Stochastic design of high altitude propellers

[EN] High-Altitude Platform Stations or High-Altitude Pseudo-Satellites (HAPS) use propulsion systems which are commonly based on propellers. In this paper, an algorithm for the design of those propellers considering uncertainties is developed and applied. The algorithm is based on the non intrusive polynomial chaos expansion scheme, which converts the stochastic design problem into an equivalent deterministic one. Two uncertainties are studied and characterized: 1) the stratospheric wind fluctuations using reanalysis datasets and 2) the variability of the aerodynamic coefficients caused by the low Reynolds number. The results of the method are analyzed to tackle how relevant the uncertainties are in the propulsion of the stratospheric platforms. The case of study is an ideal stratospheric airship that operates at a mean wind speed of 9 m/s and requires a thrust of 100 N, both uncertain magnitudes. The propeller is built on NACA4412 airfoils and the cost function to be maximized is the mean net propulsion efficiency. The new method provides a relevant gain in the mean efficiency when compared with the deterministic optimization.S

Advances in CFD Modeling of Urban Wind Applied to Aerial Mobility

[EN] The feasibility, safety, and efficiency of a drone mission in an urban environment are heavily influenced by atmospheric conditions. However, numerical meteorological models cannot cope with fine-grained grids capturing urban geometries; they are typically tuned for best resolutions ranging from 1 to 10 km. To enable urban air mobility, new now-casting techniques are being developed based on different techniques, such as data assimilation, variational analysis, machine-learning algorithms, and time series analysis. Most of these methods require generating an urban wind field database using CFD codes coupled with the mesoscale models. The quality and accuracy of that database determines the accuracy of the now-casting techniques. This review describes the latest advances in CFD simulations applied to urban wind and the alternatives that exist for the coupling with the mesoscale model. First, the distinct turbulence models are introduced, analyzing their advantages and limitations. Secondly, a study of the meshing is introduced, exploring how it has to be adapted to the characteristics of the urban environment. Then, the several alternatives for the definition of the boundary conditions and the interpolation methods for the initial conditions are described. As a key step, the available order reduction methods applicable to the models are presented, so the size and operability of the wind database can be reduced as much as possible. Finally, the data assimilation techniques and the model validation are presented.S

Maneuver Optimization for Simultaneous Airspeed Calibration and Wind Estimation

[EN] The purpose of this work is to optimize systematically the maneuver required to identify the wind and calibrate the airspeed sensor of a subsonic aircraft using a GPS method. The optimization is based on sensitivity analyses that require a considerable number of flight simulations. To face this challenging computational effort, we adapted and parallelized a particle swarm optimization algorithm. We also introduced a new formulation of the sensor model in the Bernstein form. The results show stability using the selected formulation and bring out non-obvious aliasing and precision loss effects that depend on the maneuver configuration. The knowledge of these effects allowed us to fine-tune the maneuver in order to improve the estimation's precision. Finally, we validated the method using the JSBSim flight simulator under calm and light turbulence conditions.S

World of Warcraft Stats System: Evolution and Casualization

Since World of Warcraft release, it has remained as the MMORPG with more subscribers of the market, and during that time, it has evolved in diverse ways. One of the aspects that have suffered more changes is its character stats system, which is an elemental part of this game. By studying it, we can learn much about the game evolution. Some players feel that the game has evolved to appeal to more casual audiences. In this study, we will analyze the development of World of Warcraft character stats system through the expansions while trying to determine if these changes have promoted the casualization of the game. Study results could be interesting for game designers and game researchers as an example of the long-term evolution of one of the most important computer games in history

Station-keeping HAPS mission through optimal sprint and drift trajectories

[EN] Due to the latest technological breakthroughs, High-Altitude Pseudo Satellites (HAPS) have recently become a feasible solution with great potential in the aerospace industry for Earth observation and communications, among other applications. Minimizing the energy consumption of these solar powered platforms is critical and, in the case of lighter than air vehicles, leads to smaller and more manageable platforms. When stratospheric airships perform a station-keeping mission, a certain displacement from the Earth surface reference point is usually admissible. This flexibility makes it possible to define an optimal control law for the airship that minimizes the energy required to fly in a 24-hour cycle, leading to a sprint and drift trajectory. This study analyzes the impact on the energy balance of the mission that stems from the changes in the allowed station-keeping radius. It also considers the effects of the daylight hours, the wind intensity, and the characteristics of the onboard energy system. The associated optimal control problems are rigorously solved numerically by means of a transcription method with regularization. The results define the optimal sprint and drift trajectories adapted to every scenario, providing the time evolution of the available power that controls the flight. The analysis indicates that following the optimal trajectory leads to weight savings in the energy system of about 5.4 kilograms per kilometer of the station-keeping radius. It entails that, for example, if a 20 kilometer radius is allowed, the energy required decreases more than 6% and the payload capacity increases about a 43% when compared to the fixed-point flight.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Caracterización geotécnica y mineralógica de bentonitas. Comparativa de distintos métodos de análisis de tamaño de partícula

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Objetos virtuales de aprendizaje para ciencias de la salud

[EN] From the beginning, the "Bologna Declaration" sought to achieve full university homologation given the heterogeneity of European educational systems. In this environment, where professional practices are combined with continuous assessment and personalized tutoring, the use of the Internet-ICT binomial enhances teaching methods and speeds up knowledge acquisition times. Universities must integrate them to train competent professionals. Some technologies that make use of ICT are Augmented Reality (AR) and Virtual Reality (VR). These allow the creation of educational content capable of supporting the teaching-learning process, such as Virtual Learning Objects (OVA). Objective: To develop multiple OVAs for the training of students and professionals in nursing and health sciences. Methodology: Study where various OVAs are generated divided into three blocks [Theoretical Foundations (FT), Basic Clinical Practice (PCB), Advanced Clinical Practice (PCA)]. Each block contains a series of teaching units that will be dealt with using VR / AR. The materials are generated by a multidisciplinary group of professionals working collaboratively. Results: materials have been generated in poster format, virtual tours and mental health interventions. Conclusion: The interaction between professionals generates educational materials in OVA format that can be used by health sciences students and promote their learning.[ES] Desde un primer momento, la “Declaración de Bolonia” buscó lograr una total homologación universitaria ante la heterogeneidad de los sistemas educativos europeos. En este espacio, donde las prácticas profesionales se unen con la evaluación continua y la tutoría personalizada, la utilización del binomio Internet-TIC potencia los métodos de enseñanza y agiliza los tiempos de captación de conocimientos. Las universidades deben integrarlas para formar profesionales competentes. Algunas tecnologías que hacen uso de las TIC son la Realidad Aumentada (RA) y Realidad Virtual (RV). Estas permiten crear contenidos educativos capaces de apoyar el proceso de enseñanza-aprendizaje, como son los Objetos Virtuales de Aprendizaje (OVA). Objetivo: Elaborar múltiples OVA para la formación de estudiantes y profesionales de enfermería y ciencias de la salud. Metodología: Estudio donde se generan diversas OVA divididas en tres bloques [Fundamentos Teóricos (FT), Práctica Clínica Básica (PCB), Práctica Clínica Avanzada (PCA)]. Cada bloque contiene una serie de unidades docentes que se tratarán haciendo uso de la RV/RA. Los materiales son generados por un grupo multidisciplinar de profesionales trabajando colaborativamente. Resultados: se han generado materiales en formato póster, tours virtuales e intervenciones de salud mental. Conclusión: La interacción entre profesionales genera materiales educativos en formato OVA que pueden ser utilizados por los alumnos de ciencias de salud y favorecer su aprendizaje.De Castro Peraza, M.; Delgado Rodriguez, N.; Castro Molina, F.; Lorenzo Rocha, N.; Torres Jorge, J.; De Vega De Castro, A.; Alonso Quintana, M.... (2021). Objetos virtuales de aprendizaje para ciencias de la salud. En IN-RED 2021: VII Congreso de Innovación Edicativa y Docencia en Red. Editorial Universitat Politècnica de València. 983-995. https://doi.org/10.4995/INRED2021.2021.13745OCS98399

Strontium hexaferrite platelets: a comprehensive soft X-ray absorption and Mössbauer spectroscopy study

IBERMÖSS-2019, Bilbao, 30-31 may 2019. --https://www.ehu.eus/es/web/ibermossmeetingStrontium ferrite (SFO, SrFe12O19) is a ferrite employed for permanent magnets due to its high magnetocrystalline anisotropy. Since its discovery in the mid-20th century, this hexagonal ferrite has become an increasingly important material both commercially and technologically, finding a variety of uses and applications. Its structure can be considered a sequence of alternating spinel (S) and rocksalt (R) blocks. All the iron cations are in the Fe3+ oxidation state and it has a ferrimagnetic configuration with five different cationic environments for the iron (three octahedral sites, a tetraedrical site and a bipiramidal site)[1,2]. We have studied the properties of SrFe 12O19 in the shape of platelets, up to several micrometers in width, and tens of nanometers thick, synthesized by a hydrothermal method. We have characterized the structural and magnetic properties of these platelets by Mössbauer spectroscopy, x-ray transmission microscopy (TMX), transmission electron microscopy (TEM), x-ray diffraction (XRD), vibrating-sample magnetometry (VSM), x-ray absorption spectroscopy (XAS), x-ray circular magnetic dichroism (XMCD) and photoemission electron microscopy (PEEM). To the best of our knowledge this is the first time that the x-ray absorption spectra at the Fe L 2,3 edges of this material in its pure form have been reported. The Mössbauer results recorded from these platelets both in the electron detection and transmission modes have helped to understand the iron magnetic moments determined by XMCD (Fig.1). The experimental results have been complemented with multiplet calculations aimed at reproducing the observed XAS and XMCD spectra at the Fe L 2,3 absorption edge, and by density functional theory (DFT) calculations to reproduce the oxygen K- absorption edge. Finally the domain pattern measured in remanence is in good agreement with micromagnetic simulations [3]

Risk Factors and Predictive Score for Bacteremic Biliary Tract Infections Due to Enterococcus faecalis and Enterococcus faecium: a Multicenter Cohort Study from the PROBAC Project

Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 [66%] were E. faecium and 25 [34%] E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 [95% CI0.67 to 0.80]. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score # 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score.8 página

The SADDEN DEATH Study: Results from a Pilot Study in Non-ICU COVID-19 Spanish Patients

Introduction: The worldwide pandemic, coronavirus disease 2019 (COVID-19) is a novel infection with serious clinical manifestations, including death. Our aim is to describe the first non-ICU Spanish deceased series with COVID-19, comparing specifically between unexpected and expected deaths. Methods: In this single-centre study, all deceased inpatients with laboratory-confirmed COVID-19 who had died from March 4 to April 16, 2020 were consecutively included. Demographic, clinical, treatment, and laboratory data, were analyzed and compared between groups. Factors associated with unexpected death were identified by multivariable logistic regression methods. Results: In total, 324 deceased patients were included. Median age was 82 years (IQR 76–87); 55.9% males. The most common cardiovascular risk factors were hypertension (78.4%), hyperlipidemia (57.7%), and diabetes (34.3%). Other common comorbidities were chronic kidney disease (40.1%), chronic pulmonary disease (30.3%), active cancer (13%), and immunosuppression (13%). The Confusion, BUN, Respiratory Rate, Systolic BP and age ≥65 (CURB-65) score at admission was >2 in 40.7% of patients. During hospitalization, 77.8% of patients received antivirals, 43.3% systemic corticosteroids, and 22.2% full anticoagulation. The rate of bacterial co-infection was 5.5%, and 105 (32.4%) patients had an increased level of troponin I. The median time from initiation of therapy to death was 5 days (IQR 3.0–8.0). In 45 patients (13.9%), the death was exclusively attributed to COVID-19, and in 254 patients (78.4%), both COVID-19 and the clinical status before admission contributed to death. Progressive respiratory failure was the most frequent cause of death (92.0%). Twenty-five patients (7.7%) had an unexpected death. Factors independently associated with unexpected death were male sex, chronic kidney disease, insulin-treated diabetes, and functional independence. Conclusions: This case series provides in-depth characterization of hospitalized non-ICU COVID-19 patients who died in Madrid. Male sex, insulin-treated diabetes, chronic kidney disease, and independency for activities of daily living are predictors of unexpected death