Hysteresis phenomena in transverse galloping of triangular cross-section bodies

Transverse galloping is a type of aeroelastic instability characterised by large amplitude, low frequency oscillation of a structure in the direction normal to the mean wind direction. It normally appears in bodies with small stiffness and structural damping, provided the incident flow velocity is high enough. In the simplest approach transverse galloping can be considered as a one-degree-of-freedom oscillator subjected to aerodynamic forces, which in turn can be described by using a quasi-steady description. In this frame it has been demonstrated that hysteresis phenomena in transverse galloping is related to the existence of inflection points in the curve giving the dependence with the angle of attack of the aerodynamic coefficient normal to the incident flow. Aiming at experimentally checking such a relationship between these inflection points and hysteresis, wind tunnel experiments have been conducted. Experiments have been restricted to isosceles triangular cross-section bodies, whose galloping behaviour is well documented. Experimental results show that, according to theoretical predictions, hysteresis takes place at the angles of attack where there are inflection points in the lift coefficient curve, provided that the body is prone to gallop at these angles of attack.

On the design and measurement of a novel non-orthogonal multi-beam network for triangular arrays of three radiating elements

An innovative dissipative multi-beam network for triangular arrays of three radiating elements is proposed. This novel network provides three orthogonal beams in θ0 elevation angle and a fourth one in the broadside steering direction. The network is composed of 90º hybrid couplers and fixed phase shifters. In this paper, a relation between network components, radiating element distance and beam steering directions will be shown. Application of the proposed dissipative network to the triangular cells of three radiating elements that integrate the intelligent antenna GEODA will be exhibited. This system works at 1.7 GHz, it has a 60º single radiating element beamwidth and a distance between array elements of 0.57 λ. Both beam patterns, theoretical and simulated, obtained with the network will be depicted. Moreover, the whole system, dissipative network built with GEODA cell array, has been measured in the anechoic chamber of the Radiation Group of Technical University of Madrid, demonstrating expected performance.

Study of a new 4×3 beam forming network for triangular arrays of three radiating elements

An innovative dissipative multi-beam network for triangular arrays of three radiating elements is proposed. This novel network provides three orthogonal beams in θ0 elevation angle and a fourth one in the broadside steering direction. The network is composed of 90º hybrid couplers and fixed phase shifters. In this paper, a relation between network components, radiating element distance and beam steering directions will be shown. Application of the proposed dissipative network to the triangular cells of three radiating elements that integrate the intelligent antenna GEODA will be exhibited. This system works at 1.7 GHz, it has a 60º single radiating element beamwidth and a distance between array elements of 0.57λ. Both beam patterns, theoretical and simulated, obtained with the network will be depicted. Moreover, the whole system, dissipative network built with GEODA cell array, has been measured in the anechoic chamber of the Radiation Group of Technical University of Madrid, demonstrating expected performance

Kinematic geometry of mass-triangles and reduction of Schrödinger’s equation of three-body systems to partial differential equations solely defined on triangular parameters

Schrödinger’s equation of a three-body system is a linear partial differential equation (PDE) defined on the 9-dimensional configuration space, ℝ9, naturally equipped with Jacobi’s kinematic metric and with translational and rotational symmetries. The natural invariance of Schrödinger’s equation with respect to the translational symmetry enables us to reduce the configuration space to that of a 6-dimensional one, while that of the rotational symmetry provides the quantum mechanical version of angular momentum conservation. However, the problem of maximizing the use of rotational invariance so as to enable us to reduce Schrödinger’s equation to corresponding PDEs solely defined on triangular parameters—i.e., at the level of ℝ6/SO(3)—has never been adequately treated. This article describes the results on the orbital geometry and the harmonic analysis of (SO(3),ℝ6) which enable us to obtain such a reduction of Schrödinger’s equation of three-body systems to PDEs solely defined on triangular parameters.

Monitoring compliance with E-contracts and norms

Date of Acceptance: 09/07/2015

La cooperación triangular: los donantes tradicionales ante la cooperación Sur-Sur

La cooperación triangular constituye una modalidad novedosa con relevantes potencialidades para el sistema internacional de ayuda y para la cooperación española. Además de constituirse como un instrumento mediante el que impulsar la cooperación Sur-Sur, de creciente interés en la nueva arquitectura de la ayuda, le otorga a la cooperación española claras oportunidades para dar contenido práctico a la agenda con los países de renta media y, específicamente, con América Latina. Conocedora de estas implicaciones, España inició su andadura en esta modalidad de ayuda en 2005, con una actividad centrada en los países latinoamericanos. Sin embargo, no existen estudios que analicen estas intervenciones y sus implicaciones. Esto es lo que motivó un estudio promovido por la Fundación Carolina sobre dos experiencias concretas de cooperación triangular. El presente artículo presenta las principales enseñanzas extraídas de ese análisis sobre el terreno, al tiempo que recoge algunas orientaciones que puedan ser de utilidad para la práctica futura en este ámbito.

A public key cryptosystem based on block upper triangular matrices

We propose a public key cryptosystem based on block upper triangular matrices. This system is a variant of the Discrete Logarithm Problem with elements in a finite group, capable of increasing the difficulty of the problem while maintaining the key size. We also propose a key exchange protocol that guarantees that both parties share a secret element of this group and a digital signature scheme that provides data authenticity and integrity.

The European Union's promotion of regional economic integration in Southeast Asia: Norms, markets or both? Bruges Political Research Paper No. 25/May 2012

The EU‘s external action includes a preference for regional interlocutors and a tendency to promote regionalism. This work concentrates on the southeast Asian area and it aims at investigating the nature of EU‘s promotion of ASEAN regional integration. The EU‘s ideas and practices of regionalism as well as the single market experience influence the EU‘s international action. The power deriving from the EU‘s institutionalized market is used by the Union in a normative way to diffuse the EU‘s ideas and principles, advance the EU‘s interests and spread its model of economic integration through political dialogue, development cooperation and preferential trade arrangements. This action seems to result in a certain diffusion of the EU‘s ideas and practices in southeast Asia as well as in a subsequent reappropriation and redefinition of external inputs by ASEAN.

The Triangular Relationship between Fundamental Rights, Democracy and the Rule of Law in the EU: Towards an EU Copenhagen Mechanism. CEPS Paperbacks. November 2013

This study examines the protection of fundamental rights, democracy and rule of law in the European Union, and the challenges that arise in reflecting on ways to strengthen EU competences in these contested terrains. It provides a ‘state of play’ and critical account of EU-level policy and legal mechanisms assessing the relationship between rule of law, democracy and fundamental rights in the member states of the Union. The cross-cutting challenges affecting their uses, effective implementation and practical operability constitute a central point of the analysis. The study argues that the relationship between rule of law, democracy and fundamental rights is co-constitutive. Any future rule of law-related policy discussion in the EU should start from an understanding of the triangular relationship between these dimensions from the perspective of ‘democratic rule of law with fundamental rights’, i.e. the legally based rule of a democratic state that delivers fundamental rights. The three criteria are inherently and indivisibly interconnected, and interdependent on each of the others, and they cannot be separated without inflicting profound damage to the whole and changing its essential shape and configuration.

Triangular Geopolitics in Europe’s Eastern Neighbourhood. CEPS Commentary, 2 December 2014

Over the last few months, Russia has employed a number of economic and security measures to derail the Deep and Comprehensive Free Trade Agreement (DCFTA) between the EU and Ukraine. Russia’s opposition to the Agreement was based on the argument that it would damage its economy and weaken its trade ties with Ukraine. Russia’s actions ultimately led to war in Ukraine, but did not succeed in reversing Ukraine’s EU integration policies; instead there are now trilateral negotiations between the EU, Ukraine and Russia on mere technical trade aspects of the DCFTA. The Kremlin is using similar rhetoric and, to some extent, similar coercive measures against the DCFTAs with Moldova and Georgia. But the small scale of Moldovan and Georgian trade with Russia is not a legitimate reason for the EU to replicate the Ukraine ‘trialogue’ on the DCFTAs in these countries. Instead, Moldova’s heavy dependence on Russia’s energy and the former’s transit role for the EU offers a greater possibility to set up trilateral negotiations, similar to the recently finalised gas trialogue between the EU, Ukraine and Russia.

How EU Fiscal Norms Will Become a Safety Net for the Failure of National Golden Rules. European Policy Brief No. 6, January 2012

If introduced successfully, national Golden Rules will completely overturn fiscal governance in the eurozone. Golden Rules would almost always be more stringent than EU-level fiscal norms. EU fiscal norms will hence evolve into a safety net in case a Golden Rule fails. The possibility of such a failure is, indeed, not to be dismissed. Because of the severity of the Golden Rules, eurozone leaders should reflect on their design. There is a real risk that they will undercut public investment, which would be at the cost of the EU’s other long-term challenges.

Restoring Order in Global Health Governance: Do Metagovernance Norms Affect Interorganizational Convergence? CES Open Forum Series #23, 2014-2015

This paper theorizes about the convergence of international organizations in global health governance, a field of international cooperation that is commonly portrayed as particularly hit by institutional fragmentation. Unlike existing theories on interorganizationalism that have mainly looked to intra- and extraorganizational factors in order to explain why international organizations cooperate with each other in the first place, the paper is interested in the link between causes and systemic effects of interorganizational convergence. The paper begins by defining interorganizational convergence. It then proceeds to discuss why conventional theories on interorganizational- ism fail to explain the aggregate effects of convergence between IOs in global (health) governance which tend to worsen rather than cushion fragmentation — so-called "hypercollective action" (Severino & Ray 2010). In order to remedy this explanatory blind-spot the paper formulates an alternative sociological institutionalist theory on interorganizational convergence that makes two core theoretical propositions: first that emerging norms of metagovernance are a powerful driver behind interorganizational convergence in global health governance, and secondly that IOs are engaged in a fierce meaning-struggle over these norms which results in hypercollective action. In its empirical part, the paper’s core theoretical propositions are corroborated by analyzing discourses and practices of interorganizational convergence in global health. The empirical analysis allows drawing two far-reaching conclusions. On the one hand, interorganizational harmonization has emerged as a largely undisputed norm in global health which has been translated into ever more institutionalized forms of interorganizational cooperation. On the other, discourses and practices of interorganizational harmonization exhibit conflicts over the ordering principles according to which the policies and actions of international organizations with overlapping mandates and missions should be harmonized. In combination, these two empirical findings explain why interorganizational convergence has so far failed to strengthen the global health architecture.