The coexistence of commodity money and fiat money

In reaction to the monetary turmoil created by the financial crisis of September 2008, both legislative and constitutional reforms have been proposed in different Countries to introduce Commodity Money longside existing National Fiat Currency. A thorough evaluation of the Economic consequences of these new proposals is warranted. This paper surveys some of the existing knowledge in Monetary and Financial Economics for the purpose of answering the significant Economic questions raised by these new political initiatives.Currency competition, commodity money, fiat money, gold, safe haven, search models

Singular inextensible limit in the vibrations of post-buckled rods: Analytical derivation and role of boundary conditions

In-plane vibrations of an elastic rod clamped at both extremities are studied. The rod is modeled as an extensible planar Kirchhoff elastic rod under large displacements and rotations. Equilibrium configurations and vibrations around these configurations are computed analytically in the incipient post-buckling regime. Of particular interest is the variation of the first mode frequency as the load is increased through the buckling threshold. The loading type is found to have a crucial importance as the first mode frequency is shown to behave singularly in the zero thickness limit in the case of prescribed axial displacement, whereas a regular behavior is found in the case of prescribed axial load.This publication is based in part upon work supported by Award no. KUK-C1-013-04, made by King Abdullah University of Science and Technology (KAUST) (A.G.). A.G. is a Wolfson/Royal Society Merit Award holder. Support from the Royal Society, through the International Exchanges Scheme (Grant IE120203), is also acknowledge

Influence of Process and Material Parameters on Impact Response in Composite Structure: Methodology Using Design of Experiments

Even if the mechanical performances of composite materials give new perspectives for the aircraft and space design, the variability of their behavior, linked to the presence of initial microscopic defects or led in service, constitute however a still important brake in their development. As regards particularly the response to fatigue loads or ageing, the behavior of these materials is affected by several sources of uncertainties, notably on the nature of the physical mechanisms of degradation, which are translated by a strong dispersion in life time. In aerospace industry, low energy impact phenomenon is not well known concerning composite materials and composite structures. Many manufacturers use important safety factors to design structures. The aim of this work is to define the most predominant parameters which permit a good response of damage using experiences plans. The differences of these parameters by using Resin Transfer Molding (RTM) or Liquid Resin Infusion (LRI) process than prepreg one is also studied in this work

Influence and optimization of the electrodes position in a piezoelectric energy harvesting flag

Fluttering piezoelectric plates may harvest energy from a fluid flow by converting the plate's mechanical deformation into electric energy in an output circuit. This work focuses on the influence of the arrangement of the piezoelectric electrodes along the plate's surface on the energy harvesting efficiency of the system, using a combination of experiments and numerical simulations. A weakly non-linear model of a plate in axial flow, equipped with a discrete number of piezoelectric patches is derived and confronted to experimental results. Numerical simulations are then used to optimize the position and dimensions of the piezoelectric electrodes. These optimal configurations can be understood physically in the limit of small and large electromechanical coupling.Comment: To appear in Journal of Sound and Vibratio

Evaluation of the Risks of Collective Dominance in the Audit Industry in France

The financial crisis drew attention to the crucial role of transparency and the independence of financial certification intermediaries, in particular, statutory auditors. Now any anticompetitive practice involving coordinated increases in prices or concomitant changes in quality that impacts financial information affects the effectiveness of this intermediation. It is therefore not surprising that the competitive analysis of the audit market is a critical factor in regulating financial systems, all the more so as this market is marked by various barriers to entry, such as the incompatibility of certification tasks with the preparation of financial statements or consulting, the expertise on (and the ability to apply) international standards for the presentation of financial information, the need to attract top young graduates, the prohibition of advertising, or the two-sided nature of this market where the quality of financial information results from the interaction between the reputation of auditors and audited firms. Against this backdrop, we propose a legal and economic study of the risks of collective dominance in the statutory audit market in France using the criteria set by Airtours case and, in particular, by analyzing how regulatory obligations incumbent on statutory auditors may favour the appearance of tacit collusion. Our analysis suggests that nothing prevents collective dominance of the auditors of the Big Four group in France to exist, which is potentially detrimental to the economy as a whole as the audit industry may fail to provide the optimal level of financial information.Collective dominance ; Airtours criteria; Audit industry

Identification of damaged zone in composite materials using displacement field measurements

This work presents an identification strategy of local elastic properties of orthotropic carbon-epoxy laminates for aviation industry. Based on global and local stages of study, this methodology uses the Finite Element Model Updating (FEMU) method as identification technique with simulated kinematic fields corresponding to tensile test response. The aim of this paper is to predict the spatial variation of elastic plane properties and to deduce the localization of damaged zones

Cavitation inception in fast startup

The start-up of rocket engine turbopumps is generally performed only in a few seconds. It implies that these pumps reach their nominal operating conditions after only a few rotations. During these first rotations of the blades, the flow evolution in the pump is governed by transient phenomena, based mainly on the flow rate and rotation speed evolution. These phenomena progressively become negligible when the steady behaviour is reached. The pump transient behaviour induces significant pressure fluctuations which may result in partial flow vaporization, i.e. cavitation. An existing experimental test rig has been updated in the LML laboratory (Lille, France) for the start-ups of a centrifugal pump. The study focuses on cavitation induced during the pump start-up. Instantaneous measurement of torque, mass flow rate, inlet and outlet unsteady pressures, and pump rotation velocity enable to characterize the pump behaviour during rapid starting periods

Study of image characteristics on digital image correlation error assessment

In this paper, errors related to digital image correlation (DIC) technique applied to measurements of displacements are estimated. This work is based on the generation of synthetic images representative of real speckle patterns. With these images, various parameters are treated in order to determine their impact on the measurement error. These parameters are related to the type of deformation imposed on the speckle, the speckle itself (encoding of the image, image saturation) or the software (subset size)