Computational issues of an electromagnetics transient meshless method

In this paper we refer to the computational issues in solving Maxwell’ s curl equations without using any connectivity among the points in which the problem domain is discretized. The adopted procedure is able to approximate the electric and magnetic vector fields making use of the derivatives of a kernel function at points arranged in the computational domain. In order to improve the numerical accuracy, dealing with irregular data distribution or data located near the boundary, a suitable strategy is considered. The computational core of the overall process requires elementary linear algebra operations. In the paper the method is presented and the discussion is revolved to the computationa…

Modulating spatial orientation by Non-Invasive Brain Stimulation

Different scenarios of electric mobility: Current situation and possible future developments of fuel cell vehicles in Italy

The diffusion of electric vehicles in Italy has started but some complications weight its spread. At present, hybrid technology is the most followed by users, due particularly to socioeconomic factors such as cost of investment and range anxiety. After a deep discussion of the Italian scenario, the aim of the paper is to recognize whether fuel cell technology may be an enabling solution to overcome pollution problems and respect for the environment. The opportunity to use fuel cells to store electric energy is quite fascinating&mdash

Optimized design of high power density EMI filters for power electronic converters

Nowadays, power density of power converters and related EMI filters is gaining more and more attention. This severely impacts on the design constraints in several application domains. A conventional design of the EMI filter does not guarantee the selection of components/configuration leading to the best power density. For this reason, an optimized design procedure of discrete EMI filters in terms of power density is proposed in this paper. It is based on a previously developed rule-based design procedure, introducing here additional features to obtain a more effective optimization of EMI filter's power density. The proposed approach has been validated in terms of EMI filter's performance an…

Thunderclap Headache and Reversible posterior Leukoencephalopathy: Case Report

TRANSCRANIAL DIRECT STIMULATION (TDCS) CAN MODULATE ESOPHAGEAL MOTILITY IN GASTROESOPHAGEAL REFLUX DISEASE (GERD) PATIENTS

ODEF: An interactive tool for optimized design of EMI filters

The impact of EMI filters on volume and weight of power converters is significant. For this reason, filter's size optimization is a strategic step towards the improvement of the power converter's power density. An EMI filter design that follows a conventional procedure does not guarantee the selection of components/configuration leading to the best power density. Therefore, in order to help EMI engineers and scientists in pursuing a fast and effective choice of optimal discrete EMI filter components and configuration, a novel tool is proposed in this paper, namely ODEF (Optimized Design of EMI Filters). ODEF is an interactive software application running in Matlab® environment. It suitably …

Modelling, simulation and characterization of Li-Ion battery cell

The decarbonizing process of the transportation system and the spread of unplanned renewables energy source, such as photovoltaic and wind energies, brought the constant need of ever more efficient energy storage technologies. Among these technologies, batteries, particularly the li-ion chemistry, are widely used in automotive and energy storage applications. For an optimized management of the cell it is advisable to have models that can accurately describe cell behaviour. In this paper a battery model for performance simulation in automotive application is identified. The main shapes of battery cells with their own advantages and disadvantages are shown, and a roundup of the best available…

FILTRI EMI COMPATTI NEI CONVERTITORI ELETTRONICI DI POTENZA

The goal of the research recently started is to create efficient EMI filters compact that allow to obtain converters with low dimensions and economically competitive.

Impairment of Temporal Binding Window in Migraine Patients

EFFECTS OF TMS OVER RIGHT POSTERIOR PARIETAL CORTEX AND VISUOSPATIAL NEGLECT IN NEAR AND FAR SPACE USING LINE BISECTION

Computer Aided Optimal Design of High Power Density EMI Filters

Power density of power converter systems is becoming an increasingly stringent design constraint for a wide range of applications. Size reduction of EMI filter in power converters is an important aspect due to its significant impact on the overall converter volume and weight. In order to take on this issue, a computer aided procedure for a fast selection of optimal discrete EMI filter components and configuration is described in this paper. The proposed technique is a rule-based automatic procedure based on suitable databases that consider datasheets information of commercially available passive components (e.g. magnetic cores, capacitors). It allows the minimization of the filter's volume …

Experimental Investigation on the Performances of Innovative PV Vertical Structures

The sustainable development of our planet is considerably related to a relevant reduction of CO2 global emissions, with building consumption contributing more than 40%. In this scenario, new technological conceptions, such as building-integrated photovoltaic technology, emerged in order to satisfy the requirements of sustainability imposed by the European Union. Therefore, the aim of this work is to provide a technical and economical comparison of the performances of different vertical-mounted innovative photovoltaic systems, potentially integrated on a building instead of on traditional windows or glass walls. The proposed investigation was carried out by means of experimental tests on thr…

Effect of Heat Exchange Transient Conditions with Moving Water-Air Interface on Space Charge Accumulation in Undersea HVdc Cables

The accumulation of space charge inside the dielectric layer of an HVdc cable is one of the most important issue to be considered in the design stage and during the operating conditions. The separation of space charge is due to several factors including the dependence on temperature of the electrical conductivity of the insulation and the establishment of a thermal gradient under load conditions. This article is focused on the investigation of the effect of an axial heat transmission on the space charge and electric field distributions in an HVdc cable. In order to assess the impact of this phenomenon, a case study involving a cable immersed partly in water and partly in air has been simula…

An Efficient Numerical Method for Time Domain Computational Electromagnetic Simulation

In this paper an efficient numerical method in approximating the electric and magnetic fields is provided. The method is based on an implicit leapfrog arrangement in time and without mesh in space. Moreover, a projection scheme is introduced in order to improve the accuracy of the proposed approach and applied into the computational electromagnetic (CEM) framework. The PDEs governing the process are solved and some numerical results are reported to validate the numerical process.

On the distribution of lightning current among interconnected grounding systems in medium voltage grids

This paper presents the results of a first investigation on the effects of lightning stroke on medium voltage installations' grounding systems, interconnected with the metal shields of the Medium Voltage (MV) distribution grid cables or with bare buried copper ropes. The study enables us to evaluate the distribution of the lightning current among interconnected ground electrodes in order to estimate if the interconnection, usually created to reduce ground potential rise during a single-line-to-ground fault, can give place to dangerous situations far from the installation hit by the lightning stroke. Four different case studies of direct lightning stroke are presented and discussed: (1) two …

Power Density Optimization of EMI Filters for Power Electronic Converters

The switching power converters are used in a broad variety of applications, from the consumer electronics to the DC distribution systems, from the vehicle applications (road vehicles, marine vehicles, aircraft) to the industrial automation. In each of these application fields, the conversion systems which present more compact size and reduced weight, at the same power, are strongly required in relation to stringent design constraints. In this context, the optimization of the power density of the converter becomes an essential requirement. The increase of the switching frequency of the static devices allows an improvement of the power density, thanks to the possibility of reducing the sizes …

Design and Performance Evaluation of a High Power-Density EMI Filter for PWM Inverter-Fed Induction-Motor Drives

This paper presents the design of an electromagnetic interference (EMI) filter for a low-voltage high-current induction-motor drives supplied by dc power grids. In order to effectively design the EMI filter, a suitable common-mode/differential-mode (CM/DM) separation technique has been used. Due to the high operating currents, the software-based separation technique using time-domain measurements has been applied. The proposed technique allows the CM and DM sections of the EMI filter to be properly selected in a more economical way, i.e., without the need of a dedicated hardware or costly radio frequency (RF) instrumentation. The design has been done according to a power-density criterion. …

Acoustic Wave Behavior in a Specimen Containing an Air Void Defect

The PEA method is the most used technique for the space charge measurements. As is well known, this method uses pressure waves to detect the charges accumulated in solid dielectrics. Based on its working principle, the generated acoustic waves travel within PEA cell and the specimen under test in order to be finally detected by the piezoelectric sensor. For a multilayer specimen and, in particular, in case of different materials that make up the specimen, the acoustic wave reflection is inevitable. Considering that, in several cases, the reflected waves could be detected by the piezoelectric sensor before than the main signals, the PEA cell output profile could results distorted. Based on t…

Lightning-current distribution in MV grids interconnected earthing systems

The paper presents first investigations results on the effects of lightning stroke on medium voltage (MV) installations' earthing systems, connected together with the metal shields of the MV distribution grid cables. The study enables to evaluate the distribution of the lightning current among interconnected earth electrodes in order to assess if the interconnection, usually done for reducing earth potential rise during an earth fault, can give place to dangerous situations far from the installation hit by the lightning stroke. Two case studies of direct lightning stroke are presented and discussed: two interconnected MV substations of the MV grid; a high voltage/medium voltage (HV/MV) stat…

Are paradoxical intensity-dependent effects of 5Hz rTMS train in motor cortex of migraine with aura patients evidence of abnormal homeostatic plasticity

Energy Storage by using HVDC Power Cables

The development of HVDC (high voltage direct current) systems closely follow the growth of global energy requirements. In particular, HVDC cables are conveniently used for the interconnection of geographical areas which need a low environmental impact and/or when submarines interconnections have to be built up. The paper investigates the stored energy value in an HVDC cable during its normal duty and if it is possible to take advantage of this energy when the cable is disconnected for some reason. In particular, the idea is to store the cable energy, which would be dissipated uselessly, by using a dedicated system and then reuse it when favorable conditions hold, e.g a convenient economic s…

Space charge accumulation in undersea HVDC cables as function of heat exchange conditions at the boundaries – water-air interface

Transmission lines with undersea HVDC cables are an interesting technological solution for the supply of electrical energy to islands. The accumulation of space charge inside the dielectric layer of a HVDC cable is one of the most important element to consider in its design and during operation. The formation of space charge is due to various factors including the high dependence on the temperature of the electrical conductivity of the insulation and the establishment of a thermal gradient under load conditions. This research is focused on the space charge accumulation phenomenon around a section of a HVDC cable half dipped in water and half in air. Due to the high difference in thermal con…

PROGETTO DI FILTRI EMI PER CONVERTITORI DC/AC AD ELEVATA POWER DENSITY

Il lavoro tratta del progetto di filtri EMI per convertitori DC/AC ad elevata power density

Electromagnetic Full-Wave Simulation of Partial Discharge Detection in High Voltage AC Cables

Partial discharge (PD) activity in the insulation system of an electrical equipment can determine the failure of the whole apparatus. PD sensors are widely used in high-voltage electrical systems as the main elements of a detecting system oriented to real time monitoring. Recently, non-invasive sensors have been proposed in industrial applications for cable and other sensitive electrical parts: they are based both on capacitive and on the electromagnetic radiating coupling. In order to assess the real performance of a new sensor produced by a high voltage AC cables manufacturer, the paper proposes electromagnetic fullwave simulation results.

Orally administered indicaxanthin is able to modulate human motor cortical excitability and plasticity

Opuntia Ficus Indica contains Indicaxanthin (IX), an antinflammatory and antioxidant betalaine pigment. This phytochemical is also able to cross the blood brain barrier (BBB) in rats and modulate neuronal activity. Considering these evidence, we aimed at investigating if orally administered IX could affect human brain tissue. 8 healthy and right-handed male subjects were recruited (20-45 years) with no history or clinical signs of neurological diseases, brain trauma or use of drugs acting on neuronal process, as assessed by a clinical neurologist. Non invasive Brain Stimulation and Neuromodulation (NIBS and NIN) instructions were applied in basal condition (T0) and 2 hours after having assu…

Automatic EMI filter design for power electronic converters oriented to high power density

In this paper, a complete computer aided procedure based on the power density concept and aimed at the automatic design of EMI filters for power electronic converters is presented. It is rule-based, and it uses suitable databases built-up by considering information on passive components available from commercial datasheets. The power density constraint is taken into consideration by imposing the minimization of the filter volume and/or weight; nevertheless, the system in which the automatically designed filter is included satisfies the electromagnetic compatibility standards limits. Experimental validations of the proposed procedure are presented for two real case studies, for which the per…

Reversed Pseudoneglect in a Virtual Reality Environment

Transcranial Direct Current Stimulation in Post-Stroke Aphasia Rehabilitation: Bilateral vs Unilateral Online Stimulation

Here we aim to evaluate the efficacy of repeated sessions of transcranial Direct Current Stimulation (tDCS) as additional treatment to standard behavioural rehabilitation in post-stroke aphasic patients comparing bilateral with unilateral left-sided and sham-tDCS. Background: Aphasia is the most common post-stroke cognitive disorder and it severely impacts activities of daily living and social interactions. tDCS recently showed good results in post-stroke aphasia rehabilitiation, even if no agreement at now exists about the stimulation parameters to employ to achieve the best rehabilitative outcome. Design/Methods: We enrolled twenty-two patients with single left-brain lesion at CT or MRI s…

Quantitative EEG differentiates multiple sclerosis with and without cognitive impairment from healthy controls at the beginning of the disease: preliminary data

Background and aims: The present study aims to assess possible qEEG differences between newly diagnosed multiple sclerosis (MS) patients with or without cognitive impairment (CI). Methods: We enrolled 22 patients (18-55-years-old) treated with first-line drugs for <6 months, and 11 healthy controls. All subjects underwent neuropsychological assessment including BICAMS and BDI. EEG recordings were performed during a cognitive task (computerised “SDMT” subtest of BICAMS) and at rest. Based on neuropsychological assessment, patients were considered as affected (MSCI group) or not (MS group) by cognitive impairment. We analysed data comparing MSCI patients matched by sex, age (±5years) and e…

The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables

In the field of high-voltage transmission systems, different degradation phenomena affect the reliability of the employed components. In particular, under dc stress, the space charge accumulation phenomenon is believed to be the most responsible of the dielectrics lifetime reduction. To measure the accumulated space charges in flat specimens, the pulsed electro-acoustic (PEA) method is one of the most used techniques. The working principle of the PEA cell is based on the acoustic waves propagation and detection. As is well known, the acoustic waves propagating in different means are partially transmitted and partially reflected. Therefore, the piezoelectric sensor of the PEA cell is subject…

Role of endocannabinoids and TRPV1 channels in the bioelectric activity of hippocampal neurons

It has been reported that endocannabinoid system is an important player in the regulation of neuronal bioelectrical activity, relying on receptor-mediated mechanisms. Amongst these, Cannabinoid receptor type 1 (CB1r) and Transient Receptor Potential Vanilloid type 1 (TRPV1) are both modulated by endocannabinoids, involved in the transduction of stimuli in the pre-synaptic neuron and prompt downstream pathways in the post-synaptic neuron. To investigate the role of CB1r/TRPV1 interplay, we applied whole-cell patch clamp technique to visualize the eventual variations in terms of membrane current and action potentials induced by pharmacological manipulation in rat hippocampal neurons. We modul…

Design and performance evaluation of a high power density EMI filter for PWM inverter-fed induction motor drives

This paper presents the design of an electromagnetic interference (EMI) filter for a low voltage high current induction motor drives supplied by DC power grids, such as those used in several vehicle applications. In order to effectively design the EMI filter a suitable Common Mode/Differential Mode (CM/DM) separation technique has been used. In consideration of the high operating currents, a software based separation technique using time domain measurements has been applied. The proposed technique allows the CM and DM sections of the EMI filter to be properly selected in a more economical way, i.e. without the need of dedicated hardware or costly radio frequency (RF) instrumentation. The de…

Allodinia, Disabilità E Parametri Clinici Dell’emicrania: Risultati Di Uno Studio Con Questionario Retrospettivo In Pazienti Affetti Da Emicrania

Design and Assessment of Optimized EMI Filters for Avionic Applications

This paper presents a procedure to design EMI filters to reduce the electromagnetic disturbances generated by electrical apparatus used in avionic environment. The method proposed can be useful to save weight and size of the attenuation systems, and keep their effectiveness in agreement with the standard requirements. A design of a set of different filters with different topological characteristics is presented for a case study about an electrical actuator used for an aircraft onboard application. Performances and reliabilities of the attenuation systems are assessed by suitable full compliance experimental tests.