Mineral chemistry of late Variscan gabbros from central Spain: constraints on crystallisation processes and nature of the parental magmas

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Experimental study of magneto-inertially driven, differentially rotating plasma flows

This thesis presents experimental results from a novel laboratory platform to produce high-energy-density rotating plasmas implemented at the MAGPIE pulsed-power generator. The experiments are probed using a combination of self-emission imaging, laser interferometry and Thomson Scattering diagnostics. Two configurations of the experiment were implemented, demonstrating control of the amount of angular momentum in the flow. Rotating plasma flows are produced by the convergence of eight ablation flows generated from a cylindrical wire array Z pinch, which are azimuthally deflected by an external magnetic field. The ablation flows provide mass, angular momentum and confining ram pressure. The resulting plasma density structure is characterized by a higher density thin shell (e.g., with electron density $n_e = (5\pm 1)\times10^{17}$ cm$^{-3}$ in the initial experiments) surrounding a low density core (e.g., $n_e = (1.0\pm 0.2)\times10^{17}$ cm$^{-3}$), supported by the centrifugal barrier introduced by angular momentum. The results demonstrate the formation of a differentially rotating plasma flow. In the initial (low angular momentum experiments), the rotation velocity $u_\theta = 23.9 \pm 2.1$ km/s; whereas in the increased angular momentum experiments, $u_\theta = 39.0 \pm 2.9$ km/s. The plasma undergoes between 0.5 to 2 full rotations in the experimental time-frame, with the inner region completing more revolutions. It is also discovered that the rotation profile corresponds to a quasi-Keplerian stratification, meaning that it is expected to be hydrodynamically stable whilst being unstable under the magneto-rotational instability. However, no evidence of the instability was observed, probably due to the absence of out-of-plane magnetic fields.Open Acces

Fast Thermal Generation Rescheduling

A new dynamic programming algorithm for fast rescheduling thermal generation is presented. The savings in computational times are brought about by the introduction of two new techniques: the variable truncation dynamic programming and the limitation of the solution space to be searched. Several examples on a 20 machine system are used to illustrate the application of the algorithm and to show that optimal solutions are obtained at significantly reduced computational times

Representaciones sociales de pobreza y sus correlatos en política social

The profile of poverty has changed in the recent decades, transforming from one based on shortcomings to a situation of social exclusion and precarious citizen participation. This drives a reflection on social images of poverty and the need to take a new look at poverty: from representations of absolute poverty to views of relative and subjective poverty. However, these new poverty profiles co-exist with the backwardness poverty or structural poverty, showing a strong heterogeneity that demands to be recognized in public action oriented towards improvement.  The development of qualitative research enables delving in the understanding of this heterogeneity and the impacts on the prevalence of harsh poverty imaginaries in the relationship that the States generates with people in poverty. This study presents the subjective dimensions of this relationship and its mutation from poverty of income to civic poverty, characterized by increasing demands of symbolic integration and social protagonism. It presents the ratings of the bond with the State and some paradoxes of social policy that need to be addressed in public discussion on strategies for overcoming poverty. El perfil de la pobreza ha cambiado en las últimas décadas, transformándose desde uno de carencias básicas, a una situación de exclusión social y precaria participación ciudadana. Esto impulsa a una reflexión sobre las imágenes sociales de la pobreza y a la necesidad de remirar el fenómeno, adoptando perspectivas vinculadas a pobreza relativa y subjetiva por sobre las representaciones de pobreza absoluta. Con todo, estos nuevos perfiles de pobreza coexisten con las pobreza por atraso o estructural, evidenciando una fuerte heterogeneidad que demanda ser reconocida en la acción pública orientada a su superación. El desarrollo de la investigación cualitativa permite  adentrarse en la comprensión de esta heterogeneidad y en los impactos que tienen la prevalencia de imaginarios de pobreza dura en la relación que genera el Estado con las personas en pobreza. Este estudio presenta las dimensiones subjetivas de dicha relación y de su mutación desde una pobreza de ingresos a pobreza cívica, caracterizada por mayores demandas de integración simbólica y actoría social. Se presentan las valoraciones del vínculo sostenido con el Estado y algunas paradojas de la política social que requieren ser abordadas en la discusión pública sobre las estrategias de superación de pobreza

Sobre el stock adamellítico de La Granja y el sector metamórfico encajante (Guadarrama Central)

[Resumen] El stock adamellítico de La Granja (Guadarrama Central) intruye en materiales metamórficos de alto grado (con cordierita-silnmanita-ortosa), provocando neoformación de andalucita. Se describen asímismo, algunas facies litológicas de «contacto» como son los gneises porfidoclásticos o los cinturones aplograníticos de borde del granitoide. Se describen los materiales metamórficos haciendo especial hincapié en los rasgos texturales de los mismos y en el fuerte control geoquímico que ejerce el medio petrológico a las diferentes blastesis minerales. El estudio geoquímico aunado al estructural nos define un carácter ortoderivado a las formaciones glandulares sálicas y leucogneísicas con las que forman Unidad. Además se apuntan pautas de variación geoquímica de los gneises porfidoclásticos de «contacto». El stock se define como adamellita de grano grueso porfídica de tendencias calco-alcalinas y como apéndice de los materiales de grano grueso leucocráticos de la vertiente meridional de la Sierra. Se describen las redes filonianas características del stock encontrando ciertas diferencias composicionales entre ambos materiales. Finalmente encontramos una variación geoquímica, clara en elementos menores, entre las facies de borde e interior del dique[Abstract] La Granja granitoid stock in Centrat Guadarrama (Spain) intrudes in high grade metamorphic rocks (cordierite-sillimanite-ortose) inducing neoformation of andalusite. There are lithological «contact» facies, such as porphyroclastic gneiss or aplogranitic belts of chilled margin.We describe here the metamorphic materials, in special the textural features and the geochemical control of mineral blastesis by the lithology. The geochemical and structural studies determine an orthogenesis for augen and leucocratic gneiss which belong to the same formation. We describe too, some geochemical features of the porphyroclastic gneiss. The porphyritic granitoid stock is adamellitic in composition (O-monzonite), coarse grained and has a calc-alcalic character. La Granja stock is the natural appendix of leucocratic coarse grained granites from the Sierra's southern side. In this paper we deal with the characteristic stock dike-swarm, finding compositional differences between both materials. Finally we find a clear geochemical variation, specially in minor elements, between margin and core in the dike

Two-Step Optimal Thermal Generation Scheduling

A new approach to the solution of the optimal thermal generation scheduling problem is presented. The problem is solved in two steps. As a first step, the optimal production schedule for the next day is obtained based on a daily load forecast, reserve capacity requirements, and present status of generating units. The second-step algorithm uses the results of the first step and adjusts the previous schedule to meet new constraints developed during the course of the day. Variable truncation dynamic programming is proposed as a new method to reduce computation effort. To eliminate the need for solving the entire problem again in the second step, a new technique that limits the solution space to be searched is presented. Use of approach is illustrated via examples

Origin, ore forming fluid evolution and timing of the Logrosán Sn-(W) ore deposits (Central Iberian Zone, Spain)

The Logrosán Sn–(W) ore deposits in the metallogenic Sn–W province of the European Variscan Belt consist of endo- and exogranitic greisen-type and quartz–cassiterite veins associated with a S-type granite. Mineral characterization, fluid inclusion study, isotope geochemistry and Ar–Ar geochronology have been combined in order to reconstruct the conditions for Sn–(W) mineralization. The endo- and exogranitic mineralization must have been developed in a relatively long-lived system (~ 308–303 Ma), during or soon after the emplacement of the Logrosán related-granite (at ca. 308 Ma). The mineralizing fluids are characterized by complex aqueous and volatile (H2O–N2–CO2–CH4–NaCl) fluid inclusions. Microthermometry and Raman analyses indicate that fluid composition evolved from N2–CH4 to N2-rich, followed by CO2-rich fluids, with varying amounts of H2O. The presence of N2 and CH4 suggests the interaction with fluids derived from the nearby metasedimentary host rocks. A model of host-rock interaction, assimilation, and mixing of metamorphic and magmatic fluids, resulting in change of the redox conditions, is proposed for tin deposition. Later sulfide minerals were precipitated as a result of pressure and temperature release

Dynamic Modeling and Analysis of Generalized Power Flow Controller

This paper presents a unified solution to compute power quality indices in the generalized unified power flow controller (GUPFC) during steady and transient conditions using a dynamic harmonic domain technique. This technique allows the user to analyze harmonics generated in the GUPFC more precisely than using time domain techniques. The derivation of a model is presented and then simulated in the presence of voltage disturbances to demonstrate its use in power quality assessment. The results of the proposed model are validated against time domain simulations

Transient Stability Hierarchical Control in Multimachine Power Systems

The authors present the optimal transient stability control problem in a hierarchical structure for multimachine power systems. The two-level structure retains the local closed-loop controls, thereby easing its implementation on existing systems. The formulation accounts for nonlinearities and interconnections, and the optimization of the system transient performance is obtained with less computational effort. Since the computations are distributed among the many local feedback subsystems, the storage and solution times are considerably less than those required by a single overall centralized controller. This advantage becomes much stronger as the system size increases. For illustration purposes, this technique was applied successfully to a four-machine syste