Dynamical Elastic Moduli of the Ti-13Nb-13Zr biomaterial alloy by mechanical spectroscopy

Dynamical Elastic Moduli of the Ti-13Nb-13Zr biomaterial alloy were obtained using the mechanical spectroscopy technique. The sample with heat treatment at 1170K for 30 minutes and water quenched with subsequent aging treatment at 670 K for 3 hours (TNZ + WQ + 670 K/3 h), was characterized through decay of free oscillations of the sample in the flexural vibration mode. The spectra of anelastic relaxation (internal friction and frequency) in the temperature range from 300 K to 625 K not revealed the presence of relaxation process. As shown in the literature, the hcp structure usually does not exhibit any relaxation due to the symmetry of the sites in the crystalline lattice, but if there is some relaxation, this only occurs in special cases such as low concentration of zirconium or saturation of the stoichiometric ratio of oxygen for zirconium. Dynamical elastic modulus obtained for TNZ + WQ + 670 K/3 h alloy was 87 GPa at room temperature, which is higher than the value for Ti-13Nb-13Zr alloy (64 GPa) of the literature. This increment may be related to the change of the proportion of α and β phases. Besides that, the presence of precipitates in the alloy after aging treatment hardens the material and reduces its ductility.

Projections of hypersurfaces in 'R POT.4' with boundary to planes

We study orthogonal projections of generic embedded hypersurfaces in 'R POT.4' with boundary to 2-spaces. Therefore, we classify simple map germs from 'R POT.3' to the plane of codimension less than or equal to 4 with the source containing a distinguished plane which is preserved by coordinate changes. We also go into some detail on their geometrical properties in order to recognize the cases of codimension less than or equal to 1.

Low energy elastic and electronically inelastic electron scattering from biomolecules.

Reactions initiated by collisions with low-energy secondary electrons has been found to be the prominent mechanism toward the radiation damage on living tissues through DNA strand breaks. Now it is widely accepted that during the interaction with these secondary species the selective breaking of chemical bonds is triggered by dissociative electron attachment (DEA), that is, the capture of the incident electron and the formation of temporary negative ion states [1,2,3]. One of the approaches largely used toward a deeper understanding of the radiation damage to DNA is through modeling of DEA with its basic constituents (nucleotide bases, sugar and other subunits). We have tried to simplify this approach and attempt to make it comprehensible at a more fundamental level by looking at even simple molecules. Studies involving organic systems such as carboxylic acids, alcohols and simple ¯ve-membered heterocyclic compounds are taken as starting points for these understanding. In the present study we investigate the role played by elastic scattering and electronic excitation of molecules on electron-driven chemical processes. Special attention is focused on the analysis of the in°uence of polarization and multichannel coupling e®ects on the magnitude of elastic and electronically inelastic cross-sections. Our aim is also to investigate the existence of resonances in the elastic and electronically inelastic channels as well as to characterize them with respect to its type (shape, core-excited or Feshbach), symmetry and position. The relevance of these issues is evaluated within the context of possible applications for the modeling of discharge environments and implications in the understanding of mutagenic rupture of DNA chains. The scattering calculations were carried out with the Schwinger multichannel method (SMC) [4] and its implementation with pseudopotentials (SMCPP) [5] at di®erent levels of approximation for impact energies ranging from 0.5 eV to 30 eV. References [1] B. Boudai®a, P. Cloutier, D. Hunting, M. A. Huels and L. Sanche, Science 287, 1658 (2000). [2] X. Pan, P. Cloutier, D. Hunting and L. Sanche, Phys. Rev. Lett. 90, 208102 (2003). [3] F. Martin, P. D. Burrow, Z. Cai, P. Cloutier, D. Hunting and L. Sanche, Phys. Rev. Lett. 93, 068101 (2004). [4] K. Takatsuka and V. McKoy, Phys. Rev. A 24, 2437 (1981); ibid. Phys. Rev. A 30, 1734 (1984). [5] M. H. F. Bettega, L. G. Ferreira and M. A. P. Lima, Phys. Rev. A 47, 1111 (1993).

La redacción de avances de planes de manejo, para los parques temáticos ambientales

Se presenta un modelo estándar de Plan de Manejo de un territorio, con una vocación de destino y un destino de uso de Parque Temático Ambiental, que permite cuantificar logros y blindajes de calidades, en porcentajes. Se entiende por Parque Temático Ambiental un marco geográfico, que rebasa una superficie determinada, con unos límites trazados según criterios geográficos y/o invariantes, y en donde sus contenidos traducen interacciones significativas entre el Hombre y la Naturaleza. El Plan de Manejo se centra en la conservación, rehabilitación, restauración, reconversión y protección de los legados de interés de las interacciones en cuestión, y en el uso de tales activos como recursos de ocio y de aprendizaje sobre el Ambiente (formación y/o educación ambiental). Para desarrollar el Plan de Manejo, se opta, como metodología, el Análisis DAFO Compacto, Cuantitativo y Contrastable y, como herramientas, un árbol genérico de objetivos del Campo de Aplicación de los Parques Temáticos Ambientales (con niveles de diagnóstico de situación, estrategias, metas y fin, y operativo para el lugar con la incorporación de aquellos objetivos de su árbol específico, que no se encontraran ya recogidos en el general), y las matrices de un Marco Lógico de los objetivos involucrados. Se enuncian las Reglas de Aplicación de esta versión de Análisis DAFO Cuantitativo Contrastable: Las Reglas Generales (referentes a los coeficientes de importancia, espaciales, temporales y de probabilidad de presentación). Y las Reglas Procedimentales (en relación con la utilización de los Descriptores de Medición (diseñados y desarrollados con criterios de valoración definidos objetivamente y formulados de forma clara, concisa y universalista). Los resultados obtenidos con la aplicación de todos y cada uno de los Descriptores DAFO a un territorio (respecto al uso del mismo como Parque Temático Ambiental), posibilitan establecer secuencias de calidades óptimas (las que se conseguirían con la mejor de las gestiones), de calidades actuales (de las situaciones imperantes en el momento del Análisis) y de desvíos de calidad (calidades óptimas menos calidades actuales). Estas mediciones: Por una parte, dan los criterios para calificar la vocación de destino y el destino de uso (actual y potencial) de un territorio como Parque Temático Ambiental. Y, por otra, posibilitan calcular los porcentajes de logros que se alcanzarían con las eliminaciones de los desvíos de calidad. Se formula un protocolo de redacción de un Plan de Manejo, conforme con la metodología y herramientas asumidas, y calibrado con su aplicación a un caso real. Las propuestas y los planteamientos (con sus acciones específicas) de los diferentes proyectos del Plan de Manejo, se encuentran estructurados por itinerarios de objetivos (del árbol genérico), y alimentados por los desarrollos de las matrices de un Marco Lógico (de los objetivos involucrados en cada itinerario). El cronograma de actuaciones (en su conjunto y por partes) se deriva también de las temporalizaciones que impone el desarrollo del Marco Lógico. Los logros y las calidades blindadas se obtienen conforme con las correspondencias entre desvíos de calidad, cuantificadas con la DAFO, y actuaciones planificadas. Se verifica la viabilidad de esta forma de redactar Planes de Manejo con ejemplos de casos reales. La metodología y las herramientas empleadas (con las adecuadas modificaciones) son susceptibles de extrapolar a otros campos de aplicación de un territorio (como se ha demostrado).

Planificación y diagnóstico de base de las playas no vírgenes de "sol y baño" (Tópicos actualizados a 2014 para redactar planes de manejo). Aplicación al caso de la Playa de Las Canteras (Las Palmas de Gran Canaria)

[ES]Respecto a la gestión de las playas de sol y baño, se presentan 4 bloques de prácticas con sus soportes teóricos, que se denominan, por sus alcances conceptuales y procedimentales: cálculo de calidades DAFO cuantitativas y contrastables para un campo de aplicación dado en la Ordenación del Territorio (imprescindible en un diagnóstico ambiental de situación), evaluación de impactos ambientales heredados como parte del diagnóstico ambiental de situación, redacción de proyectos, propuestas y planteamientos (con sus acciones específicas), en relación con la Ordenación del Territorio, y puesta en valor de proyectos de Ordenación del Territorio (cualificación, cuantificación, catalogación y clasificación). Cada uno de los bloques de prácticas contiene: una base teórica, una batería de enunciados de ejercicios, y sus correspondientes soluciones. Los casos prácticos presentados satisfacen a las tareas propias de los gestores de un territorio y, en particular, se ajustan a las competencias profesionales asignadas a la materia de Planificación y Gestión del Litoral de grado de la ULPGC, generados a partir de los objetivos establecidos y que se alcanzan a través de los contenidos conceptuales, procedimentales y actitudinales, de una Ordenación del Territorio.

Planes de manejo de un territorio : vehiculación, eficencia y alcance (Caso del parque temático ambiental de Lucainena de las Torres, en Almería, como patrimonio arqueológico minero)

[ES]Se diseña un árbol operativo de objetivos, desde uno genérico, del campo de aplicación de los espacios protegidos, jerarquizado en estratos. De arriba abajo, en el árbol, se suceden los estratos correspondientes al fin, a las metas, a las estrategias y a los objetivos de base. El diseño de itinerarios justificados de metas con sus estrategias, desde el árbol genérico operativo de objetivos asumido, desarrolla la vehiculación (armazón) del Plan de Manejo a redactar, compatible con una gestión integral del marco geográfico involucrado. Se obtiene la eficiencia y el alcance de esta vehiculación del Plan de Manejo a partir de un diagnóstico ambiental de situación, sustentado por un Análisis DAFO cuantitativo, y por una Evaluación de Impactos Ambientales heredados.

Elastic Propagation in random media: applications to the imaging of volcano structures

High-frequency seismograms contain features that reflect the random inhomogeneities of the earth. In this work I use an imaging method to locate the high contrast small- scale heterogeneity respect to the background earth medium. This method was first introduced by Nishigami (1991) and than applied to different volcanic and tectonically active areas (Nishigami, 1997, Nishigami, 2000, Nishigami, 2006). The scattering imaging method is applied to two volcanic areas: Campi Flegrei and Mt. Vesuvius. Volcanic and seismological active areas are often characterized by complex velocity structures, due to the presence of rocks with different elastic properties. I introduce some modifications to the original method in order to make it suitable for small and highly complex media. In particular, for very complex media the single scattering approximation assumed by Nishigami (1991) is not applicable as the mean free path becomes short. The multiple scattering or diffusive approximation become closer to the reality. In this thesis, differently from the ordinary Nishigami’s method (Nishigami, 1991), I use the mean of the recorded coda envelope as reference curve and calculate the variations from this average envelope. In this way I implicitly do not assume any particular scattering regime for the "average" scattered radiation, whereas I consider the variations as due to waves that are singularly scattered from the strongest heterogeneities. The imaging method is applied to a relatively small area (20 x 20 km), this choice being justified by the small length of the analyzed codas of the low magnitude earthquakes. I apply the unmodified Nishigami’s method to the volcanic area of Campi Flegrei and compare the results with the other tomographies done in the same area. The scattering images, obtained with frequency waves around 18 Hz, show the presence of high scatterers in correspondence with the submerged caldera rim in the southern part of the Pozzuoli bay. Strong scattering is also found below the Solfatara crater, characterized by the presence of densely fractured, fluid-filled rocks and by a strong thermal anomaly. The modified Nishigami’s technique is applied to the Mt. Vesuvius area. Results show a low scattering area just below the central cone and a high scattering area around it. The high scattering zone seems to be due to the contrast between the high rigidity body located beneath the crater and the low rigidity materials located around it. The central low scattering area overlaps the hydrothermal reservoirs located below the central cone. An interpretation of the results in terms of geological properties of the medium is also supplied, aiming to find a correspondence of the scattering properties and the geological nature of the material. A complementary result reported in this thesis is that the strong heterogeneity of the volcanic medium create a phenomenon called "coda localization". It has been verified that the shape of the seismograms recorded from the stations located at the top of the volcanic edifice of Mt. Vesuvius is different from the shape of the seismograms recorded at the bottom. This behavior is justified by the consideration that the coda energy is not uniformly distributed within a region surrounding the source for great lapse time.

A BEM-FEM model for the dynamic analysis of building structures founded on elastic or poroelastic soils.

[EN]This work presents a time-harmonic boundary elementfinite element three-dimensional model for the dynamic analysis of building structures founded on elastic or porelastic soils. The building foundation and soil domains are modelled as homogeneous, isotropic, elastic or poroelastic media using boundary elements.

A 2D BEM-FEM approach for time harmonic fluid-structure interaction analysis of thin elastic bodies.

[EN]This paper deals with two-dimensional time harmonic fluid-structure interaction problems when the fluid is at rest, and the elastic bodies have small thicknesses. A BEM-FEM numerical approach is used, where the BEM is applied to the fluid, and the structural FEM is applied to the thin elastic bodies.

Structural and elastic properties of DNA and chromatin

We investigate a chain consisting of two coupled worm-like chains withconstant distance between the strands. The effects due todouble-strandedness of the chain are studied. In a previous analyticalstudy of this system an intrinsic twist-stretch coupling and atendency of kinking is predicted. Even though a local twist structureis observed the predicted features are not recovered. A new model for DNA at the base-pair level is presented. Thebase-pairs are treated as flat rigid ellipsoids and thesugar-phosphate backbones are represented as stiff harmonic springs.The base-pair stacking interaction is modeled by a variant of theGay-Berne potential. It is shown by systematic coarse-graininghow the elastic constants of a worm-like chain are related to thelocal fluctuations of the base-pair step parameters. Even though a lotof microscopic details of the base-pair geometry is neglected themodel can be optimized to obtain a B-DNA conformation as ground stateand reasonable elastic properties. Moreover the model allows tosimulate much larger length scales than it is possible with atomisticsimulations due to the simplification of the force-field and inparticular due to the possibility of non-local Monte-Carlo moves. Asa first application the behavior under stretching is investigated. Inagreement with micromanipulation experiments on single DNA moleculesone observes a force-plateau in the force-extension curvescorresponding to an overstretching transition from B-DNA to aso-called S-DNA state. The model suggests a structure for S-DNA withhighly inclined base-pairs in order to enable at least partialbase-pair stacking. Finally a simple model for chromatin is introduced to study itsstructural and elastic properties. The underlying geometry of themodeled fiber is based on a crossed-linker model. The chromatosomesare treated as disk-like objects. Excluded volume and short rangenucleosomal interaction are taken into account by a variant of theGay-Berne potential. It is found that the bending rigidity and thestretching modulus of the fiber increase with more compact fibers. Fora reasonable parameterization of the fiber for physiologicalconditions and sufficiently high attraction between the nucleosomes aforce-extension curve is found similar to stretching experiments onsingle chromatin fibers. For very small stretching forces a kinkedfiber forming a loop is observed. If larger forces are applied theloop formation is stretched out and a decondensation of the fibertakes place.