Sistema de treino para ciclistas

No trabalho �� desenvolvido um sistema de treino para ciclistas. O sistema de treino �� constitu��do por uma bicicleta de ���Spinning���, um trav��o accionado electricamente, e por um sensor de velocidade, utilizado para medir a velocidade de rota����o da roda de in��rcia. Nos primeiros cap��tulos encontra-se o estudo dos v��rios conceitos que envolvem o sistema de treino. �� realizado um estudo sobre as principais for��as que actuam numa bicicleta. Outro conceito estudado �� o filtro Kalman (FK). Este ser�� importante para o controlo do sistema de treino. O modelo do sistema de treino est�� dividido em duas partes. A primeira corresponde ao sistema mec��nico, e a segunda o sistema de controlo e actua����o. Este �� constitu��do por um sensor de velocidade, uma unidade de estima����o e o sistema de actua����o do trav��o da bicicleta. A unidade de estima����o �� composta por conjunto de filtros de Kalman que estima a velocidade, a acelera����o e a posi����o necess��rias ao c��lculo da for��a resistente ao movimento do conjunto ciclista bicicleta. Os resultados da simula����o do sistema mostram que o sistema de treino modelado apresenta um desempenho bastante razo��vel. A estima����o efectuada pelos filtros dos valores da velocidade, da acelera����o e da posi����o do ciclista, permite a unidade de controlo do sistema calcular o valor da for��a resistente ao movimento.

Electrodeposition and characterization of nickel���copper metallic foams for application as electrodes for supercapacitors

Nickel-copper metallic foams were electrodeposited from an acidic electrolyte, using hydrogen bubble evolution as a dynamic template. Their morphology and chemical composition was studied by scanning electron microscopy and related to the deposition parameters (applied current density and deposition time). For high currents densities (above 1 A cm(-2)) the nickel-copper deposits have a three-dimensional foam-like morphology with randomly distributed nearly-circular pores whose walls present an open dendritic structure. The nickel-copper foams are crystalline and composed of pure nickel and a copper-rich phase containing nickel in solid solution. The electrochemical behaviour of the material was studied by cyclic voltammetry and chronopotentiometry (charge-discharge curves) aiming at its application as a positive electrode for supercapacitors. Cyclic voltammograms showed that the Ni-Cu foams have a pseudocapacitive behaviour. The specific capacitance was calculated from charge-discharge data and the best value (105 F g(-1) at 1 mA cm(-2)) was obtained for nickel-copper foams deposited at 1.8 A cm(-2) for 180 s. Cycling stability of these foams was also assessed and they present a 90 % capacitance retention after 10,000 cycles at 10 mA cm(-2).

���Papel dos recetores purin��rgicos no crescimento e temodela����o do tecido cavernoso���

A adenosina �� um nucle��sido ub��quo envolvido na regula����o de controlo do t��nus vascular do tecido cavernoso, desempenhando um papel importante na fisiopatologia da Disfun����o Er��til (DE) resistente aos f��rmacos relaxantes musculares cl��ssicos. Apesar da import��ncia comprovada dos recetores da adenosina na fisiopatologia da DE no homem, pouca informa����o �� conhecida no que diz respeito �� express��o e localiza����o dos recetores purin��rgicos no Tecido Cavernoso de Ratazana (TCR). Neste trabalho avaliou-se o fen��tipo dos recetores purin��rgicos respons��veis pela regula����o do t��nus do tecido er��til de ratazana por imunofluoresc��ncia indireta aplicada �� microscopia confocal em co-culturas de c��lulas endoteliais e musculares lisas do TCR. Para al��m da caracteriza����o imunofenot��pica, desenvolveu-se uma t��cnica que permite diferenciar funcionalmente em tempo real (por microscopia confocal funcional) c��lulas musculares lisas e c��lulas endoteliais isoladas de TCR em co-cultura marcadas com a sonda fluorescente Fluo-4NW. Esta t��cnica permite distinguir cada um dos subtipos celulares mediante o padr��o e a magnitude das oscila����es dos n��veis intracelulares de Ca2+ ([Ca2+]i) em resposta ao ATP (agonista P2) e �� fenilefrina (PE, agonista ��-adren��rgico). Nas c��lulas musculares lisas, observou-se uma resposta mais acentuada ao agonista ��-adren��rgico, PE, e uma resposta menos significativa ao ATP. O contr��rio foi observado relativamente ��s c��lulas endoteliais. A incuba����o das c��lulas musculares lisas e endoteliais com ATP (300 ��M) causou um aumento dos n��veis de [Ca2+]i. O efeito do ATP (300 ��M) parece envolver a ativa����o de recetores dos subtipos P2X1 e P2X3 sens��veis ao bloqueio com NF023 (3��M) e A317491 (100 nM), respetivamente. J�� o aumento dos n��veis [Ca2+]i produzido pelo ADP (300 ��M) parece envolver a ativa����o de recetores P2Y1, P2Y12 e P2Y13 mediante o antagonismo produzido pelos antagonistas MRS 2179 (0,3��M), AR-C66096 (0,1 ��M) e MRS 2211 (10��M), respetivamente. Os dois tipos celulares expressam imunorreatividade contra recetores A2A, A2B, P2X1, P2X3, P2Y1, P2Y12 e P2Y13.

Simulation of the magnetic induction vector of a magnetic core to be used in FFC NMR relaxometry

This paper is a contribution for the assessment and comparison of magnet properties based on magnetic field characteristics particularly concerning the magnetic induction uniformity in the air gaps. For this aim, a solver was developed and implemented to determine the magnetic field of a magnetic core to be used in Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometry. The electromagnetic field computation is based on a 2D finite-element method (FEM) using both the scalar and the vector potential formulation. Results for the magnetic field lines and the magnetic induction vector in the air gap are presented. The target magnetic induction is 0.2 T, which is a typical requirement of the FFC NMR technique, which can be achieved with a magnetic core based on permanent magnets or coils. In addition, this application requires high magnetic induction uniformity. To achieve this goal, a solution including superconducting pieces is analyzed. Results are compared with a different FEM program.

In-situ X-ray diffraction studies during growth of Ni-Ti shape memory alloy films and their complementary ex-situ characterization

Shape Memory Alloy (SMA) Ni-Ti films have attracted much interest as functional and smart materials due to their unique properties. However, there are still important issues unresolved like formation of film texture and its control as well as substrate effects. Thus, the main challenge is not only the control of the microstructure, including stoichiometry and precipitates, but also the identification and control of the preferential orientation since it is a crucial factor in determining the shape memory behaviour. The aim of this PhD thesis is to study the optimisation of the deposition conditions of films of Ni-Ti in order to obtain the material fully crystallized at the end of the deposition, and to establish a clear relationship between the substrates and texture development. In order to achieve this objective, a two-magnetron sputter deposition chamber has been used allowing to heat and to apply a bias voltage to the substrate. It can be mounted into the six-circle diffractometer of the Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility (ESRF), Grenoble, France, enabling an in-situ characterization by X-ray diffraction(XRD) of the films during their growth and annealing. The in-situ studies enable us to identify the different steps of the structural evolution during deposition with a set of parameters as well as to evaluate the effect of changing parameters on the structural characteristics of the deposited film. Besides the in-situ studies, other complementary ex-situ characterization techniques such as XRD at a laboratory source, Rutherford backscattering spectroscopy(RBS), Auger electron spectroscopy (AES), cross-sectional transmission electron microscopy (X-TEM), scanning electron microscopy (SEM), and electrical resistivity (ER) measurements during temperature cycling have been used for a fine structural characterization. In this study, mainly naturally and thermally oxidized Si(100) substrates, TiN buffer layers with different thicknesses (i.e. the TiN topmost layer crystallographic orientation is thickness dependent) and MgO(100) single crystals were used as substrates. The chosen experimental procedure led to a controlled composition and preferential orientation of the films. The type of substrate plays an important role for the texture of the sputtered Ni-Ti films and according to the ER results, the distinct crystallographic orientations of the Ni-Ti films influence their phase transformation characteristics.

Electrodeposition and characterization of nikel-copper metallic foams for application as electrodes for supercapacitors

Nickel-copper metallic foams were electrodeposited from an acidic electrolyte, using hydrogen bubble evolution as a dynamic template. Their morphology and chemical composition was studied by scanning electron microscopy and related to the deposition parameters (applied current density and deposition time). For high currents densities (above 1 A cm(-2)) the nickel-copper deposits have a three-dimensional foam-like morphology with randomly distributed nearly-circular pores whose walls present an open dendritic structure. The nickel-copper foams are crystalline and composed of pure nickel and a copper-rich phase containing nickel in solid solution. The electrochemical behaviour of the material was studied by cyclic voltammetry and chronopotentiometry (charge-discharge curves) aiming at its application as a positive electrode for supercapacitors. Cyclic voltammograms showed that the Ni-Cu foams have a pseudocapacitive behaviour. The specific capacitance was calculated from charge-discharge data and the best value (105 F g(-1) at 1 mA cm(-2)) was obtained for nickel-copper foams deposited at 1.8 A cm(-2) for 180 s. Cycling stability of these foams was also assessed and they present a 90 % capacitance retention after 10,000 cycles at 10 mA cm(-2).

Chimpanzees Share Forbidden Fruit

PLoS ONE - www.plosone.org, V.9, e886

Rede de mobilidade sustent��vel de Beja: viabilidade de implementa����o de um sistema de bicicletas el��tricas

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil

"Lazarillo de Tormes": melhoria da mobilidade em Salamanca

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil na ��rea de Especializa����o de Vias de Comunica����o e Transportes

Magnetic flux density distribution in the air gap of a ferromagnetic core with superconducting blocks: three-dimensional analysis and experimental NMR results

The design of magnetic cores can be carried out by taking into account the optimization of different parameters in accordance with the application requirements. Considering the specifications of the fast field cycling nuclear magnetic resonance (FFC-NMR) technique, the magnetic flux density distribution, at the sample insertion volume, is one of the core parameters that needs to be evaluated. Recently, it has been shown that the FFC-NMR magnets can be built on the basis of solenoid coils with ferromagnetic cores. Since this type of apparatus requires magnets with high magnetic flux density uniformity, a new type of magnet using a ferromagnetic core, copper coils, and superconducting blocks was designed with improved magnetic flux density distribution. In this paper, the designing aspects of the magnet are described and discussed with emphasis on the improvement of the magnetic flux density homogeneity (Delta B/B-0) in the air gap. The magnetic flux density distribution is analyzed based on 3-D simulations and NMR experimental results.

Mobile cockpit system for enhanced electric bicycle use

This paper presents the project of a mobile cockpit system (MCS) for smartphones, which provides assistance to electric bicycle (EB) cyclists in smart cities' environment. The presented system introduces a mobile application (MCS App) with the goal to provide useful personalized information to the cyclist related to the EB's use, including EB range prediction considering the intended path, management of the cycling effort performed by the cyclist, handling of the battery charging process, and the provisioning of information regarding available public transport. This work also introduces the EB cyclist profile concept, which is based on historical data analysis previously stored in a database and collected from mobile devices' sensors. From the tests performed, the results show the importance of route guidance, taking into account the energy savings. The results also show significant changes on range prediction based on user and route taken. It is important to say that the proposed system can be used for all bicycles in general.

Characterisation and electrochemical behaviour of electrodeposited Cu-Fe foams applied as pseudocapacitor electrodes

Copper iron (Cu-Fe) 3D porous foams for supercapacitor electrodes were electrodeposited in the cathodic regime, on stainless steel current collectors, using hydrogen bubbling dynamic template. The foams were prepared at different current densities and deposition times. The foams were submitted to thermal conditioning at temperatures of 150 and 250 degrees C. The morphology, composition and structure of the formed films were studied by SEM, EDS and XRD, respectively. The electrochemical behaviour was studied by cyclic voltammetry, electrochemical impedance spectroscopy and chronopotentiometry. The morphology of the 3D Cu-Fe foams is sensitive to the electrodeposition current and time. The increase of the current density produces a denser, larger and more ramified dendritic structure. Thermal conditioning at high temperature induces a coarser grain structure and the formation of copper oxides, which affect the electrochemical behaviour. The electrochemical response reveals the presence of various redox peaks assigned to the oxidation and reduction of Cu and Fe oxides and hydroxides in the foams. The specific capacitance of the 3D Cu Fe foams was significantly enhanced by thermal conditioning at 150 degrees C. The highest specific capacitance values attained 297 Fg(-1) which are much above the ones typically observed for single Cu or Fe Oxides and hydroxides. These values highlight a synergistic behaviour resulting from the combination of Cu and Fe in the form of nanostructured metallic foams. Moreover, the capacitance retention observed in an 8000 charge/discharge cycling test was above 66%, stating the good performance of these materials and its enhanced electrochemical response as supercapacitor negative electrodes. (C) 2014 Elsevier B.V. All rights reserved.

Electrochemical response of 70Co-30Ni highly branched 3D-dendritic structures for charge storage electrodes

A 70Co-30Ni dendritic alloy was produced on stainless steel by pulse electrodeposition in the cathodic domain, and oxidized by potential cycling. X-ray diffraction (XRD) identified the presence of two phases and scanning electron microscopy (SEM) evidenced an open 3D highly branched dendritic morphology. After potential cycling in 1 M KOH, SEM and X-ray photoelectron spectroscopy (XPS) revealed, respectively, the presence of thin nanoplates, composed of Co and Ni oxi-hydroxides and hydroxides over the original dendritic film. Cyclic voltammetry tests showd the presence of redox peaks assigned to the oxidation and reduction of Ni and Co centres in the surface film. Charge/discharge measurements revealed capacity values of 121 mAh g(1) at 1 mA cm(2). The capacity retention under 8000 cycles was above 70%, stating the good reversibility of these redox materials and its suitability to be used as charge storage electrodes. Electrochemical impedance spectroscopy (EIS) spectra, taken under different applied bias, showed that the capacitance increased when the electrode was fully oxidized and decreased when the electrode was reduced, reflecting different states-of-charge of the electrode. (C) 2015 Elsevier Ltd. All rights reserved.

Metal ions and protein folding: conformational and functional interplay

Dissertation presented to obtain a PhD degree in Biochemistry at Instituto de Tecnologia Qu��mica e Biol��gica, Universidade Nova de Lisboa

Metal ions modulate the folding and stability of the tumor suppressor protein S100A2

Febs Journal (2009)276:1776-1786