The in-plane linear elastic constants and out-of-plane bending of 3-coordinated ligament and cylinder-ligament honeycombs

Four novel cylinder-ligament honeycombs are described, where each cylinder has 3 tangentially-attached ligaments to form either a hexagonal or re-entrant hexagonal cellular network. The re-entrant cylinder-ligament honeycombs are reported for the first time. The in-plane linear elastic constants and out-of-plane bending response of these honeycombs are predicted using finite element (FE) modelling and comparison made with hexagonal and re-entrant hexagonal honeycombs without cylinders. A laser-crafted re-entrant cylinder-ligament honeycomb is manufactured and characterized to verify the FE model. The re-entrant honeycombs display negative Poisson’s ratios and synclastic curvature upon out-of-plane bending. The hexagonal and ‘trichiral’ honeycombs possess positive Poisson’s ratios and anticlastic curvature. The ‘anti-trichiral’ honeycomb (short ligament limit) displays negative Poisson’s ratios when loaded in the plane of the honeycomb, but positive Poisson’s ratio behaviour (anticlastic curvature) under out-of-plane bending. These responses are understood qualitatively through considering deformation occurs via direct ligament flexure and cylinder rotation-induced ligament flexure.     

Duration modelling and evaluation for Arabic statistical parametric speech synthesis

Multimedia Tools and Applications - Sound duration is responsible for rhythm and speech rate. Furthermore, in some languages phoneme length is an important phonetic and prosodic factor. For...     

New lignocellulosic fibres-reinforced composite materials: A stepforward in the valorisation of the Posidonia oceanica balls

In this work, new lignocellulosic particles obtained from Posidonia oceanica were studied to reinforce a commercial biodegradable thermoplastic matrix. First, these reinforcing fillers were characterised by Fourier-transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopies. Then, they were used to prepare several composite films using BIOPLAST GF 106 matrix. Different P. oceanica fragment loadings, namely 0%, 10%, 20% and 30% (w/w with respect to the matrix) were investigated. The morphology of the ensuing materials was assessed by scanning electron microscopy (SEM), whereas their thermal and mechanical properties were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile tests. The obtained results showed that P. oceanica-based particles enhanced the thermo-mechanical properties of the thermoplastic matrix.     

Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

The Ca–Al-layered double hydroxide, the so-called AFm phase, is a product of cement hydration. It is shown that the interaction of this phase with anionic polycarboxylate ether (PCE)-based dispersant polymers is not a simple adsorption but a more complex intercalation phenomenon leading to the transient sequestration of the PCE within the AFm crystallites. As a result, part of the PCE is immobilized, forming a layered organo-mineral composite, and does not play its role of a dispersing agent. This article presents, along general considerations on the links between cement chemistry and rheology, a detailed investigation of the formation, structure, and stability of a pure poly(methacrylate-g-PEO)/hydrocalumite composite obtained by coprecipitation. The predictions of scaling laws derived from models of conformation of comb copolymers in solution were tested against small-angle X-ray diffraction, transfer of populations by double-resonance nuclear magnetic resonance, and small-angle neutron scattering experimental results. A model of adsorbed polymers in a configuration of a flexible chain of hemispheric cores is proposed and appears to be compatible with the observed interlayer spacings in the range of several nanometers. Finally, these phases are shown to persist for several hours in the presence of sulfate ions.     

Unknown input observer for state affine systems: A necessary and sufficient condition

The problem of designing an unknown input observer for linear systems and its application to fault detection is widely studied in the literature. For nonlinear systems, only subclasses of nonlinear systems and sufficient conditions have been stated. In this paper an unknown input observer design for state affine systems is considered. Based on the geometric approach, a necessary and sufficient condition is given for the existence of an unknown input observer.