Search results for "electromagnetic [coupling]"
showing 10 items of 263 documents
Electromagnetically generated extracorporeal shockwaves for fragmentation of extra-and intrahepatic bile duct stones: indications, success and proble…
1990
Electromagnetically generated extracorporeal shock waves (without waterbath) were applied after intravenous premedication with 10-15 mg diazepam and 100 mg tramadol in the treatment of 33 patients (aged 32 to 91 years) with multiple intrahepatic stones (n = 4) or huge common bile duct stones (n = 29, 18-30 mm in diameter), which could not be removed by conventional endoscopy. Stone disintegration was achieved in 70% of common bile duct stones and in all intrahepatic concrements after 800-7500 discharges, which were applied during one (n = 21), two (n = 6) or three sessions (n = 6). Apart from mild fleabite-like petechiae at the side of shock wave transmission no other side effects were obse…
Electromechanical Numerical Analysis of an Air-Core Pulsed Alternator via Equivalent Network Formulation
2017
In this paper, the numerical analysis on an air-core pulsed alternator is presented. Since compulsators are characterized by very fast electromechanical transients, their accurate analysis requires strong coupling between the equations governing the electrical and the mechanical behaviors. The device is investigated by using a dedicated numerical code capable to take into account eddy currents, compensating windings, as well as the excitation/control circuits. Furthermore, the code is capable of modeling centrifugal forces and vibrations acting on the shaft due to electric and mechanical unbalances or to misalignments of the shaft from its centered position. This makes the code a very power…
Changes in Body Composition in Anorexia Nervosa : Predictors of Recovery and Treatment Outcome
2015
The restoration of body composition (BC) parameters is considered to be one of the most important goals in the treatment of patients with anorexia nervosa (AN). However, little is known about differences between AN diagnostic subtypes [restricting (AN-R) and binge/purging (AN-BP)] and weekly changes in BC during refeeding treatment. Therefore, the main objectives of our study were twofold: 1) to assess the changes in BC throughout nutritional treatment in an AN sample and 2) to analyze predictors of BC changes during treatment, as well as predictors of treatment outcome. The whole sample comprised 261 participants [118 adult females with AN (70 AN-R vs. 48 AN-BP), and 143 healthy controls].…
Illumination Correction on MR Images
2006
Objective. An important artifact corrupting Magnetic Resonance Images is the rf inhomogeneity, also called bias artifact. This anomaly produces an abnormal illumination fluctuation on the image, due to variations of the device magnetic field. This artifact is particularly strong on images acquired with a device specialized on upper and lower limbs due to their coil configuration. A method based on homomorphic filtering aimed to suppress this artifact was proposed by Guillemaud. This filter has two faults: it doesnt provide an indication about the cutoff frequency (cf) and introduces another illumination artifact on the edges of the foreground. This work is an improvement to this method because i…
Properties of the Binary Neutron Star Merger GW170817
2019
On August 17, 2017, the Advanced LIGO and Advanced Virgo gravitational-wave detectors observed a low-mass compact binary inspiral. The initial sky localization of the source of the gravitational-wave signal, GW170817, allowed electromagnetic observatories to identify NGC 4993 as the host galaxy. In this work, we improve initial estimates of the binary's properties, including component masses, spins, and tidal parameters, using the known source location, improved modeling, and recalibrated Virgo data. We extend the range of gravitational-wave frequencies considered down to 23 Hz, compared to 30 Hz in the initial analysis. We also compare results inferred using several signal models, which ar…
Differential Leakage Factor in Electrical Machines Equipped with Asymmetrical Multiphase Windings: a General Investigation
2019
This paper presents an investigation in terms of degree of unbalance and leakage factor of electrical machines equipped with multiphase windings. The analysis has been carried out through 4800 combinations between slots/poles/phases/layers, analyzing the variability of the leakage factor for each condition and determining the optimal region for its minimization. The obtained results demonstrate that the leakage factor could be considerably reduced with the adoption of slightly asymmetrical windings, which represent a favorable option during the early design stage of electrical machines.
Significant correlations between certain spectra of atmospherics and different biological and pathological parameters.
1991
Atmospherics are very short naturally occurring electromagnetic impulses of between 4 and 50 kHz. In this review we summarize our results concerning the correlations between certain spectra of atmospherics and several biological and pathological parameters.
An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe
2009
[1] A numerical simulation of Titan's electromagnetic cavity in the VLF band is carried out using the Transmission Line Matrix (TLM) method, with the aim of assessing the VLF electric field spectra sent by the Huygens probe. In an Earth-like model, successive peaks would be expected in the spectra, associated with multiple reflections of the electromagnetic wave on the external surfaces of Titan's electromagnetic cavity, formed by the ionosphere and a conductive ground or underground surface. However, owing to high losses conferred by the electrical conductivity to Titan's atmosphere, the direct numerical and experimental spectra are decreasing functions of the frequency without resonances …
A numerical study of atmospheric signals in the Earth-ionosphere electromagnetic cavity with the Transmission Line Matrix method
2006
[1] The effect of the Earth-ionosphere electromagnetic cavity on the spectrum of an atmospheric signal generated by a broadband electrical current source is analyzed numerically by means of the Transmission Line Matrix (TLM) method. Two new TLM meshes are developed, one with transmission lines connected in parallel and the other with connections in series. The equations describing propagation through these parallel or series meshes are equivalent to the Maxwell equations for TEr or TMr modes in the spherical Earth-ionosphere cavity, respectively. The numerical algorithm obtains Schumann resonance frequencies very close to the experimental ones, confirming that this methodology is a valid nu…
A Small Power Transmission Prototype for Electric Vehicle Wireless Battery Charge Applications
2012
In this paper a low cost prototype of wireless power transfer system based on air coupling is presented. The system here proposed can be useful for electric vehicle (EV) battery charging systems. It consists mainly of two copper wire coils, placed one in front of the other on the same axis. The inductor coil can easily be placed under the road surface (in a parking), while the other (the receiver coil) in the lower side of the vehicle. By exploiting the coils resonance coupling effect, electric energy can be transferred from the inductor coil to the receiver in order to charge the batteries. Low cost experimental tests carried out at DIEETCAM - University of Palermo, demonstrated the effect…