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Structural concepts for metallic LH2 tank designs life enhancement
No full textHydrogen is positioning itself as a key solution to decarbonise aviation, offering a clean and sustainable alternative to reduce pollutant emissions in a sector that significantly contributes to climate change. This thesis presents a fatigue analysis of preliminary designs for liquid hydrogen (LH2) storage tanks manufactured from AA2219-T87 aluminium alloy with friction stir welding (FSW). A global finite element method (FEM) model has been developed to capture stress distributions under cryogenic conditions, supported by a refined submodel for precise crack propagation analysis. Two approaches have been examined: classical fatigue life estimation based on crack initiation using S–N data, and damage tolerance assessment through fracture mechanics of crack growth at cryogenic temperatures. The results indicate an overestimation of fatigue life during initiation, mainly due to assumptions and limited experimental evidence, while crack propagation is significantly faster and strongly influenced by environmental conditions and the reduced thickness of the tank walls. These findings highlight the importance of complementing structural-scale analyses with localised fracture assessments. Future work will focus on experimental validation and advanced monitoring techniques to improve the safety and reliability of liquid hydrogen tanks.El hidrógeno se está posicionando como una solución clave para descarbonizar la aviación, ofreciendo una alternativa limpia y sostenible para reducir las emisiones contaminantes en un sector que contribuye significativamente al cambio climático. Esta tesis presenta un análisis de fatiga de diseños preliminares para tanques de almacenamiento de hidrógeno líquido (LH2) fabricados con aleación de aluminio AA2219-T87 y soldadura por fricción-agitación (FSW). Se ha desarrollado un modelo global de elementos finitos (MEF) para capturar las distribuciones de esfuerzo bajo condiciones criogénicas, apoyado por un submodelo refinado para un análisis preciso de la propagación de grietas. Se han examinado dos enfoques: la estimación clásica de vida a fatiga
basada en la iniciación de grietas usando datos S–N y la evaluación de tolerancia al daño mediante mecánica de fractura de crecimiento de grietas a temperaturas criogénicas. Los resultados indican
una sobreestimación de la vida a fatiga durante la iniciación, principalmente debido a suposiciones y la limitada evidencia experimental, mientras que la propagación de la grieta es significativamente
más rápida y fuertemente influenciada por las condiciones ambientales y el espesor reducido de las paredes del tanque. Estos hallazgos resaltan la importancia de complementar los análisis a escala estructural con evaluaciones localizadas de fractura. El trabajo futuro se centrará en la validación experimental y técnicas avanzadas de monitorización para mejorar la seguridad y fiabilidad de los tanques de hidrógeno líquido.Hidrogenoa iristen ari da hegazkinaren deskarbonizaziorako soluzio gako bezala, kutsaduraren emisioak murrizteko alternatiba garbia eta jasangarria eskainiz, klima aldaketaren eragile nagusietako bat den sektorea. Tesi honek hidrogenozko tanke baten neke analisia aurkezten du.
AA2219-T87 aluminio aleazioko eta marruskadura-agitazioko (FSW) soldadurarekin fabrikatutako hidrogeno likidoko (LH2) biltegiratze-tanken diseinu aldaketa hasiberriak aztertuz. Elementu finitoen metodo orokor (EFM) eredua garatu da krio-tenperaturako baldintzetan tentsio banaketak
jasotzeko, eta azpisistema batekin haustura-propagazioaren azterketa zehatza egiteko lagundu da. Bi ikuspegi aztertu dira: haustura hasierako eta nekearen iraupenaren estimazio klasikoa S-N datuetatik
abiatuta, eta haustura-propagazioaren kalte-tolerantzia azterketa krio-tenperaturan. Emaitzek neke iraupenaren gehiegizko estimazioa erakusten dute, batez ere hipotesiak eta frogagintza mugatuaren
ondorioz; hausturaren propagazioa askoz azkarragoa da eta inguruneko baldintzak eta tankearen hormaren lodiera txikia direla eta eragin handia du. Aurkikuntzak egitura-mailako azterketak haustura lokalizatuarekin osatzea garrantzitsua dela azpimarratzen dute. Etorkizuneko lana izango
da frogak egiteko esperimentuak eta aurreratutako jarraipen-teknikak erabiliz hidrogeno likidoko tankeak segurtasun eta fidagarritasunez hobetzera bideratzea
The Statistical Reader: The Role of Orthographic Regularities in Reading
No full textAvailable online 14 April 2025Recent statistical learning views of reading posit that writing systems present to their readers a wide range of statistical regularities which are leveraged to process printed texts. While substantial research has focused on the “vertical” correlations between orthographic, phonological, and semantic units in a given writing system, here we employ information-theoretic measures to further consider “horizontal” regularities—the extent to which printed units predict and are predicted by other printed units, in one writing system compared to another. As a first step, we present a novel information-theoretic measure that captures how horizontal regularities constrain lexical access given the distribution of orthographic information in a writing system and considering realistic retinal and cognitive constraints. We then present a series of empirical studies serving as proof of concept, from both single-word reading experiments and analyses of eye movements during naturalistic reading, which examine how a reader who has internalized these regularities could leverage them for efficient uncertainty reduction regarding printed information while reading on-the-fly. Our findings converge on high-order general principles fleshed out in terms of explicit computational mechanisms that simultaneously apply to a wide range of writing systems and that can potentially explain behavioral outcomes across the trajectory of reading development and reading skill. (PsycInfo Database Record (c) 2025 APA, all rights reserved)This article was supported by the following grants: The Israel Science Foundation, Grant 705/20 awarded to Ram Frost; the Israel Science Foundation, Grant 1034/23 awarded to Noam Siegelman; an Azrieli Foundation, Early Career Faculty Fellowship awarded to NoamSiegelman; and the Natural Sciences and Engineering Research Council of Canada, Grant DG 502584 awarded to Blair C. Armstrong. This research was also funded in part by the European Commission (Grant 692502-L2STAT) awarded to Ram Frost. For the purpose of open access, the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission
Development of a decision-making method for the selection of suitable primary shaping processes in small volume production.
No full textThe selection of primary shaping processes is a critical task in manufacturing, particularly in meeting presents demands for rapid, cost-effective, and high-quality production. Defined by DIN 8580 as the "manufacturing of a solid body from a shapeless material by creating cohesion," primary shaping processes are essential in determining the geometry and defining features of manufactured parts. Despite their significance, selecting the most suitable process remains a complex challenge due to the diversity of manufacturing methods, varying process capabilities and attributes, and the large number of parameters involved. This complexity has resulted in a gap in the development of decision-making systems (DMSs) for primary shaping process selection.
This thesis addresses this gap by proposing a framework to support the selection of primary shaping processes for small-volume production. The framework utilizes a set of defined manufacturing parameters to evaluate and rank alternatives using a multi-criteria decision-making (MCDM) approach. A systematic literature review (SLR) was conducted to identify existing decision-making methods and the parameters commonly used in DMSs for manufacturing process selection. Complementary empirical research, including expert interviews and a survey, was employed to identify the parameters specific to primary shaping processes.
The findings led to the design of a hybrid MCDM method with an a posteriori approach, combining the Best Worst Method (BWM) with modified TOPSIS. Based on this method, a conceptual DMS, which integrates the identified manufacturing parameters as criteria within the hybrid MCDM framework is proposed. This framework addresses the complexities of primary shaping process selection and provides a robust, adaptable solution. This thesis concludes by outlining future research directions, including the development of a database to enhance the scalability and applicability of the proposed DMS
A simulation-based method for testing an abnormally high incidence of specific choice patterns in discrete choice data
No full textThis paper introduces a simulation-based method designed to detect unusually high frequencies of specific choice patterns in discrete choice data. Its empirical size and power are then evaluated through a series of simulation exercises. The results show that the empirical size is consistently lower than the assumed theoretical significance level, and that the test power approaches 100 % when the observed choice pattern appears approximately 2.5 times more frequently than expected. The proposed test is applied to a real data set obtained by means of a discrete choice experiment focused on air pollution in South Delhi, India.MCIN/AEI/10.13039/501100011033 through grant PID2020-113650RB-I00 and PID2023-147981OB-I00, the Basque Government through grant IT1508-22, IT1461-2
Phonological feature abstraction before 6 months: Amodal recognition of place of articulation across multiple consonants.
No full textPublished on 14 January 2025.The classical view is that perceptual attunement to the native language, which emerges by 6–10 months, developmentally precedes
phonological feature abstraction abilities. That assumption is challenged by findings from adults adopted into a new language
environment at 3–5 months that imply they had already formed phonological feature abstractions about their birth language prior
to 6 months. As phonological feature abstraction had not been directly tested in infants, we examined 4–6-month-olds’ amodal
abstraction of the labial versus coronal place of articulation distinction between consonants. In the training phase, infants heard
a series of labial non-words paired with an animal image and a series of coronal non-words (multisyllabic) paired with another
image. At test, they viewed a silent video of a talker producing coronal and labial words, paired with either the familiarised image
or the contrary image. The infants looked significantly longer on matching trials than mismatching trials, suggesting amodal
abstraction of this consonantal place of articulation distinction by 4–6 months. These findings provide direct evidence for the
inference from the adoptee findings that phonological feature abstraction emerges prior to perceptual attunement.The author would like to thank the MARCS Babylab staff for their help in conducting this study
Human‑induced Vegetation Dynamics Reconstructed through Pollen Analysis of a Recent Salt Marsh Sedimentary Sequence (Nalón estuary, N Spain)
No full textThe effects of sea-level rise due to global climate change, coupled with socioeconomic development and population growth, have exerted constant pressure on coastal wetlands, leading to their decline. Sediment dynamics, along with other natural processes, are significantly affected, resulting in a general reduction in coastal wetland areas and alteration of the ecological processes within their plant communities. In this context, the present study evaluates the vegetation dynamics of a highly-impacted salt marsh in the Nalón estuary, Asturias, Spain, using high-temporal-resolution pollen analysis, granulometry, elemental geochemistry, and sediment accumulation rates. In the early twentieth century, several flooding events influenced sediment accumulation rates and modified the structure of local marsh vegetation. Subsequently, a process of secondary succession was detected, triggered by the removal of the salt marsh herbaceous cover between the 1970s and 1990s. Aerial images from the Plan Nacional de Ortofotografía Aérea (PNOA), the Vuelo de Costas 1989–1991, and the Sistema de Información Territorial del Principado de Asturias provide evidence of these land use changes. The regional vegetation was impacted by Pinus and Eucalyptus plantations. The pollen record reveals a transition from high to low marsh vegetation during the early twenty-first century, caused by the effects of hydraulic infrastructure construction in the upper and middle basin sections and the decrease in fluvial sediment input. This study highlights the global problem of coastal wetland area reduction, reveals the effects of human activities on ecosystem dynamics, and helps to clarify the response of vegetation to constant natural and anthropogenic pressure.This research was funded by RTI2018-095678-B-C21, MCIU/AEI/FEDER, UE (MINECO) and IT1616-22 (EJ/GV) projects. Carlos Galaz is supported by predoctoral fellowship granted by Mexican Consejo Nacional de Humanidades, Ciencia y Tecnología (CONAHCYT 771105). Jon Gardoki is supported by a predoctoral fellowship granted by the Basque Government (PRE_2020_1_0035)
A review of federated learning applications in intrusion detection systems
No full textIntrusion detection systems are evolving into sophisticated systems that perform data analysis while searching for anomalies in their environment. The development of deep learning technologies paved the way to build more complex and effective threat detection models. However, training those models may be computationally infeasible in most Internet of Things devices. Current approaches rely on powerful centralized servers that receive data from all their parties — substantially affecting response times and operational costs due to the huge communication overheads and violating basic privacy constraints. To mitigate these issues, Federated Learning emerged as a promising approach, where different agents collaboratively train a shared model, without exposing training data to others or requiring a compute-intensive centralized infrastructure. This paper focuses on the application of Federated Learning approaches in the field of Intrusion Detection. Both technologies are described in detail and current scientific progress is reviewed and taxonomized. Finally, the paper highlights the limitations present in recent works and proposes some future directions for this technology.This research work is supported by the Basque Government through projects KK-2023/00012, KK-2023/00090, KK-2024/00030, KK-2024 /00068 and IT1504-22. It is also supported by grant CNS2023-144315 funded by the MICIU/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR”. It is also supported by grant PID2023-152390NB-I00 funded by the MICIU/AEI/10.130 39/ 501100011033 and by “FEDER funds”. Dr. Javier Navaridas holds a Ramón Cajal fellowship funded by the Spanish Ministry of Science, Innovation and Universities (RYC2018-024829-I), funded by MCIN/AEI/ 10.13039/ 501100011033 and, as appropriate, by “ESF Investing in your future” or by “European Union NextGenerationEU/PRTR”. Aitor Belenguer is supported by a predoctoral grant from the Basque Government
Experimental data on aerosols exhaled into the environment from different wind musical instruments
No full textBrass bands that include wind instruments are heavily affected by rules established during the pandemic. The aim of this experimental work was to assess the aerosols emitted through different wind instruments. The Aerodynamic Particle Sizer (APS) was used to measure the aerosols emitted and transmit those characteristics to a database. The results revealed that the dynamic level at which a note is produced, regardless of whether it is a clarinet, trumpet, or bassoon, significantly changes in aerosol concentrations emitted. Specifically, if there is a higher dynamic level, an increase in emissions of particle concentration will occur by comparing the levels piano, mezzo forte, and forte. These aerosols are produced with a diameter of approximately 0.8 μm, except for the Navarra bagpipe, which has a diameter of 1.8 μm. In addition, this last instrument is the one that emits more particles every second, reaching a value five times larger than that with two reeds, such as the bassoon. Staccato and legato are two well-known techniques among musicians that help in articulating a musical piece. The difference between the two methods in terms of the concentration of the number of particles is not remarkable and is almost negligible
The right and the politics of labor informality enforcement
No full textThe enforcement of labor informality is subject to electoral motivations, and political parties on the left and right have different incentives to do so. While leftist governments are more lenient not to harm their informal electorate, right-wing incumbents face an electoral dilemma: the part of its constituency that benefits from informal work is in favor of a permissive attitude, but another section demands a tough hand to deal with the unfair competition that informal work represents. Taking Chile as a case study and drawing on panel data on labor inspections, this article explores the electoral drivers behind enforcement. Our estimations, robust to fixed-effect and panel event-study approach, reveal that the left does not forbear, but the right carries out selective enforcement, concentrating inspections in competitive districts and accelerating the pace of control as presidential polls approach. The article concludes with policy recommendations to limit the electoral bias
Reported severity of psychotic, depressive and anxiety symptoms in relation to bilingual language profile: An exploratory study and the validation of Basque versions of the PQ-B, DASS-42, PHQ-9 and GAD-7
No full textPublished: March 3, 2025Background
Language plays a crucial role in health care and especially in mental health, since the use of the native language helps to make a good diagnosis as several studies have shown.
Aim
We studied the influence of language on the accurate detection of psychotic and affective symptoms, exploring differences in the severity of reported symptomatology in a bilingual Basque-Spanish population.
Methods
The study uses the Prodromal Questionnaire-Brief for the detection of psychosis and the Patient Health Questionnaire-9, Generalized Anxiety Disorder Scale-7, and Depression, Anxiety and Stress Scale-42 for the assessment of stress, anxiety and depression. Basque versions of the scales were developed and their psychometric properties were evaluated in a sample of 623 individuals, including 521 from the general population and 102 psychiatric patients. Possible relations between questionnaire scores and four linguistic factors, namely first language (L1), proficiency, age of acquisition and language exposure, were examined.
Results
The four translated questionnaires showed adequate sensitivity, goodness-of-fit, and reliability indices, thus validating their suitability for general and clinical settings. The results showed that reporting of depressive symptoms seemed to be modulated by linguistic variables, mainly L1, whereas the severity of psychotic symptoms was less reliably associated with the gathered linguistic factors.
Conclusions
Overall, our results suggest that language of assessment by means of written instruments may have a limited impact on healthcare outcomes in balanced bilingual populations. The study enriches the understanding by considering various linguistic factors beyond L1, and by exploring the effect of these factors on affective symptoms, apart from psychotic ones.This work was supported by the Health
Department of the Basque Government. The
funders had no role in study design, data collection
and analysis, decision to publish, or preparation of
the manuscript