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A novel methodology to characterize the thermal performances of additively manufactured heat pipes
No full textThis work studies experimentally the performance of an additively manufactured heat pipe with a triangular cross-section and grooved wick that uses acetone as the heat transfer fluid. The temperature time evolution at different axial positions of the heat pipe was measured for different heat transfer rates and fluid filling inventories. The experimental data analysis includes calculating heat losses and estimating the steady-state temperature, which has been shown to be critical for determining the thermal resistance and time constant accurately. We also propose a methodology to estimate the response time of the heat pipe to sudden changes in the thermal power demand. The presented prototype is able to evacuate up to 17 W in horizontal position with a thermal resistance lower than 1 KW−1.The authors acknowledge the financial support of the Regional Government of Madrid through the Industrial Doctorate program, Spain , Grant No. IND2019-TIC-17109
Microstructure evolution of WMoNbTiCrAlx (x = 0, 0.25, 0.5, 0.75, 1) multi-principal element alloys
No full textMulti-principal element alloys (MPEAs) based on refractory metals have been studied as potential candidates to replace Ni-based superalloys due to their superior melting temperatures and the promising initial high-temperature properties demonstrated by certain compositions. However, a significant drawback of these refractory metal-based alloys is their high density and low ductility at room temperature. It is known that the addition of Al in MPEAs contributes to reducing density, increasing hardness, and stabilizing the BCC phase. In this study, the influence of Al on the microstructure of five new multi-principal element refractory alloys produced by arc melting, using high-purity raw elements, WMoNbTiCrAlₓ (x = 0, 0.25, 0.5, 0.75, and 1), was analyzed. ThermoCalc software was utilized to support the interpretation of the experimental results. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed on all alloys in both as-cast and heat-treated (1200 °C/24 h) conditions. Additionally, electron backscatter diffraction (EBSD) analyses were performed on the heat-treated alloys. The as-cast alloys exhibited a highly segregated BCC phase with a dendritic structure. After heat treatment, the alloys predominantly presented a BCC phase, with a small volume fraction of the Laves phase being observed. Nanoindentation tests indicated that the addition of Al increases hardness, from 10.5 to 12.2 GPa. Regarding density, there was a decrease with increasing Al content, from 9.7982 to 8.7745 g/cm3.The authors would like to acknowledge the financial support from the Brazilian agency CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior)
Malleability and fault tolerance in ad-hoc parallel file systems
No full textIn the last few years, there has been a significant rise in I/O demands across different applications, especially those related to Big Data and Artificial Intelligence. This has resulted in the requirement for improvements to I/O capabilities in order to prevent potential data access bottlenecks. The Expand Ad-Hoc parallel file system is being designed and developed to address this. Given the possibility of variations in I/O workloads throughout an application¿s execution, it is essential that the file system employed possesses the requisite malleability to adapt accordingly to avoid wasting resources. Additionally, as these applications have long execution times, fault tolerance mechanisms within the file system are essential to ensure their continued operation in the presence of failures. The primary innovation of this work lies in the design of the support for malleability, taking into account the data replication of the fault tolerance. This approach results in a system that exhibits both expansion and reduction capability, made possible by the integration of malleability and fault tolerance. Therefore, this work presents a design for the Expand Ad-Hoc parallel file system and evaluates it on the HPC4AI Laboratory supercomputer in Turin. We have evaluated this design using benchmarks and real applications by comparing the result with the native file system used on the HPC4AI supercomputer. We have evaluated the fault tolerance support using benchmarks and real applications by comparing the result with the native file system used on the HPC4AI supercomputer. For the real application used, improvements of up to 100% have been obtained regarding the backend file system. For malleability, the time required to execute a malleability operation has been analyzed. In this case, the results show that it is possible to perform this malleability operation with very small overhead times. The results show that the malleability scales effectively with the resources, and despite the data replication in the fault tolerance, we outperform other parallel file systems without fault tolerance.This work has been partially funded by the Spanish Ministry of Science and Innovation project “Expand: High Performance Storage System for HPC and Big Data Environments”. Ref. TED2021-131798B-I00. And partially funded by the “Adaptive multi-tier intelligent data manager for Exascale (ADMIRE)” project of the European Union’s Horizon 2020 JTI-EuroHPC research and innovation programme. Ref. H2020-JTI-EuroHPC-2019-1, Project no. 956748. And partially funded by the project “New scalable I/O techniques for hybrid HPC and data intensive workloads (SCIOT)” with reference PID2022-138050NB-I00, funded by MICIU/AEI/10.13039/501100011033/. Funding for APC: Universidad Carlos III de Madrid (Agreement CRUE-Madroño 2025)
Nationalist mobilisation in the digital age: The role of social media in driving support for radical right-wing parties
Get PDFPrograma de Doctorado en Ciencias Sociales/ Social Sciences por la Universidad Carlos III de MadridPresidente: Paul Statham.- Secretario: Ignacio Sánchez-Cuenca Rodríguez.- Vocal: Silke Ada
Tú impersonal en la lengua académica: a propósito del proyecto PALABRIA
Get PDFCILG 2025: Libro de resúmenes = Llibre de resums = Book of abstracts, Alicante, 11-13 Jun. 2025El uso del pronombre de la segunda persona de singular tú como estrategia de impersonalización en la lengua hablada es común en español, mas, se trata de un fenómeno que no se reduce al ámbito hispánico, sino que también se da en otras lenguas indoeuropeas (romances, germánicas y eslavas) (Kluge 2010, Malamud 2012). A pesar de que el uso del tú impersonal es frecuente en el habla culta, su uso está sancionado por la norma en la lengua escrita. Se trata de un mecanismo de generalización propio de la inmediatez comunicativa y, por tanto, de la oralidad y de los registros más informales (Hidalgo 1996-1997, Serrano 2021). El uso desplazado del pronombre de 2ª persona del singular es posible en la lengua hablada, ya que la situación comunicativa se apoya en factores contextuales que permiten identificar que se ha anulado el valor referencial de dicho pronombre (Kratzer 2009). Sin embargo, su aparición en la lengua escrita, especialmente en el lenguaje literario y en el lenguaje periodístico, es un hecho (Alcaide Lara 2001). En estos casos podría interpretarse el tú impersonal como un mecanismo de persuasión y acercamiento al interlocutor. Ahora bien, su uso en la lengua escrita académica es cada vez más frecuente entre los estudiantes universitarios. A partir de las herramientas que ofrece PALABRIA-CM-UC3M, intentaremos determinar si la utilización de la segunda persona de singular constituye un mecanismo de indefinición referencial empleado con una intención comunicativa concreta o, si por el contrario, pone de manifiesto cierta tendencia a trasvasar unidades y usos propios de la lengua hablada a la lengua escrita por un desconocimiento de la norma. Para ello, el proyecto utilizará mecanismos de inteligencia artificial (IA), ya sean de machine learning o de inteligencia artificial generativa. Los algoritmos de aprendizaje máquina se han utilizado ampliamente en el ámbito educativo para el modelado de los estudiantes o la predicción, entre otros. Por ejemplo, en el ámbito de textos se han realizado trabajos para detectar sentimientos a partir de textos (Moreno-Marcos et al., 2018) o extraer respuestas o temas más frecuentes (Parmar et al., 2023). Asimismo, existen trabajos sobre la corrección de errores gramaticales (Bryant et al, 2023), aunque destaca la falta de modelos que tienen en cuenta el contexto o registro del hablante. Además, dado el incipiente uso de la IA generativa es posible combinar métodos de IA más tradicionales con IA generativa. Por ello, el proyecto PALABRIA-CM-UC3M, financiado por la Comunidad de Madrid a través del convenio-subvención para el fomento y la promoción de la investigación y la transferencia de tecnología en la Universidad Carlos III de Madrid (PALABRIA-CM-UC3M), tratará la detección del tú impersonal mediante el uso de diferentes mecanismos de IA
Environmental assessment and conductivity performance of calcium-based polymer electrolytes for the next generation of solid-state batteries
Get PDFThis study presents a comprehensive life cycle assessment (LCA) of calcium-based polymer electrolytes, aiming to advance sustainable solid-state post-lithium battery technologies. Despite calcium-based solid-state batteries offer safer and more reliable energy storage alternatives, research into their environmental and electrochemical performance remains limited compared to lithium-ion systems. In this work, three polymer electrolytes, based on a cross-linked polymer backbone doped with calcium salts (Ca (TFSI)2, Ca(CF3SO3)2, and CaI2), are studied through LCA and characterized in terms of electrochemical and thermal properties. Notably, it is observed that the salts exhibit a significantly higher contribution to environmental impacts compared to the polymer. The LCA identifies CaI2 as the most environmentally favorable, with climate change emissions of 8.01⋅10- 5 kg CO2 equivalent, particulate matter disease incidence of 3.12⋅10- 12 cases per kg PM2.5, and negligible ozone depletion impacts (1.27⋅10-6 kg CFC11 eq). Although Ca (TFSI)2 shows higher ozone depletion impact (2.68⋅10- 4 kg CFC11 eq) it demonstrates superior ionic conductivity, achieving 0.09 mS⋅cm 1 at 20 ◦C and 0.4 mS⋅cm- 1 at 90 ◦C. Moreover, differential scanning calorimetry confirms the fully amorphous structure of all electrolytes, with glass transition temperatures ranging from 19.61 ◦C (Ca (TFSI)₂) to -38.7 ◦C (CaI₂), which ionic conductivity at room temperature. These findings highlight a critical trade-off between environmental impact and electrochemical performance, providing actionable insights for the design of safer, more sustainable energy storage systems.The authors would like to thank the Madrid Government (Comunidad de Madrid-Spain) for funding CIRENAICA-CM-UC3M project. Through the Multiannual Agreement with UC3M (“Fostering Young Doctors Research”. And in the context of the VPRICIT (Research and Technological Innovation Regional Programme). This project has received also funding from the European Union's Horizon 2020research and innovation programme under grant agreement No 829145 (FETOPEN-VIDICAT)
An explicit substructuring method for overlapping domain decomposition based on stochastic calculus
Get PDFIn a recent paper [7], a hybrid supercomputing algorithm for elliptic equations has been proposed. The idea is that the interfacial nodal solutions solve a linear system, whose coefficients are expectations of functionals of stochastic differential equations confined within patches of about subdomain size. Compared to standard substructuring techniques, such as the Schur complement method for the skeleton, the hybrid approach produces an explicit and sparse shrunken matrix—hence suitable for substructuring again. The ultimate goal is to push strong scalability beyond the state of the art by leveraging the potential for parallelisation of stochastic calculus. Here, we present a major revamping of that framework, based on the insight of embedding the domain in a cover of overlapping circles (in two dimensions). This allows for efficient Fourier interpolation along the interfaces (now circumferences) and—crucially—for the evaluation of most of the interfacial system entries as the solution of small boundary value problems on a circle. This is both extremely efficient (as they can be solved in parallel and by the pseudospectral method) and free of Monte Carlo error. Stochastic numerics are only needed on the relatively few circles intersecting the domain boundary. In sum, the new formulation is significantly faster, simpler, and more accurate while retaining all of the advantageous properties of PDDSparse. Numerical experiments are included for the purpose of illustration.FB and JMV were funded by grants 2018-T1/TIC-10914 and 2022-5A/TIC-24233 of the Madrid Regional Government in Spain, RIKEN R-CCS Fugaku Trial Access call HP220345, and partially by Spanish AEI grant PID2020-115088RB-I00. JMV thanks the hospitality of RIKEN Center for Computational Science in Kobe (Japan)
Caracterización y tratamiento jurídico de las amenazas híbridas digitales: realidad, retos y propuestas
No full textPrograma de Doctorado en Derecho por la Universidad Carlos III de MadridPresidente: Agustín de Asís Roig.- Secretario: Pablo Acosta Gallo.- Vocal: Estrella Gutiérrez Davi
On Designing Transport Networks With Latency Guarantees for Next-Generation Services
Get PDFThis article presents an open-source network simulator and digital twin focused on the analysis of latency in Metropolitan Area Networks (MAN). Our tool can estimate delay percentiles between pairs of nodes, aiming to see if the MAN can support emerging services and applications with strict latency requirements. We show that probability bounds like Vysochanskij-Petunin (VP) inequality can be used to accurately estimate latency percentiles between pairs of nodes with minimal computational effort. Theoretical results are validated with extensive simulations leveraging the simmer package, an open-source Discrete Event Simulator (DES) written in R, along with igraph for visualization of networks and shortest path calculations. Two versions of the simulator are provided as open-source on GitHub for the research community to use and build upon: One for local PC and a second one optimized to be executed in the cloud with multiple cores and massive memory.This work was supported by the European Commission, Ministerio de Ciencia e Innovación, Project ITACA (Grant No. PDC2022-133888-I00) funded by Agencia Estatal de Investigación (MCIN, Spain); project SNS project SEASON (Grant No. 101096120) funded by the EU Horizon-Europe Program. This work is also supported by the R&D project PID2022-136684OB-C21 (Fun4Date-Redes) funded by the Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033
