Napoli, Italy


Napoli, Italy
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Galgano A.,University of Naples Federico II | Di Blasi C.,University of Naples Federico II | Milella E.,IMAST SCarl
Polymer Degradation and Stability | Year: 2010

A sensitivity analysis to assumptions and input variables is carried out for a predictive model previously developed [1] for the fire response of a glass-fibre/polyester panel and a glass-fibre/polyester-Vermiculux sandwich. It is an unsteady, one-dimensional model using the porous medium approximation and a constant gas pressure with two-step, finite rate kinetics for the thermal decomposition and combustion of the polymeric resin, moisture evaporation described by an Arrhenius rate law, heat and mass transfer by convection, heat conduction and radiation described by effective thermal conductivities, variation of the volumetric fractions of the polymeric resin and the moisture with the conversion degree, effective specific heats, external heat transfer resistances and surface ablation. The strongest impact on the model predictions is exerted by the imposed external heat flux with variations on the characteristic process times between 49 and 774%. An important role in sample heating/conversion is also played by surface ablation and/or external heat transfer resistance with variations up to 30-72% or, when ablation is disregarded, with temperatures along the core layer well below those of the degrading skin. These are also significantly affected by surface heat losses, with the assumption of adiabatic bottom surface leading to heterogeneous ignition of the lower skin, and evaporation of moisture with variations in the characteristic times up to 35%. The model for the effective thermal conductivity of the fibre-reinforced skin (the Parallel, the Maxwell-Eucken and the Effective Medium Theory models versus the Series model) is also important resulting in characteristic time variations up to 35%. The absence of local thermal equilibrium between the condensed and the gas/vapour phase and the kinetic details of the polymer reactions are comparatively less important (maximum diminution in the characteristic times of 16%). Moreover, although over-pressures, modelled by the Darcy law, become quite high especially during the moisture evaporation stage (up to ten times the atmospheric value), their effects on the thermal response of the structure are completely negligible when structural changes are not modelled. Finally, a sensitivity analysis is also carried out to input parameters.© 2010 Elsevier Ltd. All rights reserved.

Branca C.,CNR Institute for Research on Combustion | Di Blasi C.,University of Naples Federico II | Galgano A.,CNR Institute for Research on Combustion | Milella E.,IMAST SCarl
Thermochimica Acta | Year: 2011

The oxidation behavior of a composite material (Cycom 977-2/Priform by Cytec), based on a toughened epoxy resin reinforced with carbon fibers, is studied in the kinetic regime and a mixed thermal-diffusive regime. Thermogravimetric measurements for the composite material and the two single components support the existence of three main reaction stages. The first is the oxidative decomposition of the resin taking place at temperatures between 496 and 730 K that can be described by a reaction with an activation energy of 82 kJ/mol. The second and third reaction stages correspond to the oxidation of the resin char, that terminates at about 850 K, and at higher temperatures the oxidation of the carbon fibers, described by global kinetics with activation energies of 105 and 184 kJ/mol, respectively. The thermal history of thick samples burning in a furnace depends on the heating temperature, in nitrogen, and/or the maximum temperature, in air, caused by the reaction exothermicity. After an inert heating stage, when maximum sample heating rates are achieved, the process dynamics again show the existence of three main reaction stages whose characteristic times and temperatures are determined. © 2011 Elsevier B.V. All rights reserved.

Dardano P.,CNR Institute for Microelectronics and Microsystems | Calio A.,CNR Institute for Microelectronics and Microsystems | Calio A.,University of Naples Federico II | Di Palma V.,IMAST Scarl | And 6 more authors.
SAS 2016 - Sensors Applications Symposium, Proceedings | Year: 2016

Microneedles are largely applied in biomedicine, both in diagnostics and therapeutics, since they can be considered the perfect interface between patient and sensing/dispensing devices. In this paper, we present an electro-chemical biosensor based on polymeric microneedles array for the measure of glucose level in interstitial fluids. The microneedles array has been fabricated by photolithography of a polymer, PolyEthylene Glycol DiAcrylate hydrogel, mixed with an enzyme, Glucose oxidase, and a redox mediator, the Vynilferrocene. The microneedles array acts as a working electrode when gold plated by sputtering and their tips have been etched to create a sensitive area. The redox reaction with glucose creates a charge transfer, enhanced by the redox mediator, resulting in a current proportional to the glucose concentration. © 2016 IEEE.

Calio A.,National Research Council Italy | Calio A.,University of Naples Federico II | Dardano P.,National Research Council Italy | Di Palma V.,IMAST Scarl | And 7 more authors.
Sensors and Actuators, B: Chemical | Year: 2016

Polymeric microneedles (MNs) based working electrodes are fabricated by standard photolithography of poly(ethylene glycol) diacrylate (PEGDA) doped by enzyme, redox mediator and photoinitiator. This flexible device acts as working electrode in electrochemical detection of glucose and lactic acid in solution when glucose oxidase (GOx) and lactose oxidase (LOx) enzymes, respectively, are used. Biosensor showed a linear response in the ranges from 0 to 4 mM and from 0 to 1 mM, for glucose and lactic acid, respectively. A limit of detection equal to 1 μM is found. The developed technology has been patented. © 2016 Elsevier B.V. All rights reserved.

Toscano C.,Cira Italian Aerospace Research Center | Lenzi F.,IMAST Scarl
Civil-Comp Proceedings | Year: 2010

In this work, specific viscoelastic materials characterized by different complex modulus have been selected, embedded and co-cured into the graphite/epoxy structure composites in order to study the impact behaviour of the obtained structures. Therefore, an impact test campaign at the same energy has been performed on the embedded panels as well as on simple graphite/epoxy laminates. The effects of the impact have been examined via Non Destructive Testing (NDT) using the Ultrasound Pulse-Echo technique, and by optical microscopy analysis, then the results have been compared. The presented work allows to establish that the impact behaviour of graphite/epoxy laminates could be highly influenced by the presence of damping layers. In particular the damping layers seems to strongly limit the damaged area, effectively reducing the inter-lamina damage propagation. © Civil-Comp Press, 2010.

Volponi R.,Italian Aerospace Research Center | Spena P.,IMAST S.c.a.r.l. | De Nicola F.,Italian Aerospace Research Center | Grilli A.,IMAST S.c.a.r.l.
16th European Conference on Composite Materials, ECCM 2014 | Year: 2014

In this work piezo-resisitive proprieties epoxy resins charged with carbon nanotubes are been verified. An efficient solution to integrate nanocharged matrix into a carbon fiber composites are been developed, achieving a multiscale carbon fiber composite. Finally mechanical and health-monitoring capabilities of multiscale composites are been evaluated.

A composition is described comprising an epoxy resin comprising at least a difunctional epoxy resin and at least a crosslinker for epoxy resin. The difuncional epoxy resin has a viscosity of from 1000 to 5000 mPa.s.For example, the composition comprises a low viscosity diluent for modulating the composition viscosity in an amount not higher than 10% by weight.

Guadagno L.,University of Salerno | Raimondo M.,University of Salerno | Vietri U.,University of Salerno | Barra G.,University of Salerno | And 6 more authors.
AIP Conference Proceedings | Year: 2014

This work describes a successful attempt toward the development of CFRCs based on nanofilled epoxy resins. The epoxy matrix was prepared by mixing a tetrafunctional epoxy precursor with a reactive diluent which allows to reduce the viscosity of the initial epoxy precursor and facilitate the nanofiller dispersion step. As nanofiller, multiwall carbon nanotubes (MWCNTs) were embedded in the epoxy matrix with the aim of improving the electrical properties of the resin used to manufacture CFRCs. Panels were manufactured by Resin Film Infusion (RFI) using a non-usual technique to infuse a nano-filled resin into a carbon fiber dry preform. © 2014 AIP Publishing LLC.

Iannone M.,Alenia Aermacchi | Esposito F.,Alenia Aermacchi | Cammarano A.,IMAST SCaRL
AIP Conference Proceedings | Year: 2014

Blends obtained by mixing high temperature applications thermoplastics have been investigated. Namely the blends considered in this work are made by semi-crystalline thermoplastics PEEK with amorphous PEI. The final goal is to analyse the mechanical, chemical-physical and environmental resistance characteristics of these blends to evaluate their suitability as matrices of carbon reinforced composites for aeronautical structural applications. The first collected results are very promising. © 2014 AIP Publishing LLC.

Imast Scarl | Date: 2014-12-03

A microneedle array device includes a substrate and an array of microneedles on the substrate. Each microneedle includes a redox enzyme and redox mediator and an electrically conductive layer on the substrate. The electrically conductive layer may extend partway up each microneedle exposing the tip thereof.

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