useftil in considering the spectator's relation to the two film encounters with absence. I read this hybridization in terms of a feminine mode of the sublime, which suggests the possibility of the real rather than its negation in representation and contributes to current thinking in feminist philosophy, particularly the work of Elizabeth Grosz.
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Alonzo, Todd Allen. "Assessing accuracy of a continuous medical diagnostic or screening test in the presence of verification bias /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/9600.
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Tothill, Nicholas Francis Hugh. "The structure and evolution of the Lagoon Nebula : star formation in the Sagittarius Arm." Thesis, Queen Mary, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312982.
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Moeti, Lebone Tiisang. "The dependence of the continuous phase mass transfer coefficients on molecular diffusivity for liquid-liquid extraction in agitated vessels." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/11856.
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Harper, David. "The internal structure of irreducible continua." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:4682c8d5-c8dc-4ac5-a278-c7d840cec9a7.
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This thesis is an examination of the structure of irreducible continua, with a particular emphasis on local connectedness and monotone maps. A continuum is irreducible if there exist a pair of points such that no proper subcontinuum contains both, with the arc being the most basic example. Being irreducible has a number of interesting implications for a continuum, both locally and globally, and it is these consequences we shall focus on. As mentioned above, the arc is the most straightforward example of an irreducible continuum. Indeed, an intuitive understanding of an irreducible continuum would be that it is structured like an arc, with the points of irreducibility at either end joined by a subspace with no loops or offshoots. In Chapter 2 we will see that for a certain class of continua this intuition is well founded by constructing a monotone map from an irreducible continuum onto an arc. This monotone map will preserve much of the structure of our continuum and as such will provide an insight into that structure. We will next examine a generalisation of irreducibility which considers finite sets of points rather than just pairs. A number of classical results will be re-examined in this light in Chapter 3. While the majority of these theorems will be shown to have close parallels in higher finite and infinite irreducibility there will be several which do not hold without further conditions on the continuum. Such anomalies will be particularly prevalent in continua which have indecomposable subcontinua dominating their structure. In Chapter 4 monotone maps will be constructed for finitely irreducible continua similar to the map to an arc mentioned previously. Chapters 7 and 8 will generalise irreducibility further to the infinite case and we will again construct monotone maps preserving the structure of our continuum. Along with the arc, another highly significant irreducible continuum is the sin 1 x continuum. Chapter 5 will focus on this continuum, which will be the basis for a nested sequence of continua. A number of results concerning continuous images of these continua will be presented before using the sequence of continua to define an indecomposable continuum. This continuum will be investigated, and it will be shown that the union of our nested continua form a composant of the indecomposable continuum. In Chapter 6 we will turn to the question of compactifications. If a space X is connected then any metric compactification of X will be a continuum. This chapter will answer the question of when a compactification is an irreducible continuum, with the remainder of the compactification consisting of all of the irreducible points. A list of properties will given such that a continuum has such a compactification if and only if it has each property on the list. It will also be demonstrated that each of these properties is independent of the others. Finally, in Chapter 9 we will revisit the idea of structure-preserving monotone maps, but this time in continua which are not irreducible. Motivated by the fibres of the maps in previous chapters, we will introduce two categories of subcontinua of a continuum X. The first will be nowhere dense subcontinua which are maximal with this property and the second will be subcontinua about which X is locally connected and which are minimal with this property. Continua in which every point lies in a maximal nowhere dense subcontinuum will be examined, as well as spaces in which every point lies in a unique minimal subcontinuum about which X is locally connected. We will also look at the properties of monotone maps arising from partitions of X into such subcontinua, and will prove that if every point of X lies in a maximal nowhere dense subcontinuum then the resulting quotient space will be one dimensional.
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Pichinao, Huenchuleo Jimena Gloria 1973. "Todavía sigo siendo mapuche en otros espacios territoriales (Mapuchewkülekan kake Fütal mapu mew) = Todavia continuo sendo mapuche em outros espaços territoriais (Mapuchewkülekan kake Fütal mapu mew)." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/281578.
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Orientador: Vanessa Rosemary LeaTexto em espanhol
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas
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Resumo: Nesse texto pretende-se compreender como, atualmente, se manifesta a relação dos mapuche com sua filosofia social (mapuche rakizuam). Veremos como mesmo num contexto de profundas transformações, o pensamento próprio contínua fazendo sentido e intensificando a vida das pessoas mapuche. O que será abordado a partir da análise de casos de pessoas que, durante a segunda metade dos anos 1960, se deslocaram desde um espaço territorial (fütal mapu) para outro e que aqui aparecem guiando nossa reflexão. A abordagem proposta para esta pesquisa implicou o tratamento das principais categorias da filosofia mapuche, tanto aquelas relativas a seus princípios fundacionais, como as que se relacionam com a espacialidade. Procura-se expor um esquema geral disponível para a interlocução com futuros estudos sobre a temática. Da mesma maneira que, numa tentativa de construir generalização, se propõe à filosofia social ou sóciocosmologia mapuche nomes que contêm uma forte ênfase religiosa; centrada na vida e suas inter-relaciones, onde os cerimoniais constituem um vínculo inevitável; além de um componente ético moral que é sua principal consequência. Em todo o trajeto de escrita procura-se demostrar como, a pesar das mudanças que afetaram drasticamente a existência dos mapuche, chegando hoje em dia a se colocar em xeque sua sobrevivência, ainda persiste uma reflexão própria que permanentemente luta por se fazer visível
Abstract: In this research we describe how the Mapuche people relate to their social philosophy (mapuche rakizuam), how even in a context of profound transformations their own way of thinking continues to make sense and makes their lives more complex. This study is conducted from a particular case of some individuals who moved from one territory (fütal mapu) to another one during the second half of the 1960s. The approach included the treatment of the main categories of Mapuche philosophy both those relating to its basic principles, and those relating to its spatial relations. Thus, it reveals a general scheme for establishing a dialoge with future studies on this topic. Also, in an attempt to make some generalizations, names for Mapuche social philosophy or sociocosmology are proposed which contain a strong religious emphasis, focused on life and its interrelations, where ceremonials constitute the unavoidable link, and where an ethic and moral component is their main consequence. All along thesis, we try to show the persistence of a particular reflection which is permanently fighting to get visible despite the migrations which have drastically affected very the existence of the Mapuche whose survival has been threatened
Mestrado
Antropologia Social
Mestre em Antropologia Social
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Costa, José Santana Campos. "Rigidez e semi-rigidez dos expoentes de Lyapunov em dimensão mais alta e folheações patológicas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-26072017-145418/.
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Neste trabalho nós estudamos os expoentes de Lyapunov de aplicações f : Td → Td homotópicas a uma aplicação Anosov linear e a continuidade absoluta de folheações. Nós mostramos para algumas classes de homotopia de aplicações que a soma dos expoentes de Lyapunov está limitado pela soma dos expoentes de Lyapunov da aplicação Anosov linear. Além disso, admitindo uma propriedade conhecida como densidade uniformemente limitada (UBD) nas folheações, mostramos uma igualdade entre a soma dos expoentes de Lyapunov de f e do Anosov linear. Também construímos um conjunto C1 aberto de difeomorfismos parcialmente hiperbólicos do toro T4, preservando volume, com folheação central bidimensional não compacta e não absolutamente contínua. Ainda construímos um exemplo parcialmente hiperbólico com folhas centrais bidimensionais, não compactas onde a desintegração do volume ao longo da folheação central não é nem Lebesgue nem atômica.In this work we study the Lyapunov exponents of maps f : Td → Td homotopic to a linear Anosov map. We proof for some homotopic classes of maps which the sum of Lyapunov exponents is bounded by the sum of the Lyapunov exponents of the linear Anosov map. Moreover, by assuming a property known as uniformly bounded density (UBD) in the foliations, we show an equality between the sum of the Lyapunov exponents of f and the linear Anosov. We also construct an C1 open set of volume preserving partially hyperbolic diffeomorphisms with non compact two dimensional center foliation and non absolutely continuous. We still build an example of partially hyperbolic diffeomorphism with non compact bidimensional center leaves where the disintegration of volume along the center foliation is neither Lebesgue nor atomic.
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Haeri, Nejad Masoud. "Drying of Porous Particles containing Liquid Mixtures in a Continuous Vibrated Fluid Bed Dryer." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156215.
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The influence of operation parameters on the drying of spherical porous particles containing a mixture of solvents evaporating into nitrogen in a continuously worked vibrated fluid-bed dryer was studied. A simulation based on the analytical solution to heat and mass transfer equations was applied and modifications were suggested. Four different ternary liquid mixtures were selected: Acetone-Chloroform-Methanol (ACM), Ethanol- 2-propanol-Water (EIpW), Water-Ethanol-Ethyl Acetate (WEEa) and Ethanol-Methylethylketone- Toluene (EMekT). For the solid, physical properties of Pyrex was used. Comparison of composition- and temperature- profiles indicated that there is no resistance against heat transfer within the solid and that the heat transfer is much faster than mass transfer. Selectivity diagrams were drawn. The results indicated that selectivity is an important parameter in predicting the drying behavior. The retention ratio was studied as performance parameter. Its variation was studied in response to changes in operation parameters, including gas velocity and temperature, as well as solid temperature and particle size. A modification to the model was examined by assuming a liquid-content-dependent diffusion resistance factor. It was observed that implementing such an assumption yields decreased values for retention ratios. The effect of vibration on heat and mass transfer coefficients was included using a correlation suggested by Sbrodov and the resulting effect on retention ratio was examined.Inverkan av driftparameter på torkning av sfäriska porösa partiklar som innehåller lösningsmedelblandningar som avdunstar i kväve i en kontinuerligt viberande fluidbädd-tork studerades. En simuleringsmodell baserad på den analytiska lösningen till värme- och materieöverföringsekvationerna användes och ändringar föreslogs. Fyra olika tärnar vätskeblandningar valdes: aceton-kloroform-metanol(ACM), etanol-2- propanolvatten,(EIpW), vatten-etanol-etylacetat (WEEa) och etanol-metyletylketon- toluen(EMekT). För den fasta fasen användes fysikaliska egenskaper liknande Pyrex. Sammansättnings- och temperatur-profiler visade att det inte finns något motstånd mot värmeöverföring i den fasta fasen och att värmeöverföringen sker mycket snabbare än materieöverförningen. Selektivitetsdiagram ritades. Resultaten indikerar att selektivititen är en viktig parmeter för att förutsäga beteendet vid torkning. Retentionsförhållandet användes som ett prestandamått. Dess variation med avseende på förändringar av driftsparmetrar, bland annat gasen hastighet och temperatur samt den fasta fasens temperatur och partikelstorlek, studerades. En modifiering av modellen undersöktes genom att införa en vätskehalts-beroende faktor för diffusionsmotståndet. Detta minskade värdena på retentionsförhållandena. Vibrationens inverkan på värme- och materieöverföring infördes genom att använda Sbrodov samband, och den resulterande effekten på retentionsförhållandet observerades.
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Runeskog, Henrik. "Continuous Balance Evaluation by Image Analysis of Live Video : Fall Prevention Through Pose Estimation." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297541.
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The deep learning technique Human Pose Estimation (or Human Keypoint Detection) is a promising field in tracking a person and identifying its posture. As posture and balance are two closely related concepts, the use of human pose estimation could be applied to fall prevention. By deriving the location of a persons Center of Mass and thereafter its Center of Pressure, one can evaluate the balance of a person without the use of force plates or sensors and solely using cameras. In this study, a human pose estimation model together with a predefined human weight distribution model were used to extract the location of a persons Center of Pressure in real time. The proposed method utilized two different methods of acquiring depth information from the frames - stereoscopy through two RGB-cameras and with the use of one RGB-depth camera. The estimated location of the Center of Pressure were compared to the location of the same parameter extracted while using the force plate Wii Balance Board. As the proposed method were to operate in real-time and without the use of computational processor enhancement, the choice of human pose estimation model were aimed to maximize software input/output speed. Thus, three models were used - one smaller and faster model called Lightweight Pose Network, one larger and accurate model called High-Resolution Network and one model placing itself somewhere in between the two other models, namely Pose Residual Network. The proposed method showed promising results for a real-time method of acquiring balance parameters. Although the largest source of error were the acquisition of depth information from the cameras. The results also showed that using a smaller and faster human pose estimation model proved to be sufficient in relation to the larger more accurate models in real-time usage and without the use of computational processor enhancement.Djupinlärningstekniken Kroppshållningsestimation är ett lovande medel gällande att följa en person och identifiera dess kroppshållning. Eftersom kroppshållning och balans är två närliggande koncept, kan användning av kroppshållningsestimation appliceras till fallprevention. Genom att härleda läget för en persons tyngdpunkt och därefter läget för dess tryckcentrum, kan utvärdering en persons balans genomföras utan att använda kraftplattor eller sensorer och att enbart använda kameror. I denna studie har en kroppshållningsestimationmodell tillsammans med en fördefinierad kroppsviktfördelning använts för att extrahera läget för en persons tryckcentrum i realtid. Den föreslagna metoden använder två olika metoder för att utvinna djupseende av bilderna från kameror - stereoskopi genom användning av två RGB-kameror eller genom användning av en RGB-djupseende kamera. Det estimerade läget av tryckcentrat jämfördes med läget av samma parameter utvunnet genom användning av tryckplattan Wii Balance Board. Eftersom den föreslagna metoden var ämnad att fungera i realtid och utan hjälp av en GPU, blev valet av kroppshållningsestimationsmodellen inriktat på att maximera mjukvaruhastighet. Därför användes tre olika modeller - en mindre och snabbare modell vid namn Lightweight Pose Network, en större och mer träffsäker modell vid namn High-Resolution Network och en model som placerar sig någonstans mitt emellan de två andra modellerna gällande snabbhet och träffsäkerhet vid namn Pose Resolution Network. Den föreslagna metoden visade lovande resultat för utvinning av balansparametrar i realtid, fastän den största felfaktorn visade sig vara djupseendetekniken. Resultaten visade att användning av en mindre och snabbare kroppshållningsestimationsmodellen påvisar att hålla måttet i jämförelse med större och mer träffsäkra modeller vid användning i realtid och utan användning av externa dataprocessorer.
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AGASHE, NIKHIL R. "IN-SITU SMALL ANGLE X-RAY SCATTERING STUDIES OF CONTINUOUS NANO-PARTICLE SYNTHESIS IN PREMIXED AND DIFFUSION FLAMES." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1092055991.
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Jade, (B) Sridevi. "Numerical Modeling Of Jointed Rock Mass." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/257.
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The behavior of jointed rock mass is very complex and is influenced by many factors such as location of joints, joint frequency, joint orientation and joint strength. A thorough review of literature on different aspects of jointed rock mass indicate that the discontinuities or planes of weakness present in rock mass significantly influence its behavior. Numerous experimental tests were conducted to study the behavior of natural as well as artificial joints in rocks. Laboratory tests are time consuming and give results applicable to specific joint fabric and confining pressure. Numerical methods are the best alternative to laboratory tests to study the behavior of jointed rock mass. With the advent of computers numerical methods of analysis have become very popular, as they are highly flexible and can represent all complex geometries and material behavior. The accuracy of a numerical model depends upon the how well constitutive relations for the jointed rock mass are defined in the analysis. Empirical relationships for describing the mechanical behavior of discontinuities obtained from scaling the laboratory data is crucial unresolved problem, which will affect the quality of results obtained. One more important aspect in the numerical model is strength criteria used for jointed rock mass. The applicability of existing strength criteria to a particular jointed rock has to be carefully examined before they are used.
Equivalent continuum approach simplifies the modeling of jointed rock mass as the joints are not modeled separately. Instead in equivalent continuum approach the jointed rock mass is represented by an equivalent continuum whose properties are defined by a combination of intact rock properties and joint properties. The accuracy of this kind of modeling depends upon the relationships used to define the jointed rock mass properties as a function of intact rock properties and joint properties. In the present study, an effort has been made (i) to establish empirical relations to define the properties of jointed rock mass as a function of intact rock properties and joint factor (ii) to develop a numerical model based on equivalent continuum approach using the empirical relations derived above, for easy and efficient modeling of jointed rock mass (iii) comparison of existing strength criteria for jointed rock masses using the equivalent continuum model developed above (iv) Modeling of joints explicitly and comparing these results with the equivalent continuum model results.
Empirical relationships expressing the uniaxial compressive strength and elastic modulus of jointed rock as a function of corresponding intact rock properties and joint factor have been derived based on the statistical analysis of large amount of experimental data of uniaxial and triaxial tests collected from the literature. The effect of joints in the jointed rock is taken in to account by the joint factor. A comparative study of the empirical relationships arrived by the above analysis has been made to choose the best relation for the numerical analysis. Empirical relationships thus arrived for jointed rock mass are used in the equivalent continuum approach to represent the jointed rock properties as a combination of intact rock properties and joint factor. Equivalent continuum model developed is thoroughly tested, validated and applied for single, multiple and block jointed rocks. The equivalent continuum model developed has been applied for analysis of the power cavern for Shiobara power station. Different strength criteria available for jointed rock namely Mohr-Coulomb, Hoek and Drown, Yudhbir et al. and Rarnamurthy are incorporated in the equivalent continuum model to evaluate their applicability for jointed rock masses. Ramarnurthy's strength criterion gives the best values of failure stress for almost all the test cases and hence used in the equivalent continuum model.
Alternatively, the joints in jointed rock mass are represented explicitly using interface element in the nonlinear finite element analysis. The explicit finite element model has been tested and validated using the experimental stress strain curves and failure stress values. Comparison of results obtained using equivalent continuum analysis and explicit modeling of joints has been given in the form of stress strain curves and failure stress plots for jointed rock masses along with the experimental results.
Some of the major conclusions from the present study are as follows. Statistical relationships arrived to express the properties of the jointed rock as a function of intact rock and joint factor give a fair estimate of jointed rock in the absence of experimental data. Equivalent continuum model developed using statistical relations arrived above simplifies the numerical modeling of jointed rock to a large extent and also gives a fair estimate of jointed rock behavior with minimum input data. From the equivalent continuum analysis of Shiobara power cavern, it can be concluded that this approach is very advantageous for modeling highly discontinuous systems provided the joint factor is estimated properly so that it represents the real fabric of the joints present in the system. Comparison of different strength criteria shows that Ramamurthy's strength criterion is the best for jointed rocks. When the rock mass has one or two major joints it is advantageous to model it explicitly so that the behavior of the joint can be studied in detail. Explicit representation of the joints in the finite element analysis gives a lair estimate of the zones most susceptible to failure in a jointed rock. From comparison of experimental values, equivalent continuum model results and the explicit joint model results, it can be concluded that results obtained using equivalent continuum model are nearest to the experimental results in almost all the cases.
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Öhrngren, Per. "Tertiary Alcohol- or β-Hydroxy γ-Lactam-Based HIV-1 Protease Inhibitors : Microwave Applications in Batch and Continuous Flow Organic Synthesis." Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-160190.
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Since the outbreak of the HIV/AIDS pandemic in the 1980s, the disease has cost the lives of over 30 million people, and a further 33 million are currently living with the HIV infection. With the appropriate treatment, HIV/AIDS can today be regarded as a chronic but manageable disease. However, treatment is not available globally and UNAIDS still estimates that there are currently 5000 AIDS-related deaths worldwide per day. HIV protease inhibitors (PIs) constitute one of the fundaments of HIV treatment, and are commonly used in so-called highly active antiretroviral therapy (HAART), together with reverse transcriptase inhibitors. Although there are ten PIs on the market, there is still a need for novel structures. The rapid development of resistant strains, due to the high frequency of mutations, together with the commonly observed adverse effects of the drugs available, illustrate the need to develop new potent structures. Two novel scaffolds were investigated in this work. A tertiary alcohol-containing scaffold comprising a three-carbon tether, and a β-hydroxy γ-lactam-based scaffold were designed, synthesized and evaluated using enzyme- and cell-based assays. X-ray analyses of inhibitors from each class provided information on inhibitor–protease interactions. The inhibitors containing the tertiary alcohol provided at best an enzymatic inhibition (Ki) of 2.3 nM, and an inhibition in the cell-based assay (EC50) of 0.17 µM. The γ-lactam-based inhibitors exhibited better inhibition than the first series; the best values being Ki = 0.7 nM and EC50 = 0.04 µM. The second part of these studies involved the evaluation of a novel non-resonance continuous-flow microwave instrument. The instrument was validated regarding heating capacity, temperature stability and temperature homogeneity. A number of model reactions were performed with low- and high-microwave-absorbing solvents. It was found that the microwave heating source allowed rapid temperature adjustment, together with easily regulated, flow-dependent reaction times, providing an efficient tool for reaction optimisation.
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IMERI, DODONA. "The Standardization Vs. Customization Debate Continues for PCI DSS Compliant Products." Thesis, KTH, Industriell Management, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190963.
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When it comes to cloud services, security has many a times been the hot topic. This has been especially relevant within the payment card industry and the secure handling of payment card data. The Payment Card Industry Security Standards Council (the council) was formed in order to ensure a global enhancement of payment card data. The council has issued requirements that all companies that handle payment card data are obliged to follow. However, the council has become much more strict as of recently, creating an urgency to become compliant. Thus, cloud service providers (CSP) have constructed standardized, PCI DSS compliant products so as to relief such customers. Since this emerging market is somewhat new, this thesis has researched how CSPs should relate to products within that market and the potential customer base. The case study for this research was conducted at Tieto, an IT service company, and its standardized, PCI DSS compliant product TiCC. The study collected empirical data in the form of qualitative interviews as well as quantitative telephone interviews with companies within the payment card industry. The study came to the conclusion that there is a demand that is not being met within the payment card industry related to products that aid organizations to become PCI DSS compliant. Standardized products have been constructed so as to fit financial customers while overlooking the demand of another large customer base, retail. Additionally, the products are being tweaked and features are being added, thus providing customization. CSPs are striving for both standardization as well as customization, something that has been considered counterproductive. The existing demand is thus not met with the current supply in the market, which has both multiple competitors and heterogeneity in market demand. The above mentioned thus leaves room for market seizure, to create own rules and thus making all competitors irrelevant. A potential way of doing that is through mass customization by standardizing higher levels of cloud computing.
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Lehto, Heather L. "Self-Potential Anomalies and CO2 Flux on Active Volcanoes: Insights from Time and Spatial Series at Masaya, Telica, and Cerro Negro, Nicaragua." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002108.
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Mongeon, Sébastien. "Active and Passive Mixing for Immiscible Liquid-Liquid Systems: A Performance Evaluation of Novel Micro-Reactors." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37089.
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Continuous flow reaction using micro-reactors is a valued technology due to its excellent mass and heat transfer performance, reduced reactor volume, handling capacity of hazardous reactions, and many other process intensifications. These intensifications opportunities interest the fine chemicals, pharmaceuticals producers and other multiphase reaction users who currently use batch processes or already use continuous flow. In this thesis, elements of passive and active mixing are investigated for the application of immiscible liquid-liquid systems.
In the first study, the effects of geometrical arrangements of a residence time between mixing units on the interphase mass transfer rates are evaluated with four different immiscible liquid-liquid systems. A presentation of an algorithm for the optimal selection of a reactor and its operating conditions is given in order to enable easy and improved use of one’s micro-reactor.
In the second study, the impact of a secondary pulse flow on interphase mass transfer is investigated. A coil without internal baffles is used as the oscillatory-flow coil reactor with a continuous active mixing source. The best application for the reactor is determined using a comparison to other complementary continuous flow platforms in the toolbox approach.
The novel advancements presented here will help lead new molecular discoveries and connect the laboratory science scale to the process engineering production scale.
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Thomas, Lillie E. "Mass conservation analysis for the lower St. Johns River using continuous and discontinuous Galerkin finite element methods." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5057.
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The CG- and DG- finite element methods are then tested in tidal simulation performance, which the results are then compared to observed tides and tidal currents at four stations within the lower portion of the Lower St. Johns River. Since the results show that the DG model outperforms the CG model, the DG model is used in the tidally driven salinity transport simulations. Using four stations within the lower and middle part of the Lower St. Johns River, simulated and observed water levels and salinity concentrations are compared.; This thesis provides a mass conservation analysis of the Lower St. Johns River for the purpose of providing basis for future salinity transport modeling. The analysis provides an assessment of the continuous (CG) and discontinuous (DG) Galerkin finite element methods with respect to their mass conservation properties. The following thesis also presents a rigorous literature review pertaining to salinity transport in the Lower St. Johns River, from which this effort generates the data used to initialize and validate numerical simulations. Two research questions are posed and studied in this thesis: can a DG-based modeling approach produce mass conservative numerical solutions; and what are the flow interactions between the river and the marshes within the coastal region of the Lower St. Johns River? Reviewing the available data provides an initial perspective of the ecosystem. For this, salinity data are obtained and assembled for three modeling scenarios. Each scenario, High Extreme, Most Variable, and Low Extreme, is 30 days long (taken from year 1999) and represents a unique salinity regime in the Lower St. Johns River. Time-series of salinity data is collected at four stations in the lower and middle reaches of the Lower St. Johns River, which provides a vantage point for assessing longitudinal variation of salinity. As an aside, precipitation and evaporation data is presented for seven stations along the entire St. Johns River, which provides added insight into salinity transport in the river. A mass conservation analysis is conducted for the Lower St. Johns River. The analysis utilizes a segmentation of the Lower St. Johns River, which divides the domain into sections based on physical characteristics. Mass errors are then calculated for the CG and DG finite element methods to determine mass conservative abilities. Also, the flow interactions (i.e., volume exchange) between the river and marshes are evaluated through the use of tidal prisms.ID: 029808992; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.Env.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 230-241).
M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering
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Mostovaya, Alina. "Dissolved organic matter in lakes : Chemical diversity and continuum of reactivity." Doctoral thesis, Uppsala universitet, Limnologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316893.
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Dissolved organic matter (DOM) is the largest pool of organic carbon in aquatic systems and an important component of the global carbon cycle. Large amounts of DOM are decomposed within lakes, resulting in fluxes of CO2 and CH4 to the atmosphere. Therefore, there is a considerable interest in understanding the controls of DOM decomposition in freshwaters. There is evidence that in lakes intrinsic controls related to DOM composition are of primary importance, yet our knowledge about molecular drivers of DOM degradation is limited. This thesis addresses the link between chemical composition and reactivity of lake DOM by applying an experimental approach, molecular-level DOM characterization, and kinetic modeling of DOM decay. The first study shows that photoinduced transformations and partial removal of colored aromatic components of DOM have profound effects on DOM degradation kinetics, mediated by the shifts in the relative share of rapidly and slowly degrading DOM fractions. Two following studies estimate exponential decay coefficients for each individual molecular formula identified within bulk DOM. A continuous distribution of exponential decay coefficients is found within bulk DOM, which directly corroborates the central and previously empirically untested assumption behind the reactivity continuum model of DOM decay. Further, individual decay rates are evaluated in connection to specific molecular properties. On average, highly unsaturated and phenolic compounds appear to be more persistent than compounds with higher aromatic content (plant polyphenols and polycondensed aromatics), and aliphatic compounds demonstrate the highest decay rates. The reactivity of aromatics additionally increases with increasing nominal oxidation state of carbon. Molecular analysis further indicates that increasing reactivity of DOM after UV exposure is caused by disintegration of supramolecular complexes. Study IV shows that changes in relative proportion of terrestrial versus algal DOM control degradability of DOM through seasons. Under ice, when algal-derived DOM is maximally depleted, DOM degradation potential converges to similarly low levels, regardless of lake type (productive or humic), and bacterial respiration primarily relies on terrestrial carbon. This suggests a general pattern of baseline metabolism across boreal lakes. I conclude that DOM is a dynamic reactivity continuum and a tight link exists between DOM behavior and compositional properties.
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Schoeffler, Lara Elaine. "Orbital Dynamics of Space Nuclear Propulsion Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1618332162764726.
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Lima, Jonas Romero Fonseca de. "Propriedades eletrônicas da matéria topológica: heteroestruturas e efeitos da rotação." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5742.
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Previous issue date: 2014-02-19Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this thesis we study the electronic properties of several systems of condensed matter physics using two different continuum models, the effective mass theory and the effective Dirac Hamiltonian. In several systems, there is an effective mass depending on position. Some models for the kinetic energy operator were proposed to describe these systems, but there is no definition of which one is the most appropriate. It is one of the oldest open questions in solid state physics. We propose a new model, where we consider all permutations among the operators and show that it satisfies the fundamental requirements of quantum mechanics. We use this model to obtain the minibands structure of a heterostructure composed by two different materials and compare our model with other models previously proposed. We also get the Schrödinger equation for a particle constrained to a curved surface with position dependent mass. We follow the da Costa approach, where there is a geometric potential. We show that the position dependent mass does not affect the geometric potential, contributing only to the kinetic part. We use this equation to study the electronic transport in a junction of two cylinders with different radii, with the effective mass varying with the cylinder radius. Using the effective Dirac Hamiltonian, we consider a graphene sheet on a periodic substrate heterostructure composed by two different materials. Each material induces a specific energy gap and Fermi velocity in the graphene, so the Dirac Hamiltonian has a gap (mass) term and a Fermi velocity depending on position. We write this operator taking into account that it has to be Hermitian and we obtain the minigaps induced by the substrate in the electronic structure of graphene. Motivated by experimental results, we study the effects of rotation on the electronic structure of carbon nanotubes, fullerene C60 and topological insulators, using an effective Dirac operator. In the carbon nanotube and C60 cases, the rotation adds a shift in the energy levels and a break in spin degeneracy. In the topological insulator case, the rotation adds only a shift in the energy.
Nesta tese estudamos as propriedades eletrônicas de diversos sistemas físicos da matéria condensada utilizando dois modelos contínuos distintos, o modelo de massa efetiva e o hamiltoniano de Dirac efetivo. Em vários sistemas existe o aparecimento de uma massa efetiva dependente da posição. Diversos modelos para o hamiltoniano cinético com massa efetiva variável foram propostos, mas não existe uma definição de qual seja o mais adequado. Essa é uma das questões mais antigas em aberto na física do estado sólido. Nós propomos um novo modelo, levando em conta todas as permutações possíveis entre os operadores e mostramos que ele satisfaz os requisitos fundamentais da mecânica quântica. Nós usamos esse modelo para obter a estrutura de minibandas de uma heteroestrutura formada por dois materiais diferentes e comparamos o nosso modelo com outros modelos propostos anteriormente. Também obtemos a equação de Schrödinger para uma partícula confinada a uma superfície curva com massa efetiva dependendo da posição. Seguimos a abordagem de da Costa, onde surge um potencial geométrico. Mostramos que a massa variável não altera a potencial geométrico, contribuindo apenas para a parte cinética. Nós usamos a equação obtida para estudar as propriedades de transporte eletrônico em uma junção de dois cilindros de raios diferentes, com a massa efetiva variando com o raio do cilindro. Utilizando um hamiltoniano de Dirac efetivo nós consideramos o grafeno sobre um substrato formado por uma heteroestrutura com dois materiais diferentes. Cada material induz um gap de energia e uma velocidade de Fermi específica no grafeno, fazendo com que tenhamos um hamiltoniano de Dirac com termo de gap (massa) e velocidade de Fermi dependendo da posição. Nós escrevemos esse operador levando em conta que ele tem que ser hermitiano e obtemos a estrutura de minibandas induzidas na estrutura eletrônica do grafeno pelo substrato. Motivados por resultados experimentais, nós também estudamos os efeitos da rotação na estrutura eletrônica do nanotubo de carbono, fulereno C60 e isolante topológico, utilizando um hamiltoniano de Dirac efetivo. Para o nanotubo de carbono e o C60 a rotação adiciona um deslocamento nos níveis de energia e há uma quebra na degenerescência de spin. No isolante topológico a rotação induz apenas um deslocamento na energia.
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Yerlikaya, Fatma. "A New Contribution To Nonlinear Robust Regression And Classification With Mars And Its Applications To Data Mining For Quality Control In Manufacturing." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610037/index.pdf.
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Multivariate adaptive regression spline (MARS) denotes a modern
methodology from statistical learning which is very important
in both classification and regression, with an increasing number of applications in many areas of science, economy and technology.
MARS is very useful for high dimensional problems and shows a great promise for fitting nonlinear multivariate functions. MARS technique does not impose any particular class of relationship between the predictor variables and outcome variable of interest. In other words, a special advantage of MARS lies in its ability to estimate the contribution of the basis functions so that
both the additive and interaction effects of the predictors are allowed to determine the response variable.
The function fitted by MARS is continuous, whereas the one fitted by classical classification methods (CART) is not. Herewith, MARS becomes an alternative to CART. The MARS algorithm for estimating the model function consists of two complementary algorithms: the forward and backward stepwise algorithms. In the first step, the model is built by adding basis functions until a maximum level of complexity is reached. On the other hand, the backward stepwise algorithm is began by removing the least significant basis functions from the model.
In this study, we propose not to use the backward stepwise algorithm. Instead, we construct a penalized residual sum of squares (PRSS) for MARS as a Tikhonov regularization problem, which is also known as ridge regression. We treat this problem using continuous optimization techniques which we consider to
become an important complementary technology and alternative to the concept of the backward stepwise algorithm. In particular, we apply the elegant framework of conic quadratic programming which is an area of convex optimization that
is very well-structured, herewith, resembling linear programming and, hence, permitting the use of interior point methods. The boundaries of this optimization problem are determined by the multiobjective optimization approach which provides us many
alternative solutions.
Based on these theoretical and algorithmical studies, this MSc thesis work also contains applications on the data investigated in a TÜBiTAK project on quality control. By these applications, MARS and our new method are compared.
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Fourel, François. "Amélioration des outils géochimiques pour l'investigation des paléoenvironnements." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10206/document.
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L'histoire des isotopes stables débute en 1913 avec les travaux de Frederick Soddy. Dès lors les techniques analytiques dans ce domaine vont constamment évoluer permettant de répondre à des questions scientifiques de plus en plus élaborées et d'investir petit à petit de plus en plus de domaines où leur capacité de traceur devient aujourd'hui indispensable. Ce travail présente d'abord une partie décrivant l'évolution des techniques de mesures des rapports isotopiques au cours des décennies, insistant sur l'apport fondamental du flux continu et en particulier de l'analyse élémentaire. Dans la deuxième partie nous allons illustrer l'importance des analyses isotopiques dans le domaine des reconstructions paléoenvironnementales afin de mieux appréhender l'histoire climatique de la Terre et de ses habitants à diverses époques. Ceci principalement au moyen des analyses 180/160 sur des matrices phosphatées ou carbonatées. La troisième partie est consacrée à l'utilisation des isotopes stables comme traceurs de certaines réaction métaboliques fondamentales sur des échantillons fossiles mais également sur du matériel actuel. Dans ce dernier cas, nous nous sommes également servis de la capacité des isotopes stables à être utilisés comme traceurs en abondance naturelle mais également en utilisant le marquage isotopique. Pour ce faire nous avons utilisé les signatures isotopiques 180/160 sur du matériel phosphaté mais également les rapports isotopiques 13C/12C et 15N/14N de la matière organique. La quatrième partie est consacrée plus particulièrement à des travaux de développement analytiques dans divers domaines. Tout d'abord nous nous sommes intéressés aux analyses isotopiques D/H et 180/160 des eaux. Nous proposons de nouveaux paramètres de correction des analyses isotopiques sur des eaux de salinités supérieures à l'eau de mer. Puis nous avons travaillé sur les analyses isotopiques 13C/12C et 180/160 des carbonates en proposant de nouveaux paramètres pour le fractionnement isotopique de l'oxygène entre les carbonates d'apatites et l'eau, les fractionnements isotopiques du carbone et de l'oxygène entre aragonite et calcite sur des organismes vivants actuels. Nous avons également développé une technique semi-automatique pour déterminer les signatures isotopiques en carbone et en oxygène de la calcite et de la dolomite dans des mélanges de proportions variables. Enfin nous avons tenté de quantifier la variabilité naturelle et la variabilité instrumentale des analyses isotopiques du carbone et de l'oxygène sur des microfossiles. Puis, nous nous sommes intéressés à un domaine représentant une part importante de notre travail analytique sur les analyses isotopiques 180/160 des phosphates biogéniques. En collaboration avec les fabricants d'instruments nous avons développé un nouveau système afin d'améliorer la qualité des analyses, de les automatiser le plus possible et de réduire la taille de la prise d'essai dans le but d'accéder à des échantillons de taille plus réduite. Enfin nous avons développé les analyses isotopiques du soufre toujours en collaboration avec les fabricants d'instrumentation, d'une part pour évaluer la capacité d'un nouveau système analytique à produire des analyses fiables sur des quantités limitées au sein de matrices complexes, et d'autre part, la capacité du même système à produire des analyses multi-isotopiques fiables sur les trois éléments N, C, S. Dans la conclusion de ce travail, nous revenons sur la contribution de nos divers travaux à l'évolution des techniques isotopiques en essayant d'évaluer dans l'avenir les nouveaux champs d'investigation de ces techniques tout juste centenairesThe history of stable isotopes began in 1913 with the work of Frederick Soddy. Since then, analytical techniques in that domain have been in constant evolution, providing answers to more and more elaborated scientific questions and spreading into various application fields where their tracing abilities have become extremely useful today. This work first describes the evolution of those analytical techniques through time and especially the fundamental step forward with continuous flow techniques especially through elemental analysis. For the second part we illustrate the importance of stable isotope analyses for paleoenvironmental reconstructions to better understand the climatic history of the Earth and its inhabitants from different periods. This is mainly based on 180/160 analyses from phosphatic or carbonaceous matrices. The third part is dedicated to the use of stable isotopes as tracers of various fundamental metabolic pathways from both fossil and actual samples. For this latter case we have used the capacity of stable isotopes to be used at natural abundance as well as artificially labelled. We have used 180/160 isotopic signatures from phosphatic samples as well as 13C/12C and 15N/14N from organic matter. The fourth part is dedicated to analytical developments covering several domains. First we investigated D/H and 180/160 measurements from waters. We are proposing new correction parameters for isotopic measurements from waters with salinity higher than sea water. Then we have dealt with 13C/12C and 180/160 isotopic analyses from carbonates and we suggest new parameters to constrain oxygen isotopic fractionation between carbonates from apatite and water as well as carbon and oxygen isotopic fractionation between calcite and aragonite from actual living organisms. We have also developed a new semi-automated technique to measure carbon and oxygen isotopic signatures from calcite and dolomite mixtures with various proportions. Then we have attempted to quantify the natural and instrumental variability of oxygen and carbon isotopic analyses from microfossils. An important part of this analytical work has been dedicated to 180/160 isotopic analyses from biogenic phosphate material. ln collaboration with instrument manufacturers we have developed a new system to improve both quality and automation of those measurements as well as reduce the aliquot sizes in order to get access to smaller samples. Eventually we have developed sulfur isotopic analyses in collaboration with instrument manufacturers to evaluate the capacities of a new analytical setup to generate reliable N, C, S multi- isotopic analyses. Last, we summarize the contribution of this work to the evolution of stable isotope techniques and we try to evaluate the future fields of investigation for those techniques just over one hundred years old
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Skillinghaug, Bobo. "Palladium(II)-Catalysed Heck and Addition Reactions : Exploring Decarboxylative and Desulfitative Processes." Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-304746.
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Palladium complexes have the ability to catalyse cross-coupling of two organic moieties through the formation of transient metal-carbon bonds, thus bringing them closer to each other to facilitate the formation of a new bond. Palladium-catalysed coupling reactions are one of the most important carbon-carbon forming reactions available to organic chemists and many of these reactions rely on the reactivity of aryl-palladium complexes. The investigation of new aryl-palladium precursors is thus of great interest, especially as more sustainable and economic methods can be developed. This thesis describes the use of carboxylic acids and sodium arylsulfinates as such new arylating agents. Protocols for microwave-assisted palladium(II)-catalysed decarboxylative synthesis of electron-rich styrenes and 1,1-diarylethenes were developed. However, these transformations had very limited substrate scopes which prompted the investigation of sodium arylsulfinates as alternative arylating agents. These substrates were employed in the microwave-assisted palladium(II)-catalysed desulfitative addition to nitriles, and the substrate scope was demonstrated by combining a wide array of sodium arylsulfinates and nitriles to yield the corresponding aryl ketones. The application of the desulfitative reaction in a continuous flow setup was demonstrated, and aluminium oxide was identified as safe alternative to borosilicate glass as a reactor material. The mechanisms of the decarboxylative and desulfitative transformations were investigated by density functional theory (DFT) calculations. The desulfitative reaction was also investigated by direct electrospray ionization mass spectrometry (ESI-MS), providing further mechanistic insight. Finally, a protocol for the safe and convenient synthesis of a wide range of sodium arylsulfinates was developed.
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Bottinelli, Sandrine. "Hot corinos : molécules pré-biotiques autour des protoétoiles de type solaire." Grenoble 1, 2006. http://www.theses.fr/2006GRE10127.
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L'un des buts majeurs de l'astrophysique moderne est de comprendre la formation du Système Solaire. Puisque les protoétoiles de faible masse sont des soleils en formation, l'étude de ces objets est un des meilleurs moyens d'étudier le processus de formation du Soleil et de son système planétaire. Dans ma thèse, je me suis concentrée sur la chimie des premières phases d'évolution des protoétoiles de faible masse en étudiant les molécules organiques complexes dans des sources de Classe 0, qui représentent les phases les plus jeunes connues. De telles molécules ont été découvertes dans IRAS16293-2422, le prototype des sources de Classe 0, démontrant l'existence des ``hot corinos'', des régions où les manteaux des grains subliment. Certaines de ces molécules ont aussi été observées dans des comètes de notre Système Solaire, soulevant la question de savoir si (et auquel cas, comment) la chimie des Classes 0 affecte la composition chimique de la matière du disque protoplanétaire incorporée dans les comètes et autres corps planétaires. Cependant, il est d'abord nécessaire de déterminer si les hot corinos sont omniprésents dans les protoétoiles de faible masse, ou si IRAS16293-2422 est une exception. Ceci était le premier but de ma thèse. L'approche consistait principalement à observer trois sources de Classe 0 pour chercher des molécules organiques complexes. J'ai ainsi découvert et/ou confirmé trois hot corinos de plus. Le second but était de contraindre la taille de la région d'émission des molécules complexes au moyen d'observations interférométriques des deux hot corinos les plus brillants : cette émission est compacte (<150 AU), avec, dans l'un des cas, une composante étendue provenant de l'enveloppe externe. Le troisième but avait pour lieu de confronter les voies de formation possibles des molécules complexes avec les résultats de mes observations pour essayer de distinguer si ces molécules se forment en phase gazeuse ou à la surface des grains. Bien que mes données ne puissent éliminer aucun des deux cas, elles semblent favoriser le second type de formation. De plus, la comparaison entre hot corinos et leurs homologues massifs, les hot cores (qui montre que les molécules complexes sont relativement plus abondantes dans les hot corinos), soutient également la formation à la surface des grainsOne of the major goals of modern astrophysics is to understand the formation of our Solar System. Since low-mass protostars are suns in the making, the study of these objects and their environment provides one of the best ways to investigate the Sun's formation process and to peek in the past history of our Solar System. In my thesis, I focused on the chemistry occuring in Class 0 sources (the earliest known phases in the evolutionary scenario of low-mass protostars) by studying complex organic molecules in their envelopes. Such molecules have been discovered in IRAS16293--2422, the prototype of Class 0 sources, proving the existence of hot corinos, the inner regions of the protostellar envelope where the icy grain mantles sublimate. Some of these molecules have also been observed in comets in our Solar System, raising the question of whether (and if so, how) the chemistry of Class 0 objects affects the chemical composition of the protoplanetary disk material from which comets and other planetary bodies form. However, it is first necessary to determine whether hot corinos are ubiquitous in low-mass protostars or if IRAS16293-2422 is an exception. This was the first goal of my thesis. The approach consisted mainly in observing three Class 0 sources to search for complex organic molecules. I thereby discovered and/or confirmed three more hot corinos. The second goal was then to constrain the size of emission of complex molecules. For this, I carried out interferometric observations of the two brightest hot corinos: this emission is compact (<150 AU) with, in one of the sources, an extended component originating from the cooler, less dense outer envelope. The third goal consisted in confronting the possible formation pathways with the results of my observations to try and discriminate whether complex organic molecules form via gas-phase or grain-surface reactions. Although it was not possible to arrive at a definite answer, my data seem to favor the later formation route. Moreover, the comparison of hot corinos and their high-mass analogs, the hot cores (showing that complex molecules are relatively more abundant in hot corinos), also support grain-surface synthesis of these molecules
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Hadj, nacer Mustafa. "Tangential momentum accommodation coefficient in microchannels with different surface materials (measurements and simulations)." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4764/document.
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Cette thèse est consacrée à l'étude des écoulements de gaz raréfiés à travers divers micro-conduits de type circulaire et rectangulaire dans des conditions isotherme et stationnaire. L'objectif de la thèse est de contribuer à l'étude de l'interaction gaz-surface notamment en déterminant le coefficient d'accommodation de la quantité de mouvement pour différent matériaux de surface (Or, Silice, Acier inoxydable et Sulfinert) associés à différents types de gaz (hélium, azote, argon et dioxyde-de-carbone). Afin d'atteindre cet objectif, on adopte un triple point de vue : expérimental, théorique et numérique. L'aspect expérimental est réalisé par des mesures de débit massique à travers les micro-conduits, en utilisant la méthode dite « à volume constant ». L'aspect théorique original est développé à travers une nouvelle approche basée sur la résolution de l'équation de Stokes. Cette approche a permis d'écrire une expression analytique de débit massique en régime de glissement, qui prenne en compte les effets bidimensionnels dans une section de conduit rectangulaire. Cette approche complètement explicite, est conduite au deuxième ordre. Enfin l'aspect numérique permet de calculer le débit massique, en régimes transitionnel et moléculaire libre, en résolvant numériquement l'équation cinétique BGK linéarisée. La comparaison des mesures de débit massique avec l'équation analytique, en régime de glissement, ou avec les calculs numériques, en régimes transitionnel et moléculaire libre, nous a permis de déduire des coefficients de glissement et les coefficients d'accommodation correspondant à chaque couple gaz-surface dans tous les régimes de raréfactionThis thesis is devoted to the study of rarefied gas flows through micro-channels of various cross sections (circular and rectangular) under isothermal and stationary conditions. The objective of this thesis is to contribute to the study of gas-surface interaction by determining the tangential momentum accommodation coefficient for different surface materials (gold, silica, stainless steel and Sulfinert) and associated to various gases (helium, nitrogen, argon and carbon-dioxide). To achieve this goal three aspects are considered: experimental, theoretical and numerical. The experimental aspect is considered by measuring the mass flow rate through microchannels using the constant volume technique. The theoretical aspect is considered by the development of a new approach based on the Stokes equations. This approach yields to the analytical expression of the mass flow rate in the slip regime, which takes into account the second order effects. The last aspect, numerical, is considered by the numerical simulations of the mass flow rate in the transitional and free molecular flow regimes by solving the linearized BGK kinetic model. The comparison between the measured mass flow rates and the analytically expressions in the slip regime or with the results of numerical simulations in the transitional and free molecular regimes enabled to deduce the tangential momentum accommodation coefficients corresponding to each pair gas-surface in all flow regimes
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Lindner, Dominik. "Towards the fracture prediction of turbomachinery disks : a contribution of the digital image correlation." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN023/document.
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Cette thèse s'intéresse à l'amélioration de la prévision de l'éclatement des pièces tournantes des turbomachines. L'axe de recherche principal a été celui de l'identification du comportement du matériau jusqu'à rupture pour des sollicitations multi-axiales représentatives et l'identification des conditions de rupture locale elles mêmes. Pour cela une approche basée sur la corrélation d'image numérique intégrée a été suivie. L'autre axe abordé dans cette thèse a été celui de la prévision objective et robuste de la rupture par la mécanique de l'endommagement dans le cadre de simulations explicites utilisant des techniques de scaling pour diminuer les temps de calcul. Deux matériaux ont été étudiés, un alliage titane TA6V et un alliage nickel Udimet 500. Des éprouvettes ont été définies pour permettre d'avoir des sollicitations proches de celles en service et pour permettre d'utiliser des techniques de mesure de champs. Un code commercial (ABAQUS) est utilisé dans une approche intégrée de la corrélation des images numériques (CIN). Le principe de ces méthodes est d'optimiser la corrélation directement à partir des paramètres du modèle sans passer par une procédure intermédiaire demandant de reconstruire préalablement les champs de déformations. Cette technique, qui peut-être vu comme très régularisante, confère à la méthode une grande robustesse, ce qui permet d'obtenir des informations même en présence de mouchetis dégradés lors des phases ultimes de chargement. L'ensemble des paramètres constitutifs des modèles peut alors être identifié avec un seul essai hétérogène. Dans l'étude un accent particulier a été mis sur l'analyse des champs de triaxialité, dont l'importance sur les conditions de rupture est suspectée, en utilisant des éprouvettes fines et des éprouvettes épaisses. Des lois de comportement ont pu être identifié pour des niveaux de déformations plastiques jusqu'à 3 fois supérieurs à ceux atteints dans des essais de traction uni-axiaux et ceci en présence d'adoucissement global. L'intégration étroite des essais et des simulations a également permis d'analyser l'état de déformation et contraintes des éléments proches de la surface de rupture juste avant celle-ci et ainsi de tester des critères de rupture potentiels avec un grand nombre de données. Pour la seconde partie de la thèse, plus exploratoire faute de temps, une étude préliminaire a porté sur la possibilité d'utiliser des modèles à taux d'endommagement limités combinés avec des techniques de scaling pour utiliser des simulations explicites dans le cadre de sollicitations centrifuges quasi-statiques. Les premiers résultats montrent qu'une accélération est possible avec des niveaux d'erreurs relativement bas sur les vitesses de rotation conduisant à la rupture et ceci dans des temps comparables avec des simulations implicites quasi-statique, l'avantage étant la robustesse des analyses en dynamique expliciteThis thesis addresses the amelioration of the burst prediction of turbo-engines rotating parts.The principal axis of this study was the identification of the material behaviour up fracture under multi-axial loading and the identification of the local condition at failure. To accomplish this, an integrated digital image correlation approach was employed.The other thematic axis of this thesis was the objective and robust prediction of rupture using the damage mechanics in the framework of explicit simulations and the study of the influence, on the prediction, of various scaling techniques used to decrease the computation time.Two materials were studied, the titanium alloy TA6V and the nickel alloy Udimet 500. The samples were defined to guarantee similar loading conditions as those in the disks in service and to allow the use of field measurement techniques.A commercial code (ABAQUS) is used in an integrated approach to Digital Image Correlation (DIC). The principle of this method is to optimize the correlation of the test directly with the model parameters without passing by an intermediate procedure requiring the reconstruction of the deformation field beforehand. This technique, which can be seen as highly regularising, grants a considerable robustness to the method, which allows obtaining information from degraded speckle patterns encountered at the end of the test. The entire set of constitutive parameters can be identified with only one heterogeneous test. Within this study, a particular accent was laid on the analysis of triaxiality fields by using thin and thick samples. The importance of these fields for the fracture conditions is suspected.Constitutive models were identified for plastic strains that were about three times higher than the ones achievable in uniaxial tensile test on smooth sample.The close integration of the experiments and simulations allowed the analysis of deformation and stresses of the elements near the failure surface at the instant just before failure. This allowed the testing of different criteria with a large amount of data.For the second axis of the thesis, preliminary studies examined the possibility to use limited damage rate models combined with scaling techniques. These latter allow performing explicit simulations in context of a centrifugal quasi-static loading. The results show that acceleration is possible. The errors of the rotational speeds, which lead to disk fracture, are relatively low. The simulation times are comparable to implicit quasi-static simulations, while the main advantage is the maintained robustness in explicit simulations
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Čáp, Martin. "Sledování trendů elektrické aktivity srdce časově-frekvenčním rozkladem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218005.
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Work is aimed at the time-frequency decomposition of a signal application for monitoring the EKG trend progression. Goal is to create algorithm which would watch changes in the ST segment in EKG recording and its realization in the Matlab program. Analyzed is substance of the origin of EKG and its measuring. For trend calculations after reading the signal is necessary to preprocess the signal, it consists of filtration and detection of necessary points of EKG signal. For taking apart, also filtration and measuring the signal is used wavelet transformation. Source of the data is biomedicine database Physionet. As an outcome of the algorithm are drawn ST segment trends for three recordings from three different patients and its comparison with reference method of ST qualification. For qualification of the heart stability, as a system, where designed methods watching differences in position of the maximal value in two-zone spectrum and the Poincare mapping method. Realized method is attached to this thesis.
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Guinaldo, Thibault. "Paramétrisation de la dynamique lacustre dans un modèle de surface couplé pour une application à la prévision hydrologique à l’échelle globale." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0125.
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L'hydrologie continentale s'intéresse à tous les aspects du cycle de l'eau des terres émergées et représente les flux de masse d'eau qui sont échangées. Que ce soit dans le sous-sol, au sein des lacs ou dans le brassage continu des torrents, l'eau et les processus hydrologiques associés entretiennent un lien direct avec la dynamique atmosphérique et la variabilité climatique. La représentation, à l'échelle globale, de ces processus hydrologiques s'appuie sur des techniques de modélisation qui, au CNRM, passent par un système couplé composé du modèle de surface ISBA et du modèle de routage en rivière CTRIP. Ces dernières années, les progrès réalisés sur les paramétrisations existantes et la représentation des nouveaux processus dans ISBA comme dans CTRIP ont abouti à une nette amélioration des performances de ce système pour des applications hydrologiques régionales ou globales couplées avec un modèle de climat. Dans la continuité de ces efforts, l'objectif principal de cette thèse est de développer une paramétrisation dynamique des lacs pour intégrer leur bilan de masse dans le modèle global CTRIP à 1/12°. Par ailleurs, le modèle développé, MLake, propose un diagnostic sur le marnage des lacs afin de permettre le suivi du niveau d'eau basé sur des mesures satellitaires. Bénéficiant d'un réseau de mesures dense et de forçages climatiques à haute résolution, le bassin versant du Rhône a été choisi pour évaluer localement MLake sur la période 1960-2016. Les résultats sur trois stations de jaugeages montrent une progression nette des performances de CTRIP dans la simulation des débits du Rhône aboutissant à un lissage des hydrographes qui se caractérise par un écrêtement des débits de crues et un soutien à l'étiage. Par ailleurs, la confrontation du diagnostic sur les niveaux d'eau du Léman avec des mesures locales révèle une capacité du modèle à suivre les cycle annuels et inter-annuels du marnage. Une deuxième évaluation s'est ensuite portée à l'échelle globale pour confirmer le comportement du modèle dans des conditions hydroclimatiques contrastées. Cette évaluation confirme la capacité du modèle à simuler des débits réalistes mais révèle la perturbation importante du cycle hydrologique naturel par l'anthropisation. Enfin les résultats préliminaires d'une simulation globale démontre l'intérêt d'utiliser MLake avec une amélioration systématique des scores dans les zones de grande densité lacustre. Ainsi, 45% des stations évaluées, principalement dans les régions arctiques, présentent une amélioration des scores statistiques. Enfin, cette étude engage une réflexion sur les perspectives d'améliorations du modèle, notamment la mise en place d'une bathymétrie de lac à l'échelle globale, en vue d'un couplage avec un modèle de climat et de l'utilisation des données de la future mission spatiale SWOTThe water cycle encompasses the main processes related to mass fluxes that influence the atmosphere and climate variability. More specifically, continental hydrology refers to the water transfer occurring at the land surface and sub-surface. Modelling is one of the main methods used for the representation of these processes at regional to global scales. The land surface model system used in this thesis is composed of the ISBA land surface model coupled to the river routing model TRIP that combines the CNRM’s latest developments for use in stand-alone hydrological applications or coupled to a climate model. This PhD is focused on the development and evaluation of lake mass-balance dynamics and water level diagnostics using a new non-calibrated model called MLake which has been incorporated into the 1/12° version of the CTRIP model. Simulated river flows forced by high resolution hydrometeorological forcings are evaluated for the Rhone river basin against in situ observations coming from three river gauges over the period 1960-2016. Results reveal the positive contribution of MLake in simulating Rhone discharge and in representing the lake buffer effects on peak discharge. Moreover, the evaluation of the simulated and observed water level variations show the ability of MLake to reproduce the natural seasonal and interannual cycles. Based on the same framework, a final evaluation was conducted in order to assess the value of the non-calibrated MLake model for global hydrological applications. The results confirmed the capability of the model to simulate realistic river discharges worldwide. At 45% of the river gauge stations, which are mostly located within regions of high lake density, the new model resulted in improved simulated river discharge. The results also highlighted the strong effect of anthropization on the alterations of river dynamics, and the need for a global representation of human-impacted flows in the model. This study has lead to several future perspectives, such as the incorporation of a parametrization of lake hypsometry for use at global scale. The implementation of such developments will improve the representation of vertical water dynamics and facilitate both the coupling of MLake within the CNRM earth system model framework and the future spatial mission SWOT for improved future global hydrological and water resource projections
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Ignace, Richard. "Long-Wavelength, Free–Free Spectral Energy Distributions from Porous Stellar Winds." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/2685.
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The influence of macroclumps for free–free spectral energy distributions (SEDs) of ionized winds is considered. The goal is to emphasize distinctions between microclumping and macroclumping effects. Microclumping can alter SED slopes and flux levels if the volume filling factor of the clumps varies with radius; however, the modifications are independent of the clump geometry. To what extent does macroclumping alter SED slopes and flux levels? In addressing the question, two specific types of macroclump geometries are explored: shell fragments (pancake-shaped) and spherical clumps. Analytic and semi-analytic results are derived in the limiting case that clumps never obscure one another. Numerical calculations based on a porosity formalism is used when clumps do overlap. Under the assumptions of a constant expansion, isothermal, and fixed ionization wind, the fragment model leads to results that are essentially identical to the microclumping result. Mass-loss rate determinations are not affected by porosity effects for shell fragments. By contrast, spherical clumps can lead to a reduction in long-wavelength fluxes, but the reductions are only significant for extreme volume filling factors.
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Banda, Sraj Umar. "Caving mechanisms for a non-daylighting orebody." Doctoral thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63994.
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The sublevel caving mining method is a mass production method with potentially very low operational costs. The success of this method is dependent on, among other factors, the cavability of the orebody and the overlying rock mass. However, caving of the surrounding rock mass also results in deformations in the cap rock as well as on the ground surface above the orebody being mined. From this follows that any existing infrastructure on the ground surface must be relocated as not to be affected by the mining-induced deformations.This thesis work was undertaken to bring about a better understanding of the rock mass behavior in the cap rock of non-daylighting orebodies, with particular application to the Printzsköld orebody as part of the LKAB Malmberget Mine. Rock testing, field observations and underground mapping was conducted to characterize the rock mass in the caving environment. A methodology for identifying the caving front based on seismic monitoring data was derived by studying the Fabian orebody (which has caved to surface), and using laser scanning data for validation. The methodology was then applied to the Printzsköld orebody to identify the caving front.Numerical modeling was performed for various scenarios of the rock mass as mining proceeded. Modeling included (i) stress analysis to understand stress changes and their effects on the rock mass behavior, (ii) discontinuum numerical modeling to quantify the influence of large-scale geological structures on the cave progression, and (iii) discontinuum cave modeling to simulate possible cave mechanisms in the cap rock more explicitly. Laser scanning together with seismic event data were used to calibrate the numerical models.The numerical simulation results showed that as mining progresses, the cap rock and hangingwall were exposed to stress changes that resulted in yielding. Two failure mechanisms were predominantly at play (i) shear failure (dominant in the cap rock) and (ii) tensile failure (dominant in the hangingwall). The presence of the large-scale structures affected thenearfield stresses through slip along the cave boundaries. The effect of the structures on the far field stresses were less significant.Discontinuum modeling to explicitly simulate failure and caving involved simulating the rock mass as a jointed medium using Voronoi tessellations in 2D, and bonded block modeling (BBM) in 3D. Both the 2D and the 3D modeling results showed fair agreement when comparing the inferred boundary of the seismogenic zone, with that identified from seismic monitoring data. Predictive numerical modeling was conducted for future planned mining to assess future cave development in the cap rock. The results from 3D modeling indicated that cave breakthrough for the Printzsköld orebody is expected when mining the 1023 m level, corresponding to approximately year 2022, as per current mining plans. The 2D model was non-conservative with cave breakthrough predicted to occur when mining the 1109 m level, corresponding to the year 2028.The estimated boundary between the seismogenic and yielded zones, as defined in the Duplancic and Brady conceptual model of caving, was coinciding with, or was close to, the cave boundary in the Printzsköld orebody. This may imply that in some areas the yielded zone was not present and that the Duplancic and Brady model may not be universally applicable. Additional work is required to verify this indication, as well as to fine-tune the modeling methodology.
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Moore, Michael J. "Missa Papae Marcelli a comparative analysis of the Kyrie and Gloria movements of Giovanni Pierluigi da Palestrina and an adaptation by Giovanni Francesco Anerio /." Thesis, connect to online resource, 2006. http://www.unt.edu/etd/all/May2006/moore%5Fmichael%5Fjeffrey/index.htm.
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Nguyen, Van Dong. "Speciation analysis of butyl- and phenyltin compounds in environmental samples by GC separation and atomic spectrometric detection." Doctoral thesis, Umeå : Department of Chemistry, Umeå University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-892.
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Colin, Julien. "Séchage en continu du bois énergie comme moyen de préconditionnement en vue de sa conservation thermochimique : approches expérimentale et numérique." Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00861231.
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Les voies sèches de valorisation du bois énergie sont de plus en plus exigeantes vis-à-vis de la qualité de la matière première et notamment quant à sa teneur en eau. Ainsi, une étape intermédiaire de préconditionnement, sur site industriel, tend à se développer. La mise en œuvre de séchoirs en continu est alors séduisante de par son faible coût et sa parfaite intégration dans la ligne de production. Cependant, elle n'est pas sans écueil : la variabilité de la biomasse et l'hétérogénéité des conditions climatiques au sein du séchoir rendent fastidieux le dimensionnement du séchoir et de la source de chaleur associée d'une part et la maximisation du flux matière d'autre part.Notre étude a pour ambition de développer un outil informatique d'aide à la conception et à l'optimisation de séchoirs en continu traversés par un lit condensé de particules de bois. Pour y parvenir, nous associons une approche expérimentale et une approche numérique du procédé. La démarche scientifique s'articule autour de deux échelles représentatives :- A l'échelle de la particule de bois, le modèle de Van Meel, reposant sur le concept de courbe caractéristique de séchage, est étendu : le couplage entre transferts de chaleur et de masse est rendu explicite. Nous disposons dès lors d'un modèle réactif et prédictif en conditions climatiques variables. Parallèlement, un premier dispositif expérimental original est conçu et construit pour l'étude du séchage de particules de bois isolées. Les données recueillies sont alors analysées en vue d'alimenter en paramètres et de valider le modèle semi-analytique ;- A l'échelle du séchoir, une modélisation double-échelle est adoptée pour tenir compte de l'évolution des conditions climatiques. Un soin particulier est apporté à la modélisation, se voulant être la plus proche possible des installations existantes : à ce titre, les transferts au niveau de la paroi du séchoir sont pris en compte, ainsi que la variabilité des particules de bois. Parallèlement, un second dispositif expérimental original est conçu et construit pour l'étude du séchage de particules disposées en lit. Les données recueillies sont alors confrontées aux simulations du modèle double-échelle.La validation du modèle s'étant révélée probante tant à l'échelle de la particule qu'à celle du séchoir, une utilisation du code pour l'aide à la conception et à l'optimisation d'installations industrielles a pu être envisagée. Ainsi, ce travail s'achève-t-il par deux études de cas à travers lesquelles nous explorons le potentiel du modèle pour maximiser le flux matière tout en garantissant la qualité du produit et l'efficacité énergétique du séchoir.
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Gallouët, Thomas. "Transport optimal : régularité et applications." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2012. http://tel.archives-ouvertes.fr/tel-00793191.
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Cette thèse comporte deux parties distinctes, toutes les deux liées à la théorie du transport optimal. Dans la première partie, nous considérons une variété riemannienne, deux mesures à densité régulière et un coût de transport, typiquement la distance géodésique quadratique et nous nous intéressons à la régularité de l'application de transport optimal. Le critère décisif à cette régularité s'avère être le signe du tenseur de Ma-Trudinger-Wang (MTW). Nous présentons tout d'abord une synthèse des travaux réalisés sur ce tenseur. Nous nous intéressons ensuite au lien entre la géométrie des lieux d'injectivité et le tenseur MTW. Nous montrons que dans de nombreux cas, la positivité du tenseur MTW implique la convexité des lieux d'injectivité. La deuxième partie de cette thèse est liée aux équations aux dérivées partielles. Certaines peuvent être considérées comme des flots gradients dans l'espace de Wasserstein W2. C'est le cas de l'équation de Keller-Segel en dimension 2. Pour cette équation nous nous intéressons au problème de quantification de la masse lors de l'explosion des solutions ; cette explosion apparaît lorsque la masse initiale est supérieure à un seuil critique Mc. Nous cherchons alors à montrer qu'elle consiste en la formation d'un Dirac de masse Mc. Nous considérons ici un modèle particulaire en dimension 1 ayant le même comportement que l'équation de Keller-Segel. Pour ce modèle nous exhibons des bassins d'attractions à l'intérieur desquels l'explosion se produit avec seulement le nombre critique de particules. Finalement nous nous intéressons au profil d'explosion : à l'aide d'un changement d'échelle parabolique nous montrons que la structure de l'explosion correspond aux points critiques d'une certaine fonctionnelle.
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Nachtmann, Pavel. "Návrh zavedení štíhlé výroby v průmyslovém podniku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228678.
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This master´s thesis describes the production process in Japanese enterprise Daikin Device Czech Republic s.r.o. with emphasis on the production schedule, equipment and manufacturing system with elements of lean production. According to the production process analysis at the given production line a new solution of the production process has been suggested to increase production efficiency. This conception has been implemented and compared to the production process before, as well as to the assumed production process after increasing the efficiency.