One-loop mass shift formula for kinks and self-dual vortices

A formula is derived that allows us to compute one-loop mass shifts for kinks and self-dual Abrikosov-Nielsen-Olesen vortices. The procedure is based in canonical quantization and heat kernel/zeta function regularization methods.Comment: LaTex file, 8 pages, 1 figure . Based on a talk given by J. M. G. at the 7th Workshop on Quantum Field Theory under the Influence of External Conditions (QFEXT05), Barcelona, Spain. Minor corrections. Version to appear in Journal of Physics

Quantum corrections to the mass of self-dual vortices

The mass shift induced by one-loop quantum fluctuations on self-dual ANO vortices is computed using heat kernel/generalized zeta function regularization methods.Comment: 4 pages RevTex, version to appear in Physical Review

Clinkering and hydration study of non-active and active Belite-Alite-Ye'elimite (BAY) cements

The aim of AIM is to promote industry-driven, interdisciplinary research in material science and engineering in order to provide leading-edge, sustainable solutions to the challenges facing engineers in today’s changing society and environment. http://www.ucl.ac.uk/aim/conference-info/37ccsThe manufacturing process of ye'elimite rich cements emit about 15-37% less CO2 to the atmosphere than OPC. Cements that contain belite, ye’elimite and ferrite, known as BYF cements, are promising eco-friendly binders. However, belite, their main phase, shows a slow hydrating behaviour; therefore the corresponding mortars present lower mechanical strengths than OPC at early ages. To solve this problem, BYF clinkers can be activated by: i) forming alite jointly with belite and ye’elimite during clinkering, known as BAY clinkers. The alite and ye’elimite reaction with water should develop high mechanical strengths at early ages, besides, belite contributes to later curing times. ii) A second activation is based on the stabilisation of alpha forms of belite by dopants. The objective of this work is to obtain two types of BAY clinkers (standard and active BAY) using CaF2 as mineraliser and borax as dopant agent to stabilize alpha forms of belite phase. After that, anhydrite was added as sulphate source to obtain the corresponding cements. The hydration behaviour of these cements has been studied through rheological and x-ray diffraction measurements, the latter combined with Rietveld quantitative phase analysis. In addition, mechanical and dimensional properties of BAY mortars are also presented and discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Desarrollo de Competencias para la Sustentabilidad, a través del Aprendizaje Basado en Escenarios

Sustainability, proposed as a concept and strategic solution to the contemporary crisis, poses several challenges for humanity, among which is the formation of individuals capable of facing the complexity of environmental problems, as well as of visualizing and developing a free society, fair and in balance. In order to contribute to this challenge, the present work was proposed to investigate the contribution of Scenario Based Learning to the development of competencies for sustainability, both from a conceptual and practical point of view, designing an educational resource and carrying out a pilot test in students of the Autonomous University of San Luis Potosí. The specific objectives were: (1) Identify, select and formulate the systemic analysis of two cases, one in Mexico and one in Germany, to show the complexity of the relationship between sustainability dimensions and the challenges faced by the actors in the management of this and, (2) Design and test an educational resource around its contribution to the development of critical thinking and systemic thinking competencies. The pilot test of the educational resource was carried out with a multidisciplinary group, integrating undergraduate students from: Communication Sciences, Environmental Sciences and Health, Agroindustrial Engineering, Psychology and Psychopedagogy. Based on assessment interviews, it was concluded that scenario-based learning allowed to contribute to the development of competencies for sustainability. The two selected cases: Río Rin and Río Verde were effective in demonstrating complexity, and they also warned of the challenges that result from the management of the sustainability. Finally, it should be mentioned that the development of interpersonal competence (dialogue and collaboration mainly) that was not within the objectives of the thesis was evidenced.La sustentabilidad, planteada como concepto y solución estratégica frente a la crisis contemporánea, supone diversos retos para la humanidad entre los que se encuentra la formación de individuos capaces de afrontar la complejidad de la problemática ambiental, así como de visualizar y desarrollar una sociedad libre, justa y en equilibrio. Con el propósito de coadyuvar a dicho cambio, el presente trabajo se propuso investigar la contribución del Aprendizaje Basado en Escenarios al desarrollo de competencias para la sustentabilidad, tanto desde el punto de vista conceptual como práctico, diseñando un recurso educativo y realizando una prueba piloto en estudiantes de la Universidad Autónoma de San Luis Potosí. Los objetivos específicos fueron: (1) Identificar, seleccionar y formular el análisis sistémico de dos casos, uno en México y otro en Alemania, para mostrar la complejidad de la relación entre dimensiones de la sustentabilidad y los desafíos a los que se enfrentan los actores en la gestión de esta y, (2) Diseñar y probar un recurso educativo en torno a su contribución al desarrollo de las competencias de pensamiento crítico y pensamiento sistémico. La prueba piloto del recurso educativo se realizó con un grupo multidisciplinario, integrando estudiantes de las licenciaturas: Ciencias de la Comunicación, Ciencias Ambientales y Salud, Ingeniería Agroindustrial, Psicología y Psicopedagogía. Con base en entrevistas de valoración se llegó a la conclusión de que el aprendizaje basado en escenarios si permitió contribuir al desarrollo de competencias para la sustentabilidad. Los dos casos seleccionados: Río Rin y Río Verde resultaron eficaces al evidenciar la complejidad, así mismo, advirtieron los desafíos que resultan de la gestión de la sustentabilidad de ambos, mostrándose análogos. Por último, cabe mencionar que el desarrollo de la competencia interpersonal (diálogo y colaboración principalmente) que no estaba dentro de los objetivos de la tesis, se evidenció a partir de las entrevistas la valoración

Quantum fluctuations around low-dimensional topological defects

In these Lectures a method is described to analyze the effect of quantum fluctuations on topological defect backgrounds up to the one-loop level. The method is based on the spectral heat kernel/zeta function regularization procedure, and it is first applied to various types of kinks arising in several deformed linear and non-linear sigma models with different numbers of scalar fields. In the second part, the same conceptual framework is constructed for the topological solitons of the planar semilocal Abelian Higgs model, built from a doublet of complex scalar fields and one U(1) gauge field.Comment: 63 pages, 14 figures, expanded version of two lectures given by J.M.G. in 5th International School on Field Theory and Gravitation, Cuiaba, Brazi

Advanced synchrotron studies of ye'elimite-based cement pastes

Synchrotron characterization techniques [1] are being used to study Portland-based cements and recently also CSA and related cements. A key property of these techniques is that they do not require sample preparation, so the microstructures of the pastes can be preserved. The classical application of synchrotron tools is powder diffraction used to determine the crystalline phase content evolution with hydration including the overall amorphous fraction. Furthermore, other most advanced techniques are being applied to ye'elimite-containing pastes such as i) Total Scattering Synchrotron Powder Diffraction (TS-SXPD), and ii) Ptychographic Synchrotron X-ray Computed Tomography (PSXCT). All these applications will be reviewed here. TS-SXPD data coupled with the Pair Distribution Function (PDF) analysis methodology [2] allows having a better insight about the nanocrystalline/amorphous atomic arrangements in the gels. It has been very recently shown that nanogibbsite with very small particles, 3nm, is the main constituent of ye'elimite-gypsum hydration paste [2]. Nanogibbsite particles being smaller than those originated from the hydration of monocalcium aluminate. In addition, PSXCT is a tomographic technique that profits from the partly coherent nature of the synchrotron beam to provide better (smaller) resolution, which can be lower than 100 nm. It also provides the mass densities if the chemical stoichiometries are known. This technique has been applied to ye'elimite hydration to determine the microstructure and chiefly the bulk densities of nanogibbsite [3]. The microstructure evolution at early age was also followed [4]. Figure 1 shows an example of a slide of the electron density tomogram for a ye'elimite paste at 8 days of hydration and the corresponding histogram for the full volume with all phases identified.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.This work has been supported by Spanish MINECO through BIA2014-57658-C2 and BIA2017-82391-R, which are co-funded by FEDER

Rietveld Quantitative Phase Analysis of Oil Well Cement: in Situ Hydration Study at 150 Bars and 150 °C

Oil and gas well cements are multimineral materials that hydrate under high pressure and temperature. Their overall reactivity at early ages is studied by a number of techniques including through the use of the consistometer. However, for a proper understanding of the performance of these cements in the field, the reactivity of every component, in real‐world conditions, must be analysed. To date, in situ high energy synchrotron powder diffraction studies of hydrating oil well cement pastes have been carried out, but the quality of the data was not appropriated for Rietveld quantitative phase analyses. Therefore, the phase reactivities were followed by the inspection of the evolution of non‐overlapped diffraction peaks. Very recently, we have developed a new cell specially designed to rotate under high pressure and temperature. Here, this spinning capillary cell is used for in situ studies of the hydration of a commercial oil well cement paste at 150 bars and 150 °C. The powder diffraction data were analysed by the Rietveld method to quantitatively determine the reactivities of each component phase. The reaction degree of alite was 90% after 7 hours, and that of belite was 42% at 14 hours. These analyses are accurate, as the in situ measured crystalline portlandite content at the end of the experiment, 12.9 wt%, compares relatively well with the value determined ex situ by thermal analysis, i.e., 14.0 wt%. The crystalline calcium silicates forming at 150 bars and 150 °C are also discussed.This research was funded by Spanish MINECO, grant number BIA2017‐82391‐R which is co‐funded by FEDER. We thank Marc Malfois for his help during the experiment performed at NCD‐SWEET beamline at ALBA synchrotron. We also thank Marcus Paul (Dyckerhoff GmbH) for providing the OWC sample with its characterization and helpful discussions