The Eastward Enlargement of the Eurozone: Trade and FDI

Trade and FDI, Economic Integration

Image transfer through a chaotic channel by intensity correlations

The three-wave mixing processes in a second-order nonlinear medium can be used for imaging protocols, in which an object field is injected into the nonlinear medium together with a reference field and an image field is generated. When the reference field is chaotic, the image field is also chaotic and does not carry any information about the object. We show that a clear image of the object be extracted from the chaotic image field by measuring the spatial intensity correlations between this field and one Fourier component of the reference. We experimentally verify this imaging protocol in the case of frequency downconversion.Comment: 17 pages, 7 figure

The Determinants of Brazilian Pulp exports from 1980 to 2001

This paper makes an econometric analysis of the determinants of Brazil’s pulp exports. The time period from 1980 to 2001 is considered for estimating a supply equation of pulp exports. Exogenous variables considered were: price of Brazilian exported pulp, production cost of Brazilian pulp, productive capacity, exchange rate between dollar and domestic currency and lagged pulp exports. It was observed that Brazil’s pulp exports have responded little to price fluctuation; however, these exports are strongly affected by productive capacity, exchange rate fluctuation and lagged pulp exports. Those results are consistent which the fact that a large share of market-oriented pulp production is headed to foreign markets and that production is sold to these markets partially independent of the current prices that are clearing pulp market. Key words: exports, pulp, econometric model, Brazil

The Viana footbridge: construction and dynamic monitoring

A new moveable footbridge was recently built at the entrance of Marina Atlantico in the city of Viana do Castelo, Portugal. This paper presents a brief description of the global solution, with a special focus on the characterisation of the construction methods adopted. Particular consideration is given to the construction of the pivot pylon and the steel structure, showing how all the bridge components work together to ensure a safe working relationship with the marina, the river and users of the continuous bicycling and pedestrian pathway running across the closed bridge. The mechanical, hydraulic, electrical and navigational light systems play fundamental roles, especially during bridge opening and closing operations. Moreover, as this light footbridge is susceptible to vibrations due to human traffic, the paper also describes the dynamic tests performed during and after construction, including two ambient vibration tests, the measurement of cable-stay forces, and tests with groups of pedestrians used to evaluate induced vibration levels along with the monitoring of bridge accelerations over 4 months of use

Production and Characterization of Electroactive Polymeric Membranes by Electrospinning

In the last decades the development in miniaturization of devices has become a very important topic for the future of technology. Although the miniaturization of devices has been successful in de-creasing the size of devices, the same can not be said about their energy sources. Recent work in the nanomaterials filed has started to show some progress in the towards self-powered energy sources that generate power form the environment that surrounds them. This energy can be scavenged from solar, thermal, mechanical, etc. The advances in this area shows that is possible to generate this environmental energy using nanomaterials with different architectures: nanowires, nanofibers and films. In this work nanofibrous membranes produced by electrospinning were used as nanogenerators. Electrospinning is a low-cost, easy and scalable methods to produce nanofibers. The fibres and mem-branes produced can have different morphologies, thicknesses and are lightweight, therefore being good candidates for miniaturized devices and wearables, etc. The nanofiber membranes were produced with Poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-co-TrFE)), which is a polymeric electroactive material with good piezoelectric and pyroelec-tric properties, and is commonly used has an energy generator. The energy generation is highly associ-ated with the crystalline structure of its β-phase. Three different materials (Carbon Paint, PEDOT:PSS and Aluminium), were used to create the electric contacts of this nanogenerator. The contacts where deposited by electrospinning (PEDOT.PSS), airbrush (Carbon Paint and PEDOT:PSS) and by thermal evaporation (Aluminium). DSC, XRD, FTIR, Pyroelectric Constant, Impedance spectroscopy, Tensile Strength, etc. were used to characterize the behaviour and properties of the materials and device. The electrospinning process did not show any increase in β-phase fraction and the dipoles do-mains orientation. Airbrush deposition of PEDOT:PSS was the only process that produced an electric contact capable of being used on a device. After poling, the device displayed a pyroelectric response, thus showing that the poling process improved the electroactive properties of the polymer

Continuous dynamic monitoring of bridges: different perspectives of application

This paper makes a brief characterisation of some aspects related with the extensive research activity of the Laboratory of Vibrations and Structural Monitoring (ViBest) of the Faculty of Engineering of the University of Porto (FEUP) in the field of Continuous Dynamic Monitoring of Bridges and Special Structures, selecting four examples where large high quality databases have been created since 2007, namely Infante D. Henrique bridge, Pedro e Ines footbride, FEUP Campus stress-ribbon footbridge and Trezoi railway bridge