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Di Bella G.,CNR Institute of Advanced Energy Technologies Nicola Giordano | Borsellino C.,Messina University | Calabrese L.,Messina University
Materials and Design

In recent years sandwich structures have been widely used in marine industry; such reason has lead to the study of mechanical properties of the above mentioned structures through the evaluation of the effects induced by different technological procedures. Therefore, this work presents unsymmetrical sandwich structures realised using both lay up and vacuum bag technology. In order to find a static characterisation of the sandwich structure, firstly flatwise and edgewise compressive tests were performed. Afterwards, a three point flexural test was realised in order to examine the different effects of a load, which has been applied to either one or the other side of an unsymmetrical sandwich structure.Thanks to the above mentioned tests, it has been possible to find out and interpret a number of fracture mechanisms that take place when the load conditions change and/or when the technological procedure used to produce the samples varies. Moreover, a theoretical model capable of predicting the stresses inside the sandwich sample is proposed. © 2011 Elsevier Ltd. Source

Fiore V.,University of Palermo | Valenza A.,University of Palermo | Di Bella G.,CNR Institute of Advanced Energy Technologies Nicola Giordano
Composites Science and Technology

The aim of this paper is to examine the use of artichoke fibres as potential reinforcement in polymer composites. The fibres are extracted from the stem of artichoke plant, which grows in Southern Sicily. In order to use these lignocellulosic fibres as potential reinforcement in polymer composites, it is fundamental to investigate their microstructure, chemical composition and mechanical properties. Therefore, the morphology of artichoke fibres was investigated through electron microscopy, the thermal behaviour through thermogravimetric analysis and the real density through a helium pycnometer. The chemical composition of the natural fibres in terms of cellulose, lignin, and ash contents was determinated by using standard test methods. Finally, the mechanical characterization was carried out through single fibre tensile tests, analysing the results through statistical analysis. © 2011 Elsevier Ltd. Source

Lufrano F.,CNR Institute of Advanced Energy Technologies Nicola Giordano | Staiti P.,CNR Institute of Advanced Energy Technologies Nicola Giordano
International Journal of Electrochemical Science

In this paper, we report the synthesis and characterization of mesoporous carbons, which were obtained using SBA-15 silica as the template material and sucrose as the carbon source. The prepared silica template and mesoporous carbons were characterized by nitrogen adsorption-desorption, low angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). Synthesized carbons were used to prepare composite electrodes for solid-state supercapacitors. The electrochemical characteristics of mesoporous carbons in supercapacitors were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The study showed that a value of specific capacitance of 132 F g-1 (for a single electrode) was obtained with the CMK-3A mesoporous carbon, which was 68% higher than that of an activated carbon that was used as a reference material. The superior performance was 127% (12.05 μF cm-2 vs. 5.3 μF cm-2) when the double-layer capacitance of the mesoporous carbon was compared to that of the reference carbon. These findings for the mesoporous carbon-based supercapacitor were explained on the basis of a high pseudo-capacitance and other physico-chemical properties of this carbon, such as the pore structure, accessibility of pores to the electrolyte, and surface wettability by surface functional groups. All of these properties were improved compared to those of the activated carbon. © 2010 by ESG. Source

Montanini R.,Messina University | Squadrito G.,CNR Institute of Advanced Energy Technologies Nicola Giordano | Giacoppo G.,CNR Institute of Advanced Energy Technologies Nicola Giordano
Journal of Power Sources

A combined method for the simultaneous measurement of the clamping pressure distribution and endplates deformation in polymer electrolyte fuel cells (PEFC) is presented. The proposed approach, which allows overcoming some important limitations associated with the use of conventional pre-scaled pressure films, is used to investigate the correlation between the actual pressure distribution on the membrane electrode assembly (MEA), the endplate out-of-plane deformation and the applied clamping torque, for two single fuel cells assembled with either copper or aluminium/copper endplates. Results proved that, in point-load design PEFCs, both pressure magnitude and distribution are affected by endplates deformation and thickness mismatching between the sealing gasket and the MEA. Moreover, while the average pressure on the MEA displays a slight increase (+25%) as the clamping torque is raised from 5 to 10 N m, it increases monotonically on the sealing gasket, with local peaks that exceed the saturation level of the sensor array (20.7 MPa). A dimensionless uniformity index has been introduced to assess the uniformity of the pressure distribution, allowing an easy comparison of different fuel cell assembly configurations. The proposed methodology might assist the design of next-generation fuel cells or could be used as a powerful validation tool for detailed finite element models. It can also be applied to study other kind of fuel cells and batteries as well. © 2011 Elsevier B.V. All rights reserved. Source

Maggio G.,CNR Institute of Advanced Energy Technologies Nicola Giordano | Cacciola G.,CNR Institute of Advanced Energy Technologies Nicola Giordano

In this paper, a predictive model based on a variant of the multi-cyclic Hubbert approach is applied to forecast future trend in world fossil fuel production. Starting from historical data on oil (crude and NGL), natural gas, and coal production, and taking into consideration three possible scenarios for the global Ultimate (i.e. cumulative production plus remaining reserves plus undiscovered resources), this approach allowed us to determine when these important energy sources should peak and start to decline. In particular, considering the most likely scenarios, our estimated peak values were: 30 Gb/year in 2015 for oil, 132 Tcf/year in 2035 for natural gas, and 4.5 Gtoe/year in 2052 for coal. A plateau is likely to occur in the case of natural gas, if the global Ultimate is high. A comparison of the Multi-Hubbert Variant (MHV) approach used in this paper with both the Single-cycle Hubbert (SH) and the "original" Multi-cyclic Hubbert (MH) approach has also been done. © 2012 Elsevier Ltd. All rights reserved. Source

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