Electrorotation of semiconducting microspheres

We study experimentally the electrorotation (ROT) of semiconducting microspheres. ZnO microspheres obtained by a hydrothermal synthesis method are dispersed in KCl aqueous solutions and subjected to rotating electric fields. Two ROT peaks are found in experiments: a counterfield peak and a cofield peak at somewhat higher frequencies. These observations are in accordance with recent theoretical predictions for semiconducting spheres. The counterfield rotation is originated by the charging of the electrical double layer at the particle-electrolyte interface, while the cofield rotation is due to the Maxwell-Wagner relaxation. Additionally, we also found that some microspheres in the sample behaved differently and only showed counterfield rotation. We show that the behavior of these particles can be described by the so-called shell model. The microstructure of the microspheres is analyzed with electron microscope techniques and related to the ROT measurements.Spanish Government Ministry MICINN under Contract No. PGC2018-099217-B-I00Junta de Andalucía Contract No. PEJUS-

Evaluation of mechanical properties of FDM components reinforced with fibre

[EN] This research analyses the influence of different parameters of the Fused Deposition Modelling process with continuous carbon fibre reinforcement upon tensile strength of manufactured parts. For that, the appropriate behaviour of specimens designed according to ISO 527 standard was verified, in a preliminary test. Hereafter, a full factorial Design of Experiment was proposed with five parameters and two levels. After manufacturing and testing the specimens, a regression including all possible interactions of the parameters was performed with their tensile results. This model was optimized, considering the terms with the highest statistical significance (p-value less than 0.05), so that a simplified model of 14 terms with an r-squared of 97.5% was obtained. Thanks to this research the tensile response of a printed part as a function of the chosen manufacturing parameters can be predicted in advance.S

Application of Thermography in Education: A Bibliometric and Meta-Analysis

[EN] From engineering and physics to health sciences are only a few of the professional topics where infrared thermography is usually applied. Future professionals need to be thoroughly taught in its use and familiar with its fundamentals for this reason. However, because of the high cost and the difficulty in evaluating the outcomes of using this technology in teaching and learning, it may be difficult to acquire the necessary skills and to design educational research that can be used to evaluate the learning potential of the tool. Furthermore, thermography is a physical instrument that can be used to enhance the competencies acquired at different educational levels. In this work, a bibliometric analysis is implemented from a Scopus ® dataset to analyse the trend and evolution of the work linking thermography and education, also the main sources of the works. Additionally, a meta-analysis will be implemented to draw a network map for co-occurrences in order to identify the different subtopics from the relationship between the scientific works published. Since infrared thermography oriented to education is a lowly explored topic, this work may be a starting point for new developments and research lines.S

SDART Software: A Novel Tool Designed to Enhance Learning in Adjustment Computation in Surveying

[EN] This article presents a teaching-learning methodology designed for the acquisition of competences related to the subject of Adjustment of Observations in the Degree in Engineering in Geomatics and Surveying. The activity has been designed to cover the majority of the competences and learning objectives of the subject. And due to the wide scope of the activity's goal, a novel teaching support software has been developed (SDART) to be used in conjunction with other free suites (Octave). Through an application of the Project-Based Learning methodology in a simple observation project of a surveying network, the students will develop their mathematical and statistical competences. The focus of the approach is allowing the students to understand and interpret the different error sources in field observations and their role in the process of determining the optimal solution by means of least squares. This teaching-learning approach supported by the ad-hoc developed software will assist the students to achieve their learning goals and reach the professional skills required for their practical work in geomatics and surveying.SIThis work has been supported by the 2022 Educational Innovation Program of the Universidad de León (PAID – Plan de Apoyo a la Innovación Docente

Extending FuzAtAnalyzer to approach the management of classical negation

FuzAtAnalyzer was conceived as a Java framework which goes beyond of classical tools in formal concept analysis. Specifically, it successfully incorporated the management of uncertainty by means of methods and tools from the area of fuzzy formal concept analysis. One limitation of formal concept analysis is that they only consider the presence of properties in the objects (positive attributes) as much in fuzzy as in crisp case. In this paper, a first step in the incorporation of negations is presented. Our aim is the treatment of the absence of properties (negative attributes). Specifically, we extend the framework by including specific tools for mining knowledge combining crisp positive and negative attributes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A Study on the Control Loop Design of Non-Isolated Configurations for Hybrid Storage Systems

This work focuses on the control strategies for different configurations of Non-Isolated Hybrid Energy Storage Systems. Basic strategies are proposed, studied and compared. Parting from the standard parallel connection of bidirectional boost converter in hybrid storage systems, a comparison with alternate topologies is presented. These alternative schemes overcome the problems that arise in the original configuration due the high mismatch in voltage ratings of the individual storage systems. A strategy to design the control loops of the resulting Hybrid Energy Storage System is proposed, studied, simulated and experimentally implemented on a 1.5 kW demonstrator. The control strategy is implemented in the standard bidirectional boost converter approach and also in the series-parallel connection of the storage units. The reported results show how the proposed control strategy applied to the series parallel connection presents a good performance in terms of dynamic and steady state operation.Plan de Ciencia Tecnología e Innovación del Principado de Asturias (PCTI), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología (FICYT), Programa Severo Ochoa de Ayudas Predoctorales para la formación en investigación y docencia del Principado de Asturias, ID BP13-138. Research, Technological Development and Innovation Program Oriented to the Society Challenges of the Spanish Ministry of Economy and Competitiveness under grant ENE2013-44245-R and by the European Union through ERFD Structural Funds (FEDER)

Non-Isolated High-Gain Three-Port Converter for Hybrid Storage Systems

This work proposes a non-isolated power electronic topology to interface two distinct electrical energy storage units to a DC link, resulting in a Hybrid Storage System. The proposed solution, called Series-Parallel Connection, allows for interfacing these three ports in a simple, compact and reliable approach, based on the standard configuration of the H-bridge converter. The main advantage is that one of the storage units can be of much smaller voltage ratings than the other two, avoiding the use of multilevel or galvanic-isolated power stages. The resulting structure is compared against the most significant transformerless alternatives based on the H bridge converter, stating their advantages and drawbacks. An analysis of the switching and conduction losses in the power switches of the proposed solution is carried out in order to state the design constraints at which this solution presents improved efficiency versus the alternatives. A final set of experiments in a 10 kW built prototype demonstrates the feasibility and states the benefits as well as the main limitations of the proposed scheme.Plan de Ciencia Tecnología e Innovación del Principado de Asturias (PCTI), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología (FICYT), Programa Severo Ochoa de Ayudas Predoctorales para la formación en investigación y docencia del Principado de Asturias, ID BP13-138. Research, Technological Development and Innovation Program Oriented to the Society Challenges of the Spanish Ministry of Economy and Competitiveness under grant ENE2013-44245-R and by the European Union through ERFD Structural Funds (FEDER)