Entrevista amb el Dr. Miquel Siguan

M.M. L'any 1983 es crea a la Universitat d e Barcelona la Facultat d e Psicologia, fruit d'un llarg procés del qual vostd és sens dubte un dels princi- pals protagonistes. Remontant-nos en el temps, l'any 1962 vostd guanya la Catedra d e Psicologia d e la Universitat de Barcelona, després d e treballar una desena d'anys a Madrid, alguns dels quals c o m a professor de 1'Escola de Psicologia d'aquella ciutat. Quins eren els seus projectes e n tornar a Barcelo- n

Polar foliations and isoparametric maps

A singular Riemannian foliation $F$ on a complete Riemannian manifold $M$ is called a polar foliation if, for each regular point $p$, there is an immersed submanifold $\Sigma$, called section, that passes through $p$ and that meets all the leaves and always perpendicularly. A typical example of a polar foliation is the partition of $M$ into the orbits of a polar action, i.e., an isometric action with sections. In this work we prove that the leaves of $F$ coincide with the level sets of a smooth map $H: M\to \Sigma$ if $M$ is simply connected. In particular, we have that the orbits of a polar action on a simply connected space are level sets of an isoparametric map. This result extends previous results due to the author and Gorodski, Heintze, Liu and Olmos, Carter and West, and Terng.Comment: 9 pages; The final publication is available at springerlink.com http://www.springerlink.com/content/c72g4q5350g513n1

Canzona in D minor: a transcription for orchestra

Thesis (M.M.)--Boston University. Canzona in D minor [by Bach] a transcription for orchestra. A transcription presented to the faculty of the School of Fine and Applied Arts, Boston University, in partial fulfillment of the requirements for the degree Master of Music, August 1961

Microfocus X-ray scattering investigations of eggshell nanotexture

The avian eggshell is a highly ordered calcitic bioceramic composite, with both inorganic and organic constituents. The interactions between the inorganic and organic components within the structure are poorly understood but are likely to occur at the nanometre level. Thus structural variation at this level may impinge on the overall structural integrity and mechanical performance of the eggshell, and therefore analysis at this level is fundamental in fully understanding this ordered structure. In this study, structural changes in the mineral crystallites were investigated by microfocus small-angle X-ray scattering (µSAXS) using synchrotron radiation. Small-angle X-ray scattering (SAXS) can be used to investigate structures on the nanometre scale such as size, shape, arrangement and internal porosity. A microfocused X-ray beam, 1.5 µm vertically by 7 µm, was used to produce vertical linear scans of the eggshell section. SAXS patterns were taken from the eggshell membrane (inner surface of the eggshell) to the cuticle (outer surface of the eggshell). This allowed textural variations within the eggshell to be mapped. The scattering intensity profile was then used to derive the dimension of scattering objects that define the nanotexture. The nanotexture observed may result from the presence of the organic matrix, which is embedded as intracrystalline particles producing voids within the calcified framework of large (>1 µm) calcite crystals. Porod analysis revealed the average size of a scattering interface to be approximately 4.5 nm with small changes that had a depth-dependent variation. These were largest at the mammillary layer/membrane boundary. The palisade layer displayed a small upward trend in size of scattering object. Parallel scans showed that the textural variations observed within the palisade layer are significant and indicate local subtextures. In addition, many of the patterns exhibit diffuse scattering streaks that could result from reflectivity from the larger crystallite interfaces. Changes in the orientation of diffuse streaks were observed within the different layers, the membranes, mammillary layer, palisade layer, vertical crystal layer and cuticle, indicating certain preferred orientations of the crystallites within the layers. The nanotextural variations that are apparent could have implications at the macroscopic level of the resulting eggshell

A map and a pipe : a new approach to characterizing erosion-corrosion regimes of Fe in three dimensions using CFD modelling

In studies of erosion-corrosion, much work has been carried out in recent years to identify regimes of behaviour. Such regimes describe the transition between the erosion and corrosion dominated mechanisms. They can also be used, by assigning various criteria, to identify other regimes of behaviour such as extent of "synergy/antagonism" in the process, so-called "additive" behaviour and the extent of wastage. Despite this work, there has been very little effort to combine the two dimensional erosion-corrosion map with CFD modelling approaches, in which the characteristics of the fluid are accounted for in the regime description. This means that extrapolation of such maps in two dimensions to a three dimensional real surface presents some difficulties. However, it is these surfaces that corrosion engineers are required to tailor, either through modification of the material composition, the surface or the process parameters, for optimum erosion-corrosion resistance. In this paper, a methodology is generated to combine the concepts of CFD modelling, and the erosion-corrosion regime map for a specific geometry and for a range of pure metals in descending order in the Galvanic series. The changes in regimes are presented as a function of variation in the erosion and corrosion variables i.e. particle size, hardness and solution pH. Erosion-corrosion regimes are presented, based on the model results, showing the wide range of mechanistic and wastage mechanisms possible over the component surface

Singular riemannian foliations with sections, transnormal maps and basic forms

A singular riemannian foliation F on a complete riemannian manifold M is said to admit sections if each regular point of M is contained in a complete totally geodesic immersed submanifold (a section) that meets every leaf of F orthogonally and whose dimension is the codimension of the regular leaves of F. We prove that the algebra of basic forms of M relative to F is isomorphic to the algebra of those differential forms on a section that are invariant under the generalized Weyl pseudogroup of this section. This extends a result of Michor for polar actions. It follows from this result that the algebra of basic function is finitely generated if the sections are compact. We also prove that the leaves of F coincide with the level sets of a transnormal map (generalization of isoparametric map) if M is simply connected, the sections are flat and the leaves of F are compact. This result extends previous results due to Carter and West, Terng, and Heintze, Liu and Olmos.Comment: Preprint IME-USP; The final publication is available at springerlink.com http://www.springerlink.com/content/q48682633730t831

Closed String Brane-Like States, Brane Bound States and Noncommutative Branes

We study the mass and different RR charge distributions of the BPS (p,p-2)-brane bound states in the closed string brane-like $\sigma$-model. We show that such brane bound states can be realized by introducing a constant B field in the closed string theory. In addition we show that the worldvolume coordinates of these brane bound states turn out to be noncommutative.Comment: 13 pages, Latex File, v2: some misprints corrected, and a paragraph added to section 3, v3: minor changes, typos correcte

Acoustics in 2D Spaces of Constant Curvature

[EN] In this work, we will consider a locally homogeneous and isotropic (2+1)D spacetime of Robertson-Walker type and therefore with underlying de Sitter space.M. M. T. wishes to thank the Spanish Ministerio de Economía y Competitividad and the European Regional Development Fund (ERDF) for financial support under grant TIN2014-59294-PTung, MM.; Gambi, JM.; María Luisa García del Pino (2016). Acoustics in 2D Spaces of Constant Curvature. Springer. 483-489. https://doi.org/10.1007/978-3-319-63082-3_75S483489Beals, R., Szmigielski, J.: Meijer G-functions: a gentle introduction. Not. Am. Math. Soc. 60(7), 866–872 (2013)Chen, H.Y., Chan, C.T.: Acoustic cloaking and transformation acoustics. J. Phys. D 43(11), 113001 (2010)Choquet-Bruhat, Y., Damour, T.: Introduction to General Relativity, Black Holes, and Cosmology. Oxford University Press, Oxford (2015)Cummer, S.A.: Transformation acoustics. In: Craster, V.R., Guenneau, S. (eds.) Acoustic Metamaterials: Negative Refraction, Imaging, Lensing and Cloaking, pp. 197–218. Springer Netherlands, Dordrecht (2013)Cummer, S.A., Schurig, D.: One path to acoustic cloaking. New J. Phys. 9(3), 45–52 (2007)Islam, J.N.: An Introduction to Mathematical Cosmology. Cambridge University Press, Cambridge (2001)Kalnins, E.G.: Separation of Variables for Riemannian Spaces of Constant Curvature. Pitman Monographs and Surveys in Pure and Applied Mathematics. Longman Scientific & Technical, New York (1986)Kuchowicz, B.: Conformally flat space-time of spherical symmetry in isotropic coordinates. Int. J. Theor. Phys. 7(4), 259–262 (1973)Lanczos, C.: The Variational Principles of Mechanics. Dover Publications, New York (1970)Mechel, F.P.: Formulas of Acoustics. Springer, Berlin (2002)Norris, A.N.: Acoustic metafluids. J. Acoust. Soc. Am. 125(2), 839–849 (2009)Redkov, V.M., Ovsiyuk, E.M.: Quantum mechanics in spaces of constant curvature. In: Contemporary Fundamental Physics. Nova Science, New York (2012)Rosenberg, S.: The Laplacian on a Riemannian Manifold: An Introduction to Analysis on Manifolds. London Mathematical Society Student Text, vol. 31. Cambridge University Press, Cambridge (1997)Tung, M.M.: A fundamental Lagrangian approach to transformation acoustics and spherical spacetime cloaking. Europhys. Lett. 98, 34002–34006 (2012)Tung, M.M., Peinado, J.: A covariant spacetime approach to transformation acoustics. In: Fontes, M., Günther, M., Marheineke, N. (eds.) Progress in Industrial Mathematics at ECMI 2012. Mathematics in Industry, vol. 19. Springer, Berlin (2014)Tung, M.M., Weinmüller, E.B.: Gravitational frequency shifts in transformation acoustics. Europhys. Lett. 101, 54006–54011 (2013)Tung, M.M., Gambi, J.M., García del Pino, M.L.: Maxwell’s fish-eye in (2+1)D spacetime acoustics. In: Russo, G.R., Capasso, V., Nicosia, G., Romano, V. (eds.) Progress in Industrial Mathematics at ECMI 2014. Mathematics in Industry, vol. 22. Springer, Berlin (2016)Visser, M., Barceló, C., Liberati, S.: Analogue models of and for gravity. Gen. Rel. Grav. 34, 1719–1734 (2002)Wolf, J.A.: Spaces of Constant Curvature. American Mathematical Society, Providence, Rhode Island (2011

New hydrogen-like potentials

Using the modified factorization method introduced by Mielnik, we construct a new class of radial potentials whose spectrum for l=0 coincides exactly with that of the hydrogen atom. A limiting case of our family coincides with the potentials previously derived by Abraham and MosesComment: 6 pages, latex, 2 Postscript figure