257 research outputs found
Development and experimental validation of a low-frequency dynamic model for a Hybrid Electric Vehicle
This paper describes the development and experimental validation of a high-fidelity Hybrid Electric Vehicle (HEV) simulator that enables testing and calibration of energy management and driveline control strategies. The model is capable of predicting longitudinal vehicle responses that affect energy consumption and drivability in the low-to-mid frequency region (up to 10 Hz). The simulator focuses primarily on the drivetrain dynamics, while the dynamics of the actuators are represented by simplified models. The vehicle simulator is validated by a number of experiments that include electric only, engine only and hybrid operating conditions. The test vehicle has a through-the-road parallel hybrid architecture that utilises a dual electric machine configuration. Experimental results confirm that important driveline phenomena such as shunt, shuffle, torque holes and other transient disturbances related to operating mode changes are accurately predicte
Adaptive Equivalent Consumption Minimization Strategy with Rule-based Gear Selection for the Energy Management of Hybrid Electric Vehicles Equipped with Dual Clutch Transmissions
Based on observations of the behaviour of the optimal solution to the problem of energy management for plug-in hybrid electric vehicles, a novel real-time Energy Management Strategy (EMS) is proposed. In particular, dynamic programming results are used to derive a set of rules aiming at reproducing the optimal gearshift schedule in electric mode while the Adaptive Equivalent Consumption Minimization Strategy (A-ECMS) is employed to decide the powertrain operating mode and the current gear when power from the internal combustion engine is needed. In terms of total fuel consumption, simulations show that the proposed approach yields results that are close to the optimal solution and also outperforms those of the A-ECMS, a well-known EMS. One of the main aspects that differentiates the strategy here proposed from previous works is the introduction of a model to use physical considerations to estimate the energy consumption during gearshifts in dual-clutch transmissions. This, together with a series of properly tuned fuel penalties allows the controller to yield results in which there is no gear hunting behaviour
A Methodology for Parameter Estimation of Nonlinear Single Track Models from Multibody Full Vehicle Simulation
In vehicle dynamics, simple and fast vehicle models are required, especially in the framework of real-time simulations and autonomous driving software. Therefore, a trade-off between accuracy and simulation speed must be pursued by selecting the appropriate level of detail and the corresponding simplifying assumptions based on the specific purpose of the simulation. The aim of this study is to develop a methodology for map and parameter estimation from multibody simulation results, to be used for simplified vehicle modelling focused on handling performance. In this paper, maneuvers, algorithms and results of the parameter estimation are reported, together with their integration in single track models with increasing complexity and fidelity. The agreement between the multibody model, used as reference, and four single track models is analyzed and discussed through the evaluation of the correlation index. The good match between the models validates the adopted simulation methodology both during steady-state and during transient maneuvers. In a similar way, this method could be applied to experimental data gathered from a real instrumented car rather than from a multibody model
Sintering and mechanical properties of β‐SiC powder obtained from waste tires
Plasma synthesized SiC powder obtained from quartz and carbonaceous residue of waste tires was successfully sintered at 1925 ℃ by pressureless liquid-phase method using yttria and alumina as sintering aids (T-SiC). Comparison with sintered SiC obtained from commercial powder (C-SiC) put in evidence of similar sintered density (98%T.D.), but much finer microstructure of T-SiC than that of C-SiC. T-SiC also showed higher flexural strength than C-SiC both at room temperature (508 vs. 458 MPa) and at 1500 ℃ (280 vs. 171 MPa). Difference in liquid phase was responsible for the differences in hardness and fracture toughness. The high value of the Young's modulus of T-SiC (427 MPa) confirmed the high degree of sinterability of this powder and that it can be a promising candidate for structural applications with high added value. © 2016, The Author(s)
Motivação de maestria e sua relação com a parentalidade positiva e os elogios em uma amostra argentina
The aim of this study was to analyze the relationship between the motivation for child mastery and parental variables such as positive parenting and praise given by primary caregivers in Argentina. In this way, it would be possible to expand the understanding of the relational dynamics between caregivers and infants and identify which parenting behaviors promote children's motivational development. The Dimensions of Mastery Questionnaire (DMQ), the Positive Parenting Scale (E2P), and the Scale of Praise given by primary caregivers to infants were used for this purpose. The participants were 107 primary caregivers of infants aged between 0 and 3 years in Argentina. Multiple linear regression was conducted, revealing that positive parenting, along with age, contribute to child mastery motivation, while praise was not a predictor of this variable. In conclusion, the significance of positive parenting skills during infant rearing for the appropriate development of motivation and cognitive/emotional abilities is emphasized. Including the development of these skills in interventions with primary caregivers would be relevant and crucial for promoting the comprehensive development of children.El objetivo de este estudio fue analizar la relación entre la motivación de dominio de infantes y las variables parentales, como la parentalidad positiva y los elogios otorgados por cuidadores primarios de Argentina. De esta manera sería posible ampliar el conocimiento del funcionamiento vincular entre cuidadores e infantes e identificar qué conductas parentales favorecen el desarrollo motivacional infantil. Para ello se utilizó el cuestionario de Dimensiones de Motivación de Dominio (Dimensions of Mastery Questionnaire; DMQ), la Escala de Parentalidad Positiva (E2P) y la escala de elogios otorgados por cuidadores primarios a infantes. Los participantes evaluados fueron 107 cuidadores primarios de Argentina, de infantes de entre 0 y 3 años. Se realizó una regresión lineal múltiple, que mostró como resultado que la parentalidad positiva junto con la edad contribuyen a la motivación de dominio infantil, mientras que los elogios no fueron predictores de esta variable. Se concluye y se enfatiza la relevancia de las competencias parentales positivas durante la crianza de los infantes para un desarrollo adecuado de la motivación y habilidades cognitivas/emocionales. Incluir el desarrollo de estas competencias en intervenciones con cuidadores primarios sería pertinente y sustancial para favorecer el desarrollo integral de los menores.O objetivo deste estudo foi analisar a relação entre a motivação de maestria de crianças e variáveis parentais, como a parentalidade positiva e ps elogios concedidos pelos cuidadores primários na Argentina. Dessa forma, seria possível expandir o conhecimento do funcionamento do vínculo entre cuidadores e crianças e identificar quais comportamentos parentais favorecem o desenvolvimento motivacional infantil. Para isso, foi utilizado o Questionário de Dimensões de Motivação de Maestria (Dimensions of Mastery Questionnaire - DMQ), a Escala de Parentalidade Positiva (E2P) e a Escala de Elogios concedidos pelos cuidadores primários a crianças. Os participantes avaliados foram 107 cuidadores primários de crianças de 0 a 3 anos na Argentina. Foi realizada uma regressão linear múltipla, mostrando como resultado que a parentalidade positiva, juntamente com a idade, contribuem para a motivação de maestria infantil, enquanto os elogios não foram preditores dessa variável. Conclui-se enfatizando a relevância das competências parentais positivas durante a criação das crianças para um desenvolvimento adequado da motivação e habilidades cognitivas/emocionais. Incluir o desenvolvimento dessas competências em intervenções com cuidadores primários seria pertinente e substancial para favorecer o desenvolvimento integral das crianças
Contrasting responses of forest growth and carbon sequestration to heat and drought in the Alps
>Climate change is expected to increase both the frequency and the intensity of climate extremes, consequently increasing the risk of forest role transition from carbon sequestration to carbon emission. These changes are occurring more rapidly in the Alps, with important consequences for tree species adapted to strong climate seasonality and short growing season. In this study, we aimed at investigating the responses of a high-altitude Larix decidua Mill. forest to heat and drought, by coupling ecosystem- and tree-level measurements. From 2012 to 2018, ecosystem carbon and water fluxes (i.e., gross primary production, net ecosystem exchange, and evapotranspiration) were measured by means of the eddy covariance technique, together with the monitoring of canopy development (i.e., larch phenology and normalized difference vegetation index). From 2015 to 2017 we carried out additional observations at the tree level, including stem growth and its duration, direct phenological observations, sap flow, and tree water deficit. Results showed that the warm spells in 2015 and 2017 caused an advance of the phenological development and, thus, of the seasonal trajectories of many processes, at both tree and ecosystem level. However, we did not observe any significant quantitative changes regarding ecosystem gas exchanges during extreme years. In contrast, in 2017 we found a reduction of 17% in larch stem growth and a contraction of 45% of the stem growth period. The growing season in 2017 was indeed characterized by different drought events and by the highest water deficit during the study years. Due to its multi-level approach, our study provided evidence of the independence between C-source (i.e., photosynthesis) and C-sink (i.e., tree stem growth) processes in a subalpine larch forest
Trazando puentes entre las neurociencias y la educación. Aportes, límites y caminos futuros en el campo educativo
Las neurociencias son el conjunto de disciplinas cuyo objetivo de investigación es el sistema nervioso, poniendo el acento en la actividad del cerebro y su relación con nuestros comportamientos. Abordan aspectos neurobiológicos de la conducta y se apoyan en la psicología cognitiva, la lingüística, la antropología y la inteligencia artificial. La neuroeducación, también llamada neurociencia educativa, es una disciplina en expansión que se ocupa de estudiar la optimización del proceso de enseñanza y aprendizaje con base en el funcionamiento del cerebro y los fundamentos neurobiológicos que lo sustentan. El artículo se
propone revisar aportes de las neurociencias al campo educativo, y a su vez críticas y futuros caminos para establecer relaciones aún más estrechas entre ambos. Se concluye que a pesar de que los aportes de la neuroeducación son variados y se esperan avances en el área, derivados de nuevas tecnologías, debemos ser cautos y críticos a la hora de analizarlos o ponerlos en práctica, ya que aún se deben generar estudios con mayor validez ecológica, en entornos educativos con seres humanos y con distintos niveles de análisis, sin dejar de lado la interdisciplina
Associações entre exposição à mídia eletrônica e comunicação na primeira infância: uma revisão integrativa
Purpose: to evaluate the amount of average use that infants make of electronic media, and to observe how it is associated with early childhood communication through an integrative review of the last 10 years (2010-2020).
Topic: screen use during early childhood and its associations with verbal and pre-verbal communication skills.
Development: verbal and non-verbal communication in the early years are essential skills, since they predict the later development of other cognitive skills and academic performance. Given that exposure to technological devices has increased in recent years, both in adults and in early childhood, it becomes important to review studies on this subject. We found 15 studies that met the inclusion criteria. In the first three years of life, on average the use of technological devices was 1 to 3 hours a day, they were negatively associated with the development of communication. However, it is necessary to take into account whether the activity is accompanied by an adult, the educational level, and the type of content that is consumed.
Conclusions: it is necessary to carry out more research in the Latin American context, taking into account the diversity of electronic devices and content that we currently have.Propósito: evaluar la cantidad de uso promedio que los infantes realizan de los medios electrónicos, y observar cómo se asocian con la comunicación infantil temprana a través de una revisión integrativa de los últimos 10 años (2010-2020).
Tema: el uso de pantallas durante la infancia temprana y sus asociaciones con habilidades de comunicación verbales y preverbales.
Desarrollo: la comunicación verbal y no verbal en los primeros años son habilidades fundamentales, ya que predicen el desarrollo posterior de otras habilidades cognitivas y del rendimiento académico. Siendo que la exposición a dispositivos tecnológicos ha aumentado en los últimos años, tanto en adultos como en la infancia temprana, se vuelve importante revisar estudios sobre esta temática. Se encontraron 15 estudios que cumplían con los criterios de inclusión. En los primeros tres años de vida, en promedio el uso de dispositivos tecnológicos fue de 1 a 3 horas diarias, y los mismos se asociaron de forma negativa con el desarrollo de la comunicación. Sin embargo, es necesario tener en cuenta si la actividad está acompañada por un adulto, el nivel educativo, y el tipo de contenido que se consume.
Conclusiones: es necesario realizar más investigaciones en el contexto latinoamericano, teniendo en cuenta la diversidad de dispositivos electrónicos y contenidos con los que contamos en la actualidad.Objetivo: avaliar o uso médio que os bebês fazem da mídia eletrônica e observar como ela está associada à comunicação na primeira infância por meio de uma revisão integrativa dos últimos 10 anos (2010-2020).
Tema: uso da tela na primeira infância e suas associações com habilidades de comunicação verbal e pré-verbal.
Desenvolvimento: a comunicação verbal e não verbal nos primeiros anos são habilidades essenciais, pois predizem o desenvolvimento posterior de outras habilidades cognitivas e desempenho acadêmico. Tendo em vista que a exposição a dispositivos tecnológicos tem aumentado nos últimos anos, tanto em adultos quanto na primeira infância, torna-se importante revisar estudos sobre esse assunto. Encontramos 15 estudos que atenderam aos critérios de inclusão. Nos primeiros três anos de vida, em média, o uso de dispositivos tecnológicos era de 1 a 3 horas por dia, eles se associaram negativamente ao desenvolvimento da comunicação. No entanto, é necessário levar em consideração se a atividade é acompanhada por um adulto, o nível de escolaridade e o tipo de conteúdo que é consumido.
Conclusões: é necessário realizar mais pesquisas no contexto latino-americano, levando em consideração a diversidade de dispositivos eletrônicos e conteúdos que temos atualmente
The microstructure of bimetallic Ru---Cu/SiO2 catalysts: A chemisorption and analytical electron microscopy study
Supported bimetallic Ru---Cu/SiO2 catalysts are characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, electron microdiffraction, and chemisorption. Metal particles up to 4 nm in diameter are bimetallic, while particles larger than 4 nm contain only Cu. Considerable compositional nonuniformity is observed from one individual metal particle to the next. Microdiffraction patterns obtained from individual particles can be attributed to either Ru or Cu suggesting no significant modification in crystallographic structure of either metal component. Addition of Cu to Ru results in a drastic suppression of H2 chemisorption while the extent of O2 chemisorption is not as strongly affected. The suppressed H2 chemisorption capability of Ru in the bimetallic catalysts is an indication of atomic interdispersion of Ru and Cu on the surface of the bimetallic clusters, leading to the break-up of the Ru ensembles which would be necessary for dissociation of molecular hydrogen. The influence of catalyst preparation techniques on the relative interdispersion of Ru and Cu and consequent discrepancies in the Ru---Cu literature are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26092/1/0000168.pd
Empatía en niños de 11 a 12 años. Una comparación entre pedagogía Waldorf y pedagogía tradicional
Para Eisenberg (2000) la empatía es una respuesta emocional que procede de la comprensión del estado o situación de otra persona y es similar a lo que la otra persona está sintiendo. La misma incluye la capacidad para diferenciar entre los estados afectivos de los demás y la habilidad para tomar una perspectiva tanto cognitiva como afectiva. Esta se ve modificada por procesos de socialización. La presente investigación tuvo como objetivo evaluar los niveles de empatía en niños de 11 y 12 años de edad en función de su asistencia a instituciones educativas bajo el modelo de la pedagogía tradicional o la pedagogía Waldorf, a partir del Interpersonal Reactivity Index (IRI). Los resultados indicaron que los alumnos que asistían al establecimiento Waldorf puntuaron más alto en toma de perspectiva y preocupación empática que los alumnos que asistían al establecimiento bajo el modelo de pedagogía tradicional. Se puede concluir que las diferencias encontradas entre los alumnos de las distintas escuelas podrían deberse a los distintos modelos pedagógicos que recibieron. La escuela Waldorf hace énfasis en estimular la competencia social, por lo que esto pudo repercutir en las habilidades empáticas de los niños
- …