Turbulent premixed propane/air and methane/air flames were studied using planar Rayleigh scattering and particle image velocimetry on a stabilized Bunsen type burner. The fuel-air equivalence ratio was varied from Φ=0.7 to 1.0 for propane flames, and from Φ=0.6 to 1.0 for methane flames. The non-dimensional turbulence intensity, u'/SL (ratio of fluctuation velocity to laminar burning velocity), covered the range from 3 to 24, equivalent to conditions of corrugated flamelets and thin reaction zones regimes. Temperature gradients decreased with the increasing u'/SL and levelled off beyond u'/SL > 10 for both propane and methane flames. Flame front thickness increased slightly as u'/SL increased for both mixtures, although the thickness increase was more noticeable for propane flames, which meant the thermal flame front structure was being thickened. A zone of higher temperature was observed on the average temperature profile in the preheat zone of the flame front as well as some instantaneous temperature profiles at the highest u'/SL. Curvature probability density functions were similar to the Gaussian distribution at all u'/SL for both mixtures and for all the flame sections. The mean curvature values decreased as a function of u'/SL and approached zero. Flame front thickness was smaller when evaluated at flame front locations with zero curvature than that with curvature. Temperature gradients and FSD were larger when the flame curvature was zero. The combined thickness and FSD data suggest that the curvature effect is more dominant than that of the stretch by turbulent eddies during flame propagation. Integrated flame surface density for both propane and methane flames exhibited no dependance on u'/SL regardless of the FSD method used for evaluation. This observation implies that flame surface area may not be the dominant factor in increasing the turbulent burning velocity and the flamelet assumption may not be valid under the conditions studied. Dκ term, the product of diffusivity evaluated at conditions studied and the flame front curvature, was a magnitude smaller than or the same magnitude as the laminar burning velocity.

The user of an image database often wishes to retrieve all images similar to the one (s)he already has. In this thesis, shape analysis methods for retrieving shape are investigated. Shape analysis methods can be classified in two groups as contour-based and region-based according to the shape information used. In such a classification, curvature scale space (CSS) representation and angular radial transform (ART) are promising methods for shape similarity retrieval respectively. The CSS representation operates by decomposing the shape contour into convex and concave sections. CSS descriptor is extracted by using the curvature zero-crossings behaviour of the shape boundary while smoothing the boundary with Gaussian filter. The ART descriptor decomposes the shape region into a number of orthogonal 2-D basis functions defined on a unit disk. ART descriptor is extracted using the magnitudes of ART coefficients. These methods are implemented for similarity comparison of binary images and the retrieval performances of descriptors for changing number of sampling points of boundary and order of ART coefficients are investigated. The experiments are done using 1000 images from MPEG7 Core Experiments Shape-1. Results show that for different classes of shape, different descriptors are more successful. When the choice of approach depends on the properties of the query shape, similarity retrieval performance increases.

ABSTRACT AN ANALYTICAL STUDY ON THE MINIMUM CONFINEMENT IN SPIRAL COLUMNS &Ouml / zkaya, Cenan M.S., Department of Civil Engineering Supervisor: Prof. Dr. G&uuml / ney &Ouml / zcebe Co-Supervisor: Prof. Dr. Ugur Ersoy July 2005, 135 pages The minimum spiral ratio equation given in the codes is derived by equating the strength at the second peak to the strength at the first peak for spiral columns tested under uniaxial load. In this study, specimen behavior under combined bending and axial load was taken as basis while deriving proposed equations. Analyses were carried out by using a Moment-Curvature program. For normal strength concrete, one regression and one simplified equation giving minimum spiral ratio are proposed. Difference between two equations arises from the number in front of (Ac/Ack). In regression equation, this number is calculated by means of a function. In simplified equation, this number is a constant. For high strength concrete, a different regression equation is proposed which is valid for concrete strengths up to 95 MPa. Simplified equation proposed for normal strength concrete is also proposed for high strength concrete up to concrete strengths of 120 MPa. It was found that / (i) Simplified equation proposed for normal and high strength concrete yielded consistent results in the range of variables studied / (ii) Except some points, regression equations yielded consistent results / (iii) It is recommended to use simplified equation instead of regression and code equations since it yields more consistent results than code and regression equations. Keywords: Confined Concrete, Ductility, Moment-Curvature, Minimum Spiral Volumetric Ratio

abstract: The theory of geometric quantum mechanics describes a quantum system as a Hamiltonian dynamical system, with a projective Hilbert space regarded as the phase space. This thesis extends the theory by including some aspects of the symplectic topology of the quantum phase space. It is shown that the quantum mechanical uncertainty principle is a special case of an inequality from J-holomorphic map theory, that is, J-holomorphic curves minimize the difference between the quantum covariance matrix determinant and a symplectic area. An immediate consequence is that a minimal determinant is a topological invariant, within a fixed homology class of the curve. Various choices of quantum operators are studied with reference to the implications of the J-holomorphic condition. The mean curvature vector field and Maslov class are calculated for a lagrangian torus of an integrable quantum system. The mean curvature one-form is simply related to the canonical connection which determines the geometric phases and polarization linear response. Adiabatic deformations of a quantum system are analyzed in terms of vector bundle classifying maps and related to the mean curvature flow of quantum states. The dielectric response function for a periodic solid is calculated to be the curvature of a connection on a vector bundle. / Dissertation/Thesis / Ph.D. Mathematics 2011

PINTO, V. G. Caracterizações da esfera em formas espaciais. 2017. 79 f. Dissertação (Mestrado em Matemática) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Andrea Dantas (pgmat@mat.ufc.br) on 2017-07-20T20:40:07Z No. of bitstreams: 1 2017_dis_vgpinto.pdf: 1180135 bytes, checksum: f3aa196ed8b0d38c5a2a33642fdb7d0b (MD5) / Rejected by Rocilda Sales (rocilda@ufc.br), reason: Bom dia Andrea, Favor informar ao aluno os motivos da rejeição. Faltou a conclusão (item obrigatório) E as referências não estão normalizadas. Seguem os modelos ARTIGOS DE PERIÓDICOS: ALENCAR, H. ; COLARES, A. G. - Integral formulas for the r-mean curvature linearized operator of a hypersurface. Annals of Global Analysis and Geometry, v. 16, p. 203-220, 1998. OBS: o TÍTULO DO PERIÓDICO DEVE FICAR EM NEGRITO OU ITÁLICO. LIVROS: CARMO, M. P. do. Geometria riemanniana. Rio de Janeiro : IMPA, 2008.( Projeto Euclides) OBS: O TÍTULO DO LIVRO DEVE FICAR EM NEGRITO OU ITÁLICO DISSERTAÇÕES: PINHEIRO, N. R. Hipersuperfíıcies com curvatura média constante e hiperplanos. Ano. Nº de folhas. Dissertação ( Mestrado) em nome do curso, local, ano. OBS: o TÍTULO DA DISSERTAÇÃO DEVE FICAR EM NEGRITO OU ITÁLICO Rocilda on 2017-07-21T11:38:59Z (GMT) / Submitted by Andrea Dantas (pgmat@mat.ufc.br) on 2017-07-21T18:48:58Z No. of bitstreams: 1 2017_dis_vgpinto.pdf: 1184804 bytes, checksum: 357d2ee050e65edb2839093ba455b0db (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2017-07-24T15:34:13Z (GMT) No. of bitstreams: 1 2017_dis_vgpinto.pdf: 1184804 bytes, checksum: 357d2ee050e65edb2839093ba455b0db (MD5) / Made available in DSpace on 2017-07-24T15:34:13Z (GMT). No. of bitstreams: 1 2017_dis_vgpinto.pdf: 1184804 bytes, checksum: 357d2ee050e65edb2839093ba455b0db (MD5) Previous issue date: 2017-07-06 / In this work we present three characterizations of the sphere. Initially, it will be shown that given a compact and oriented hypersurface Mn e x: M → Q^(n+1)_c a isometric immersion, x(M) is a geodesic sphere in Q^n+1_c if, and only if, Hr+1 is a nonzero constant and the set of points that are omitted in Qn+1 c by the totally geodesic hypersurfaces (Q^n_c)p tangent to x(M) is non-empty. As a second result, let M be an orientable compact and connected hypersurface with non-negative support function of the Euclidean space Rn+1 and Minkowski's integrand . We prove that the mean curvature function of the hypersurface M is the solution of the Poisson equation = if, and only if, M is isometric to the n-sphere Sn(c) of constant curvature c. similar characterization is proved for a hypersurface with the scalar curvature satisfying the same equation. For the third result we consider an isometric immersion x : M ! Qn+1, where M is a compact hypersurface such that x(M) is convex, and it will be proved that if any r-mean curvature is such that Hr 6= 0 and there are nonnegative constants C1;C2; :::;Cr1 such that Hr = Pr1 i=1 CiHi; then x(M) is a geodesic sphere, where Qn+1 is Rn+1, Hn+1 or Sn+1 + . / Neste trabalho serão apresentadas três caracterizações da esfera. Primeiramente, será mostrado que dada uma hipersuperfície compacta e orientada Mn e x: M → Q^(n+1)_c uma imersão isométrica, onde Q^n+1_c é uma forma espacial simplesmente conexa, isto é, uma variedade Riemanniana de curvatura seccional constante c, x(M) é uma esfera geodésica em Q^n+1_c se, e somente se, a (r + 1)-ésima curvatura média Hr+1 é uma constante não nula e o conjunto dos pontos que são omitidos em Q^n+1_c pelas hipersuperfícies totalmente geodésicas (Q^n_c)p tangentes a x(M) é não vazio. Como segundo resultado, seja uma hipersuperfície compacta, conexa e orientável M do espaço euclidiano R^(n+1), com função suporte não negativa e integrando de Minkowski σ. Será provado que a função curvatura média α da hipersuperfície é solução da equação de Poisson Δϕ = σ se, e somente se, M é isométrica à n-esfera S^n(c) de curvatura média c. Uma caracterização similar é provada para uma hipersuperfície com a curvatura escalar satisfazendo a mesma equação. Para o terceiro resultado é considerado uma imersão isométrica x: M → Q^(n+1), onde M é uma hipersuperfície compacta tal que x(M) é convexa, e será provado que, se alguma curvatura r-média é tal que Hr ≠ 0 e existem constantes não negativas C1, C2, ..., Cr-1 tais que Hr =∑_(i=1)^(r-1)▒〖C_i H_i 〗 ; então x(M) é uma esfera geodésica, onde Q^(n+1) é R^(n+1), H^(n+1) ou S^(n+1)_+ .

Neste trabalho estudamos o problema de Dirichlet assintótico para a equação das superfícies mínimas em uma superfície de Cartan-Hadamard rotacionalmente simétrica e mostramos que o problema e unicamente solúvel para qualquer dado contínuo em seu bordo assintótico. / In this work we study the asymptotic Dirichlet problem for the minimal surface equation on rotationally symmetric Cartan-Hadamard surfaces. We prove that the problem is uniquely solvave for any continuous asymptotic boundary data.

O objetivo central deste trabalho consiste em demonstrar a existência de gráficos mínimos C2,x com fronteira assintótica prescrita na variedade produto M R, onde M e completa, simplesmente conexa, com curvatura seccional KM satisfazendo KM ≤ -k2 < 0 e tal que, para algum p Є M, o subgrupo de isotropia de Iso(M) em p age de modo 2-pontos homogêneo nas esferas geodésicas centradas em p. / The main purpose of this work consists on proving the existence of minimal C2,x graphics with prescribed asymptotic boundary in the product manifold M R, where M is a complete, simply connected manifold with sectional curvature KM satisfying KM ≤ -k2 < 0 and such that, for some p 2 M, the isotropy subgroup of Iso(M) in p acts in a 2-points homogeneous way in the geodesic spheres centered in p.

Dans cette thèse nous étudions deux problèmes issus de la relativité générale : la construction de données initiales pour le problème de Cauchy des équations d’Einstein et le théorème de la masse positive. Nous construisons tout d’abord des données initiales en utilisant la méthode dite conforme introduite par Lichnerowicz [Lichnerowicz, 1944], Y. Choquet-Bruhat–J. York [Choquet-Bruhat et York, 1980] et Y. Choquet-Bruhat–J. Isenberg– D. Pollack [Choquet-Bruhat et al., 2007a]. Plus particulièrement, nous étudions les équations –de contrainte conforme– qui apparaissent dans cette méthode sur des variétés riemanniennes compactes de dimension n > 3. Dans cette thèse, nous donnons une preuve simplifiée du résultat de [Dahl et al., 2012], puis nous étendons et nous généralisons les théorèmes de M. Holst–G. Nagy–G. Tsogtgerel [Holst et al., 2009] et de D. Maxwell [Maxwell, 2009] dans le cas de données initiales à courbure moyenne fortement nonconstante. Nous donnons au passage un point de vue unifié sur ces résultats. En parallèle, nous donnons des résultats de non-existence et de non-unicité pour les équations de la méthode conforme sous certaines hypothèses. / The aim of this thesis is the study of two topical issues arising from general relativity: finding initial data for the Cauchy problem with respect to the Einstein equations and the positive mass theorem. For the first issue, in the context of the conformal method introduced by Lichnerowicz [Lichnerowicz, 1944], Y. Choquet-Bruhat–J. York [Choquet-Bruhat et York, 1980] and Y. Choquet-Bruhat–J. Isenberg–D. Pollack [Choquet-Bruhat et al., 2007a], we consider the conformal constraint equations on compact Riemannian manifolds of dimension n > 3. In this thesis, we simplify the proof of [Dahl et al., 2012, Theorem 1.1], extend and sharpen the far-from CMC result proven by Holst– Nagy–Tsogtgerel [Holst et al., 2009], Maxwell [Maxwell, 2009] and give an unifying viewpoint of these results. Besides discussing the solvability of the conformal constraint equations, we will also show nonexistence and nonuniqueness results for solutions to the conformal constraint equations under certain assumptions.

Neste trabalho mostramos que dado um domínio exterior de classe C0 contido em uma superfície umb lica de H3; com curvatura média constante H 2 [0; 1); existe uma família de gracos de Killing com curvatura média constante H: O bordo de cada um destes gracos está contido nesta superfície umbílica e a norma do gradiente da função no bordo pode ser prescrita por um certo valor s 0. / In this paper we show that given an exterior domain of class C0 contained in an umbilical surface of H3; with constant mean curvature H 2 [0; 1); there exists a family of Killing graphs with constant mean curvature H: The boundary of each of these graphs is contained in this umbilical surface and the norm of the gradient of the function in the boundary can be prescribed by a certain value s 0:

Referências de tensão integradas sempre foram um bloco fundamental de qualquer sistema eletrônico e um importante tópico de pesquisa que tem sido estudado extensivamente nos últimos 50 anos. Uma tensão de referência é um circuito que provê uma tensão estável com baixa sensibilidade a variações em temperatura, alimentação, carga, características do processo de fabricação e tensões mecânicas de encapsulamento. Elas são normalmente implementadas através da soma ponderada de dois fenômenos físicos diferentes, com comportamentos em temperatura opostos. Normalmente, a tensão térmica, relacionada à constante de Boltzmann e à carga do elétron, fornece uma dependência positiva com temperatura, enquanto que a tensão base-emissor VBE de um transistor bipolar ou a tensão de limiar de um MOSFET fornece o termo complementar. Um bloco auxiliar é às vezes utilizado para fornecer as correntes de polarização do circuito, e outros blocos adicionais implementam a soma ponderada. A evolução da tecnologia de processos é o principal fator para aplicações em baixa tensão, enquanto que a emergência de dispositivos portáteis operados a bateria, circuitos biomédicos implantáveis e dispostivos de captura de energia do ambiente restringem cada circuito a consumir o mínimo possivel. Portanto, alimentações abaixo de 1 V e consumos na ordem de nanoWatts se tornaram características fundamentais de tais circuitos. Contudo, existem diversos desafios ao projetar referências de tensão de alta exatidão em processos CMOS modernos sob essas condições. As topologias tradicionais não são adequadas pois elas provêm uma referência de tensão acima de 1 V, e requerem resistências da ordem de G para atingir tão baixo consumo de potência, ocupando assim uma grande área de silício. Avanços recentes atingiram tais níveis de consumo de potência, porém com limitada exatidão, custosos procedimentos de calibração e grande área ocupada em silício. Nesta dissertação apresentam-se duas novas topologias de circuitos: uma tensão de junção bipolar com compensação de curvatura que não utiliza resistores e é auto-polarizada; e um circuito de referência bandgap sem resistores que opera abaixo de 1 V (também chamado de sub-bandgap). Ambos circuitos operam com consumo na ordem de nanoWatts e ocupam pequenas áreas de silício. Resultados de simulação para dois processos diferentes, 180 nm e 130 nm, e resultados experimentais de uma rodada de fabricação em 130 nm apresentam melhorias sobre tais limitações, mantendo as características desejadas de não conter resistores, ultra baixo consumo, baixa tensão de alimentação e áreas muito pequenas. / Integrated voltage references have always been a fundamental block of any electronic system, and an important research topic that has been extensively studied in the past 50 years. A voltage reference is a circuit that provides a stable voltage with low sensitivity to variations in temperature, supply, load, process characteristics and packaging stresses. They are usually implemented through the weighted sum of two independent physical phenomena with opposite temperature dependencies. Usually the thermal voltage, related to the Boltzmann’s constant and the electron charge, provides a positive temperature dependence, while the silicon bandgap voltage or a MOSFET’s threshold voltage provide the complementary term. An auxiliary biasing block is sometimes necessary to provide the necessary currents for the circuit to work, and additional blocks implement the weighted sum. The scaling of process technologies is the main driving factor for low voltage operation, while the emergence of portable battery-operated, implantable biomedical and energy harvesting devices mandate that every circuit consume as little power as possible. Therefore, sub-1 V supplies and nanoWatt power have become key characteristics for these kind of circuits, but there are several challenges when designing high accuracy voltage references in modern CMOS technologies under these conditions. The traditional topologies are not suitable because they provide a reference voltage above 1 V, and to achieve such power consumption levels would require G resistances, that occupy a huge silicon area. Recent advances have achieved these levels of power consumption but with limited accuracy, expensive calibration procedures and large silicon area.