Search results for "electromagnetic induction"
showing 10 items of 11 documents
Numerical modeling and design of a disk-type rotating permanent magnet induction pump
2016
Abstract Electromagnetic induction pumps with rotating permanent magnets appear to be the most promising devices to transport liquid metals in high-temperature applications. Here we present a numerical methodology to simulate the operation of one particular modification of these types of pumps: a disk-type induction pump. The numerical model allows for the calculation and analysis of the flow parameters, including the pressure–flow rate characteristics of the pump. The simulations are based on an iterative fully coupled scheme for electromagnetic and hydrodynamic solvers. The developed model is verified by comparing with experimental data obtained using a Pb-Bi loop test facility, for press…
Load Torque Estimation Method to Design Electric Drivetrains for Offshore Pipe Handling Equipment
2016
One of the main design objectives for electric drivetrains operating in offshore drilling equipment is to keep them as small, yet as effective, as possible, to minimize space they occupy on drill floor and maximize their performance. However, practical experience shows that typically choices made by design engineers are too conservative due to the lack of enough data characterizing load conditions. This results in too costly and too heavy selected components. Therefore, in the current paper we present a method to estimate required full-scale motor torque using a scaled down experimental setup and its computational model. A gripper arm of an offshore vertical pipe handling machine is selecte…
Magneto-Electro-Elastic Bimorph Analysis by the Boundary Element Method
2008
The influence of the magnetic configuration on the behavior of magneto-electro-elastic bimorph beams is analyzed by using a boundary element approach. The problem is formulated by using the generalized displacements and generalized tractions. The boundary integral equation formulation is obtained by extending the reciprocity theorem to magneto-electro-elastic problems; it is numerically implemented by using the boundary element method multidomain technique to address problems involving nonhomogeneous configurations. Results under different magnetic configurations are compared highlighting the characteristic features of magnetopiezoelectric behavior particularly focusing on the link between …
Test of the generation of High-Frequency Gravitational Waves by irradiating a dielectric film in a resonant cavity
2004
A recent proposal for generating High Frequency Gravitational Waves (HFGW) is based on the conversion of electromagnetic waves into gravitational waves by irradiating a dielectric film in the extreme conditions of a high vacuum and a strong magnetic field. These HFGWs can be tested using an electron paramagnetic resonant spectrometer (EPRS). This device contains all the necessary ingredients: a vacuum chamber, microwave generator, a strong magnetic field, and a resonant cavity where the substance to be analysed is introduced. The EPR spectrum of a very small paramagnetic core in a substance is the graph of the absorption of the paramagnetic core as a function of the strong magnetic field B.…
Laminated carbonate deposits in Roman aqueducts: Origin, processes and implications
2013
Carbonate deposits in Roman aqueducts of Patara and Aspendos (southern Turkey) were studied to analyse the nature of their regular layering. Optical microscopy and electron-backscattered diffraction results show an alternation of dense, coarsely crystalline, translucent laminae composed of bundles and fans of elongate calcite crystals with their c-axes parallel to the long axis, and porous, fine-grained laminae with crystals at near-random orientation. The ?18O and ?13C data show a strong cyclicity and anti-correlation, whereby high and low ?18O values correspond to dense columnar and porous fine-grained laminae, respectively. Geochemical analyses show similar cyclic changes in carbonate co…
Comparative Determinations of Magnetic Induction in AC and DC Circuits
2019
The influence of the electromagnetic field on the human body, although still heavily studied, can have long-term negative effects. The static electromagnetic field is generated by a continuous current source and has a current flow characteristic conventionally set + from -. The variable electromagnetic field is produced by the alternating current and has the ability to change its direction over time with a frequency of 50 or 60 Hz. It is considered that the non-hazardous limit value for the magnetic field (according to Federal Office for Radiation Security in Germany) is 100 microT for 50 Hz and 83 microT for 60 Hz. For the electric field, the exposure limit value is 5kV/m. Electromagnetic …
Induction mechanisms in a von Kármán swirling flows of liquid Gallium
2004
International audience; Using in situ magnetic field measurements, we study the induction mechanisms in a swirling flow of liquid Gallium generated inside a cylinder, in the gap between two coaxial rotating discs. The von Kármán flow generated in this manner has both helicity and differential rotation. Magnetic Reynolds numbers Rm up to 7 (based on the disc rim speed) are generated. We study the magnetic induction when an external field is applied successively along the axis, in the azimuthal direction or tranverse to the axis of rotation. In the first two cases, both the flow and the magnetic field are axisymmetric, and an effective mechanism of conversion from poloidal to toroidal field e…
The modelling of the behaviour of solid inclusions in the EM induced recirculated turbulent flows of liquid metal
2014
Promocijas darbā skaitliski un eksperimentāli pētītas noslēgtas elektromagnētiski ierosinātas šķidrā metāla turbulentās plūsmas ar cietām daļiņām. Šādas plūsmas veidojas metalurģiskajās indukcijas krāsnīs. Darbā ir izveidots uz LES plūsmas aprēķina pieejas bāzēts Lagranža modelis ar paplašinātu spēku kopu inerciālo daļiņu pārneses aprakstam. Veikts eksperimentāls daļiņu koncentrācijas pētījums kvazi-stacionārā stāvoklī, izmantojot jaunu ideju: ferromagnētiskās daļiņas izmantotas kā nevadošu daļiņu fiziskais modelis šķidrajā metālā - tas ir pirmais zināmais eksperimentālais darbs cietu ieslēgumu sadalījuma analīzē elektormagnētiski ierosinātu šķidro metālu plūsmu iekšienē. Eksperiments pierā…
Anomalous magnetic hysteresis in the microwave surface resistance of MgB2 superconductor
2007
We report experimental results of the field-induced variations of the microwave surface resistance in samples of MgB2, produced by different methods. By sweeping the DC magnetic field at increasing and decreasing values, we have detected a magnetic hysteresis that can be ascribed to the different magnetic induction, due to the critical state of the fluxon lattice. The hysteresis observed in the bulk samples has an unusual shape, which cannot be justified in the framework of the critical-state models.
Intracranial measurement of current densities induced by transcranial magnetic stimulation in the human brain
2003
Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses the principle of electromagnetic induction to generate currents in the brain via pulsed magnetic fields. The magnitude of such induced currents is unknown. In this study we measured the TMS induced current densities in a patient with implanted depth electrodes for epilepsy monitoring. A maximum current density of 12 microA/cm2 was recorded at a depth of 1 cm from scalp surface with the optimum stimulation orientation used in the experiment and an intensity of 7% of the maximal stimulator output. During TMS we recorded relative current variations under different stimulating coil orientations and at different points…