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Bluetooth Low Energy Driver for Varifocal Liquid Crystal Lenses
No full textLiquid crystal (LC) adjustable lenses require numerous electrodes for precise phase modulation. This article presents an electronic driver for varifocal LC lenses, engineered to control devices featuring up to 80 electrodes and requiring activation voltages below 10 Vrms. The system leverages 14-bit digital-toanalog converters (DACs) and a programmable system-on-chip (SoC) microcontroller with integrated Bluetooth low energy (BLE) for wireless control via a smartphone graphical user interface (GUI). Its performance is validated using 24-electrode spiral phase plates (SPPs) and 72-electrode spiral diffractive lenses (SDLs), demonstrating the ability to address diverse topologies at refresh rates up to 180 frames/s. This capability enables advanced functionalities such as dynamic focusing and chromatic aberration correction.The authors would like to thank the research group CEMDATIC, Universidad Politecnica de Madrid, Madrid, Spain, for giving them the lenses and their characterization parameters. Funding for APC: Universidad Carlos III de Madrid (Agreement CRUE-Madrono 2025)
A coadjoint orbit like construction for Jordan superalgebras
No full textWe investigate the canonical pseudo-Riemannian metrics on the Jordan-analogues of the coadjoint superorbits of a unital pseudo-Euclidean Jordan superalgebra with a positive even part.F. M. C. acknowledges that this work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UC3M in the line of “Research Funds for Beatriz Galindo Fellowships” (C&QIG-BG-CM-UC3M), and in the context of the V PRICIT (Regional Program of Research and Technological Innovation). S. J. acknowledges support by the International Max Planck Research School Mathematics in the Sciences. L. S. acknowledges partial support by grant SCHW893/5-1 of the Deutsche Forschungsgemeinschaft, and also expresses his gratitude for the hospitality of the Max Planck Institute for the Mathematics in the Sciences in Leipzig during numerous visits. This publication is based upon work from COST Action CaLISTA CA21109 supported by COST (European Cooperation in Science and Technology, http://www.cost.eu)
Atmospheric drag uncertainty quantification for orbit determination and propagation via Stochastic Consider Parameters
No full textThe efficiency and sustainability of spacecraft operations is a growing challenge due to the accelerated increase of the space objects population. Thus, the quality of Space Traffic Management (STM) and Space Situational Awareness (SSA) services is essential to ensure the sustainability of the space environment. The quality of such services relies not only on an accurate knowledge of the Resident Space Object (RSO) state, but also on its associated uncertainty. However, there is a lack of accurate and cost-effective methodologies for Uncertainty Quantification (UQ) in the context of SSA, where a large number of objects are maintained in the catalogues. The atmospheric drag is one of the largest sources of uncertainty in Low Earth Orbits (LEO). Stochastic models have been widely proposed in the literature to represent its aleatoric nature. However, the introduction of stochastic dynamics increases the complexity of orbit propagation and determination. On the other side, classical implementations to characterize the uncertainty from dynamical models in batch least-squares orbit determination such as the consider parameters theory fail to represent the stochastic nature of the atmospheric drag uncertainty, despite maintaining a tractable level of complexity. This work presents the validation with real data of the Stochastic Consider Parameters (SCP) model, a methodology developed for uncertainty quantification via covariance estimation applied to batch least-squares orbit determination and propagation that allows considering the effect of stochastic time-correlated errors to improve the covariance realism efficiently. To estimate the parameters that govern the stochastic noise, the SCP model is combined with a previously developed uncertainty quantification method. Such method receives as input estimated and propagated orbits, quantifying the uncertainty of the system offline of the orbit determination and propagation processes, not requiring modification of operational Space Surveillance and Tracking (SST) systems. In this work, real radar observations from the Spanish Space Surveillance Radar (S3TSR) are used to test the covariance realism improvement of the SCP method for several RSOs at different altitudes with respect to deterministic constant error models. The results analyse the physical interpretation of the estimated noise parameters with real data, while also evaluating key metrics to assess covariance realism such as Cramer-von-Mises metric and covariance containment.This project has received funding from the Comunidad de Madrid under "Ayudas destinadas a la realización de doctorados industriales" program (project IND2020/TIC-17539). JM acknowledges the support of Spain's Agencia Estatal de Investigación (Ref. PID2021-125159NB-I00 TYCHE) funded by MCIN/AEI/10.13039/501100011033 and by ERDF "A way of making Europe". Moreover, the authors would like to acknowledge the Spanish Space Agency (Agencia Espacial Española - AEE) and in particular Cristina Pérez Hernández for the provision of the S3TSR observations under the S3T program. Finally, special thanks to GMV Precise Orbit Determination department for their support to provide precise ephemeris for Sentinel 3A
Modeling of a Hall thruster plume: influence of plume boundary conditions and size, and cathode location
No full textThe current-free plasma plume of a Hall effect thruster is investigated through a 2D axisymmetric hybrid (particle-in-cell/fluid) model and code. First, since the simulated plume is necessarily finite, attention is paid to the boundary conditions at the plume boundary P. A novel global plume condition (GPC) model, which directly imposes the global current-free condition at P and determines the potential far downstream, is implemented. This is compared with the widely used local plume condition (LPC) model, which over-forces the current-free condition by imposing zero current density locally at P, thus artificially distorting plasma plume characteristics. Second, the influence of the cathode location on plume characteristics, electron current paths, and the cathode-to-plume coupling voltage is studied in detail. Configurations with centrally and laterally-mounted cathodes are compared. Central cathodes have better discharge performance due to the improved cathode-beam coupling. Laterally-mounted cathodes behave very differently depending on whether they are located inside or outside a magnetic separatrix (MS) surface, generally present in the plume. MS-external cathodes present much worse cathode-plume coupling. These trends with the cathode location are in line with previous experimental and numerical studies. Finally, the influence of the plume size has been assessed within all the above studies: the GPC, with a much better physical basis than the LPC, makes the plume solution less dependent on plume size; and the MS-external lateral cathodes are more affected by plume sizes and thus require working with larger plume domains.This work has been supported by the CHEOPS LOW POWER project, funded by the European Union’s Horizon 2020 Research and Innovation Program, under Grant Agreement Number 101004331
Production and characterization of the Cu5Cr35Fe35V20Mo5 high entropy alloy as a coupling interlayer for plasma facing components
No full textThis work presents the development of a high entropy alloy (HEA) that can act as a thermomechanical coupling layer in high heat flux components of next generation fusion reactor cooling systems, such as DEMO, which are based on W monoblocks coupled to CuCrZr components. A novel non-equiatomic HEA, Cu5Cr35Fe35V20Mo5 was produced by arc melting, and its microstructure, mechanical and thermal properties were analyzed in the as-cast and aged states. Consistent with model predictions, the as-cast alloy exhibits a BCC single phase, and the presence of sparsely V-enriched submicron precipitates that are retained up to 700 ◦C. Heat treatment at 750 ◦C results in the formation of the sigma phase, which causes hardening of the alloy and promotes the formation of Cu precipitates. The alloy aged at 700 ◦C exhibits exceptional compressive ductility, even at room temperature, with serration behavior in the initial stages. Mechanical twinning was observed after nanoindentation and compression tests at room temperature. However, samples deformed at 500 ◦C did not show mechanical twinning, presenting a deformed microstructure in which slip deformation is present. The 700 ◦C aged material presents a good combination of thermal conductivity (15.5 W/K⋅m at RT), thermal expansion coefficient (11.2 × 10- 6 K.-1) and mechanical properties to act as a thermal barrier interlayer between the W and the CuCrZr. Through the application of an analytical model, it has been demonstrated that the residual stresses generated in the W-HEA-CuCrZr system, in which the HEA has been used as a coupling interlayer, resulting from the maximum temperature variations allowed for the CuCrZr-based heat extraction system, ΔT ≈ - 350 ◦C, are below the yield stress of the materials, thereby ensuring the integrity of the components and improving themechanical performance of the heat sink components of the divertor.This research has been supported by the Ministerio de Ciencia e Innovación of Spain and the Agencia Estatal de Investigación (PID2019-105325RB-C33/MCIN/AEI/10.13039/501100011033) and by the Regional Government of Madrid through the program TECHNOFUSIÓN(III)CM (S2018/EMT-4437), project cofinanced with Structural Funds (ERDF and ESF). The support of the Regional Government of Madrid through the multi-annual agreement with UC3M (“Excelencia para el Profesorado Universitario” - EPUC3M14) is also acknowledged
Evaluación de exosomas de leche de cabra como plataformas naturales de liberación controlada de curcumina
Full text linkEn los últimos años, el desarrollo de sistemas de liberación de fármacos (DDS por sus siglas en inglés) ha experimentado grandes avances, principalmente por la incorporación de nuevas herramientas nanotecnológicas. En este contexto, las nanopartículas surgen como potencial herramienta para el transporte y liberación controlada de tratamientos, gracias a disponer de pequeño tamaño (a escala de procesos biológicos) y fabricarse con cierta facilidad a partir de gran variedad de materiales. A pesar de que son numerosas las nanopartículas empleadas en el campo de la biomedicina, tanto de naturaleza metálica (nanopartículas de hierro o de oro), como poliméricas (liposomas o dendrímeros), su traslación clínica se ha visto limitada en gran medida por problemas de toxicidad asociados a su naturaleza sintética. De ello surge el interés de desarrollar nanopartículas naturales capaces de solventar estas limitaciones de las nanopartículas artificiales. En el conjunto de las nanopartículas naturales destacan los exosomas, un subtipo de vesículas extracelulares de tamaño nanométrico, como nanoplataformas de origen celular. Los exosomas son pequeñas vesículas con estructura de bicapa lipídica que actúan como mediadores de la comunicación célula-célula. Entre sus propiedades más relevantes destacan su tamaño nanométrico por debajo de los 150 nm, sus elevados tiempos de circulación en sangre y su baja inmunogenicidad, que les convierte en perfectos candidatos para ser utilizados como DDS. Además, su estructura de bicapa lipídica permite la incorporación de moléculas lipofílicas e hidrofílicas.
La curcumina es un polifenol procedente de la planta denominada cúrcuma, al que se atribuyen propiedades antioxidantes y antiinflamatorias. No obstante, se trata de una molécula hidrofóbica que presenta dificultades para su biodistribución. Esta molécula lipofílica presenta baja solubilidad y biodisponibilidad, además de experimentar una rápida excreción. Para superar estas limitaciones asociadas a su solubilidad, en las últimas décadas se han comenzado a emplear nanosistemas para su vehiculización en sistemas vivos. Frente al origen no natural de nanovehículos sintéticos tales como liposomas o nanopartículas metálicas, en los últimos años ha comenzado a emerger el uso de nuevas nanoplataformas naturales como los exosomas. Los exosomas pueden ser utilizados como nanovehículos de carga capaces de proteger el fármaco, incrementando su vida media de circulación y mejorando su biodistribución, lo que aumenta su biodisponibilidad en el tejido o proceso diana.
Este trabajo de tesis presenta por primera vez el uso de exosomas (o pequeñas vesículas extracelulares) derivadas de leche de cabra como sistemas de encapsulación del fármaco natural curcumina para su posterior evaluación in vivo como nuevos sistemas terapéuticos antiinflamatorios en enfermedades hepáticas crónicas. Para ello, se han optimizado dos técnicas de carga de fármaco, una metodología pasiva basada en una incubación a 37ºC (ExoCurPas) y otra activa mediada por saponina (detergente permeabilizador) (ExoCurAc). Los exosomas cargados con curcumina fueron analizados físico-químicamente mediante dispersión dinámica de luz (DLS por sus siglas en inglés), análisis de seguimiento de nanopartículas (NTA por sus siglas en inglés), microscopía confocal electrónica (TEM por sus siglas en inglés), así como ópticamente por citometría de flujo (FC por sus siglas en inglés) y nanofotometría, lo que permitió verificar que tanto la estructura de la nanopartícula como las propiedades inherentes de la curcumina no se vieron alteradas. Los sistemas obtenidos mediante aproximación activa (ExoCurAc) fueron seleccionados para los posteriores análisis in vitro e in vivo al presentar unas propiedades óptimas en tamaño, morfología y carga de curcumina. La capacidad de liberación controlada del fármaco (curcumina) a partir de los sistemas exosomas-curcumina fue evaluada in vitro por fluoroespectrometría de la curcumina liberada al medio. Una vez se comprobó que la nanoplataforma había sido optimizada y que cumplía su función, se analizó su efectividad en ensayos celulares in vitro. Se evaluó el efecto terapéutico de exosoma-curcumina a través de ensayos de citotoxicidad y captación en dos líneas celulares (RAW 264.7 y HepG2) y una línea primaria de hepatocitos. El impacto de las nanoplataformas exosomas-curcumina se analizó mediante FC, microscopía confocal y espectrofotometría del agente bromuro de 3-(4,5-dimetiltiazol-2-il)-2,5,-difenil tetrazolio (MTT por sus siglas en inglés) a distintos tiempos y dosis para evaluar los daños celulares. Por último, la evaluación in vivo de la nueva nanoplataforma como herramienta terapéutica se llevó a cabo mediante un modelo de daño hepático crónico en ratón mediado por , analizando el efecto antiinflamatorio y hepatoprotector de la curcumina encapsulada. Se evaluó la administración intravenosa de 3 dosis de de exosomas-curcumina administradas cada 5 días. Se realizó un estudio longitudinal en el que los animales fueron sacrificados a las 48 h de recibir la última inyección del inductor químico (). El efecto terapéutico de la curcumina encapsulada se analizó mediante reacción en cadena de la polimerasa (PCR por sus siglas en inglés) de factores inflamatorios y análisis histológico de hígado a través de las tinciones hematoxilina-eosina (H\&E por sus siglas en inglés), rojo de sirio (SR por sus siglas en inglés) e inmunohistoquímica del marcador hemo-oxigenasa-1 (HO-1). Además, se evaluaron dos marcadores séricos de daño hepático, alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST).Programa de Doctorado en Ciencia y Tecnología Biomédica por la Universidad Carlos III de MadridPresidente: Alberto Benito Martín.- Secretaria: Aurora Bernal Mera.- Vocal: María Luisa Soto Montenegr
V Seminario Internacional LabDINTEC. Propiedad inmobiliaria y tokenización. Libro de actas
Full text linkEsta publicación es parte del proyecto I+D+i PID2021-124961NB-I00, financiado por MCIN/AEI/10.13039/501100011033/FEDER Una manera de hacer EuropaEsta edición contó con el apoyo de la Universidad Carlos III de Madrid, a través de su programa de ayudas para la organización de congresos científicos correspondiente al año 2024
Interface logistic problems: Large diffusion and singular perturbation results
Full text linkIn this work we consider an interface logistic problem where two populations live in two different regions, separated by a membrane or interface where it happens an interchange of flux. Thus, the two populations only interact or are coupled through such a membrane where we impose the so-called Kedem¿atchalsky boundary conditions. For this particular scenario we analyse the existence and uniqueness of positive solutions depending on the parameters involved in the system, obtaining interesting results where one can see for the first time the effect of the membrane under such boundary conditions. To do so, we first ascertain the asymptotic behaviour of several linear and nonlinear problems for which we include a diffusion coefficient and analyse the behaviour of the solutions when such a diffusion parameter goes to zero or infinity. Despite their own interest, since these asymptotic results have never been studied before, they will be crucial in analysing the existence and uniqueness for the main interface logistic problems under analysis. Finally, we apply such an asymptotic analysis to characterize the existence of solutions in terms of the growth rate of the populations, when both populations possess the same growth rate and, also, when they depend on different parameters.This paper has been partially supported by Ministry of Economy and Competitiveness and Ministry of Science, Innovation and Universities of Spain under research projects PID2019-106122GB-I00 and PID2023-149509NB-I00, respectively
A Piezoresistive Printable Strain Sensor for Monitoring and Control of Soft Robotic Links
Full text linkProceedings of 2025 IEEE International Conference on Robotics and Automation (ICRA), 19-23 May 2025, Atlanta, USAIntegrating sensors into soft links with complex geometries without compromising their flexibility, precision, or structural integrity remains one of the main challenges in soft robotics. This article presents the design, fabrication, and electromechanical evaluation of a 3D-printed flexible strain sensor tailored for monitoring and controlling these links. By combining Fused Filament Fabrication (FFF) and Direct Ink Writing (DIW) technologies, we manufactured a sensor composed of a thermoplastic polyurethane (TPU) substrate and a pattern of silver (Ag) nanoparticles ink, ensuring high flexibility and conductivity. We performed electromechanical tests to assess the sensor's performance, including three-point bending tests, cyclic loading to evaluate its durability, and angular deflection measurements to confirm its precision in detecting bending angles. The sensor demonstrated efficient piezoresistive behavior within a defined working range between 3% and 8% of flexure strain with a Gauge Factor (GF) of 0.24 and stable repeatability. We also tested its integration into a soft link, showing that the sensor maintains flexibility and accuracy during deformation.The research leading to these results has been partially funded by the project SIROCO, with reference PID2023-147343OB-I00, funded by MICIU /AEI /10.13039/501100011033 and FEDER, UE; the ADAPTA project, reference PLEC2023-010218, funded by MCIN/AEI/10.13039/501100011033; and by projects funded by the Instituto de Competitividad Empresarial (IVACE) within the nominative line granted to the Asociación de Investigación de Materiales Plásticos y Conexas (AIMPLAS) to support its activity in independent I+D, dissemination of research results, and the transfer of knowledge and technology to companies in the Comunitat Valenciana (File IMAMCA/2023/4)
Computational analysis of submerged submarine bow hull dynamics subjected to torpedo blunt impact and warhead detonation events
Full text linkIn the maritime sector, ensuring the survivability of ships and submarines against diverse threats such as torpedo impacts, Underwater Explosion (UNDEX) events, and environmental factors is paramount. Comprehensive analysis of hull dynamics under various impact scenarios is essential. Numerical simulations of these impacts utilize different material models, ship grounding tests, impact modes, UNDEX simulations, and failure mechanisms. In the current study, the blunt impact of a torpedo on the submarine bow and the surface detonation effects of the torpedo warhead (at different distances from the hull) on the submarine bow structure were analyzed within an underwater enclosure. The torpedo design was based on the MK-48, with Ti-6Al-4V alloy used for the torpedo hull and HY-80 steel for the submarine hull. The impact simulations were conducted using ANSYS Explicit Dynamics® computational software. For the blunt impact scenario, a torpedo speed of 55 knots (102 km/h) was used. For the UNDEX studies, the warhead at the front end of the torpedo was modeled using PBX-9501 (a commonly used high explosive in warheads). The novelty of the current work was the employment of a water enclosure in the model to simulate the underwater impacts. The analysis focused on hull deformation, equivalent plastic and elastic strains, equivalent stress and damage profiles for the different impact scenarios. To effectively capture fluid–structure interactions, the study also examined pressure variations within the Eulerian domain. Among the scenarios analyzed, the near-field detonation of the warhead emerged as the most destructive, resulting in severe structural damage to the bow hull. In contrast, the blunt impact of the torpedo induced moderate plastic deformation, while the far-field detonation resulted in minimal damage