Export 437 results:
Sort by: Author Title Type [ Year  (Desc)]
2011
Rocha, H. Teachers’ use of graphing calculators in high school mathematics classroom. Proceedings of CERME 7 – Seventh Congress of European Research in Mathematics Education. Rzezów, Poland: ERME, 2011.
Sallem, Amin, Pedro Pereira, Mourad FahkFahk, Helena Fino, and Fernando Coito. "A Technology-Aware Optimization of RF Integrated Inductors . Esteban Tlelo-Cuautle." Analog Circuits: Applications, Design & Performance (Electrical Engineering Developments) . Nova Science Publishers, 2011. 34-50.
Micaelo, Rui, Maria Colás, Arnaud Mazars, Julio Arias, Gillaume Crauzzo, and Laurent Lascroux. "Técnicas Rodoviárias Adaptadas às Mudanças Climáticas – Selecção e Avaliação." XVI Congresso Ibero-Latinoamericano do Asfalto. Rio de Janeiro, Brasil: IBP, 2011.
Micaelo, Rui, and André Santos. "Temperaturas de Compactação e Mistura de Misturas Betuminosas com Betumes Modificados." XVI Congresso Ibero-Latinoamericano do Asfalto. Rio Janeiro, Brasil: IBP, 2011.
Martins, Rui M. S., F. Beckmann, R. Castanhinha, R. Araújo, O. Mateus, and P. K. Pranzas Tomographic techniques for the study of exceptionally preserved dinosaur and crocodile fossils from the mesozoic of Portugal. VII Encontro Nacional de Biologia Evolutiva, Coimbra, 21 Dezembro 2011., 2011. Abstractmartins_et_al_mateus_2011_tomographic_techniques_for_the_study_of_exceptionally_preserved_dinosaur_and_crocodile.pdf

Portugal is ranked within the ten countries with more dinosaur taxa and the Lourinhã Formation is known
by the Late Jurassic findings of dinosaurs and other fossils. Often, studies of the external morphological
characteristics of the fossils are not sufficient and, observations of internal structures, using non-
destructive techniques, are required. The fossils here presented belong to the Museum da Lourinhã
(Portugal) and comprise a lower jaw of a basal crocodilian (possibly a Tomistomidae), eggshells and
several vertebrae from the exceptionally well preserved in ovo remains of Late Jurassic theropod dinosaur
Lourinhanosaurus. Neutron Tomography (NT) experiments with this material has been carried out at the
Geesthacht Neutron Facility in Germany. Additionally, eggshell fragments and several vertebrae have
been studied by Synchrotron-Radiation based Micro-Computed Tomography (SRμCT) at the HARWI II and
BW2 beamlines, respectively. These beamlines are operated by the Helmholtz-Zentrum Geesthacht at the
storage ring DORIS III at the Deutsches Elektronen–Synchrotron DESY in Hamburg, Germany. In both cases
(NT and SRμCT) complete 3D recordings have been obtained using a non-destructive procedure. The high-
quality tomographic datasets can be effectively studied through interactive digital visualization. Hence,
these visualization methods provide precious information about the 3D internal micro morphology of
fossils, like the network of the eggshell pores, often invisible in more traditional techniques, and provide a
direct window into the evolutionary history of organisms.

Afonso, Fábio, Fernanda Barbosa, and Armanda Rodrigues Trajectory Data Similarity with Metric Data Structures. Proceedings of Geographical Information Systems Research UK (GISRUK ). Portsmouth, UK, 2011.
Cunha, Jácome, Joost Visser, Tiago Alves, and João Saraiva. "Type-Safe Evolution of Spreadsheets." Proceedings of the 14th International Conference Fundamental Approaches to Software Engineering (FASE '11): Part of the Joint European Conferences on Theory and Practice of Software (ETAPS '11). Eds. Dimitra Giannakopoulou, and Fernando Orejas. Vol. 6603. Lecture Notes in Computer Science, 6603. Springer, 2011. 186-201. Abstractfase11.pdf

Spreadsheets are notoriously error-prone. To help avoid the introduction of errors when changing spreadsheets, models that capture the structure and interdependencies of spreadsheets at a conceptual level have been proposed. Thus, spreadsheet evolution can be made safe within the confines of a model. As in any other model/instance setting, evolution may not only require changes at the instance level but also at the model level. When model changes are required, the safety of instance evolution can not be guarded by the model alone. We have designed an appropriate representation of spreadsheet models, including the fundamental notions of formulæand references. For these models and their instances, we have designed coupled transformation rules that cover specific spreadsheet evolution steps, such as the insertion of columns in all occurrences of a repeated block of cells. Each model-level transformation rule is coupled with instance level migration rules from the source to the target model and vice versa. These coupled rules can be composed to create compound transformations at the model level inducing compound transformations at the instance level. This approach guarantees safe evolution of spreadsheets even when models change.

Pinto, R. M., A. A. Dias, M. Coreno, M. de Simone, B. M. Giuliano, J. P. Santos, and M. L. Costa. "Tautomerism in 5-methyltetrazole investigated by core-level photoelectron spectroscopy and ΔSCF calculations." Chemical Physics Letters. 516 (2011): 149-153. AbstractWebsite

The relative populations of the 1H- and 2H-tautomer of gas-phase 5-methyltetrazole (5MTZ) have been assessed through core-level photoelectron spectroscopy, and compared with the results obtained from Gaussian-n (Gn, n = 1, 2 and 3) and Complete Basis Set methods (CBS-4M and CBS-Q). The C 1s and N 1s core‚Äìelectron binding energies (CEBEs) for each ionization site of both tautomers have been computed using the Œîself-consistent-field (ŒîSCF) approach. The C 1s and N 1s XPS spectra, obtained at 313 K, yield a 1H/2H tautomer ratio of ca. 0.16/0.84 and 0.21/0.79, respectively.

Pinto, R. M., A. A. Dias, M. Coreno, M. de Simone, B. M. Giuliano, J. P. Santos, and M. L. Costa. "Tautomerism in 5-methyltetrazole investigated by core-level photoelectron spectroscopy and ΔSCF calculations." Chemical Physics Letters. 516 (2011): 149-153. AbstractWebsite

The relative populations of the 1H- and 2H-tautomer of gas-phase 5-methyltetrazole (5MTZ) have been assessed through core-level photoelectron spectroscopy, and compared with the results obtained from Gaussian-n (Gn, n = 1, 2 and 3) and Complete Basis Set methods (CBS-4M and CBS-Q). The C 1s and N 1s core‚Äìelectron binding energies (CEBEs) for each ionization site of both tautomers have been computed using the Œîself-consistent-field (ŒîSCF) approach. The C 1s and N 1s XPS spectra, obtained at 313 K, yield a 1H/2H tautomer ratio of ca. 0.16/0.84 and 0.21/0.79, respectively.

Baptista, AC, JI Martins, E. Fortunato, R. Martins, J. P. Borges, and I. Ferreira. "Thin and flexible bio-batteries made of electrospun cellulose-based membranes." Biosensors and Bioelectronics. 26.5 (2011): 2742-2745. Abstract
n/a
Baptista, A.C.a, Martins Fortunato Martins Borges Ferreira J. I. b E. "Thin and flexible bio-batteries made of electrospun cellulose-based membranes." Biosensors and Bioelectronics. 26 (2011): 2742-2745. AbstractWebsite

The present work proposes the development of a bio-battery composed by an ultrathin monolithic structure of an electrospun cellulose acetate membrane, over which was deposited metallic thin film electrodes by thermal evaporation on both surfaces. The electrochemical characterization of the bio-batteries was performed under simulated body fluids like sweat and blood plasma [salt solution - 0.9% (w/w) NaCl]. Reversible electrochemical reactions were detected through the cellulose acetate structure. Thus, a stable electrochemical behavior was achieved for a bio-battery with silver and aluminum thin films as electrodes. This device exhibits the ability to supply a power density higher than 3μWcm-2.Finally, a bio-battery prototype was tested on a sweated skin, demonstrating the potential of applicability of this bio-device as a micropower source. © 2010 Elsevier B.V.

Elangovan, E., Saji Parthiban Goncalves Barquinha Martins Fortunato K. J. S. "Thin-film transistors based on indium molybdenum oxide semiconductor layers sputtered at room temperature." IEEE Electron Device Letters. 32 (2011): 1391-1393. AbstractWebsite

Thin-film transistors (TFTs) were fabricated using a 20-nm-thick indium molybdenum oxide (IMO) semiconductor layer at room temperature. The grazing incidence X-ray diffraction patterns confirmed that the deposited films are amorphous. The average transmittance (400-2500 nm) and the optical band gap are ∼88% and 3.95 eV, respectively. The TFTs fabricated on glass substrates showed a saturation mobility of 4.0 cm2/Vċ s with an I ON/IOFF ratio of 2 × 103 and a threshold voltage of-1.1 V, which are encouraging preliminary results in order to develop IMO as high-performance semiconductor layer. © 2011 IEEE.

Santos-Silva, T., A. Mukhopadhyay, J. D. Seixas, G. J. L. Bernardes, C. C. Romão, and MJ Romão. "Towards improved therapeutic CORMs: Understanding the reactivity of CORM-3 with proteins." Current Medicinal Chemistry. 18 (2011): 3361-3366. Abstract
n/a
Tillak, JB, I. Bernacka-Wojcik, D. Barata, PAS Jorge, H. Águas, and AG Oliva. "Towards single cell spectroscopy and refractometry in microfluidic chip platforms." International Conference on Applications of Optics and Photonics. International Society for Optics and Photonics, 2011. 800112. Abstract
n/a
Palma, L. B., and F. V. Coito. "Tuning PCA controllers based on manual control data." Emerging Technologies & Factory Automation (ETFA), 2011 IEEE 16th Conference on. IEEE, 2011. 1-4. Abstract
n/a
Todorov, G., T. Todorov, I. Ivanov, S. Valtchev, and B. Klaassens. "Tuning techniques for kinetic MEMS energy harvesters." INTELEC, International Telecommunications Energy Conference (Proceedings) (2011). Abstract
n/a
Surzhykov, A., P. Indelicato, J. P. Santos, P. Amaro, Th Stöhlker, and S. Fritzsche. "Two-photon absorption of few-electron heavy ions." Physical Review A. 84 (2011): 022511. AbstractWebsite

The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac's relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.

Surzhykov, A., P. Indelicato, J. P. Santos, P. Amaro, Th Stöhlker, and S. Fritzsche. "Two-photon absorption of few-electron heavy ions." Physical Review A. 84 (2011): 022511. AbstractWebsite

The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac's relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.

2010
Martins, R. M. S., N. Schell, H. Reuther, L. Pereira, K. K. Mahesh, R. J. C. Silva, and F. M. Braz Fernandes. "Texture development, microstructure and phase transformation characteristics of sputtered Ni-Ti Shape Memory Alloy films grown on TiN < 111 >." Thin Solid Films. 519.1 (2010): 122-128. Abstract
n/a
Fortunato, Elvira, Vitor Figueiredo, Pedro Barquinha, Elangovan Elamurugu, Raquel Barros, Goncalo Goncalves, Sang-Hee Ko Park, Chi-Sun Hwang, and Rodrigo Martins. "Thin-film transistors based on p-type Cu2O thin films produced at room temperature." Applied Physics Letters. 96 (2010). AbstractWebsite
n/a
Fortunato, Elvira, Vitor Figueiredo, Pedro Barquinha, Elangovan Elamurugu, Raquel Barros, Goncalo Goncalves, Sang-Hee Ko Park, Chi-Sun Hwang, and Rodrigo Martins. "Thin-film transistors based on p-type Cu2O thin films produced at room temperature (vol 96, 192102, 2010)." Applied Physics Letters. 96 (2010). AbstractWebsite
n/a
Botas, Jose D., Alexandre Velhinho, and Rui JC Silva. "A theoretical approach to the elastic behaviour of compact and hollow spherical particles reinforced metal-matrix composites." International Journal of Materials Research. 101.6 (2010): 752-757. Abstract
n/a
Jacobs, LL, M. J. Polcyn, O. Mateus, A. Schulp, K. Ferguson, C. Scotese, B. F. Jacobs, C. Strganac, D. Vineyard, TS Myers, and ML Morais. "Tectonic Drift, Climate, and Paleoenvironment of Angola Since the Cretaceous." AGU Fall Meeting Abstracts, 1:. Journal of Vertebrate Paleontology. 2010. 02. Abstractjacobs_polcyn_mateus_et_al_2010_tectonic_drift_climate_and_paleoenvironment_of_angola_since_the_cretaceous.pdf

Africa is the only continent that now straddles arid zones located beneath the descending limbs of both the northern and southern Hadley cells, and it has done so since it became a distinct continent in the Early Cretaceous. Since that time, Africa has drifted tectonically some 12 degrees north and rotated approximately 45 degrees counterclockwise. This changing latitudinal setting and position of the landmass under the relatively stable Hadley Cells is manifested as southward migration of climatic zones over the past 132 million years. Data from kerogen, X-ray diffraction analysis of sedimentary matrix, carbon isotopes from shell samples and tooth enamel,new 40Ar/39Ar radiometric dates, pollen and plant macrofossils, and fossil vertebrates indicate a productive upwelling system adjacent to a coastal desert since the opening of the South Atlantic Ocean; however, the position of the coastal desert has migrated southward as Africa drifted north, resulting in today's Skeleton Coast and Benguela Current. This migration has had a profound effect on the placement of the West African coast relative to areas of high marine productivity and resulting extensive hydrocarbon deposits, on the placement of arid zones relative to the continent especially the Skeleton Coast desert, on the climatic history of the Congo Basin (which shows a Late Cretaceous decrease in aridity based on the relative abundance of analcime in the Samba core), and in reducing the southern temperate region of Africa from 17% of continental area during the Cretaceous to 2% today. We show here that these related geographic and environmental changes drove ecological and evolutionary adjustments in southern African floras and faunas, specifically with respect to the distribution of anthropoid primates, the occurrence of modern relicts such as the gnetalean Welwitschia mirabilis, endemism as in the case of ice plants, and mammalian adaption to an open environment as in springhares. Africa's tectonic drift through climate zones has been a first-order environmental determinant since the Early Cretaceous.

Botas, JD, Velhinho, A, Silva, M. A. G., and RJC. "A theoretical approach to the elastic behaviour of compact and hollow spherical particles reinforced metal-matrix composites." Int. J. of Mater. Research. 101 (2010): 752-757. Abstract

n/a

Paulo, Quaresma, Lopes Adriano, Medeiros Pedro, Preto Bruno, and Velhinho Alexandre. "Tomo-GPU: Um Ambiente de Resolução de Problemas Destinado à Análise de Dados Tomográficos Relativos à Caracterização Estrutural de Materiais." 5 (2010): NONE. Abstract
n/a