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Methodology for the assessment of the friction torque of ball slewing bearings considering preload scatter

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Friction 2024年第8期12卷 1838-1857页

作者： iñigo ESCANCiANO iker HERAS Florian SCHLEiCH Josu AGUiRREBEiTiA Department of Mechanical Engineering University of the Basque CountryBilbao 48080Spain Fraunhofer-institute for Wind Energy Systems iWES Hamburg 27572Germany

This manuscript presents an innovative methodology for the assessment of the friction torque of ball slewing *** methodology aims to overcome the limitations of state-of-the-art approaches,especially when the friction torque is conditioned by the preload of the *** this end,the authors propose to simulate the preload scatter when solving the load distribution problem,prior to the friction torque *** preload scatter allows to simulate a progressive transition of the balls from a four-point contact state to a two-point contact *** implementing this capability into an analytical model,the authors achieve a successful correlation with experimental ***,depending on the stiffness of the structures to which the bearing is assembled,it is demonstrated that the rigid ring assumption can lead to inaccurate friction torque results when a tilting moment is *** methodology described in this research work is meant to have a practical ***,the manuscript provides guidelines about how to use and tune the analytical model to get a reliable friction torque prediction tool.

关键词： slewing bearing ball bearing friction torque preload scatter

High-temperature tribological performance of functionally graded Stellite 6/WC metal matrix composite coatings manufactured by laser-directed energy deposition

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Friction 2024年第3期12卷 522-538页

作者： Marta OSTOLAZA Alaitz ZABALA Jon inaki ARRiZUBiETA iñigo LLAVORi Nagore OTEGi Aitzol LAMiKiZ Department of Mechanical Engineering University of the Basque Country UPV/EHUPlaza Torres Quevedo 1Bilbo 48013Spain Faculty of Engineering Mechanics and Industrial ProductionMondragon UnibertsitateaLoramendi 4Mondragon 20500Spain

Wear-driven tool failure is one of the main hurdles in the *** issue can be addressed through surface coating with ceramic-reinforced metal matrix ***,the maximum ceramic content is limited by *** this work,the tribological behaviour of the functionally graded WC-ceramic-particlereinforced Stellite 6 coatings is *** that end,the wear resistance at room temperature and 400°C is ***,the tribological analysis is supported by crack sensitivity and hardness evaluation,which is of utmost importance in the processing of composite materials with *** indicate that functionally graded materials can be employed to increase the maximum admissible WC content,hence improving the tribological behaviour,most notably at high ***,a shift from abrasive to oxidative wear is observed in high-temperature wear testing.

关键词： friction coating metal matrix composite functionally graded materials high temperature laserdirected energy deposition

Neuropilin-1: A feasible link between liver pathologies and COViD-19

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World Journal of Gastroenterology 2021年第24期27卷 3516-3529页

作者： Aitor Benedicto iñigo García-Kamiruaga Beatriz Arteta Department of Cellular Biology and Histology School of Medicine and NursingUniversity of the Basque CountryLeioa 48940BizkaiaSpain Department of Gastroenterology and Hepatology San Eloy HospitalBarakaldo 48902Spain

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)pandemic has a tremendous impact on the health of millions of people ***,those suffering from previous pathological conditions are more vulnerable and tend to develop more severe disease upon infection with the new *** coronavirus interacts with the angiotensin-converting enzyme 2 receptor to invade the ***,another receptor,neuropilin-1(NRP-1),has been reported to amplify the viral ***,NRP-1 is expressed in nonparenchymal liver cells and is related to and upregulated in a wide variety of liver-related *** has been observed that SARS-CoV-2 infection promotes liver injury through several pathways that may be influenced by the previous pathological status of the patient and liver expression of ***,coronavirus disease 2019 causes an inflammatory cascade called cytokine storm in patients with severe *** cytokine storm may influence liver sinusoidal-cell phenotype,facilitating viral *** this review,the shreds of evidence linking NRP-1 with liver pathologies such as hepatocellular carcinoma,liver fibrosis,nonalcoholic fatty liver disease and inflammatory disorders are discussed in the context of SARS-CoV-2 *** addition,the involvement of the infection-related cytokine storm in NRP-1 overexpression and the subsequent increased risk of SARS-CoV-2 infection are also *** review aims to shed some light on the involvement of liver NRP-1 during SARSCoV-2 infection and emphasizes the possible involvement this receptor with the observed liver damage.

关键词： Liver Liver sinusoidal endothelial cells Hepatic stellate cells SARS-CoV-2 COViD-19 Pathology

impact of surface roughness on the coefficient of friction of polymer-on-polymer contacts for deflection pulley-rope systems in the lift industry

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Friction 2024年第9期12卷 2126-2138页

作者： Ainhoa GUiNEA Andrea AGiNAGALDE Wilson TATO iñigo LLAVORi Pablo GARCiA Leire ARRAiAGO Alaitz ZABALA Mechanical and industrial Production Department Mondragon UnibertsitateaMondragon 20500Spain Orona EiC Orona IdeoHernani 20120Spain

The coefficient of friction(CoF)between the deflection pulley and rope in a lift strongly affects the life span of the *** surface roughness is a key factor affecting the metallic pulley–rope CoF,its effect on polymeric pulleys is *** present study analyses the effect of roughness and working conditions on cast polyamide 6(PA6G)deflection pulley–thermoplastic polyurethane(TPU)-coated rope *** statistical analysis revealed that the effect of surface roughness on the CoF for low-load tests was *** present study contributes significantly to parameter selection in deflection pulley machining to minimise friction between the pulley and rope.

关键词： polymer-on-polymer friction roughness dry sliding

Contrasting demographic trends and asymmetric migration rates in a spatially structured amphibian population

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integrative Zoology 2020年第6期15卷 482-497页

作者： Berta CAPELLÀ-MARZO Gregorio SÁNCHEZ-MONTES iñigo MARTÍNEZ-SOLANO Department of Biodiversity and Evolutionary Biology Museo Nacional de Ciencias NaturalesCSICMadridSpain

N_(a)tural populations often persist at the landscape scale as metapopulations,with breeding units(subpopulations)experiencing temporal extinction and recolonization *** parameters to forecast population viability in these systems include the ratio of the effective number of breeders(N_(b))to the total number of adults(N_(a))and migration rates among ***,we present the results of a 10-year integrative monitoring program of a metapopulation of the iberian green frog(Pelophylax perezi)in central *** characterized population dynamics at two main breeding ponds(Gravera and Laguna)using capture-mark-recapture data to estimate N_(a)in each breeding season,and multilocus genotypes to estimate the effective population size(Ne),N_(b),individual breeding success,and migration *** ponds experienced population decline after a dry season,with Gravera subsequently recovering and Laguna suffering a bottleneck associated with genetic *** this subpopulation,average allelic richness and private alleles decreased from 2010(10.87 and 1.67,respectively)to 2018(8.0 and 0.20).The N_(b)/N_(a)ratio in Laguna in 2018 was twice as high(0.95)than in Gravera(0.41)or in pre-bottleneck Laguna(0.50),suggesting plasticity or genetic compensation through increased individual breeding *** rates were asymmetric between ponds,with a stronger contribution from Gravera to Laguna(29.9%vs.16.2%in the opposite direction)that may result in a rescue *** study emphasizes the importance of integrative demographic approaches for the monitoring of natural populations based on a better understanding of their spatio-temporal dynamics,which provides valuable information for conservation actions.

关键词： bottleneck capture-mark-recapture genetic monitoring metapopulation N_(b)/N_(a)ratio

Momentum considerations inside near-zero index materials

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Light(Science & Applications) 2022年第8期11卷 1782-1789页

作者： Michaël Lobet iñigo Liberal Larissa Vertchenko Andrei VLavrinenko Nader Engheta Eric Mazur John A.Paulson School of Engineering and Applied Sciences Harvard University9 Oxford StreetCambridgeMA02138USA Department of Physics and Namur institute of Structured Materials University of NamurRue de Bruxelles 515000NamurBelgium Electrical and Electronic Engineering Department Universidad Pública de NavarraCampus ArrosadíaPamplona31006Spain Department of Photonics Engineering Technical University of DenmarkØrsteds Plads 345ADK-2800 KgsLyngbyDenmark Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA

Near-zero index (NZi) materials, i.e., materials having a phase refractive index close to zero, are known to enhance or inhibit light-matter interactions. Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. Because momentum exchange should also be incorporated into theoretical models, we investigate momentum inside the three categories of NZi materials, i.e., inside epsilon-and-mu-near-zero (EMNZ), epsilon-near-zero (ENZ) and mu-near-zero (MNZ) materials. in the context of Abraham–Minkowski debate in dispersive materials, we show that Minkowski-canonical momentum of light is zero inside all categories of NZi materials while Abraham-kinetic momentum of light is zero in ENZ and MNZ materials but nonzero inside EMNZ materials. We theoretically demonstrate that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZi materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZi materials. Absence of diffraction pattern in slits experiments is seen as a consequence of zero Minkowski momentum. Lastly, consequence on Heisenberg inequality, microscopy applications and on the canonical momentum as generator of translations are discussed. Those findings are appealing for a better understanding of fundamental light-matter interactions at the nanoscale as well as for lasing applications.

关键词： materials. momentum Minkowski

Non-systemic fungal endophytes in Festuca rubra plants infected by Epichloë festucae in subarctic habitats

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Fungal Diversity 2013年第3期60卷 25-32页

作者： iñigo Zabalgogeazcoa Pedro E.Gundel Marjo Helander Kari Saikkonen instituto de Recursos Naturales y Agrobiología(iRNASA-CSiC) Apartado 257SalamancaSpain MTT Agrifood Research Finland Plant Production Research31600 JokioinenFinland iFEVA-CONiCET–Faculty of Agronomy Buenos Aires University(UBA)Av.San Martín 4453(C1417DSE)Buenos AiresArgentina Section of Ecology Department of BiologyUniversity of Turku20014 TurkuFinland

Epichloëfestucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca *** fungus is transmitted vertically from the mother plant to ***,the presence of *** could affect the infection of a plant by other fungal *** could occur if *** metabolites produced in planta interfere negatively with other fungal infections;or alternatively,if the modulation of plant defenses by the endophyte favour further fungal *** have analyzed the presence of culturable non-systemic endophytes in plants of *** infected(E+)and not infected(E−)by *** in two subarctic habitats,meadows and riverbanks in Northern *** observed non-systemic endophyte infection frequencies were similar among E+and E−plants from riverbanks,and E+plants from *** contrast to these,the infection frequency was significantly lower in E−plants from *** result suggests that the presence of *** is not a main factor determining the presence of non-systemic endophytes in ***,plant genetic characteristics related to compatibility with *** and other endophytes in the more stable meadow populations might play a role in these fungus–fungus–plant *** a result of the survey,18 different taxa of non-systemic endophytes were identified in plants of *** were ascomycetes except for one *** endophytic taxa could not be ascribed to a genus,but sequence data indicated that they were conspecific with other unidentified endophytes that have been isolated in cold biomes at different locations.

关键词： Grass Fungi Diversity Finland

Large anomalous Hall, Nernst effect and topological phases in the 3d-4d/5d-based oxide double perovskites

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npj Computational Materials 2023年第1期9卷 613-622页

作者： Kartik Samanta Jonathan Noky iñigo Robredo Juergen Kuebler Maia G.Vergniory Claudia Felser Max Planck institute for Chemical Physics of Solids 01187 DresdenGermany Donostia international Physics Center 20018 Donostia-San SebastiánSpain Technische Universitaet Darmstadt 64289 DarmstadtGermany Department of Physics and Astronomy University of Nebraska-LincolnLincolnNE 68588USA

Magnetism and spin-orbit coupling are two fundamental and interconnected properties of oxide materials,that can give rise to various topological transport phenomena,including anomalous Hall and anomalous Nernst *** transport responses can be significantly enhanced by designing an electronic structure with a large Berry *** this context,rocksalt-ordered double perovskites(DP),denoted as A2BB’O6,with two distinct transition metal sites are very powerful platforms for exploration and *** this work,we present a comprehensive study based on the intrinsic anomalous transport in cubic and tetragonal stable DP compounds with 3d-4d/5d *** findings reveal that certain DP compounds show a large anomalous Hall effect,displaying topological band crossings in the proximity of the Fermi energy.

关键词： topological perovskite Nernst

Multiphysics Simulation of a Novel Concept of MEMS-based Solid Propellant Thruster for Space Propulsion

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Journal of Thermal Science 2011年第6期20卷 527-533页

作者： José A.Moríigo José Hermida-Quesada Dept.of Space Programmes National Institute for Aerospace Technology Ctra.Ajalvir km.4Torrejón de Ardoz 28850 MadridSpain Propulsion EngineerPh.D. Dept.of Aerodynamics and Propulsion National Institute for Aerospace Technology Ctra.Ajalvir km.4Torrejón de Ardoz 28850 MadridSpain

This work analyzes a novel MEMS-based architecture of submillimeter size thruster for the propulsion of small spacecrafts,addressing its preliminary characterization of *** architecture of microthruster comprises a setup of miniaturized channels surrounding the solid-propellant reservoir filled up with a high-energetic *** channels guide the hot gases from the combustion region towards the nozzle entrance located at the opposite side of the *** simulations of the transient response of the combustion gases and wafer heating in thruster firings have been conducted with FLUENT under a multiphysics modelling that fully couples the gas and solid parts *** approach includes the gas-wafer and gas-polymer thermal exchange,burnback of the polymer with a simplified non-reacting gas pyrolysis model at its front,and a slip-model inside the nozzle portion to incorporate the effect of gas-surface and rarefaction onto the gas ***,accurate characterization of thruster operation requires the inclusion of the receding front of the polymer and heat transfer in the moving gas-solid *** study stresses the improvement attained in thermal management by the inclusion of lateral micro-channels in the *** particular,the temperature maps reveal the significant dependence of the thermal loss on the instantaneous surface of the reservoir wall exposed to the heat flux of hot ***,the simulations stress the benefit of implementing such a pattern of micro-channels connecting the exit of the combustion reservoir with the *** results prove that hot gases flowing along the micro-channels exert a sealing action upon the heat flux at the reservoir wall and partly mitigate the overall thermal loss at the inner-wall vicinity during the *** analysis shows that propellant decomposition rate is accelerated due to surface preheating and it suggests that a delay of the flame extinction into the reservoir

关键词： micronozzles spacecraft micropropulsion solid propellant thrusters