A Model of ICDT Internet flows on mobile devices for the travel and tourism consumer

Despite the increasing use of mobile devices and their applications in the travel and tourism arena, there is a lack of literature that considers how mobile device tourism applications could be evaluated. Built around a discussion of information attributes (a series of dimensions by which the delivery of information can be assessed) that have been specifically developed for the tourism sector and an examination of the specific characteristics of mobile devices, this theoretical article classifies different online tourism applications that can be accessed by mobile devices according to Angehrn's four virtual spaces (information, communication, distribution, and transaction). This is for the purpose of demonstrating that the majority of applications in the mobile tourism arena eventually fall within the realm of information provision and can thus be assessed according to how they perform in relation to information attributes. A model of ICDT Internet flows on mobile devices for the travel and tourism consumer is presented

Mixed-mode delamination growth prediction in stiffened CFRP panels by means of a novel fast procedure

Carbon fiber reinforced plastic (CFRP) structures are highly sensitive to delaminations, resulting from low energy impacts or manufacturing defects. Non-linear numerical algorithms are mandatory to investigate the complex mechanisms governing the delamination growth phenomena. Although the high computational costs associated to the non-linear algorithms are acceptable in a detail verification design stage, less expensive procedures are desired in a preliminary design stage or during optimization procedure. In this work, a fast numerical procedure, able to determine the delamination growth initiation in composite structures in the framework of a damage tolerant design approach when mixed mode I and II growth is expected, is introduced. The state of the art of the fast delamination growth procedures is critically discussed and improvements to the existing approaches are proposed to extend their applicability and to increase their accuracy. Comparisons with the standard non-linear delamination growth approaches are presented to assess the effectiveness of the proposed novel Fast approach. The results of the proposed fast approach are comparable with the ones obtained by means of standard numerical non-linear technique, allowing up to 95% computational cost saving

Cross-influence between intra-laminar damages and fibre bridging at the skin-stringer interface in stiffened composite panels under compression

In this paper, the skin-stringer separation phenomenon that occurs in stiffened composite panels under compression is numerically studied. Since the mode I fracture toughness and, consequently, the skin-stringer separation can be influenced by the fibre bridging phenomenon at the skin-stringer interface, in this study, comparisons among three different material systems with different fibre bridging sensitivities have been carried out. Indeed, a reference material system has been compared, in terms of toughness performance, against two materials with different degrees of sensitivity to fibre bridging. A robust numerical procedure for the delamination assessment has been used to mimic the skin-stringer separation. When analysing the global compressive behaviour of the stiffened panel, intra-laminar damages have been considered in conjunction with skin-stringer debonding to evaluate the effect of the fibre and matrix breakage on the separation between the skin and the stringer for the three analysed material systems. The latter are characterised by different toughness characteristics and fibre bridging sensitivities, resulting in a different material toughness

Kob-Andersen model: a non-standard mechanism for the glassy transition

We present new results reflecting the analogies between the Kob-Andersen model and other glassy systems. Studying the stability of the blocked configurations above and below the transition we also give arguments that supports their relevance for the glassy behaviour of the model. However we find, surprisingly, that the organization of the phase space of the system is different from the well known organization of other mean-field spin glasses and structural glasses.Comment: New reference added and one update

Reply to Comment on " Universal Fluctuations in Correlated Systems"

Reply to the comment, cond-mat/0209398 by by N.W. Watkins, S.C. Chapman, and G. RowlandsComment: To appear In Physical Review Letter

Application of an additive manufactured hybrid metal/composite shock absorber panel to a military seat ejection system

In this work, a preliminary numerical assessment on the application of an additive manufactured hybrid metal/composite shock absorber panels to a military seat ejection system, has been carried out. The innovative character of the shock absorber concept investigated is that the absorbing system has a thickness of only 6 mm and is composed of a pyramid‐shaped lattice core that, due to its small size, can only be achieved by additive manufacturing. The mechanical behaviour of these shock absorber panels has been examined by measuring their ability to absorb and dissipate the energy generated during the ejection phase into plastic deformations, thus reducing the loads acting on pilots. In this paper the effectiveness of a system composed of five hybrid shock absorbers, with very thin thickness in order to be easily integrated between the seat and the aircraft floor, has been numerically studied by assessing their ability to absorb the energy generated during the primary ejection phase. To accomplish this, a numerical simulation of the explosion has been performed and the energy absorbed by the shock‐absorbing mechanism has been assessed. The performed analysis demonstrated that the panels can absorb more than 60% of the energy generated during the explosion event while increasing the total mass of the pilot‐seat system by just 0.8%

Two time scales and FDT violation in a Finite Dimensional Model for Structural Glasses

We study the breakdown of fluctuation-dissipation relations between time dependent density-density correlations and associated responses following a quench in chemical potential in the Frustrated Ising Lattice Gas. The corresponding slow dynamics is characterized by two well separated time scales which are characterized by a constant value of the fluctuation-dissipation ratio. This result is particularly relevant taking into account that activated processes dominate the long time dynamics of the system.Comment: 4 pages, 3 figs, Phys. Rev. Lett. (in press

Facilitated spin models on Bethe lattice: bootstrap percolation, mode-coupling transition and glassy dynamics

We show that facilitated spin models of cooperative dynamics introduced by Fredrickson and Andersen display on Bethe lattices a glassy behaviour similar to the one predicted by the mode-coupling theory of supercooled liquids and the dynamical theory of mean-field disordered systems. At low temperature such cooperative models show a two-step relaxation and their equilibration time diverges at a finite temperature according to a power-law. The geometric nature of the dynamical arrest corresponds to a bootstrap percolation process which leads to a phase space organization similar to the one of mean-field disordered systems. The relaxation dynamics after a subcritical quench exhibits aging and converges asymptotically to the threshold states that appear at the bootstrap percolation transition.Comment: 7 pages, 6 figures, minor changes, final version to appear in Europhys. Let

A sensitivity analysis of the damage behavior of a leading-edge subject to bird strike

This paper aims to investigate the crashworthiness capability of a commercial aircraft metallic sandwich leading edge, subjected to bird strike events. A sensitivity analysis is presented, aimed to assess the influence of the skin parameters (inner and outer faces and core thicknesses) on the leading-edge crashworthiness and to determine, among the configurations able to withstand a bird strike event, the best compromise in terms of weight and structural performances. In order to easily manage the design parameters and the output data, the ModeFrontier code was used in conjunction with the FE code Abaqus/Explicit. A dedicated python routine was developed to define a fully parametric simplified leading-edge model. To fulfill the aerodynamic requirements, the external surfaces were considered fixed during the sensitivity analysis, and, thus, only the internal leading edge’s components were modified to study their influence on the structural response. The total mass of the model, the maximum deformation and the energy dissipated due to material failure and the plastic deformations were monitored and used to compare and assess the behavior of each configuration