Wetting behaviour of femtosecond laser textured Ti-6Al-4V surfaces

The aim of the present work was to investigate the wetting behaviour of biomedical grade Ti-6Al-4V alloy surfaces textured by a femtosecond laser treatment. The material was treated in ambient atmosphere using an Yb: KYW chirped-pulse-regenerative amplification laser with a wavelength of 1030 nm and a pulse duration of 500 fs. Four main types of surface textures were obtained depending on the processing parameters and laser treatment method. These textures consist of: (1) nanoscale laser-induced periodic surface structures (LIPSS); (2) nanopillars; (3) a bimodal roughness distribution texture formed of LIPSS overlapping microcolumns; (4) a complex texture formed of LIPSS overlapping microcolumns with a periodic variation of the columns size in the laser scanning direction. The wettability of the surfaces was evaluated by the sessile drop method using distilled-deionized (DD) water and Hank's balanced salt solution (HBSS) as testing liquids. The laser treated surfaces present a hydrophilic behaviour as well as a high affinity for the saline solution, with equilibrium contact angles in the ranges 24.1-76.2. for DD water and 8.4-61.8. for HBSS. The wetting behaviour is anisotropic, reflecting the anisotropy of the surface textures. (c) 2012 Elsevier B.V. All rights reserved.

Anomaly-free U(1) gauge symmetries in neutrino seesaw flavor models

Agência Financiadora: Fundação para a Ciência e a Tecnologia (FCT) - PEst-OE/FIS/UI0777/2013; CERN/FP/123580/2011; PTDC/FIS-NUC/0548/2012

Relativistic time effects in financial dynamics

Financial time series have a complex dynamic nature. Many techniques were adopted having in mind standard paradigms of time flow. This paper explores an alternative route involving relativistic effects. It is observed that the measuring perspective influences the results and that we can have different time textures.

Le retable majeur de la Sé velha de Coimbra et la polychromie dans le diocèse de Coimbra à l’époque baroque: aspects techniques et esthétiques

Doutoramento em Conservação e Restauro, especialidade Teoria, História e Técnicas

Lisboa, cidade cenográfica: memorando do projecto

Lisboa, cidade cenográfica é uma instalação que resulta dum processo de sucessivos registos de momentos, experiências e vivências da cidade de Lisboa, com diferentes narrativas. Através do método de assemblage de elementos retirados à rua e reconstruindo composições de blocos volumétricas que incluem desde imagens gráficas, à presença de fontes de luz e de som, e texturas várias, produzi uma instalação destinada a ser ocupada, como se do próprio processo de deambulação por uma cidade se tratasse – neste caso Lisboa. A instalação final, – Lisboa, cidade cenográfica -, constitui em si uma maqueta, como ponto de partida para um outro processo, quase interminável, que conduzisse a uma outra instalação que nos engolisse e se apoderasse da nossa presença. Manipulando diferentes escalas, composições e morfologias de espaço obter-se-ia uma instalação quase infindável, como a própria cidade. A actual instalação é como a síntese dum Fóssil Urbano. Na observação e captação de imagens da cidade houve a preocupação de efectuar a diferentes horas do dia. Os sons utilizados na instalação, foram gravados nas ruas de Lisboa e incluem desde sinos de igreja, ao chilrear de pássaros, aos aviões que sobrevoam, ao trânsito e respectivas buzinas e sirenes de ambulâncias, entre outros. No âmbito do desenvolvimento do projecto e desta Memória Descritiva, tive a preocupação de pedir a algumas pessoas – Cartas de Lisboa -, testemunhando o modo como habitam ou habitaram a cidade. Nos headphones presentes na instalação, ouve-se o poema Lisbon Revisited (1923), de Álvaro de Campos, completando assim o som ambiente de Lisboa, cidade cenográfica. Aquele poema só audível daquele modo, acaba por se sobrepor assim, dum modo subtil, aos outros sons ambiente (exteriores aos headphones).

Confronting predictive texture zeros in lepton mass matrices with current data

Several popular Ansatze of lepton mass matrices that contain texture zeros are confronted with current neutrino observational data. We perform a systematic chi(2) analysis in a wide class of schemes, considering arbitrary Hermitian charged-lepton mass matrices and symmetric mass matrices for Majorana neutrinos or Hermitian mass matrices for Dirac neutrinos. Our study reveals that several patterns are still consistent with all the observations at the 68.27% confidence level, while some others are disfavored or excluded by the experimental data. The well-known Frampton-Glashow-Marfatia two-zero textures, hybrid textures, and parallel structures (among others) are considered.

Effects of Soil Compaction and Organic Carbon Content on Preferential Flow in Loamy Field Soils

Abstract: Preferential flow and transport through macropores affect plant water use efficiency and enhance leaching of agrochemicals and the transport of colloids, thereby increasing the risk for contamination of groundwater resources. The effects of soil compaction, expressed in terms of bulk density (BD), and organic carbon (OC) content on preferential flow and transport were investigated using 150 undisturbed soil cores sampled from 15 × 15–m grids on two field sites. Both fields had loamy textures, but one site had significantly higher OC content. Leaching experiments were conducted in each core by applying a constant irrigation rate of 10 mm h−1 with a pulse application of tritium tracer. Five percent tritium mass arrival times and apparent dispersivities were derived from each of the tracer breakthrough curves and correlated with texture, OC content, and BD to assess the spatial distribution of preferential flow and transport across the investigated fields. Soils from both fields showed strong positive correlations between BD and preferential flow. Interestingly, the relationships between BD and tracer transport characteristics were markedly different for the two fields, although the relationship between BD and macroporosity was nearly identical. The difference was likely caused by the higher contents of fines and OC at one of the fields leading to stronger aggregation, smaller matrix permeability, and a more pronounced pipe-like pore system with well-aligned macropores.

Influence of abiotic stress factors on VOCs emission from Portuguese rice paddy fields: relation with increased climate change

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente Perfil de Gestão de Sistemas Ambientais

Reconnaissance study of macrofossils from the upper purus river - Western Amazônia.

Fossils of wood, bone and teeth found along the Upper Purus River οf Amazonia. were studied using conventional microscopy and scanning electron microscopy. Mass spectometry was also used to investigate minor and trace element signatures of bone samples.The microsopy studies showed that there was little alteration of original textures. In the fossil wood samples, identified In thin section as tropical hardwood trees, the replacement of the original material with siderite suggests that fossilization occured in shallow sediments in which interstitial waters were saturated with respect to iron carbenate. In samples of both fossilized bone and wood, precipitation of secondary iron phases was commonly observed in cracks and voids. Other secondary phases Included silica, iron oxides, manganese carbonate. The intimate assοciation οf these secondary phases with the original biological structures could be evidence for a microbiological role in the formation of these phases. The similarity in rare earth element (REE) signatures for 2 fossil bone samples from different modern locations indicates their having shared similar diagenetic histories.The virtually complete preservation of original textures suggests that microscοpic studies could be useful in classifying fossil and even in identifying original materials. Rare carth signatures in fossilized bone may reflect ground water compositions at the time of fossilization.

Exploring TM image texture and its relationships with biomass estimation in Rondônia, Brazilian Amazon

Many texture measures have been developed and used for improving land-cover classification accuracy, but rarely has research examined the role of textures in improving the performance of aboveground biomass estimations. The relationship between texture and biomass is poorly understood. This paper used Landsat Thematic Mapper (TM) data to explore relationships between TM image textures and aboveground biomass in Rondônia, Brazilian Amazon. Eight grey level co-occurrence matrix (GLCM) based texture measures (i.e., mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment, and correlation), associated with seven different window sizes (5x5, 7x7, 9x9, 11x11, 15x15, 19x19, and 25x25), and five TM bands (TM 2, 3, 4, 5, and 7) were analyzed. Pearson's correlation coefficient was used to analyze texture and biomass relationships. This research indicates that most textures are weakly correlated with successional vegetation biomass, but some textures are significantly correlated with mature forest biomass. In contrast, TM spectral signatures are significantly correlated with successional vegetation biomass, but weakly correlated with mature forest biomass. Our findings imply that textures may be critical in improving mature forest biomass estimation, but relatively less important for successional vegetation biomass estimation.

Garnet growth in the Nufenen Pass area (Swiss Alps)

Abstract : Textural division of a mineral in pyramids, with their apices located at the centre of the mineral and their bases corresponding to the mineral faces is called textural sector zoning. Textural sector zoning is observed in many metamorphic minerals like andalousite and garnet. Garnets found in the graphite rich black shales of the Mesozoic cover of the Gotthard Massif display textural sector zoning. The morphology of this sector zoning is not the same in different types of black shales observed in the Nufenen pass area. Garnets in foliated black shales display a well developed sector zoning while garnets found in cm-scale layered black shales display well developed sectors in the direction of the schistosity plane. This sector zoning is always associated with up to 30μm sized birefringent lamellae emanating radial from the sector boundaries. They alternate with isotrope lamellae. The garnet forming reaction was determined using singular value decomposition approach and results compared to thermodynamic calculations. It is of the form chl + mu + cc + cld = bt + fds + ank + gt + czo and is similar in both layered and foliated black shales. The calculated X(O) is close to 0.36 and does not significantly vary during the metamorphic history of the rock. This corresponds to X CO2, X CH4, and X H2O BSE imaging of garnets on oriented-cuts revealed that the orientation of the lamellae found within the sectors is controlled by crystallography. BSE imaging and electron microprobe analysis revealed that these lamellae are calcium rich compared to the isotropic lamellae. The addition of Ca to an almandine rich garnet causes a small distortion of the X site and potentially, ordering. Ordered and disordered garnet might have very similar free energies for this composition. Hence, two garnets with different composition can be precipitated with minor overstepping of the reaction. It is enough that continued nucleation of a new garnet layer slightly prefers the same structure to assure a fiber-like growth of both garnet compositions side by side. This hypothesis is in agreement with the thermodynamic properties of the garnet solid solution described in the literature and could explain the textures observed in garnets with these compositions. To understand the differences in sector zoning morphology, and crystal growth kinetics, crystal size distribution were determined in several samples using 2D spatial analysis of slab surfaces. The same nucleation rate law was chosen for all cases. Different growth rate law for non-layered black shales and layered black shales were used. Garnet in layered black shales grew according to a growth rate law of the form R=kt ½. The transport of nutrient is the limiting factor. Transport will occur preferentially on the schistosity planes. The shapes of the garnets in such rocks are therefore ovoid with the longest axis parallel to the schistosity planes. Sector zoning is less developed with sectors present only parallel to the schistosity planes. Garnet in non-layered blackshales grew according to a growth rate law of the form R=kt. The limiting factor is the attachment at the surface of the garnet. Garnets in these rocks will display a well developed sector zoning in all directions. The growth rate law is thus influenced by the texture of the rock. It favours or hinders the transport of nutrient to the mineral surface. Résumé : La zonation sectorielle texturale consiste en la division d'un cristal en pyramides dont les sommets sont localisés au centre du minéral. La base de ces pyramides correspond aux faces du minéral. Ce type de zonation est fréquemment observé dans les minéraux métamorphiques tels que l'andalousite ou le grenat. Les grenats présents dans les marnes riches en graphites de la couverture Mésozoïque du Massif du Gotthard présent une zonation sectorielle texturale. La morphologie de cette zonation n'est pas la même dans les marnes litées et dans les marnes foliées. Les grenats des marnes foliées montrent des secteurs bien développés dans 3 directions. Les grenats des marnes litées montrent des secteurs développés uniquement dans la direction des plans de schistosité. Cette zonation sectorielle est toujours associée à des lamelles biréfringentes de quelques microns de large qui partent de la limite des secteurs et qui sont perpendiculaires aux faces du grenat. Ces lamelles alternent avec des lamelles isotropes. La réaction de formation du grenat a été déterminée par calcul matriciel et thermodynamique. La réaction est de la forme chl + mu + cc + cld= bt + fds + ank + gt + czo. Elle est similaire dans les roches litées et dans les roches foliées. L'évaluation des conditions fluides montrent que le X(O) est proche de 0.36 et ne change pas de façon significative durant l'histoire métamorphique de la roche. Des images BSE sur des coupes orientées ont révélé que l'orientation de lamelles biréfringentes est contrôlée parla crystallographie. La comparaison des analyses à la microsonde électronique et des images BSE révèle également que les lamelles biréfringentes sont plus riches en calcium que les lamelles isotropes. L'addition de calcium va déformer légèrement le site X et ainsi créer un ordre sur ce site. L'énergie interne d'un grenat ordré et d'un grenat désordonné sont suffisamment proches pour qu'un léger dépassement de l'énergie de la réaction de formation permette la coexistence des 2 types de grenat dans le même minéral. La formation de lamelles est expliquée par le fait qu'un grenat préférera la même structure. Ces observations sont en accord avec la thermodynamique des solutions solides du grenat et permet d'expliquer les structures similaires observées dans des grenats provenant de lithologies différentes. Une étude de la distribution des tailles des grenats et une modélisation de la croissance a permis de mettre en évidence 2 mécanismes de croissance différents suivant la texture de la roche. Dans les 2 cas, la loi de nucléation est la même. Dans les roches litées, la loi de croissance est de forme R=kt½. Le transport des nutriments est le facteur limitant. Ce transport a lieu préférentiellement dans la direction des niveaux de schistosité. Les grenats ont une forme légèrement allongée car la croissance des secteurs est facilitée sur les niveaux de schistosité. La croissance des grenats dans les roches foliées suit une loi de croissance de la forme R=kt. Les seuls facteurs limitant la croissance sont les processus d'attachement à la surface du grenat. La loi de croissance de ces grenats est donc contrainte par la texture de la roche. Cela se marque par des différences dans la morphologie de la zonation sectorielle.

Shallow-level migmatization of gabbros in a metamorphic contact aureole, Fuerteventura Basal Complex, Canary Islands

Migmatization of gabbroic rocks at 2-3 kbar has occurred in the metamorphic contact aureole of a mafic pluton in the Fuerteventura Basal Complex (Canary Island;). Migmatites are characterized by a dense network: of closely spaced millimetre-wide leucocratic veins with perfectly preserved igneous textures. They are all relatively enriched in Al, Na I: Sr Ba, Nb, Y and the rare earth elements compared with the unaffected country rock beyond the aureole. Migmatization under such low-pressure conditions war possible because of the unusual tectonic and magmatic contact in which ii occurred. Multiple basic intrusions associated with extrusive volcanic activity created high heat flow in a small area. Alkaline and metasomatized rocks present in the country rock of the intruding pluton were leached by high-temperature fluids during contact metamorphism. These enriched fluids then favoured partial melting of the host gabbroic rocks, and contaminated both the leucosomes and melanosomes. A transpressive tectonic setting at the time of intrusion created shearing along the contact between the intrusion and its host rock. This shearing enhanced circulation of the fluids and allowed segregation of the nea-formed melts from their restite by opening tension veins into which the melts migrated. Depending on the relative timing of melt segregation and recrystallization leucosomes range in composition from a 40-60% mixture of clinopyroxene (+/- amphibole) and plagioclase to almost pure feldspathic veins. Comparable occurrences of gabbros migmatized at low pressure are expected only at a snail scale in localized areas of high heat flow in the presence of fluids, such as in. mid-ocean ridges or ocean-islands.

Pessebre virtual: disseny i exportació

Aquest projecte és una part d’un projecte més ampli consistent en estudiar un format gràfic que permeti exportar una escena modelada en Blender i importar aquesta mateixa escena en un entorn interactiu basat en Visual C++ amb OpenGL. D’aquesta forma, disposem de la capacitat de modelat de Blender i de la interacció i visualització de la llibreria OpenGL. Aquest format ha de representar geometria i textures imprescindiblement, i si és possible, d’altres factors importants com il·luminació, visualització i moviment. La part del projecte explicada en aquesta memòria consisteix en estudiar el format gràfic més adient per representar els diferents factors de realisme de l’escena (geometria, textura, etc.) havent triat el format OBJ per la seva capacitat de representació i fàcil edició. Per a provar el format, s’ha dissenyat un diorama de pessebre utilitzant les capacitats de modelatge de Blender. Pel que respecta les figures, aspecte important per a considerar l’escena com a pessebre, s’ha utilitzat un escàner 3D que ha obtingut representacions de malla 3D, a partir de figures reals de pessebre, que posteriorment han estat texturades. S’ha generat un vídeo del diorama de pessebre que permet veure’n tots els detalls navegant amb el punt de vista per l’escena. Aquest vídeo s’ha exposat en la mostra de pessebres de la Associació Pessebrista de Sabadell el Nadal del 2008.

Estudi comparatiu del sòl d'una vinya de Sant Pere de Ribes

Treball de recerca realitzat per una alumna d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. Anàlisi comparatiu de diferents propietats del sòl d’una vinya on s’ha observat que els peus presenten un creixement desigual. A partir d'una observació a simple vista de les plantes de la vinya i del sòl sobre el qual es desenvolupen, es proposa la hipòtesi de que el sòl pot ser un factor determinant per aquest creixement desigual. Després de fer una recerca bibliogràfica sobre l’edafologia, les propietats del sòl i els tipus de sòl que es poden trobar als voltants de Sant Pere de Ribes, l’autora ha fet una selecció de propietats físico-químiques que poden estar més relacionades amb el creixement de les plantes. Després de fer el mostreig i seguir els protocols de laboratori s’han analitzat els resultats i s’han redactat les conclusions. Les propietats estudiades han permès determinar els tipus de sòl, uns sòls de textures entre franco-arenoses i areno-franques. S’ha trobat també una correlació entre les diverses propietats estudiades: un sòl de porositat elevada, que presenta valors alts de velocitat d’infiltració i per tant amb baixa capacitat de retenció d’aigua disponible, no sembla el sòl ideal per al desenvolupament de les plantes de vinya. A partir del treball es plantegen noves incògnites sobre les adaptacions dels ceps a aquests tipus de sòl o sobre la qualitat del raïm que s'hi pot desenvolupar.

On the writer identification in old handwritten music scores

Report for the scientific sojourn at the University of Bern, Swiss, from Mars until June 2008. Writer identification consists in determining the writer of a piece of handwriting from a set of writers. Even though an important amount of compositions contains handwritten text in the music scores, the aim of the work is to use only music notation to determine the author. It’s been developed two approaches for writer identification in old handwritten music scores. The methods proposed extract features from every music line, and also features from a texture image of music symbols. First of all, the music sheet is first preprocessed for obtaining a binarized music score without the staff lines. The classification is performed using a k-NN classifier based on Euclidean distance. The proposed method has been tested on a database of old music scores from the 17th to 19th centuries, achieving encouraging identification rates.