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2016
Mateus, O. Late Jurassic of Morrison Formation and Portugal tetrapods compared: a model to explain faunal exchange and similarity. Annual Meeting of the Society of Vertebrate Paleontology. Salt Late City: Journal of Vertebrate Paleontology, Program and Abstracts, 2016, 2016. Abstract

The precursor of the North Atlantic existed between the North American and Iberian blocks from the earliest Jurassic Hettangian and has been ever expanding since. By the Kimmeridgian and Tithonian, when much of the Morrison Fm rocks were deposited, the proto-Atlantic was more than 300 km wide at 27° paleolatitude between North America and Iberia. Macrovertebrate paleontology reveals a unique story to the isolation of Iberia and instead suggest a paleogeographic land connection between North American and Iberia. Torvosaurus, Allosaurus, Ceratosaurus, Stegosaurus, Supersaurus and others have a distribution restricted to Morrison Formation in North America and Lourinhã Formation in Portugal. A novel paleogeographic model is here suggested: (1) around the Middle–Late Jurassic transition there is a major palaeoceanographic and palaeoclimatic reorganization, coincidental to a major eustatic sea-level drop and uplift associated with the Callovian– Oxfordian Atlantic Regressive Event; (2) creating an ephemeral land bridge presenting a temporary opportunity for terrestrial gateways likely across the Flemish Cap and Galician Bank land masses, allowing large dinosaurian taxa to cross the northern proto-Atlantic in both directions; (3) finally, a Callovian–Oxfordian faunal exchange around the 163 Ma, through latest Kimmeridgian at 152 Ma (the age of equivalent genera in both Morrison and Portugal), is was an interval that allowed speciation, but retaining generic similarity of vertebrates. This model is consistent with the chronology and taxonomy required for speciation of the Iberian and American forms, exemplified by the coeval sister-taxa pairs Torvosaurus tanneri and T. gurneyi, Allosaurus fragilis and A. europaeus, or Supersaurus vivianae and S. lourinhanensis. While some of the smaller animals in the fauna show Morrison/Portugal affinities, most from Iberia have European or even Asian affinities. The larger-bodied fauna are more closely related to Morrison than to mainland Europe (except for dacentrurine stegosaurs). The body size differences and affinities of taxa across paleogeography is comparable to what is observed today across the Wallace Line. Migration may have also occurred in both directions. The closest relative of Torvosaurus is likely the European Bathonian Megalosaurus, thus the presence of the genus in North America represents a European migration. On other hand, Allosaurus and Supersaurus origins are consistent with a North American origin, representing an westto-east migration.

Mateus, O. "Late Jurassic of Morrison Formation and Portugal tetrapods compared: a model to explain faunal exchange and similarity." Annual Meeting of the Society of Vertebrate Paleontology. Salt Late City 2016. 185. Abstract
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Lopes, Rui Amaral, Adriana Chambel, João Neves, Daniel Aelenei, and João Martins. "A Literature Review of Methodologies Used to Assess the Energy Flexibility of Buildings." Energy Procedia. 91 (2016): 1053-1058. AbstractWebsite

Abstract Due to the introduction of distributed renewable energy technologies with variable resource availability, the need of flexible electrical systems is evident. In general, flexibility is achieved from the supply side and often using carbon intensive energy generators. Therefore, improving the flexibility of the electrical system by taking advantage of renewable energy generation capacities and demand response measures in buildings is of major importance for a sustainable development. Control systems to implement these demand response measures need to quantify the flexibility of the respective buildings. Having this into consideration, this paper aims at presenting a literature review on methodologies to quantify the energy flexibility of buildings.

Leal, A. A., A. Dion{\'ısio, M. A. S. Braga, and O. Mateus. "The long term preservation of Late Jurassic sandstone dinosaur footprints in a museum environment." International Journal of Conservation Science. 7 (2016): 627-646. AbstractWebsite

This study focuses on the assessment of the degradation processes occurring in three sandstone infills of fossilized Late Jurassic ornithopod tridactyl footprints, found in 2001 in a coastline cliff in Porto das Barcas (Lourinhã, Portugal) and exhibited in a museum display since 2004. These dinosaur footprints present nowadays severe decay phenomena compromising their physical integrity and are leading gradually to their loss of value. The deterioration patterns were recorded, a map of their distribution was prepared and several samples were collected both in the dinosaur footprints and in the coastline cliff. Different analytical procedures were applied such as XRD, FTIR, FESEM and Ion Chromatography. A microclimatic survey was also performed and air temperature and relative humidity was measured during eight months both indoor and also outdoor. The decay patterns observed are a combination intrinsic and extrinsic factors the stone material, namely swelling of clay minerals in the rock matrix (smectite and chlorite-smectite mixed-layer), presence of salts (mainly chlorides), application of past conservation treatments (poly(vinyl) acetate and epoxy resins) and with the museum’s indoor thermohygrometric conditions (mainly non-stable hygrometric conditions). This scientific knowledge is therefore essential to the sustainable preservation of this paleontological heritage.

Leal, A. A., A. Dion\{\'ı\}sio, M. A. S. Braga, and O. Mateus. "The long term preservation of Late Jurassic sandstone dinosaur footprints in a museum environment." International Journal of Conservation Science. 7 (2016): 627-646. Abstract
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Leal, AS, A. Dionísio, M. A. Sequeira Braga, and O. Mateus. "The long term preservation of late jurassic sandstone dinossaur footprints in a museum environment." International Journal of Conservation Science. 7 (2016): 627-646. Abstract
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Lyubchyk, Andriy, António Vicente, Bertrand Soule, Pedro Urbano Alves, Tiago Mateus, Manuel J. Mendes, Hugo Águas, Elvira Fortunato, and Rodrigo Martins. "Mapping the Electrical Properties of ZnO-Based Transparent Conductive Oxides Grown at Room Temperature and Improved by Controlled Postdeposition Annealing." Advanced Electronic Materials. 2 (2016). Abstract
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Braslavsky, I., I. Plotnikov, and S. Valtchev. "The mathematical modeling of alternating current electric drive with DC-DC converter and ultracapacitors." Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016 (2016): 511-515. Abstract
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Wojcik, P.J., Pereira Martins Fortunato L. R. E. Metal oxide nanoparticle engineering for printed electrochemical applications. Handbook of Nanoelectrochemistry: Electrochemical Synthesis Methods, Properties, and Characterization Techniques., 2016. AbstractWebsite

Engineering procedures governing the selection or development of printable nanostructured metal oxide nanoparticles for chromic, photovoltaic, photocatalytic, sensing, electrolyte-gated TFTs, and power storage applications are established in this chapter. The main focus is given on how to perform the material selection and formulation of printable dispersion in order to develop functional films for electrochemical applications. This chapter is divided into four main parts. Firstly, a brief introduction on electrochemically active nanocrystalline metal oxide films developed via printing techniques is given. This is followed by the description of the film morphology, structure, and required functionality. A theoretical approach to understand the impact of size and shape of nanoparticles on an ink formulation and electrochemical performance being the subject of the third section provides a greater control over the material selection. We attempt to describe these properties and show that for a given material, geometry and size of the nanoparticles have a major influence on the electrochemical reactivity and response time. This gives the ability to tune the performance of the film simply by varying the morphology of incorporated nanostructures. This section is completed by the recommendations on each major step of an ink formulation, together with imposed critical constraints concerning the fluid control. Finally, the performance of the ink-jetprinted dual-phase electrochromic films is discussed as a case study. By providing such a rather systematic survey, we aim to stress the importance of proper design strategy that would result in both improved physicochemical properties of nanoparticle-loaded inks and enhanced electrochemical performance of printed functional films. © Springer International Publishing Switzerland 2016.

Pimentel, A., Ferreira Nunes Calmeiro Martins Fortunato S. H. D. "Microwave synthesized ZnO nanorod arrays for UV sensors: A seed layer annealing temperature study." Materials. 9 (2016). AbstractWebsite

The present work reports the influence of zinc oxide (ZnO) seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was produced using the spin-coating method and several annealing temperatures, ranging from 100 to 500 °C, have been tested. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and spectrophotometry measurements have been used to investigate the structure, morphology, and optical properties variations of the produced ZnO nanorod arrays regarding the seed layer annealing temperatures employed. After the growth of ZnO nanorod arrays, the whole structure was tested as UV sensors, showing an increase in the sensitivity with the increase of seed layer annealing temperature. The UV sensor response of ZnO nanorod arrays produced with the seed layer annealed temperature of 500 °C was 50 times superior to the ones produced with a seed layer annealed at 100 °C. © 2016 by the authors.

Silva, F. G. A., M. F. S. F. de Moura, N. Dourado, J. Xavier, F. A. M. Pereira, J. J. L. Morais, and M. I. R. Dias. "Mixed-mode I+II fracture characterization of human cortical bone using the Single Leg Bending test." Journal of the Mechanical Behavior of Biomedical Materials. 54 (2016): 72-81. AbstractWebsite

Abstract Mixed-mode I+II fracture characterization of human cortical bone was analyzed in this work. A miniaturized version of the Single Leg Bending test (SLB) was used owing to its simplicity. A power law criterion was verified to accurately describe the material fracture envelop under mixed-mode I+II loading. The crack tip opening displacements measured by digital image correlation were used in a direct method to determine the cohesive law mimicking fracture behavior of cortical bone. Cohesive zone modeling was used for the sake of validation. Several fracture quantities were compared with the experimental results and the good agreement observed proves the appropriateness of the proposed procedure for fracture characterization of human bone under mixed-mode I+II loading.

Mota, Pedro P., and Manuel L. Esquível. "Model selection for stock prices data." Journal of Applied Statistics. 43 (2016): 2977-2987. AbstractWebsite

The geometric Brownian motion (GBM) is very popular in modeling the dynamics of stock prices. However, the constant volatility assumption is questionable and many models with nonconstant volatility have been developed. In the papers [7,12] the authors introduce a regime switching process where in each regime the process is driven by GBM and the change in regime is defined by the crossing of a threshold. In this paper we used Akaike's and Bayesian information criteria to show that the GBM with regimes provides a better fit than the GBM. We also perform a forecasting comparison of the models for two selected companies.

Brito, V., L. B. Palma, F. V. Coito, and S. Valtchev. "Modeling and supervisory control of a virtual X8-VB quadcopter." Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016 (2016): 686-693. Abstract
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Conejero, José Mar{\'ı}a, Isabel Sofia Brito, Ana Moreira, Jácome Cunha, and João Araújo. "Modeling the Impact of UAVs in Sustainability." 24th {IEEE} International Requirements Engineering Conference, {RE} 2016, Beijing, China, September 12-16, 2016. 2016. 208-216. Abstract
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Mendes, Manuel J., Andreia Araújo, António Vicente, Hugo Águas, Isabel Ferreira, Elvira Fortunato, and Rodrigo Martins. "Nano Energy." (2016). Abstract
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João, Carlos FC, Ana C. Baptista, Isabel M. M. Ferreira, Jorge C. Silva, and João P. Borges. "Natural Nanofibres for Composite Applications." Fibrous and Textile Materials for Composite Applications. Springer Singapore, 2016. 261-299. Abstract
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Coelho, Carlos A., Filipe J. Marques, and Sandra Oliveira. "Near-exact distributions for likelihood ratio statistics used in the simultaneous test of conditions on mean vectors and patterns of covariance matrices." Mathematical Problems in Engineering. 2016 (2016). Abstract
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Marques, Filipe J., and Carlos A. Coelho. "Near-exact distributions for positive linear combinations of independent non-central Gamma random variables." AIP Conference Proceedings. Vol. 1738. AIP Publishing, 2016. 190005. Abstract
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Myers, TS, O. Mateus, M. J. Polcyn, D. Vineyard, and LL Jacobs A new chelonioid turtle from the Paleocene of Cabinda, Angola. Journal of Vertebrate Paleontology, Program and Abstracts, 2016, p. 194., 2016. Abstract

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skull is missing the left quadrate, squamosal, and prootic, both opisthotics, and the mandible. The skull possesses a rod-like basisphenoid rostrum, which is a synapomorphy of Chelonioidea, but it differs from other chelonioid skulls in that the contact between the parietal and squamosal is absent, and the posterior palatine foramen is present. Phylogenetic analysis recovers the new taxon as a basal chelonioid. The Paleocene– Eocene strata near Landana have produced a wealth of turtle fossils, including the holotype of the pleurodire Taphrosphys congolensis. A turtle humerus collected from the Landana locality differs morphologically from the humeri of chelonioids and Taphrosphys, indicating the presence of a third taxon. Chelonioid fossil material in the Landana assemblage is rare compared to the abundant fragmentary remains of Taphrosphys that are found throughout the stratigraphic section. This disparity in abundance suggests the new chelonioid taxon preferred open marine habitats, whereas Taphrosphys frequented nearshore environments.

Myers, TS, O. Mateus, M. J. Polcyn, D. Vineyard, and LL Jacobs. "A new chelonioid turtle from the Paleocene of Cabinda, Angola." Journal of Vertebrate Paleontology, Program and Abstracts, 2016, p. 194. 2016. 194. Abstract
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Myers, TS, O. Mateus, {M. J. } Polcyn, D. Vineyard, and LL Jacobs A new chelonioid turtle from the Paleocene of Cabinda, Angola., 2016. Abstract

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skull is missing the left quadrate, squamosal, and prootic, both opisthotics, and the mandible. The skull possesses a rod-like basisphenoid rostrum, which is a synapomorphy of Chelonioidea, but it differs from other chelonioid skulls in that the contact between the parietal and squamosal is absent, and the posterior palatine foramen is present. Phylogenetic analysis recovers the new taxon as a basal chelonioid. The Paleocenetextendash Eocene strata near Landana have produced a wealth of turtle fossils, including the holotype of the pleurodire Taphrosphys congolensis. A turtle humerus collected from the Landana locality differs morphologically from the humeri of chelonioids and Taphrosphys, indicating the presence of a third taxon. Chelonioid fossil material in the Landana assemblage is rare compared to the abundant fragmentary remains of Taphrosphys that are found throughout the stratigraphic section. This disparity in abundance suggests the new chelonioid taxon preferred open marine habitats, whereas Taphrosphys frequented nearshore environments.

Caeiro, Frederico, Filipe J. Marques, Ayana Mateus, and Serra Atal. "A note on the Jackson exponentiality test." AIP Conference Proceedings. Vol. 1790. AIP Publishing, 2016. 080005. Abstract
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Bahubalindruni, P.G.a c, Tavares Fortunato Martins Barquinha V. G. b E. "Novel linear analog-adder using a-IGZO TFTs." Proceedings - IEEE International Symposium on Circuits and Systems. Vol. 2016-July. 2016. 2098-2101. Abstract

A novel linear analog adder is proposed only with n-type enhancement IGZO TFTs that computes summation of four voltage signals. However, this design can be easily extended to perform summation of higher number of signals, just by adding a single TFT for each additional signal in the input block. The circuit needs few number of transistors, only a single power supply irrespective of the number of voltage signals to be added, and offers good accuracy over a reasonable range of input values. The circuit was fabricated on glass substrate with the annealing temperature not exceeding 200° C. The circuit performance is characterized from measurements under normal ambient at room temperature, with a power supply voltage of 12 V and a load of ≈ 4 pF. The designed circuit has shown a linearity error of 2.3% (until input signal peak to peak value is 2 V), a power consumption of 78 μW and a bandwidth of ≈ 115 kHz, under the worst case condition (when it is adding four signals with the same frequency). In this test setup, it has been noticed that the second harmonic is 32 dB below the fundamental frequency component. This circuit could offer an economic alternative to the conventional approaches, being an important contribution to increase the functionality of large area flexible electronics. © 2016 IEEE.

Panigrahi, S., Calmeiro Martins Nunes Fortunato T. R. D. "Observation of Space Charge Dynamics Inside an All Oxide Based Solar Cell." ACS Nano. 10 (2016): 6139-6146. AbstractWebsite

The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell. © 2016 American Chemical Society.