Comparative life cycle assessment (LCA): Conventional TES system versus alternative steel slag-based TES system for CSP plants

Treballs Finals del Màster d’Energies Renovables i Sostenibilitat Energètica, Facultat de Física, Universitat de Barcelona. Curs: 2022-2023. Tutors: Alejandro Calderón Díaz, Adela SvobodovaThere is a demand for alternative thermal energy storage (TES) materials to support the global deployment of concentrated solar power (CSP) plants. These materials should fulfil specific criteria concerning technical, economic, and ecological performance. This research work focuses on the comparative life cycle assessment (LCA) of a concentrating solar power (CSP) plant that utilizes Electric Arc Furnace (EAF) steel slag as a thermal energy storage material in a thermocline configuration, compared to a conventional CSP plant that uses molten salts. The study aims to evaluate the potential environmental impacts and identify opportunities for sustainability improvement in CSP plants technology. The results demonstrate a significant reduction in the material inventory demand and in the overall environmental impact for the scenarios where the thermocline configuration was chosen. The thermocline TES system showcases notable reductions in the following environmental impact indicators: a) “Damage to the resources availability” and b) “Global warming potential”. Thus, the study highlights the potential of using steel slag to improve the sustainability of CSP plants, while revalorising materials that other case could finish in a landfill. The research and analysis performed indicate that the use of steel slag as a thermal storage material is technically feasible and it has the potential to increase the environmental and economic sustainability, as this material is abundant, energy efficient and sustainable enough for industrial scale applications. In fact, the use of steel slag as TES material could contribute positively to the Sustainable Development Goals (SDGs) through: including cleaner energy solutions, promoting innovation in green power generation, responsible managing of resources, and mitigating the climate chang

Evaluación de la vulnerabilidad sísmica de estructuras de acero residenciales del Ecuador

Nowadays, there are a large number works focused on determining the seismic vulnerability of structures. This feature is not accidental, but rather the product of concern to the scientific, professional and organizations responsible for risk management community to reduce the destructive effects caused by earthquakes in the infrastructure and society. Globally destructive events that have occurred during the previous and present decades have contributed to this initiative; among them, the Sichuan, China (2008), Port au Prince, Haiti (2010), Maule, Chile (2010) or Tohoku, Japan (2011) earthquakes can be mentioned, which had as consequences many dead, injured and homeless people. It is well known that an earthquake can cause humanitarian disasters not only by the number of casualties and injured people but also for the destruction of cities where thousands of families live and work. All the above mentioned reasons reveal the need of revision and improvement of the seismic design codes, construction practices and policies that allow buildings to have a better performance against the strong ground motions. This is the context in which this work was developed. It contains results of a research entitledPostprint (published version

Solution strategies to the stochastic design of mineral flotation plants

The aim of this study is two-fold: first, to analyze the effect of stochastic uncertainty in the design of flotation circuits and second, to analyze different strategies for the solution of a two-stage stochastic problem applied to a copper flotation circuit. The paper begins by introducing a stochastic optimization problem whose aim is to find the best configuration of superstructure, equipment design and operational conditions, such as residence time and stream flows. Variability is considered in the copper price and ore grade. This variability is represented by scenarios with their respective probability of occurrence. The resulting optimization problem is a two-stage stochastic mixed integer nonlinear program (TS-MINLP), which can be extremely challenging to solve. For this reason, several solvers for this problem are compared and two stochastic programming methodologies are applied. The combination of these techniques allows the production of high quality solutions and an analysis of their sensitivity to epistemic uncertainty. The results show that the stochastic problem gives better designs because it allows operational parameters to adapt to the uncertainty of the parameters. The results also show that the flotation circuit structure can vary with the feed grade and copper price. The sensitivity analysis shows small to moderate variability with epistemically uncertain parameters

Non-linear analyses to assess the seismic performance of RC buildings retrofitted with FRP

Post-seismic reinforcement is extensively used to repair structural elements of buildings hit by strong earthquakes, while pre-seismic reinforcement can be very convenient to improve the seismic performance of buildings designed according to less stringent standards than current. One of the most commonly used techniques for both pre and post-seismic retrofit of structures is that of wrapping elements previously identified as weak or damaged with sheets of fiber-reinforced polymers (FRP). This technique may be in fact more advantageous than other strengthening approaches, due to speed of placement, low environmental impact and small load increase. Non-linear methods of analysis can be very helpful for planning the retrofit strategy and assessing in advance its effectiveness. Based on non-linear static and dynamic numerical analyses, the effectiveness of the FRP pre-seismic reinforcement on the global performance of buildings was investigated in this paper with reference to a residential Italian building designed according to obsolete standards. The seismic capacity of the building, before and after the FRP retrofit, was assessed and the efficacy of the seismic rehabilitation was evaluated. The results show that, by improving the local resistance of the most vulnerable elements and the global ductility of the building, the FRP wrapping of the ground-floor columns of the considered building has an important impact on the overall seismic response of the structure, although it cannot entirely avoid undesirable global collapse mechanisms

Attitudes present in teachers and postgraduate students of education. An approach to their identity and professional ethics.

Se presentan los resultados de una investigación orientada a identificar cómo se integra el comportamiento ético en la identidad profesional docente. En esta oportunidad tal cuestión se trató a partir de la Escala de Actitudes sobre Ética Profesional (Hirsch, 2005), la cual fue aplicada a un grupo de docentes y estudiantes de posgrado de tres instituciones de educación universitaria en Venezuela. Los resultados demuestran una actitud favorable hacia las competencias éticas, cognitivas y afectivo-emocionales. Se evidencia una valoración muy dispar en relación con las competencias técnicas (habilidades didácticas) y resulta particularmente preocupante la valoración que se hace de las relaciones con los otros docentes (competencias sociales). Se concluye destacando la necesidad de promover el desarrollo profesional de los docentes, lo cual permitirá el fortalecimiento de su identidad profesional y un desempeño enmarcado en la ética profesional.In this paper, we present the results of a research whose objective was to identify how ethical behavior is incorporated into teachers’ professional identity. For that purpose, we worked with the Attitude Scale on Professional Ethics (Hirsch, 2005), which was applied to a group of teachers and graduate students of three universities from Venezuela. The results show us that, in general, there is a favorable attitude towards the ethical competencies, as well as to the cognitive and affective-emotional competencies. However, there is a very different assessment regarding the technical competencies (didactic skills) and the social competencies; regarding the latter, the assessment given to the item about the relationship with other teachers is particularly worrying. We conclude by highlighting the need to foster the professional development of teachers, which in turn will allow them to strengthen their professional identity and to have a performance based on professional ethics.Educació

La responsabilidad del docente entre el ser funcionario y el ejercicio ético de la profesión

La profesión docente se presenta como un espacio complejo sometido a múltiples demandas por parte de la sociedad, situación que afecta el desempeño del cuerpo docente en el ejercicio de su labor. Con el objetivo de definir desde el pensamiento de los profesores cuál es la responsabilidad que asumen, se desarrolla la presente investigación, la cual forma parte de un trabajo más amplio que pretende analizar la integración del comportamiento ético en la identidad profesional docente. Es un trabajo de carácter descriptivo, como instrumento se aplicó un cuestionario (Hirsch, 2005), este incluía la pregunta: Desde su punto de vista, cuáles son los principales rasgos de un docente responsable. Para analizar las respuestas aportadas por 88 docentes (estudiantes de posgrado de tres universidades de Venezuela) se utilizó como técnica el análisis de contenido a partir del cual se obtuvo como resultado que existe una visión dual en relación con la responsabilidad docente; en primer lugar, asociada con la condición de funcionario que cumple un horario y desarrolla las tareas que le son encomendadas; en segundo lugar, la responsabilidad se asume desde una perspectiva ética en la cual priman ideas de autonomía y respeto. De lo anterior se desprende la necesidad de implementar programas de desarrollo profesional docente y la búsqueda de condiciones de ejercicio que respeten y promuevan la autonomía del cuerpo docente como una forma de buscar el bienestar en su trabajo cotidiano y al mismo tiempo asegurar la calidad de la labor desempeñada