England's Helicon, a collection or lyrical and pastoral poems: published in 1600,

Title vignette.

The Helicon of love. : A selection from the poets of the sixteenth and seventeenth centuries.

Publisher's advertisements on p. [1] and [3-6] at end.

England's Helicon

Short-title catalogue no. 3191.

Development of numerical tools for the simulation, design and optimization of a Helicon Plasma Thruster

This work thesis focuses on the Helicon Plasma Thruster (HPT) as a candidate for generating thrust for small satellites and CubeSats. Two main topics are addressed: the development of a Global Model (GM) and a 3D self-consistent numerical tool. The GM is suitable for preliminary analysis of HPTs with noble gases such as argon, neon, krypton, and xenon, and alternative propellants such as air and iodine. A lumping methodology is developed to reduce the computational cost when modelling the excited species in the plasma chemistry. A 3D self-consistent numerical tool is also developed that can treat discharges with a generic 3D geometry and model the actual plasma-antenna coupling. The tool consists of two main modules, an EM module and a FLUID module, which run iteratively until a steady state solution is converged. A third module is available for solving the plume with a simplified semi-analytical approach, a PIC code, or directly by integration of the fluid equations. Results obtained from both the numerical tools are benchmarked against experimental measures of HPTs or Helicon reactors, obtaining very good qualitative agreement with the experimental trend for what concerns the GM, and an excellent agreement of the physical trends predicted against the measured data for the 3D numerical strategy.

Development of iodine and air chemistry models for the simulation of plasma in Helicon Plasma Thrusters

The aim of this work is to analyse the chemistry models of low pressure Helicon discharges fed with iodine and air. In particular the focus of this research is to understand the plasma dynamics in order to predict propulsive performances of iodine and air-breathing Helicon Plasma Thrusters. The two systems have been simulated and analysed with the use of global models, i.e. a 0 dimensional tool to solve the set of governing equations by assuming that all quantities are volume averaged. Furthermore, some strategies have been implemented to improve the accuracy of this approach. A verification have been accomplished on the global models for both iodine and air, comparing results against simulations taken from literature. Moreover, the iodine global model has been validated against the experimental measurements of REGULUS, an helicon plasma thruster developed by the Italian company T4i, with a good agreement. From the analysis of iodine model, it has been found a significantly higher density for atomic positive ions with respect to molecular ions. Negative ions, instead, have shown to have negligible effect on the propulsive results. Also, the influence of reactions between heavy particles has been analysed with the global model. Results have demonstrated that, in the iodine case, chemistry is almost entirely affected by electronic collisions. For what concerns air-breathing results, it has been investigated the effects of the orbital height on propulsive performances. In particular, the global model has shown that at lower height, the values of thrust and specific impulse are lower due a change in atmosphere concentration. Finally, the iodine chemistry model has been introduced in the fluid code 3D-VIRTUS in order to preliminary assess the plasma properties of a Helicon discharge chamber for electric propulsion.

Comprendiendo a Podemos

"A través del peronismo llegué a comprender a Gramsci". Con esta frase, pronunciada por Ernesto Laclau en una entrevista concedida a una revista izquierdista estadounidense en 1983, se puede resumir lo que este politólogo argentino entendía como la vía más adecuada para alcanzar el poder político en un Estado, al menos a nivel de la capa conjuntiva (ejecutivo, legislativo y judicial) (Bueno, 1991). Junto a Laclau, en dicha entrevista, estaba su mujer, la también politóloga belga Chantal Mouffé. Ambos se encontraban en aquel año en París celebrando el centenario de la muerte de Carlos Marx. Estas palabras de Laclau fueron reproducidas en un artículo publicado en el diario El País del por Ludolfo Paramio (1983), sociólogo, periodista y físico español, militante del Partido Socialista Obrero Español (PSOE) desde 1982, adscrito durante una época a la corriente guerrista (de Alfonso Guerra), profesor de sociología en la Universidad Complutense de Madrid, entre otras, y Director del Departamento de Análisis y Estudios del Gabinete de la Presidencia del Gobierno de España en la primera legislatura de José Luis Rodríguez Zapatero, de 2004 a 2008. Además ha sido miembro de la Asociación Latinoamericana de Ciencia Política y dirige actualmente un postgrado sobre política en Iberoamérica en el Instituto Universitario de Investigación Ortega y Gasset. ¿Qué más tienen en común Laclau, Mouffé y Paramio además de esta interrelación ideológica, sentimental y periodística? Que no se puede entender Podemos sin estos tres nombres, como tampoco puede entenderse sin las conexiones ideológicas entre estos ideólogos y la propia familia de Pablo Manuel Iglesias Turrión (Pablo Iglesias II) y sus quehaceres político-vitales.