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Hydraulic fracture behavior in the presence of hydrogen in notched miniature cylindrical specimens of a 42CrMo4 steel
Get PDFThe influence of internal hydrogen on the mechanical behavior of the 42CrMo4 steel grade has been evaluated by means of internal pressure fracture tests performed on hydrogen precharged notched cylindrical specimens. The notched cylindrical specimens were precharged in a 1 M H2SO4 solution + 0.25 g/l As2O3 for 3 h and 1.2 mA/cm2. Thereupon, hydraulic fracture tests were done under different ramps of pressure: 208, 100, 52, 35 and 25 MPa/h, respectively. Hydrogen content introduced into the notched cylindrical specimens (∼1 ppm) was determined by thermal desorption analysis (TDA), using a LECO DH 603 hydrogen analyser. Hydrogen damage was observed as testing time increased until 2 h. The burst pressure is reduced around 28 % while the Notch Mouth Opening Displacement decreased around 50 %. Hydrogen embrittlement susceptibility is discussed through the hydrogen embrittlement micromechanisms.The authors would like to thank the Spanish Government for the financial support received to perform the research projects RTI2018-096070-B-C33 and PID2021-124768OB-C21. L.B. Peral is grateful for his Margarita Salas Postdoctoral contract (Ref.: MU-21-UP2021-030) funded by the University of Oviedo through the Next Generation European Union
Portal del empleado
Get PDFMaterial del curso del IFIE "Soy profesor novel en la UBU. ¿Y ahora qué?", 28 de noviembre al 5 de diciembre de 202
The proyect of Friar Antonio de San José Pontones for the vestry in the Cathedral of Burgos. 1759
Get PDFDesde el siglo XVI, el Arzobispado y Cabildo de Burgos alimentaron el propósito de levantar una
nueva sacristía en correspondencia con la solemnidad del culto que se celebraba en la Catedral.
A pesar de los distintos intentos, solo se alcanza tal objetivo de forma definitiva ya avanzado el
siglo XVIII. Entonces, el prestigioso maestro jerónimo fray Antonio de San José Pontones elaboró un proyecto que se ha localizado recientemente. Y, aunque tampoco se llevó a cabo, resulta un
interesante testimonio del universo en el que se movía la Seo burgalesa en el contexto del último
barroco.Since the 16th Century, the Archbishopric and the Town Council of Burgos intended to carry out
a new vestry for the Cathedral in accordance to worship celebrations held back then. After several
attempts, such goal was achieved only by the last decades of the 18th century. In this context,
the prestigious Jerome master friar Antonio de San José Pontones developped a Project that has
been recently brought to light. And even when the plan was never materialised, proved to be an
important evidence of the atmosphere in which the Cathedral was building on those days, in the
baroque sunset
The Fábrica Confraternities as episcopal funding plan. The case of Salamanca old cathedral in 14th and 15th centuries
No full textLas Cofradías de Fábrica u Obra constituyeron una fuente de financiación extraordinaria utilizada
a menudo por obispos y cabildos para poder hacer frente a los gastos, ordinarios y extraordinarios,
de construcción de las grandes catedrales medievales. Por desgracia, la escasa documentación
conservada de estas dificulta la comprensión de su funcionamiento y trascendencia. El objetivo
de este artículo es poder conocerlas mejor a través de las noticias conservadas de tres cofradías
bajomedievales que fueron fundadas en la catedral vieja de Salamanca, en los siglos XIV y XV.The Confraternities of Fábrica were an important source of income for bishops and chapters in
order to face up to ordinary and extraordinary expenses of the building of medieval cathedrals.
Unfortunately, we have scarce documents and can hardly understand their working and relevance. This article tries to know better these brotherhoods through the documentation preserved
from three late gothic confraternities founded in the old cathedral of Salamanca, during 14th and
15th centuries.El presente artículo se ha elaborado en el marco del proyecto de investigación El patronazgo artístico en el reino de Castilla y León (1230-1500). Obispos y catedrales II, financiado por el Ministerio de Economía y Competitividad y Fondos FEDER, HAR2017-88045, y del GIR “Patrimonio artístico medieval” (GIR ULE 435)
Combining reinforcement learning and conventional control to improve automatic guided vehicles tracking of complex trajectories
Get PDFWith the rapid growth of logistics transportation in the framework of Industry 4.0,
automated guided vehicle (AGV) technologies have developed speedily. These systems present two coupled control problems: the control of the longitudinal velocity,
essential to ensure the application requirements such as throughput and tag time,
and the trajectory tracking control, necessary to ensure the proper accuracy in loading and unloading manoeuvres. When the paths are very short or have abrupt
changes, the kinematic constraints play a restrictive role, and the tracking control
becomes more challenging. In this case, advanced control strategies such as those
based on intelligent techniques, including machine learning (ML) can be useful.
Hence, in this work, we present an intelligent hybrid control scheme that combines
reinforcement learning-based control (RLC) with conventional PI regulators to face
both control problems simultaneously. On the one hand, PIs are used to control the
speed of each wheel. On the other hand, the input reference of these regulators is
calculated by the RLC in order to reduce the guiding error of the path tracking and to
maintain the longitudinal speed. The latter is compared with a PID path following
controller. The PID regulators have been tuned by genetic algorithms. The RLC allows
the vehicle to learn how to improve the trajectory tracking in an adaptive way and
thus, the AGV can face disturbances or unknown physical system parameters that
may change due to friction and degradation of AGV mechanical components. Extensive simulation experiments of the proposed intelligent control strategy on a hybrid
tricycle and differential AGV model, that considers the kinematics and the dynamics
of the vehicle, prove the efficiency of the approach when following different
demanding trajectories. The performance of the RL tracking controller in comparison
with the optimized PID gives errors around 70% smaller, and the average maximum
error is also 48% lower.Open access funding enabled and organized by Projekt DEAL
NIS/HFIP‐Mediated Synthesis of Indene‐Based β‐Iodoalkenyl Sulfides from Propargylic Sulfides
Get PDFA tandem 1,3-sulfur migration followed
by iodocyclization reaction of propargylic sulfides
in the presence of NIS in HFIP has been developed
to synthesize indene-based β-iodoalkenyl sulfides.
The choice of the reaction media is crucial to
promote the reaction. The proposed mechanism
involving the initial NIS activation by HFIP and
favoring the sulfur migration of the starting propargylic thioether via cationic intermediates is experimentally supported. In addition, the suitability of
selected indene-based β-iodoalkenyl sulfides as
building blocks for subsequent C C bond-forming
reactions has been demonstrated.We gratefully acknowledge MICINN (PID2020-115789GBC21); and “NextGenerationEU/PRTR” (PDC2021-120825- C21), and Junta de Castilla y León and FEDER (BU049P20) for financial support. The project leading to these results has also received funding from “la Caixa” Foundation, under the Agreement LCF/PR/PR18/51130007> (CAIXA-UBU001). N.V. and S.S.-P. thank Junta de Castilla y León (Consejería de Educación) and Fondo Social Europeo for predoctoral (N.V) and postdoctoral (S.S.-P.) contracts, respectively
Developing a Tutorial for Improving Usability and User Skills in an Immersive Virtual Reality Experience
No full textThe fast development and progressive price reduction of Virtual Reality
(VR) devices open a broad range of VR applications. Especially interesting are
those applications focused on educational objectives. However, before these VR
applications can be extensively presented in the educational system, some main
issues to optimize their efficiency in the student’s autonomous learning process
should be solved. While in non-VR games designers have consistently developed
introductory tutorials to prepare new players for the game’s mechanics, in the case
of VR, the design of these tutorials is still an open issue. This research presents
a tutorial for VR educational applications to help the users to become familiar
with the virtual environment and to learn the use of the interaction devices and
the different mechanics within the experiences. In addition, the usability of this
tutorial was tested with final users to assure its effectiveness.This work was partially supported by the ACIS project (Reference Number INVESTUN/21/BU/0002) of the Consejeria de Empleo e Industria of the Junta de Castilla y León (Spain), the Erasmus+ RISKREAL Project (Reference Number 2020-1-ES01-KA204-081847) of the European Commission and the FLEXIMEC20 project (Reference Number 10/18/BU/0012 of the Planes Estrategicos de I+D) of the Instituto para la Competitividad Empresarial de Castilla y León (Spain) cofinanced with European Union FEDER funds
Los partidos (I): las ofertas de los partidos nacionales
No full textEsta publicación está integrada por un conjunto sistemático de aproximaciones académicas a los aspectos más relevantes de los procesos electorales autonómicos celebrados en España entre 2017 y 2019: la legislatura, los precedentes, las distintas arenas de competición, los candidatos, los partidos nacionales y territoriales, la campaña, el papel de las redes sociales, la movilización electoral y su patrón diferencial, el balance de resultados, la geografía electoral del nuevo mapa autonómico, los efectos de los sistemas electorales, los factores explicativos del voto, la volatilidad, los perfiles de las élites parlamentarias electas, los sistemas de partidos regionales y la nueva gobernanza autonómica. Al estudio sistemático de las elecciones autonómicas de este ciclo, se han añadido análisis de urgencia de los nuevos procesos electorales vividos en plena crisis epidémica en Galicia y País Vasco (2020) y Cataluña (2021), no pudiendo llegar a tiempo a las de Madrid (2021) y Castilla y León (2022).Son unas elecciones que se producen en España en plena crisis de gobernabilidad por la profunda inestabilidad y fragmentación del sistema de partidos y en un ciclo de alternancia política en medio de una nueva repetición de elecciones generales en el año 2019, que desembocan en el primer gobierno de coalición a nivel nacional y una fuerte polarización política y territorial. En este contexto se generalizan los gobiernos de coalición basados en una dinámica de bloques y de alternancia, que dotan de especial relevancia a este ciclo electoral
Density, Viscosity, Refractive Index, and Related Thermophysical Properties of Dibutyl Ether +2-Butanol + Cyclohexane Ternary Systems
No full textNew measured data for density, (ρ), dynamic and kinematic viscosities, (μD and μc), and refractive index, (nD), are presented at T = 298.15 K and p = 0.1 MPa for binary and ternary mixtures containing dibutyl ether, 2-butanol, and cyclohexane. As a result, the derived properties are estimated based on the measured data. Excess molar volume, (VE), dynamic viscosity deviation (ΔμD), and deviation in refractive index, (ΔnD), as derived properties, are fitted using the Redlich–Kister equation. In addition, perturbed-chain statistical associating fluid theory equation of state is employed to correlate the measured data of density
Los símbolos republicanos entre la prensa y la calle: el gorro frigio en el Sexenio
No full textTrabajo realizado en el marco del proyecto de I+D+I «La construcción del imaginario monárquico. Monarquías y repúblicas en la Europa meridional y América Latina en la época contemporánea (siglos XIX y XX)», del Ministerio de Ciencia e Innovación (ref. PID2019-109627GB-I00). Agradezco a la profesora Marie-Angèle Orobon su gentileza por facilitarme algunas de las referencias que cito; y a Eduardo Higueras por la ayuda brindada para confirmar la identidad de algunos personajes