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Among the different composite architectures, nanolaminates are emerging as interesting materials for structural and functional applications. Nanolaminate is a biomimetic architecture copying the structure of nacre consisting of the assembly of well-oriented nanoscopically thin laminae held together by a low content of matrix. In this work an aeronautical grade epoxy resin (RTM6) has been chosen as the matrix of the pre-impregnated nanolaminates constituted by the assembly of well-oriented Graphite NanoPlatelets, GNPs. Composition, morphology, tension and bending performance have been investigated for the single ply at two nominal contents of epoxy (20 and 30% wt/wt). [ABSTRACT FROM AUTHOR]

Two types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor delaminated area was detected, even if a higher absorbed energy was recorded [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the ability of two different interferometric NDT techniques to detect and evaluate barely visible impact damage on composite laminates. The interferometric techniques allow to investigate large and complex structures. Electronic Speckle Pattern Interferometry (ESPI) works through real-time surface illumination by visible laser (i.e. 532 nm) and the range and the accuracy are related to the wavelength. While the ESPI works with the "classic" holographic configuration, that is reference beam and object beam, the Shearography uses the object image itself as reference: two object images are overlapped creating a shear image. This makes the method much less sensitive to external vibrations and noise but with one difference, it measures the first derivative of the displacement. In this work, different specimens at different impact energies have been investigated by means of both methods. The delaminated areas have been estimated and compared. [ABSTRACT FROM AUTHOR]

Epoxy/Kevlar composites have been manufactured by conventional Vacuum Infusion process and the Pulse Infusion technique. Pulse Infusion allows to control the pressure of the vacuum bag on the dry fiber reinforcement by using a proper designed pressure distributor that induces a pulsed transverse action and promotes the through thickness resin flow. The realized composite panel have been mechanically characterized by performing tensile and short beam shear tests according with the ASTM D3039 and ASTM D2344/D 2344M standard respectively in order to investigate the effect of Pulse Infusion on the tensile strength and ILSS. [ABSTRACT FROM AUTHOR]

Light nuclides produced in collisions of 1 A GeV 238U with hydrogen have been observed with a high-resolution forward magnetic spectrometer, the fragment separator (FRS), at GSI. Fragments were identified in A and Z and their production cross-sections measured. For each nuclide the velocity was precisely determined from the measured magnetic rigidity. This insight into the kinematics of the relativistic nuclear collisions allowed disentangling different reaction mechanisms. Thanks to the combined results on A, Z, and velocity of the fragments it was found out that all the observed isotopes, from Z=37 down the last element measured (Z=7), were formed in a binary decay process, interpreted as fission. A qualitative analysis of the cross sections revealed that the charge distribution of these light fragments, which forms a plateau around Z=15 and increases below Z=13, is in agreement with the theoretical expectations of the statistical model. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Production cross sections and kinematical properties of the complete set of fission fragment residues from the reaction 238U (1 A.GeV) + p have been obtained. Isotopic distributions are measured for all elements from O (Z = 8) to W (Z = 74). Fission velocities and production cross sections are shown as a function of Z, the charge and N, the number of neutrons of the fragments. The very asymmetric pairs of fragments can be attributed to excited fissioning parent nuclei of charge Z, 88< Z < 92. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The isotopic distributions and recoil velocities of the fission fragments produced in the spallation reaction 208Pb+p at 500 A MeV have been measured using the inverse kinematics technique. The shapes of the different distributions are found in good agreement with previously published data while the deduced total fission cross-section is higher than expected. From the experimental data, the characteristics of the average fissioning system can be reconstructed in charge, mass and excitation energy and the number of post-fission neutrons can be inferred. The results are also compared to different models describing the spallation reaction. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Statistical approaches have been widely used for describing the nuclear-fission process. They were quite successful in explaining several prominent features of the global nuclide distributions and many other aspects, while there are controversial conclusions on the origin of the even-odd effect in the nuclear-charge yields. We analyze the ingredients of the main statistical approaches to the even-odd effect in fission and show up that many of their deficiencies rely on unrealistic assumptions. Finally, we demonstrate that the large body of experimental results, obtained in the recent years to a great part at GSI, Darmstadt, is very successfully reproduced by a new stringent statistical approach. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

It is proposed to use transfer-induced fission in inverse kinematics coupled to the large acceptance spectrometer VAMOS to identify in atomic and mass number the complete distribution of the fission fragments. The measure of the kinetic properties of the transfer partner allows for determining precisely the excitation of the fissioning system. For the first time, the isotopic yields of the heavy and light fragments may be measured as a function of the excitation energy in neutron-rich actinides. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The production of residual nuclei in p + Fe collisions has been measured at GSI on the FRS facility by means of the reverse kinematic techniques at 300, 500, 750, 1000 and 1500 MeV/A. The cross-sections larger than 0.01 mb of all isotopes with Z larger than 8 have been obtained. Velocity distributions were also measured. Comparisons to models describing spallation reactions and some empirical formulae often used in astrophysics are presented. These data are directly used to calculate impurety production and DPAs in a thin window as foreseen in spallation sources or accelerator-driven systems. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]