Encontrados 53 documentos, a visualizar página 1 de 6
Piezoelectric co-axial filaments produced by co-extrusion of poly(vinylidene fl...
Martins, R. S.; Gonçalves, Renato Ferreira; Rocha, J. G.; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.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...
Processing and electrical response of fully polymer piezoelectric filaments for...
Martins, R. S.; Silva, Marco Aur??lio Pinto; Gon??alves, Renato Ferreira; Rocha, J. G.; N??brega, J. M.; Carvalho, Helder; Souto, A. PedroThis paper describes the production and characterization of novel geometries for piezoelectric products with a large potential in the design and implementation of flexible sensors produced at low cost and high rates. In particular, the filament geometry, appropriate for integration into textiles, is analyzed. Piezoelectric filaments producing electrical signals under bending or traction stress, thus acting as m...
Three layer polymer piezoelectric filaments produced by extrusion
Martins, R. S.; Gonçalves, Renato Ferreira; Azevedo, Tiago; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.; Rocha, J. G.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...
Martins, R. S.; Gonçalves, Renato Ferreira; Azevedo, Tiago; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.; Rocha, J. G.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...
Optimization of piezoelectric ultrasound emitter transducers for underwater com...
Martins, Marcos da Silva; Correia, Vítor; Cabral, José; Lanceros-Méndez, S.; Rocha, J. G.Ultrasound transducers are typically based on piezoelectric materials, due to their good response at high frequencies. Depending on the application, ceramics, polymers and composite materials can be used. In this work, an optimization study of ultrasound transducers for underwater communications is addressed, focusing on a piston type emitter transducer operating in thickness mode (d33). The piston is constitut...
As brandas de gado das Serras da Peneda e do Soajo (NW de Portugal)
Silva, M. A.; Silva, F. A.; Alves, M. I. Caetano; Rocha, J. G.Neste estudo são analisadas as brandas de gado do complexo montanhoso das Serras da Peneda e Soajo, situadas acima de 900 metros de altitude e com bom acesso, circunscritas ao Parque Nacional da Peneda-Gerês. Os resultados obtidos por análise geomorfológica e espacial, indicam que o local de edificação das brandas seguiu critérios comuns: todas têm disponibilidade de água, de pastagem espontânea, de proteção e ...
Influence of processing conditions on the b-Phase content of PVDF samples produ...
Martins, R. S.; Carneiro, O. S.; Lanceros-Méndez, S.; Nóbrega, J. M.; Carvalho, Helder; Rocha, J. G.; Silva, M. P.This research team has been working during the last couple of years on the development of industrial scalable technologies, based on the extrusion processing technique, for the prodution of piezoeletric products. This specific work comprises a study on the effect of tape extrusion processing conditions on the content of PVDF β-phase. For this purpose the extruded samples were uniaxially stretched up to ratios o...
Processing and electrical response of fully polymer piezoelectric filaments for...
Martins, R. S.; Silva, Marco Aurélio Pinto; Gonçalves, Renato Ferreira; Rocha, J. G.; Nóbrega, J. M.; Carvalho, Helder; Souto, A. PedroThis paper describes the production and characterization of novel geometries piezoelectric products with a large potential in the design and implementation of flexible sensors produced at low cost and high rates. In particular, filament shaped geometry, appropriate for integration into textiles, is developed and described.
Production of polymer filament-shaped piezoelectric sensors for e-textiles appl...
Carvalho, Helder; Martins, R. S.; Gonçalves, Renato Ferreira; Rocha, J. G.; Nóbrega, J. M.; Lanceros-Méndez, S.This work aims at the development of piezoelectric materials for flexible sensors produced with various geometries, at low cost and high production rates, adequate for the industrial scale. In particular the filament form, appropriate for integration into textiles, is described, but other geometries, such as tape, are also being studied. The filaments are produced by co-extrusion of multiple layers with piezoel...
Piezoelectric filaments produced by coextrusion
Martins, R. S.; Gonçalves, Renato Ferreira; Rocha, J. G.; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.Considering the significant interest of both the academic and industrial communities in the fields of i/e-textiles (interactive/electronic textiles), the number of developed applications is far below the expected. This fact is mainly related to the difficulties on the development of production methodologies adequate to industrial scale processes. In this areas the integration of piezoelectric materials, that po...
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