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Wheel-rail contact model for railway vehicle-structure interaction applications:development and validation

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Railway Engineering Science 2023年第3期31卷 181-206页

作者： P.a.montenegro R.Calçada CONSTRUCT-LESE Faculty of EngineeringUniversity of PortoRua Dr.Roberto Frias S/N4200-465 PortoPortugal

An enhancement in the wheel-rail contact model used in a nonlinear vehicle-structure interaction(VSI)methodology for railway applications is presented,in which the detection of the contact points between wheel and rail in the concave region of the thread-flange transition is implemented in a simplified *** presenting the enhanced formulation,the model is validated with two numerical applications(namely,the Manchester Benchmarks and a hunting stability problem of a sus-pended wheelset),and one experimental test performed in a test rig from the Railway Technical Research Institute(RTRI)in *** its finite element(FE)nature,and contrary to most of the vehicle multibody dynamic commercial software that cannot account for the infrastructure flexibility,the proposed VSI model can be easily used in the study of train-bridge systems with any degree of *** validation presented in this work proves the accuracy of the proposed model,making it a suitable tool for dealing with different railway dynamic applications,such as the study of bridge dynamics,train running safety under different scenarios(namely,earthquakes and crosswinds,among others),and passenger riding comfort.

关键词： Vehicle-structure interaction Wheel-rail contact Manchester Benchmarks Thread-flange transition Dynamic analysis Model validation

Overcast sky condition prevails on and influences the biometeorology of the tropical Andean Páramos

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Journal of Mountain Science 2023年第1期20卷 78-86页

作者： Paola.montenegro-DÍAZ Rolando CELLERIALVEAR Galo CARRILLO-ROJAS Departamento de Recursos Hídricos y Ciencias Ambientales Universidad de CuencaCuenca010207Ecuador Facultad de Ingeniería Universidad de CuencaCuenca010207Ecuador Facultad de Ciencias Químicas Universidad de CuencaCuenca010207Ecuador

Clouds play a major role in modulating the biometeorological processes. We studied the influence of cloudiness on four biometeorological variables:daily air temperature(Tair), relative humidity(RH),reference evapotranspiration(ETr),and photosynthetic active radiation(PAR), recorded at four sites of Andean Páramos in southern Ecuador during 2.5 to 5.5 years. First, we quantified both the cloud cover percentage(Cloud%) creating cloud masks over the visible bands of Landsat 7 images and the sky condition(K_(T)) using the records of solar and extraterrestrial radiation. Second, we estimated KTfrom Cloud%. Finally, we quantified T_(air), RH, ET_(r), and PAR under clear, cloudy, and overcast K_(T) and their dependence on KT. The average Cloud% ranged between 65%–76%, and KTcorroborated the prevailing overcast sky(between 55% and 72.5% of the days) over the páramos. The proposed model performed well in the sites of calibration(R^(2)= 0.80;MBE = 0.00;RMSE = 0.05) and validation(R^(2)= 0.74;MBE =-0.07;RMSE = 0.11). The overcast sky diminished T_(air)(≤ 10℃), ET_(r)(≤ 1.6 mm day-1), and PAR(4 MJ m^(-2)day^(-1)) and increased RH(≥ 88%),while the variables showed the opposite behavior during the uncommon clear sky(≤ 5.5% of the days).Thus, mostly the dynamic of RH(R^(2)≥ 0.62), ETr(R^(2)≥ 0.85), and PAR(R2≥ 0.77) depended on K_(T). Hence,the prevailing overcast sky influenced the biometeorology of the páramos.

关键词： Cloudiness indicator Clearness index Satellite imagery Tropical Andes

Ecophysiological basis of the Jack-and-Master strategy:Taraxacum officinale(dandelion)as an example of a successful invader

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Journal of Plant Ecology 2018年第1期11卷 147-157页

作者： Marco A.Molina.montenegro Alejandro del Pozo Ernesto Gianoli Centro de Ecología Molecular y Aplicaciones Evolutivas en Agroecosistemas(CEM) Instituto de Ciencias BiológicasUniversidad de TalcaAvda.Lircay s/nTalcaChile Centro de Estudios Avanzados en ZonasÁridas(CEAZA) Facultad de Ciencias del MarUniversidad Católica del NorteLarrondo 1281CoquimboChile Research Program“Adaptation of the Agriculture to Climate Change”PIEI A2C2 Universidad de TalcaTalcaChile Centro de Mejoramiento Genético y Fenómica Vegetal Facultad de Ciencias AgráriasUniversidad de TalcaAvda.Lircay s/nTalcaChile Departamento de Botánica Universidad de ConcepciónCasilla 160-CConcepciónChile Departamento de Biología Universidad de La SerenaCasilla 554La SerenaChile

Aims Successful invasive plants are often assumed to display significant levels of phenotypic *** possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing environments have been suggested:(i)via plasticity in morphological or physiological traits,invasive plants are able to maintain a higher fitness than native plants in a range of environ-ments,including stressful or low-resource habitats:a‘Jack-of-all-trades’strategy;(ii)phenotypic plasticity allows the invader to better exploit resources available in low stress or favorable habitats,show-ing higher fitness than native ones:a‘Master-of-some’strategy and(iii)a combination of these abilities,the‘Jack-and-Master’*** We evaluated these strategies in the successful invader Taraxacum officinale in a controlled experiment mimicking natural environmen-tal *** set up three environmental gradients consisting of factorial arrays of two levels of temperature/light,temperature/water and light/water,*** compared several ecophysiologi-cal traits,as well as the reaction norm in fitness-related traits,in both *** and the closely related native Hypochaeris thrin-cioides subjected to these environmental *** Findings Overall,*** showed significantly greater accumulation of biomass and higher survival than the native ***,with this difference being more pronounced toward both ends of each *** also showed significantly higher plasticity than its native counterpart in several ecophysiological ***,*** exhibits a Jack-and-Master strategy as it is able to main-tain higher biomass and survival in unfavorable conditions,as well as to increase fitness when conditions are *** suggest that this strategy is partly based on ecophysiological responses to the environment,and that it may contribute to explaining the successful invasion of *** across diffe

关键词： biological invasion competition ecophysiological traits environmental gradients Taraxacum officinale

1D alignment of proteins and other nanoparticles by using reversible covalent bonds on cyclic peptide nanotubes

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Organic Chemistry Frontiers 2022年第5期9卷 1226-1233页

作者： Juan M.Priegue Iria Louzao Ivan Gallego Javier montenegro Juan R.Granja Singular Research Centre in Chemical Biology and Molecular Materials (CIQUS)Organic Chemistry DepartmentUniversity of Santiago de Compostela(USC)15782 Santiago de CompostelaSpain

Self-assembling cyclic peptide nanotubes are supramolecular structures whose diameter and external surface properties are precisely *** this communication we describe a general strategy to align different molecules on... 详细信息

关键词： nanoparticles alignment surface

Neural Network Based Diagnostics of Actuator for an Attitude Control System

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Computer Aided Drafting,Design and Manufacturing 2010年第2期20卷 59-67页

作者： SALOMON montenegro School of Astronautics Beijing University of Aeronautics and Astronautics

The objective of this paper is to develop a neural network-based residual generator to detect the fault in the actuators for a specific communication satellite in its attitude control system （ACS）. First, a dynamic multilayer perceptron network with dynamic neurons is used, these neurons correspond to a second order linear Infinite Impulse Response （IIR） filter and a nonlinear activation function with adjustable parameters. Second, the parameters from the network are adjusted to minimize a performance index specified by the output estimated error, with the given input-output data collected from the specific ACS. Then, the proposed dynamic neural network is trained and applied for detecting the faults injected to the wheel, which is the main actuator in the normal mode for the communication satellite. Then the performance and capabilities of the proposed network were tested and compared with a conventional model-based observer residual, showing the differences between these two methods, and indicating the benefit of the proposed algorithm to know the real status of the momentum wheel. Finally, the application of the methods in a satellite ground station is discussed.

关键词： satellite attitude control momentum wheel neural network fault detection

A discussion about the limitations of the Eurocode’s high-speed load model for railway bridges

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Railway Engineering Science 2024年第2期32卷 211-228页

作者： Gonçalo Ferreira Pedro montenegro JoséRui Pinto António Abel Henriques Rui Calçada CONSTRUCT-LESE Faculty of EngineeringUniversity of PortoRua Dr.Roberto Frias4200-465 PortoPortugal CONSTRUCT-LABEST Faculty of EngineeringUniversity of PortoRua Dr.Roberto Frias4200-465 PortoPortugal

High-speed railway bridges are subjected to normative limitations concerning maximum permissible deck *** the design of these structures,the European norm EN 1991-2 introduces the high-speed load model(HSLM)—a set of point loads intended to include the effects of existing high-speed ***,the evolution of current trains and the recent development of new load models motivate a discussion regarding the limits of validity of the *** this study,a large number of randomly generated load models of articulated,conventional,and regular trains are tested and compared with the envelope of HSLM *** each type of train,two sets of 100,000 load models are considered:one abiding by the limits of the EN 1991-2 and another considering wider *** comparison is achieved using both a bridge-independent metric(train signatures)and dynamic analyses on a case study bridge(the Canelas bridge of the Portuguese Railway Network).For the latter,a methodology to decrease the computational cost of moving loads analysis is *** show that some theoretical load models constructed within the stipulated limits of the norm can lead to effects not covered by the *** is especially noted in conventional trains,where there is a relation with larger distances between centres of adjacent vehicle bogies.

关键词： High-speed load model Dynamic analysis High-speed railways Train signature Railway bridges Deck acceleration

A Saccharomyces cerevisiae RC016-based feed additive reduces liver toxicity,residual aflatoxin B1 levels and positively influences intestinal morphology in broiler chickens fed chronic aflatoxin B1-contaminated diets

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Animal Nutrition 2020年第1期6卷 31-38页

作者： Valeria Poloni Alejandra Magnoli Analía Fochesato Andrea Cristofolini Matias Caverzan Cecilia Merkis Maríana.montenegro Lilia Cavaglieri Departamento de Microbiología e Inmunología Universidad Nacional de Río CuartoRío CuartoArgentina Consejo Nacional de Investigaciones Científicas y Tecnólogicas(CONICET) Buenos AiresArgentina Departamento de Microscopía Electrónica Universidad Nacional de Río CuartoRío CuartoArgentina Centro de Investigaciones y Transferencia Villa María Universidad Nacional de Villa MaríaVilla MaríaArgentina

The present study was conducted to investigate the ability of Saccharomyces cerevisiae RC016(Sc)-based feed additive to reduce liver toxicity,residual aflatoxin B1(AFB1)levels and influence intestinal structure in broiler chickens fed chronic aflatoxin B1-contaminated diets.A total of 100 one-day-old male commercial line(Ross)broiler chickens were divided into 4 treatments,with 5 pens per treatment and 5 broiler chickens per *** were randomly assigned to 4 treatments,which were namely treatment 1(T1),control diet(CD);T2,CD+Sc at 1 g/kg;T3,CD+AFB1 at 100μg/kg;T4,CD+Sc at 1 g/kg+AFB1 at100μg/*** liver histopathology of broiler chickens fed diets with AFB1 showed diffused microvacuolar fatty *** addition of Sc showed normal hepatocytes similar to the *** small intestine villi from AFB1 group showed atrophy,hyperplasia of goblet cells,prominent inflammatory infiltrate and *** contrast,the small intestine villi from birds that received the yeast plus AFB1 showed an absence of inflammatory infiltrate,and atrophy;moreover,a lower number of goblet cells compared to the groups with AFB1 was *** morphometric intestine studies showed that a significant decrease(P0.05),there was a tendency to improve these *** residual levels of AFB1 in livers were significantly reduced(P<0.05)in the presence of the *** present work demonstrated that the addition of Sc alone or in combination with AFB1 in the broiler chicken diets had a beneficial effect in counteracting the toxic effects of AFB1 in livers besides improving the histomorphometric parameters and modulating the toxic effect of AFB1 in the intestine.

关键词： Aflatoxin B1 Broiler chickens Histomorphometry Histopathology toxic effects

Design of Station Keeping Mode for Attitude Orbit Control Subsystem of T-SAT

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Computer Aided Drafting,Design and Manufacturing 2010年第2期20卷 78-84页

作者： SALOMON montenegro KENDRICK Amezquita School of Astronautics Beijing University of Aeronautics and Astronautics School of Automation Science and Electrical Engineering Beijing University of Aeronautics and Astronautics

Station keeping mode （SKM） for Attitude Orbit Control Subsystem （AOCS）; it is an operational approach regarding the attitude dynamics control. The essential features of the design methodology is researching the basic theory and then afterwards, make an iterative design approach using some premise/assumptions, implementing the system simulation through the Simulink Matlab software package, designing the required controllers, monitor and analyzing the responses until the design give the best results within the range required. Firstly the thruster configuration is designed to acquire the parameters of the torque on the satellite. Next, the controllers are based on the well known PID control law. Controllers optimize the attitude and are used during the maneuvers for SKM. Afterwards the simulation results are given, and presented to demonstrate the performance and validity of the AOCS design approach. Finally the simulation results demonstrate that all the requirements were accomplished and the Station Keeping Mode was successfully designed.

关键词： communication satellite AOCS East/West station keeping

Symbolism of the Shadows in Son of Man by Roa Bastos

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Cultural and Religious Studies 2015年第4期3卷 185-200页

作者： Patricia G. montenegro Cheyney University of Pennsylvania Cheyney USA

In his novel Son of Man, Augusto Roa Bastos uses images and symbols of shadows to represent the ramifications ofthe Paraguayan Dr. Jose Rodriguez de Francia＇s dictatorship. Rodriguez de Francia＇s legacy, which begins duringthe postcolonial years and extends well into the 20th century, resonates in the novel in soeio-political structures andcharacters＇ ideologies and behaviors. It allows for plantation owners to enslave workers and their families; itconfines and oppresses people through unfounded legends and myths; and among other things, it creates a falseidea of purpose and patriotism in the Chaco War （1932-1935）, which in the end lets down the soldiers. Tocounteract these deleterious social conditions, Roa Bastos creates surreal characters, such as a fantastic helper whoaids plantation workers to escape dehumanizing situations. Roa Bastos also narrates how the people in Itapr, asmall town, make an idol of a Christ statue carved by one of their own. However, when the two Goiburfl brothersreplace the statue by crucifying their sister＇s rapist, the people＇s myth is destroyed. Likewise, Roa Bastos availshimself of Christian and Catholic concepts and symbols to transpose them into a humanistic ideology so as toconvey hope to his people through a new perspective. In this way, a new Annunciation takes place when the son ofa raped woman is born. In the end, Roa Bastos lets the course of these warped transpositions take their logicaldenouement： In the absence of a purpose beyond an earthly existence, death becomes the narrator＇s option.

关键词： Paraguay, Dr. Rodriguez de Francia, dictatorship, surrealism, myth, Chaco War, Annunciation, bornagain, halo