Involutivity of the Hamilton-Cartan equations of a second-order Lagrangian admitting a first-order Hamiltonian formalism

Involutivity of the Hamilton-Cartan equations of a second-order Lagrangian admitting a first-order Hamiltonian formalism

Static and Dynamic Experimental Analysis of the Galloping Stability of Porous H-Section Beams

The phenomenon of self-induced vibrations of prismatic beams in a cross-flow has been studied for decades, but it is still of great interest due to their important effects in many different industrial applications. This paper presents the experimental study developed on a prismatic beam with H-section.The aim of this analysis is to add some additional insight into the behaviour of the flow around this type of bodies, in order to reduce galloping and even to avoid it. The influence of some relevant geometrical parameters that define the H-section on the translational galloping behaviour of these beams has been analysed. Wind loads coefficients have been measured through static wind tunnel tests and the Den Hartog criterion applied to elucidate the influence of geometrical parameters on the galloping properties of the bodies under consideration.These results have been completed with surface pressure distribution measurements and, besides, dynamic tests have been also performed to verify the static criterion. Finally, the morphology of the flow past the tested bodies has been visualised by using smoke visualization techniques. Since the rectangular section beam is a limiting case of the H-section configuration, the results here obtained are compared with the ones published in the literature concerning rectangular configurations; the agreement is satisfactory.

Experimental and numerical assessment of the aeroelastic stability of blade pair packages

The stabilizing effect of grouping rotor blades in pairs has been assessed both, numerically and experimentally. The bending and torsion modes of a low aspect ratio high speed turbine cascade tested in the non-rotating test facility at EPFL (Ecole Polytechnique Fédérale de Lausanne) have been chosen as the case study. The controlled vibration of 20 blades in travelling wave form was performed by means of an electromagnetic excitation system, enabling the adjustement of the vibration amplitude and inter blade phase at a given frequency. Unsteady pressure transducers located along the blade mid-section were used to obtain the modulus and phase of the unsteady pressure caused by the airfoil motion. The stabilizing effect of the torsion mode was clearly observed both in the experiments and the simulations, however the effect of grouping the blades in pairs in the minimum damping at the tested frequency was marginal in the bending mode. A numerical tool was validated using the available experimental data and then used to extend the results at lower and more relevant reduced frequencies. It is shown that the stabilizing effect exists for the bending and torsion modes in the frequency range typical of low-pressure turbines. It is concluded that the stabilizing effect of this configuration is due to the shielding effect of the pressure side of the airfoil that defines the passage of the pair on the suction side of the same passage, since the relative motion between both is null. This effect is observed both in the experiments and simulations.

Peptide interfacial adsorption is kinetically limited by the thermodynamic stability of self association

We present a study of the adsorption of two peptides at the octane–water interface. The first peptide, Lac21, exists in mixed monomer–tetramer equilibrium in bulk solution with an appreciable monomer concentration. The second peptide, Lac28, exists as a tetramer in solution, with minimal exposed hydrophobic surface. A kinetic limitation to interfacial adsorption exists for Lac28 at moderate to high surface coverage that is not observed for Lac21. We estimate the potential energy barrier for Lac28 adsorption to be 42 kJ/mol and show that this is comparable to the expected free energy barrier for tetramer dissociation. This finding suggests that, at moderate to high surface coverage, adsorption is kinetically limited by the availability of interfacially active monomeric “domains” in the subinterfacial region. We also show how the commonly used empirical equation for protein adsorption dynamics can be used to estimate the potential energy barrier for adsorption. Such an approach is shown to be consistent with a formal description of diffusion–adsorption, provided a large potential energy barrier exists. This work demonstrates that the dynamics of interfacial adsorption depend on protein thermodynamic stability, and hence structure, in a quantifiable way.

The EU’s Economic Policy Architecture after Ratification of the Fiscal Stability Treaty. CEPS Commentary, 30 August 2013

In his presentation of the new Fiscal Stability Treaty, which came into force in January 2013, Jørgen Mortensen questions the extent to which the new inter-governmental agreement can be expected to solve the fundamental problem of consistency between budgetary and monetary policy.

The Judicial ‘Bail Out’ of the European Stability Mechanism: Comment on the Pringle Case. Research Paper in Law 09/2013

Since the beginning of the crisis, many responses have been taken to stabilise the European markets. Pringle is the awaited judicial response of the European Court of Justice on the creation of the European Stability Mechanism (ESM), a crisis-related intergovernmental international institution which provides financial assistance to Member States in distress in the Eurozone. The judgment adopts a welcome and satisfactory approach on the establishment of the ESM. This article examines the feasibility of the ESM under the Treaty rules and in light of the Pringle judgment. For the first time, the Court was called to appraise the use of the simplified revision procedure under article 48 TEU with the introduction of a new paragraph to article 136 TFEU as well as to interpret the no bail out clause under article 125 TFEU. The final result is rather positive as the Court endorses the establishment of a stability mechanism of the ESM-kind beyond a strict reading of the Treaty rules. Pringle is the first landmark ECJ decision in which the Court has endorsed the use of new and flexible measures to guarantee financial assistance between Member States. This judgment could act as a springboard for more economic, financial and, possibly, political interconnections between Member States.

The Market Stability Reserve in Perspective. CEPS Special Report No. 91, October 2014

This Special Report aims to contribute to the debate on the Market Stability Reserve (MSR), which was introduced by the European Commission in a legislative proposal of January 2014. The MSR would introduce a degree of supply management into the EU Emissions Trading System (ETS). This report is the result of various meetings with ETS-stakeholders throughout 2014. It discusses the MSR’s rationale and reviews the different options available for its design, governance and timing, as well as its consequences for the functioning of the EU ETS and the EU’s climate and energy policy.

The financial stability risks of ultra-loose monetary policy. Bruegel Policy Contribution Issue 2015/03

Ultra-loose monetary policies, such as very low or even negative interest rates, large-scale asset purchases, long-maturity lending to banks and forward guidance in central bank communication, aim to increase inflation and output, to the benefit of financial stability. But at the same time, these measures pose various risks and might create challenges for financial institutions. • By assessing the theoretical literature and developments in the United States, United Kingdom and Japan, where very expansionary monetary policies were adopted during the past six years, and by examining the euro-area situation, we conclude that the risks to financial stability of ultra-loose monetary policy in the euro area could be low. However, vigilance is needed. • While monetary policy should focus on its primary mandate of area-wide price stability, other policies should be deployed whenever the financial cycle deviates from the economic cycle or when heterogeneous financial developments in the euro area require financial tightening in some but not all countries. These policies include micro-prudential supervision, macro-prudential oversight, fiscal policy and regulation of sectors that pose risks to financial stability, such as construction.

A computer research program for solving the reaction rate equations in the E ionospheric region /

Ionospheric Physics Laboratory Project 8653.