Finite size effects in perturbed boundary conformal field theories

We discuss the finite-size properties of a simple integrable quantum field theory in 1+1 dimensions with non-trivial boundary conditions. Novel off-critical identities between cylinder partition functions of models with differing boundary conditions are derived.Comment: 7 pages, 11 figures, JHEP proceedings style. Uses epsfig, amssymb. Talk given at the conference `Nonperturbative Quantum Effects 2000', Pari

Perturbed Defects and T-Systems in Conformal Field Theory

Defect lines in conformal field theory can be perturbed by chiral defect fields. If the unperturbed defects satisfy su(2)-type fusion rules, the operators associated to the perturbed defects are shown to obey functional relations known from the study of integrable models as T-systems. The procedure is illustrated for Virasoro minimal models and for Liouville theory.Comment: 24 pages, 13 figures; v2: typos corrected, in particular in (2.10) and app. A.2, version to appear in J.Phys.

Plastification of PLA: Is the interaction parameter a significant factor?

International audienc

Plastification of PLA: Is the interaction parameter a significant factor?

International audienc

Effect of Reprocessing Cycles on the Morphology and Properties of Polypropylene/Wood Flour Composites Compatibilized with EBAGMA Terpolymer

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Tensile behaviour of biopolymers reinforced by randomly scattered flax fibre

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Tensile behaviour of biopolymers reinforced by randomly scattered flax fibre

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Crossed investigation of damage in composites with embedded quantum resistive strain sensors (sQRS), acoustic emission (AE) and digital image correlation (DIC)

International audienceIn a previous paper, we had evidenced that the memory effect of the resistance of embedded quantum resistive strain sensors (sQRS) could be used to quantitatively assess the damage accumulation in glass fibre reinforced polymers (GFRP). In this work, to comfort this finding and to better understand the mechanisms making sQRS able to monitor the composite's damage, three techniques have been combined to look for correlations during incremental cyclic tensile tests. Experiments were performed on composite samples of different typologies, all instrumented with sQRS in their core. The strain profile measured in the vicinity of defects such as a hole or a notch by digital image correlation (DIC), has been used to determine the strain profile to which the percolated carbon nanotube network based resistive sensors (sQRS) were exposed. Further on, acoustic emission (AE) counts were used to identify the strain level over which damages were recorded to interpret the events detected on the piezo-resistive trace of sQRS, i.e., matrix fracture, interface decohesion, fibres breakage. It is found that sQRS, through the variation of their apparent gauge factor GF, are able to detect strain concentration in their surroundings and to identify damage events in the composite, provided that the fracture behaviour has been previously analysed by AE. Finally, sQRS can keep the memory of the damage accumulated in the composite as their initial resistance shift monitors the non-reversible events associated to damage. Their implementation in composite structures should offer interesting prospects to secure their use by helping to locate stress/strain singularities and potentially anticipate the complete failure. (C) 2018 Elsevier Ltd. All rights reserved