The increasing penetration of Renewable Energy Sources (RES) into transmission grids requires advanced reactive power compensation solutions to meet the stringent grid code demands. In this context, Static Synchronous Compensators (STATCOMs) have emerged as the preferred technology to ensure grid code compliance. Modular Multilevel Cascaded Converter (MMCC) topologies, especially the Single Delta Bridge Cell (SDBC) STATCOM, have become attractive options for high-power applications due to their modularity, scalability, and industrial maturity. Despite their widespread adoption, academic literature lacks systematic reviews that comprehensively address the integral design and sizing methodologies tailored to this topology, particularly regarding the translation of grid code requirements into hardware-level parameters. This paper addresses this gap by proposing a holistic framework for the design and sizing of SDBC STATCOMs. Based on this framework, this paper presents a critical review of the complete design process, synthesizing scattered literature into a coherent workflow. The analysis begins by translating international grid code requirements into converter performance specifications. Following this, the paper evaluates critical design choices for transformer coupling and insulation coordination. Furthermore, the paper critically compares existing methodologies for core converter dimensioning, including voltage sizing (number of submodules, DC capacitance) and current sizing (semiconductor stress, unbalanced operation). This review provides a unified reference for researchers and engineers, facilitating the optimized design of SDBC STATCOMs specifically tailored to enhance the stability of renewable-dominated grids.
The present research studies, through a quantitative approach, and using the AMO (Ability, Motivation and Opportunity) framework, the relationship between High Performance Working Systems (HPWS) with the commitment and satisfaction of workers, placing special emphasis on focus on the professional groups of blue-collar workers (blue-collar) and white-collar workers (white-collar). The study is carried out in an industrial worker cooperative where, through a survey, 123 valid responses have been obtained. The results show two conclusions. On the one hand, it has been shown that perceptions of people management practices influence both satisfaction and commitment. And, on the other hand, the results have shown that belonging to one professional group or another has a significant influence on the satisfaction variable; but not on commitment. The present study aims to open future lines of research, emphasizing the importance and need to explore in greater depth the blue-collar and white-collar variables in the field of people management and in cooperative environments.
This work investigates how moderate turbulence and surface roughness jointly affect the aerodynamics of a NACA0021 airfoil operating at transitional Reynolds numbers ( Re=0.8- 1.2 & times;10(5)). Wind-tunnel tests were performed under two controlled flow paradigms: a low-disturbance Clean condition and a Combined condition including both freestream turbulence ( I approximate to 3.8%) and leading-edge roughness. In addition to the baseline (Bare) configuration, two unilateral passive device (PD) layouts were tested, with triangular protrusions placed at x/c=0.25 (PD25) and x/c=0.5 (PD50). Results show that the Combined inflow linearizes the lift curve and softens stall but reduces lift slope and aerodynamic efficiency by up to 60% compared with the Clean baseline. The effect of the PDs depends on their position and on Re: PD25 can delay stall and recover efficiency at high angles of attack, while PD50 offers only limited or negative impact once the boundary layer becomes fully turbulent. Overall, the findings demonstrate that turbulence-roughness interactions dominate aerodynamic behavior at transitional scales, and that small passive elements can provide only local improvements. These results underline the need to assess low- Re airfoils under realistic inflow conditions when developing flow-control strategies for distributed or urban wind-energy systems.
Learners' extramural exposure (EE) to English beyond the classroom is becoming increasingly relevant as a site for language learning. EE has risen as a crucial variable in language development, learning and acquisition; however, the interaction between different types of EE and learners' age remains insufficiently studied. This study explores the interface between biological age (operationalised as school years) and EE in English as a foreign language (EFL) writing performance in secondary school. A cross-sectional sample (N = 527) of Basque-Spanish bilingual 12-16-year-old students from the Basque Autonomous Community (Spain) participated in this study. The learners studied EFL as a third language at school and completed a written task about a disciplinary topic. Three EE-related variables were measured: informal exposure, formal private tuition, and parental variables. Multiple regressions, Mann-Whitney U tests, and correlations were used to explore potential differences related to the variables in writing performance. The analyses indicated that age was the strongest predictor, followed by both informal exposure and private tuition, while parental factors were non-significant. Furthermore, EE effects interacted differently with age: private tuition had a stronger impact on younger learners' scores but gradually diminished, while older learners showed greater gains from informal exposure, particularly from watching TV/films and social media. The study suggests that maturity is a crucial factor and that EE mediation effects need to be understood as a dynamic process. Pedagogical and theoretical implications are discussed to foster EFL learning inside and outside the classroom by considering maturational constraints. La exposici & oacute;n extramural (EE) del alumnado al ingl & eacute;s fuera del aula est & aacute; ganando importancia como contexto de aprendizaje de lenguas. De hecho, la EE ha emergido como una variable clave en el desarrollo, aprendizaje y adquisici & oacute;n de lenguas; sin embargo, la interacci & oacute;n entre los distintos tipos de EE y la edad del alumnado no se ha estudiado lo suficiente. Este estudio explora la interacci & oacute;n entre la edad biol & oacute;gica (cursos escolares) y la EE en el rendimiento en escritura en ingl & eacute;s como lengua extranjera en educaci & oacute;n secundaria. En el estudio particip & oacute; una muestra transversal (N = 527) de estudiantes biling & uuml;es euskera-espa & ntilde;ol que estudiaban ingl & eacute;s como L3, de entre 12 y 16 a & ntilde;os de la Comunidad Aut & oacute;noma del Pa & iacute;s Vasco. La muestra complet & oacute; una tarea escrita sobre un tema disciplinar. Se midieron tres variables relacionadas con la EE: exposici & oacute;n informal, clases particulares y variables parentales. Para explorar posibles diferencias en el rendimiento escrito en funci & oacute;n de estas variables, empleamos regresiones m & uacute;ltiples, pruebas U de Mann-Whitney y correlaciones. Los resultados muestran que la edad es el predictor m & aacute;s fuerte, seguida de la exposici & oacute;n informal y las clases particulares, mientras que los factores parentales no tienen efecto significativo. Asimismo, los efectos de diferentes tipos de EE interact & uacute;an diferentemente con la edad: las clases particulares tienen un mayor efecto en los/las aprendices m & aacute;s j & oacute;venes, pero este efecto disminuye gradualmente, mientras que los estudiantes de mayor edad mostraron mayores beneficios de la exposici & oacute;n informal, especialmente a trav & eacute;s del consumo de televisi & oacute;n/pel & iacute;culas y redes sociales. El estudio sugiere que la madurez es un factor crucial, y que los efectos mediadores de la EE deben entenderse como un proceso din & aacute;mico. En conclusi & oacute;n, el estudio tiene implicaciones pedag & oacute;gicas y te & oacute;ricas para fomentar el aprendizaje de EFL dentro y fuera del aula, teniendo en cuenta las limitaciones madurativas.
This article offers a republican-socialist reading of unconditional basic income, arguing that its political significance and emancipatory potential are not inherent but contingent on the broader sociopolitical project in which it is embedded. Challenging claims of ideological neutrality, we differentiate between right- and left-wing unconditional basic income proposals, focusing on fiscal design, institutional frameworks and implications for labour relations. Drawing on a republican conception of freedom - understood as inseparable from the material conditions that sustain it - we conceptualise unconditional basic income as an intervention against market dependency and economic coercion. When implemented within a framework of economic democracy, unconditional basic income can serve not merely as income support but as a lever for redistributing power, enhancing autonomy and challenging systemic inequalities. Rather than a technocratic fix, it may constitute a cornerstone for democratising economic life - provided it is shielded from neoliberal co-optation. Conversely, when financed and framed as a substitute for public guarantees, unconditional basic income risks entrenching market logics and private domination.
