1,247 research outputs found
A Review of Innovative Electromagnetic Technologies for a Totally Artificial Heart
No full textA total artificial heart (TAH) represents a challenge in medical science to provide a survival perspective for patients with severe cardiac problems. Although cardiac transplantation represents the optimal therapeutic solution for end-stage heart failure, its application is limited by organ shortages. However, innovative technologies that can fit the operation and constraints of a physical heart are now under experimentation, making the target of a reliable and minimally invasive TAH much closer. The electromagnetic devices involved in system supply and actuation could potentially improve patient quality of life and expectancy. The purpose of this paper is to provide an overview of the operating principle, ratings, and key performance of the main electromagnetic components, with a particular focus on actuators that emulate the pumping effect of the heart ventricles. Linear oscillating actuators are very promising for their compactness and straightforward integration; therefore, an exhaustive overview considering both the single and the dual-mover configurations is worth being carried out. Taking a cue on the projects under development and after a detailed literature investigation, the pros and cons of the different solutions are discussed with the purpose of providing a critical analysis of the state-of-the-art
Design issues of a rotating to linear motion magnetic converter for short-distance transport applications
No full textThis paper discusses some design issues of a magnetic rotating to linear motion converter (RLMC), suitable for the propulsion system of a short-distance low-capacity vehicle. It basically operates like a magnetic rack, which executes the contactless conversion of the motor torque into a propulsion thrust, deriving from the interaction of on-board permanent magnet (PM) modules and stationary ferromagnetic steel pieces. A design procedure is set up that deals with both the PM module arrangement and the geometric shape of the steel pieces to optimize different performance aspects. A simplified modeling based on 2D transient finite element analyses is carried out to determine the thrust profile and the RLMC losses, which are essential to assess its practical feasibility. Finally, the characteristics as functions of the load angle and speed are determined to enable the prediction of the dynamic power exchange and then of the net energy demand useful to size the on-board source
COVID-led consumption displacement: A longitudinal analysis of hotel booking patterns()
No full textThis research contributes to the literature on consumption displacement by exploring the pandemic-led shifts in hotel booking patterns. We perform a longitudinal analysis and a critical comparison of bookings before and after COVID-19 outbreak, focusing on the booking window, length of stay, and booking channel. Data include weekly bookings of a representative sample of Balearic Islands’ hotels between 2018 and 2021. Results indicate that the pandemic has led to a drop in the volume of bookings and a remarkable change in booking patterns. Specifically, we find a temporal shift in booking behavior, characterized by a lower anticipation and a change in the tourism supply chain, namely a decrease in the share of intermediated bookings. The expected increase in the frequency of exogenous shocks, such as weather-related and sanitary crises, could affect purchasing behaviors, thus enhancing the relevance of this study, with managerial implications for industry and destination managers
Motor Skill acquisition: from Affordances to Capabilities for Physical and Mental Health of Children
No full textMotor skill acquisition is essential in motor and cognitive development. It requires time and practice and kindergarten teachers can limit, discourage or encourage actions. Italian children spend lot of their time in kindergarten, which may be a great opportunity to practice physical activity and develop motor skills. With this study we want to look at the affordances (possibility of action) of Italian kindergartens and at the capabilities (real actions) in kindergartens. After signing the informed consent 434 kindergarten teachers of 16 Italian kindergartens completed a questionnaire. Often, verbally, teachers refer lack of space for physical activity, but unexpectedly we found that 55,8% of them may use a gym and 83,3% a park or a garden, related to their kindergarten. Despite they have the affordances (possibility of action) and are aware of the advantages and needs of physical activity for children only few teachers use the environmental opportunities to provide children the capabilities to implement physical activity and to increase motor development. More research is needed to study how to implement physical activity in indoor and outdoor spaces of kindergartens and how to cross from affordances to capabilities for physical and mental health
Simulation Results from a Kinetic-Electrochemical Energy Storage Model for Network Frequency Regulation
No full textThe aim of this paper is to summarize the simulation results obtained by applying a suitable power control to a hybrid storage system electrical model consisting of batteries and a flywheel. The focus of this research is to investigate whether, by controlling the power shared between the batteries and the flywheel, it is possible to effectively counter the battery aging during the grid frequency regulation service. By exploiting experimental aging tests performed on a lithium-manganese oxide battery module, an electrical battery model which takes into account the battery aging has been developed and joined to a flywheel model in Simulink environment. Hence, simulation tests have been carried out in order to investigate if the flywheel system can be an effective solution to tackle the aging of the batteries
Design and modeling of an integrated flywheel magnetic suspension for kinetic energy storage systems
No full textThe paper presents a novel configuration of an axial hybrid magnetic bearing (AHMB) for the suspension of steel flywheels applied in power-intensive energy storage systems. The combination of a permanent magnet (PM) with excited coil enables one to reduce the power consumption, to limit the system volume, and to apply an effective control in the presence of several types of disturbances. The electromagnetic design of the AHMB parts is carried out by parametric finite element analyses with the purpose to optimize the force performances as well as the winding inductance affecting the electrical supply rating and control capability. Such investigation considers both the temperature dependence of the PM properties and the magnetic saturation effects. The electrical parameters and the force characteristics are then implemented in a control scheme, reproducing the electromechanical behavior of the AHMB-flywheel system. The parameter tuning of the controllers is executed by a Matlab/Simulink code, examining the instantaneous profiles of both the air-gap length and the winding ampere-turns. The results of different dynamic tests are presented, evidencing the smooth air-gap changes and the optimized coil utilization, which are desirable features for a safe and efficient flywheel energy storage
Lo sviluppo motorio del bambino da 0 a 6 anni.
No full textAspetti relativi allo sviluppo motorio dei bambini da 0 a 6 anni secondo le recenti evidenze scientifiche
Nuovi spazi per l'educazione dei bambini da 0 a 6 anni: cosa pensano gli insegnanti dei parco giochi come luogo di educazione formale e non formale. New environments for the education of 0-6 year old children: what teachers think about the playground for formal and non formal education.
No full textL’attività fisica nei bambini da 0 a 6 anni può prevenire problemi di salute e educare ad un sano stile di vita. Nonostante le raccomandazioni internazionali i bambini si muovono mediamente solo 60 minuti alla settimana.
Gli insegnanti coinvolti nel progetto al parco giochi “Primo Sport 0246” di Treviso (Italia) suggeriscono che il parco giochi possa essere un’opportunità educativa per incrementare il movimento nei bambini e altri importanti aspetti dello sviluppo, in connessione con i programmi scolastici. Gli insegnanti considerano il parco giochi un luogo di educazione formale e non formale anche per favorire l’inclusione di tutti i bambini, soprattutto di coloro che non hanno possibilità fuori da scuol
Mente e corpo nella relazione educativa nelle scuole dell'infanzia: lo sviluppo delle capabilities per una buona qualità della vita. Mind and body in the educational relationship in Kindergarten: the development of capabilities for a good quality of life
No full textL’infanzia è un periodo di totale dipendenza dagli adulti. Il periodo 0-6 è considerato di “imprinting” per le sue conseguenze nello sviluppo e nella salute. Le capabilities per promuovere il benessere si sviluppano tenendo conto di ambiente fisico e di contesto socio-relazionale, elementi fondamentali per lo sviluppo, secondo la prospettiva ecologica. Studi cross-culturali mettono in luce quanto le competenze motorie siano dipendenti dall’esperienza. Differenti tipi di cura del bambino promuovono bambini differenti. E’ importante promuovere l’attività motoria nelle scuole dell’infanzia, dove i bambini italiani trascorrono molto del loro tempo al fine di migliorare la salute, la capacità di prevedere pericoli, prevenire la malattia cronica. Le pratiche di cura delle insegnanti sono guidate dalle loro credenze e teorie. L’obiettivo di questa ricerca è: 1. conoscere le credenze e le teorie degli insegnanti sullo sviluppo motorio; 2. conoscere come essi organizzano l’attività motoria e l’ambiente delle scuole dell’infanzia; 3. definire una teoria corpo-mente nella relazione educativa; 4. promuovere la pratica dell’attività motoria nelle scuole dell’infanzia; 5. favorire negli insegnanti la capacità di progettare attività motorie “evidence based”
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