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Piezoelectric co-axial filaments produced by co-extrusion of poly(vinylidene fl...

Documento submetido para revisão pelos pares. A publicar em "Journal of applied polymer science". ISSN 1097-4628. Article first published online: 3 APR 2014 : http://onlinelibrary.wiley.com/doi/10.1002/app.40710/abstract. DOI 10.1002/app.40710. ; The development of new thermoplastic polymer-based piezoelectric sensors with filament geometry is described. These filaments are appropriate for integration into tex...

Three layer polymer piezoelectric filaments produced by extrusion

Poly(vinylidene fluoride) (PVDF) is extensively studied due to its piezo-, pyro- and ferroelectric properties. These properties enable the use of this polymer in a number of applications either as sensor or actuator. PVDF is a semi-crystalline polymer and can crystallize in four different crystalline phases, called α, β, γ and δ. The β-phase presents the most interesting electroactive activity. These properties...

Properties and processing by extrusion of electrically conductive multilayer fi...

This work describes the production and characterization of three-layer piezoelectric filaments using two different electrically conductive polymers. The filaments were produced in a filament extrusion line, equipped with a coextrusion die that enabled a coaxial arrangement for a three-layer filament. For the inner and outer layers two different electrically conductive compounds were used, and the middle layer w...

Adenoma ectópico das paratiróides, um achado na radiografia do tórax!

Role of central obesity in risk stratification after an acute coronary event: D...

BACKGROUND: Accurate risk stratification is an important step in the initial management of acute coronary syndrome (ACS), and current guidelines recommend the use of risk scores, such as the Global Registry of Acute Coronary Events risk score (GRACE RS). Recent studies have suggested that abdominal obesity is associated with cardiovascular events in patients with ACS. However, little is known about the addition...

Development and Optimization of an Online SPE-HPLC-FD Method for Quantification...

Fluoroquinolones are antimicrobial agents widely found in environmental matrices and extensively studied due to their persistence and implications for multiresistant bacteria. The presence of fluoroquinolones in the environment is mainly due to the incapability of wastewater treatment plants (WWTPs) to completely remove those compounds. The amount of fluoroquinolones released through effluents depends on the ty...

Drilling delamination outcomes on glass and sisal reinforced plastics

Nowadays, fibre reinforced plastics are used in a wide variety of applications. Apart from the most known reinforcement fibres, like glass or carbon, natural fibres can be seen as an economical alternative. However, some mistrust is yet limiting the use of such materials, being one of the main reasons the inconsistency normally found in their mechanical properties. It should be noticed that these materials are ...

Damage evaluation of drilled carbon/epoxy laminates based on area assessment me...

The characteristics of carbon fibre reinforced laminates had widened their use, from aerospace to domestic appliances. A common characteristic is the need of drilling for assembly purposes. It is known that a drilling process that reduces the drill thrust force can decrease the risk of delamination. In this work, delamination assessment methods based on radiographic data are compared and correlated with mechani...

Dano na furação de placas carbono/epóxido

A produção de peças estruturais em materiais compósitos, nomeadamente os de matriz epóxida reforçada com fibras de carbono, tem-se tornado cada vez mais importante face à combinação das suas características específicas, como elevada rigidez e o baixo peso. Embora por um lado o custo destes materiais tenha vindo a tornar-se numa barreira cada vez menor para a sua utilização, a necessidade de operações de acabame...

Acoustics of Modern and Old Museums

The goal of this study is to acoustically characterize typical modern and old museums. Modern museums can easily have a bad acoustic behavior due to the widespread use of very smooth and reflective coatings, hard floors, high-ceilings and very expressive volumes. This situation is not usually seen in "old" museums. Acoustic analyses of two case-studies (the 1999 Contemporary Art Museum of Serralves and the Nati...