TECNALIA Publications

Welcome to TECNALIA Publications, the Institutional Repository of Fundación TECNALIA Research & Innovation. TECNALIA Publications' main objective is to collect, preserve and disseminate the intellectual production resulting from the research activity of TECNALIA to generate transferable knowledge and contribute thereby to development and social progress.


Recent Submissions

Evaluation of the Specific Capacitance of High-Entropy Oxide-Based Electrode Materials in View of Their Use for Water Desalination via Capacitive Method
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-01-04) Triolo, Claudia; Santangelo, Saveria; Petrovičovà, Beatrix; Musolino, Maria Grazia; Rincón, Inés; Atxirika, Ainhoa; Gil, Silvia; Belaustegui, Yolanda
Water pollution and scarcity are serious concerns for the growing world population. To meet the ever-pressing demand of fresh water, a variety of desalting techniques of seawater have been developed. Due to its environmental friendliness, high efficiency, easy regeneration of the electrodes, ambient operating pressure, and low operating potential suitable for the use in remote areas, the capacitive deionization (CDI) method is one of the most sustainable among them. This work focuses on the preparation of high-entropy oxides (HEOs) and carbon/HEO composites and the evaluation of their specific capacitance in view of their possible use as CDI electrode materials. CrMnFeCoNi-HEO, having spinel structure (sHEO), is obtained in the form of nanoparticles (NPs) and nanofibers (NFs) by the sol–gel method and electrospinning, respectively. Composite NFs with embedded sHEO NPs or MgCoNiCuZn-HEO NPs with rock-salt structure (rHEO) are also produced. In the 5–100 mV s−1 scan rate range, the specific capacitance improves in the order C/rHEO NFs (8–32 F g−1) ≅ sHEO NPs (9–32 F g−1) < sHEO NFs (8–43 F g−1) < C/sHEO NFs (12–66 F g−1). The highest capacitance is obtained when the beneficial contributions of the carbon matrix and smaller-sized HEO NPs are synergistically coupled.
Novel Assessment Methodology for Laser Metal Deposition of New Metallic Alloys
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-01-09) Cearsolo, Xabier; Arrue, Mario; Gabilondo, Maitane; Sanchez, Jon Mikel; Galarraga, Haize; Garcia de Cortazar, Maider; Girot Mata, Franck
Metal additive manufacturing technologies are gaining great interest. However, the existing metallic alloys are generally formulated for conventional manufacturing processes. Thus, it is necessary to adapt their chemical composition or develop new alloys for the manufacturing conditions of additive manufacturing processes. The main method for manufacturing metal powder is gas atomization, but it is very expensive with long manufacturing times. Therefore, it is necessary to develop alloy validation methods that simplify the development process of new alloys. This paper deals with a methodology based on thermodynamic heat transfer equations, simulation, and powderless tests. This novel methodology enabled the determination of the optimal conditions for the laser melting deposition process of the commercial AA7075 alloy with a reduced number of experimental tests with powder, reducing the difficulties inherent to powder processing. The developed process was divided into two stages. In the first stage, the heating of the substrate was studied. In the second stage, the depositions of single tracks were validated with the parameters extrapolated from the previous stage. Hence, it was possible to manufacture single tracks free of cracks with an adequate aspect ratio.
Augmented Reality for Supporting Workers in Human–Robot Collaboration
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-04-10) Moya, Ana; Bastida, Leire; Aguirrezabal, Pablo; Pantano, Matteo; Abril-Jiménez, Patricia
This paper discusses the potential benefits of using augmented reality (AR) technology to enhance human–robot collaborative industrial processes. The authors describe a real-world use case at Siemens premises in which an AR-based authoring tool is used to reduce cognitive load, assist human workers in training robots, and support calibration and inspection tasks during assembly tasks. The study highlights the potential of AR as a solution for optimizing human–robot collaboration and improving productivity. The article describes the methodology used to deploy and evaluate the ARContent tool, which demonstrated improved usability, reduced task load, and increased efficiency in the assembly process. However, the study is limited by the restricted availability of workers and their knowledge of assembly tasks with robots. The authors suggest that future work should focus on testing the ARContent tool with a larger user pool and improving the authoring tool based on the shortcomings identified during the study. Overall, this work shows the potential for AR technology to revolutionize industrial processes and improve collaboration between humans and robots.
Superhydrophobic and oleophobic microtextured aluminum surface with long durability under corrosive environment
(Springer Nature, 2023-01-31) Adarraga, Olatz; Agustín-Sáenz, Cecilia; Bustero, Izaskun; Brusciotti, Fabiola
Superhydrophobic (SHP) and oleophobic aluminum surfaces have been prepared through the combination of a scalable chemical microtexturing process and surface functionalization with long-chained polyfluoroalkyl moieties. The effect of an anodic layer on the microtextured surface has been assessed considering surface morphology, superhydrophobicity, surface mechanical properties and corrosion protection enhancement. The surface functionalization with polyfluoroalkyl moieties has been tackled in two different ways: (i) grafting of the polyfluoroalkyl moieties and (ii) deposition of a thin hybrid coating with low content of polyfluoroalkyl-containing compound. Aluminum surfaces showing high durability in salt spray environments, which maintain SHP and oleophobic properties at least up to 2016 h have been attained. Applications for this kind of surfaces range from easy-to-clean surfaces to anti-icing or anti-condensation functionalities that could be of interest for several sectors.
Control of dual three-phase IPMSM drive with cascaded DC-link capacitors for third generation EV
(IEEE, 2021) Sierra-Gonzalez, Andres; Pescetto, Paolo; Trancho, Elena; Ibarra, Edorta; Pellegrino, Gianmario; Alvarez-Gonzalez, Fernando
In this work, a dual three-phase Interior Permanent Magnet Synchronous Machine (IPMSM) drive connected to a high voltage DC/DC converter (800 V) at its input is considered for electric vehicle (EV) applications. The drive is constituted by two cascaded three-phase inverters, enabling fast charging capabilities. In this particular configuration, balancing the input voltages of the two inverters is mandatory during operation. A novel control approach that not only provides such voltage balancing but also considers the cross-coupling effects of the dual-three phase IPMSM is proposed, guaranteeing an adequate torque regulation through the whole operation range of the drive. Simulation results, generated by means of a high fidelity platform, are provided to validate the proposed approach. Additionally, preliminary experimental results are also included.
Carbon molecular sieve membranes for selective CO2 separation at elevated temperatures and pressures
(Elsevier, 2023-02) Rahimalimamaghani, A.; Godini, H.R.; Mboussi, M.; Pacheco Tanaka, A.; Llosa Tanco, M.; Gallucci, F.
The use of Carbon Molecular Sieve Membranes (CMSM) for selective CO2 separation from post-combustion CO2-rich streams from steel plant was experimentally evaluated and reported in this paper. Efficient CMSMs were developed for such application and their promising potentials in operating at elevated temperatures and pressures were experimentally demonstrated. The best performance in terms of flux as well as perm-selectivity, above the Robeson upper bound, was obtained using a CMSM developed with ethylenediamine in the dip-coating stage of the fabrication. In fact, adding ethylenediamine was proven to be particularly important in narrowing down the pore size distribution to ultra-micropore and establishing effective CO2 adsorption site over the membrane surface and the pores wall. It was shown that using a tailored CMSM with a precursor synthesized by co-polymerization of ethylenediamine with Novolac can improve the CO2/N2 ideal perm-selectivity from 33 to 97 at operational conditions of 200 °C and 20 bar.
The Future of Wood Construction: Opportunities and Barriers Based on Surveys in Europe and Chile
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-04-06) Leszczyszyn, Ewa; Heräjärvi, Henrik; Verkasalo, Erkki; Garcia-Jaca, Javier; Araya-Letelier, Gerardo; Lanvin, Jean-Denis; Bidzińska, Gabriela; Augustyniak-Wysocka, Dobrochna; Kies, Uwe; Calvillo, Alex; Wahlströmh, Margareta; Kouyoumji, Jean-Luc
The demand for wood has increased in recent years due to new technical possibilities and environmental concerns. This paper provides an analysis of the factors that affect the use of wood in the construction sector, and an assessment of their importance in individual countries and for groups of stakeholders. The study covers the technical, societal, political, economic, and gender aspects of wood construction, with the aim of increasing global understanding regarding national differences, the current situation, and the potential for further development. The subject was investigated using a survey, and the most important opportunities for and barriers to growth in the use of wood in the construction sector were selected, following a statistical analysis. The results indicate strong regional and cultural differences regarding the acceptance of some of the opportunities and barriers related to the development of wood construction. The findings indicate that there is a need to promote wood construction based on its technical and economic benefits rather than its societal ones. On the other hand, the current societal barriers should be addressed as a priority, together with the establishment of common and harmonized policies. The results of this study, therefore, will contribute to the generation of regional-sensitive information that can be useful for policymakers when updating the building codes in their individual countries.
Maker culture and its potential for STEM education
(Springer Nature, 2022-04-19) Tabarés, Raúl; Boni, Alejandra
During the last decade, different values, tools and practices promoted by maker culture have been adopted in formal educational settings with the aim of reinvigorating Science, Technology, Engineering and Mathematics (STEM) education. Higher education institu tions (HEIs) have also engaged with maker culture to explore its potentialities regarding education, entrepreneurship and innovation. However, these collaborations with various stakeholders are not always smooth and educators need to deal with significant challenges that arise in these engagements, despite the problem-solving learning opportunities that they can offer their students. This paper presents the results of a case study that dealt with these issues through the establishment of an open and collaborative learning ecosystem (OCLE) between different educators, students and external stakeholders. The empirical work was based on thirty-three semi-structured interviews across four countries, eight focus groups and a final participatory workshop. The study argues that maker culture can offer several potentialities for pushing forward an integrative vision of STEM education as well as other disciplines from social sciences and humanities. An emphasis is placed on how tertiary education can benefit greatly from the adoption of OCLEs and how these communities of practices can encourage an education oriented to meeting societal chal lenges. The paper also warns that these kinds of interventions face significant organisa tional challenges in HEIs that demand significant institutional recognition and support to overcome this organisational resistance.
Evolutionary Multitask Optimization: a Methodological Overview, Challenges, and Future Research Directions
(Springer, 2022-04-12) Osaba, Eneko; Del Ser, Javier; Martinez, Aritz D.; Hussain, Amir
In this work, we consider multitasking in the context of solving multiple optimization problems simultaneously by conducting a single search process. The principal goal when dealing with this scenario is to dynamically exploit the existing complementarities among the problems (tasks) being optimized, helping each other through the exchange of valuable knowledge. Additionally, the emerging paradigm of evolutionary multitasking tackles multitask optimization scenarios by using biologically inspired concepts drawn from swarm intelligence and evolutionary computation. The main purpose of this survey is to collect, organize, and critically examine the abundant literature published so far in evolutionary multitasking, with an emphasis on the methodological patterns followed when designing new algorithmic proposals in this area (namely, multifactorial optimization and multipopulation-based multitasking). We complement our critical analysis with an identification of challenges that remain open to date, along with promising research directions that can leverage the potential of biologically inspired algorithms for multitask optimization. Our discussions held throughout this manuscript are offered to the audience as a reference of the general trajectory followed by the community working in this field in recent times, as well as a self-contained entry point for newcomers and researchers interested to join this exciting research avenue.
Development of a Sustainable Metallurgical Process to Valorize Copper Smelting Wastes with Olive Stones-Based Biochar
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-10-14) Adrados, Aitziber; Merchán, Mikel; Obregón, Alejandro; Artola, Antxon; Iparraguirre, Jon Ander; García de Cortázar, Maider; Eguizabal, David; Demey, Hary
Flue dust waste coming from a copper (Cu) smelting company has been valorized using a newly developed metallurgical process with the aim of recovering a dust concentrated in valuable metals, such as lead (Pb) and zinc (Zn), and studying the feasibility of replacing anthracite with biochar as reducing agent. Metallurgical trials using different mixtures of reducing agents have been performed in a furnace at 1400 °C. This furnace employs a high-power thermal plasma (HPTP) system as energy source. Using copper as the base metal, pellets containing a mixture of the waste, different reducing agents, and binder were introduced into the furnace for their dissolution. Recovery yields in the range of 45–85 wt.% for Pb and Zn were obtained in the flue dusts. All the trials proved the effectiveness of the developed process to enrich the flue dusts in valuable metals, including those only using biochar as reducing agent. Further trials will be carried out in order to better control the parameters involved in the metallurgical process developed and improve its efficiency.