Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"Maria Evelina MOGNASCHI"

Field models in low-frequency bioelectromagnetics DOI:10.15199/48.2016.12.01

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In the paper, a review of the state of the art on numerical models of the electromagnetic field in biological entities is proposed. In particular, the field produced by cells and the one in which cells and biological tissues are exposed to, is considered; low frequency problems are investigated. Issues and drawbacks of field models in bioelectromagnetics with respect to field models for industrial applications are discussed. Streszczenie. W artykule dokonano przeglądu stanu wiedzy na temat numerycznych modeli pola elektromagnetycznego w biologicznych komórkach. W szczególności, rozważane jest pole wytwarzane przez komórki i to, na które narażone są komórki i tkanki biologiczne; badane są problemy niskiej częstotliwości.. W artykule omówiono problemy i wady spotykane w adaptacji modeli polowych w bioelektromagnetyzmie w odniesieniu do modeli polowych w zastosowaniach przemysłowych. (Modele polowe w niskoczęstotliwościowych problemach bioelektromagnetyzmu). Keywords: numerical field models, low frequency, bioelectromagnetics. Słowa kluczowe: polowe modele numeryczne, niska częstotliwość, bioelektromagnetyzm Introduction In the last decades the investigation of electric, magnetic and electromagnetic fields related to biological systems has become a more and more mature research field. At the beginning, for evaluating electromagnetic quantities, only analytical or experimental models were performed. At first, numerical models were applied in biomechanics in the early Seventies like e.g. [1] and then, as it happened in industrial electromagnetics, they were subsequently applied to bioelectromagnetics in the late Seventies like e.g. [2]. For the sake of an example, in Fig. 1 the number of papers published in the last decades which used finite element or finite difference time domain models in low frequency (Fig. 1) and high frequency (Fig. 2), respectively, are reported [3]. 1970 1980 1990 2000 2010 2020 0 50 100 150 200 Year Num[...]

Automated optimal design of wells for electromagnetic cell stimulation DOI:10.15199/48.2019.05.01

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In the last decades, the electromagnetic stimulation in vitro and in vivo has become a promising research field because it allows to modulate the behaviour of cells and tissues. In particular, when the cells are exposed to a timevarying magnetic field, an electric field is induced and thus a current density arises, because the cell culture medium is conductive. The interaction between the induced current density and the time-varying magnetic field gives rise to mechanical stress acting on the cells [1]. In this paper, new kind of wells for obtaining a homogeneous stress and stimulation of a considerable large amount of cells are designed [2]. This design problem is formulated as a multiobjective one and its solution is found by means of the Biogeography-Inspired Multi-objective Optimization algorithms, BiMO [3,4] and the μ-BiMO algorithms [5]. These methods have shown to be successful for various applications [6-10]. In particular, when the forward problem requires a high computational time e.g. when Finite Element FE simulations are used, the μ-BiMO algorithm gave good results. In general, the aim of this study has been to design different optimally-shaped wells for electromagnetic stimulation of cells [11-15]. The forward problem The electromagnetic stimulation of cells is done by means of the so-called “electromagnetic bioreactor" (Fig. 1), which is a device based on two solenoids connected in series and powered by a pulse generator (Igea, Carpi, Italy) at 75 Hz [11]. In order to simulate the electric E and magnetic B fields in the bioreactor, a 3D time-dependent finite-element model was implemented in MagNet, a commercial code by Mentor-Infolytica. Fig.1. Electromagnetic bioreactor Fig.2. Magnetic induction field [T] distribution in the middle of the bioreactor In the conductive regions, the electromagnetic problem is solved in terms of the phasors of the electric vector potential T and the scalar ma[...]

Field models of induction heating for industrial applications DOI:10.15199/48.2018.03.01

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In the community of computational electromagnetics, the set of benchmark problems proposed by the TEAM (Testing Electromagnetic Analysis Methods) series of workshop is a reference for testing numerical methods in a comparative way [1]-[2]. Nevertheless, there is a lack of problems specifically focused on induction heating devices, as far as numerical modelling is concerned. More generally, in the past some benchmarks of induction heating was proposed, but the attention was focused rather on the inverse problem [3]-[7] related to the optimal design of the power inductor than on the direct problem of field analysis [8], [9]. In fact, in computational induction heating, analysis problems are challenging because they involve different physical domains; therefore, the development of non-linear coupledfield models and the consequent choice of suitable solvers is mandatory [8]-[10]. Too often numerical solvers, like e.g. finite-element solvers which are commercially available, are used by designers as general-purpose black boxes. Moving from this background, it was proposed to define a benchmark of coupled-field analysis [5]; the problem is taken from industrial applications of induction heating: it deals with the transient thermal analysis of a steel-made cylindrical billet, subject to the changing magnetic field of a multi-turn winding. It is a clear example showing that stiff analysis problem can originate even in the case of very simple geometries. Benchmark description: the device The device under study is composed of an inductor winding and a cylindrical billet; winding and billet are coaxially located. A. Geometry The billet has a radius r and height h. The inductor is made of 20 hollow circular turns, connected in series; each of them has height hc and width wc, while their radial distance from Y axis is rc. The thickness of the copper of each hollow turn is tc. Numerical data about the geometry are summarized in Table [...]

ViMeLa Project: An innovative concept for teaching mechatronics using virtual reality DOI:10.15199/48.2019.05.05

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Nowadays, traditional education and teaching methods, although with significantly improved teaching techniques, can not keep enough interest of the students that grew up with Internet, mobiles and tablets. Especially sensitive to these issues are students in engineering, in particular, in mechatronics. Modern information technology is rapidly being adopted in Mechatronics Engineering education as a tool for enriching the practical experience of the students. The practical training is a vital part of Mechatronics Engineering education [1]. However, the high cost needed to implement laboratory experiments (for educational purposes) led to development of virtual facilities where physical systems can be virtually controlled via the Virtual Reality (VR) simulations. Multimedia and VR technologies offer great potential for presenting theory and laboratory experiments in an enhancing and interesting, but in an economical, way. Teaching and learning Mechatronics Mechatronics is synergy and interaction of mechanical, electrical and computer systems as seen in Fig. 1. Hence, it is an interactive combination of mechanical engineering, electronic control and computer technology, with the aim of achieving an ideal balance between mechanical structure and its overall control and performance. Fig.1. Structure and key elements of mechatronics Currently, mechatronics classes are divided into two parts: the theoretical lectures and laboratory courses with experiments following the "learning by doing" model. Expensive equipment and limited time for training do not provide sufficient educational platforms [2,3]. In some cases the students conduct based simulations and learn how mechatronic systems and devices operate in reality, despite it may seem abstract and unclear for students, and does not fully reflect the physical phenomena of particular processes. The described drawbacks of mechatronics study are greatly improved when classroom teac[...]

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