Search results for " electromagnetic"

showing 10 items of 102 documents

Un metodo numerico incodizionatamente stabile mesh-free per l'analisi elettromagnetica

2012

Settore ING-IND/31 - Elettrotecnicameshfree numerical method computational electromagnetics
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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Studies in thermal and dynamical duality

2011

Settore MAT/07 - Fisica MatematicaT-duality vortex loops cosmic string loops electromagnetic radiation
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Smoothed Particle Electromagnetics Modelling on HPC-GRID Environment

2012

In this paper a meshless approach on a high performance grid computing environment to run fast onerous electromagnetic numerical simulations, is presented. The grid computing and the message passing interface standard have been employed to improve the computational efficiency of the Smoothed Particle Electromagnetics meshless solver adopted. Applications involving an high number of particles can run on a grid computational environment simulating complex domains not accessible before and offer a promising approach for the coupling of particle models to continuous models. The used meshless solver is straightforward to program and fully parallelizable. The results of the parallel numerical sch…

Settore MAT/08 - Analisi NumericaSettore ING-IND/31 - ElettrotecnicaElectromagnetic Simulation Grid Computing Meshless method Smoothed Particle Electromagnetics
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An improved Smoothed Particle ElectroMagnetics method in 3D time domain simulations

2012

In this paper, an enhanced variant of the meshless smoothed particle electromagnetics (SPEM) method is performed in order to solve PDEs in time domain describing 3D transient electromagnetic phenomena. The method appears to be very efficient in approximating spatial derivatives in the numerical treatment of Maxwell's curl equations. In many cases, very often, accuracy degradation, due to a lack of particle consistency, severely limits the usefulness of this approach. A numerical corrective strategy, which allows to restore the SPEM consistency, without any modification of the smoothing kernel function and its derivatives, is presented. The method allows to restore the same order of consiste…

Settore MAT/08 - Analisi NumericaSettore ING-IND/31 - ElettrotecnicaNumerical modellingconsistency restoringSmoothed Particle Electromagnetics smoothed particle electromagnetics (SPEM)
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Mobile phone and auditory system: update

2009

The aim of this study is to asses the non-thermal effects of the electromagnetic fields generated by 915 MHz GSM cellular phones on the human cochlear activity using transient evoked otoacoustic emissions (TEOAE). The study was carried on 205 young and healthy volunteers (age 18-30 years) with normal hearing which were randomly divided into two samples consisting of 85 (Gcase) and 120 (Gcontrol) respectively. The first one was exposed to genuine 10 minutes of GSM electromagnetic fields while the second, undergone sham exposure, was considered as control group for the statistical investigations. All the participants were blind to the genuine or sham exposure. The TEOAEs were measured in the …

Settore MED/31 - OtorinolaringoiatriaGSM Electromagnetic Fields Auditory system Outer sensory cells TEOAESettore MED/32 - Audiologia
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Probing the radio emission from air showers with polarization measurements

2014

The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed which cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially wit…

SignalsAstronomy01 natural sciencesElectric fieldComputational physicsCosmic-raysComposition energy spectra and interactionscosmic rayRadio wavePhysicsEarth's magnetic fieldHigh Energy Astrophysical Phenomena (astro-ph.HE)Radiation[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph][SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]PhysicsAstrophysics::Instrumentation and Methods for AstrophysicsPolarization (waves)Polarization (waves)BolometersThunderstormsMagnetic fieldComputingMethodologies_DOCUMENTANDTEXTPROCESSINGFísica nuclearAstrophysics - Instrumentation and Methods for AstrophysicsAstrophysics - High Energy Astrophysical PhenomenaCAMPO MAGNÉTICOradio emissionRadio waveNuclear and High Energy Physics[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE][PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]Air showerComposition energy spectra and interactions; Solar electromagnetic emission; BolometersAstrophysics::High Energy Astrophysical Phenomenainfrared submillimeter wave microwave and radiowave receivers and detectorsFieldFOS: Physical sciencesPierre Auger Observatory ; air shower ; radio emissionRadiationMonte-carlo SimulationsOpticsElectric field0103 physical sciencesddc:530Pierre auger observatory010306 general physicsPulsesInstrumentation and Methods for Astrophysics (astro-ph.IM)Pierre Auger Observatory010308 nuclear & particles physicsbusiness.industrySolar electromagnetic emissionFísicaOpticsDetectorComputational physics[SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]Air showerEarth's magnetic fieldMagnetic fieldExperimental High Energy PhysicsbusinessCodalema
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Associations of Maternal Cell-Phone Use During Pregnancy With Pregnancy Duration and Fetal Growth in 4 Birth Cohorts

2019

Results from studies evaluating potential effects of prenatal exposure to radio-frequency electromagnetic fields from cell phones on birth outcomes have been inconsistent. Using data on 55,507 pregnant women and their children from Denmark (1996-2002), the Netherlands (2003-2004), Spain (2003-2008), and South Korea (2006-2011), we explored whether maternal cell-phone use was associated with pregnancy duration and fetal growth. On the basis of self-reported number of cell-phone calls per day, exposure was grouped as none, low (referent), intermediate, or high. We examined pregnancy duration (gestational age at birth, preterm/postterm birth), fetal growth (birth weight ratio, small/large size…

Time FactorsEpidemiologyDenmarkOriginal ContributionsFetal Developmentstress0302 clinical medicinePregnancyRisk FactorsFetal growthBirth outcomes030212 general & internal medicineNetherlandsObstetricsConfoundingHazard ratio1. No povertyPregnancy OutcomeGestational age3. Good healthbehavioral-problems1st trimesterPremature birth030220 oncology & carcinogenesisPremature BirthFemaleAdultmedicine.medical_specialtyradio-frequency electromagnetic fieldsBirth weightCell phonescell phonesGestational AgeExposure03 medical and health sciencesRepublic of KoreamedicineHumansradio-frequency electronRadio-frequency electromagnetic fieldsPregnancybusiness.industryabsorption ratesbirth outcomespreterm birthweightPreterm birthmedicine.diseaseConfidence intervalwhole-bodyradiationSpainexposurebusinessCell PhoneAmerican Journal of Epidemiology
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Extremely low frequency electromagnetic fields (ELF-EMFs) induce in vitro angiogenesis process in human endothelial cells.

2008

Effects of extremely low frequency (ELF) electromagnetic fields (EMFs) on activation of angiogenesis were analysed using cultured umbilical human vein endothelial cells (HUVECs). The cultures were exposed to a sinusoidal EMF to intensity of 1 mT, 50 Hz for up to 12 h. EMFs increased the degree of endothelial cell proliferation and tubule formation, coupled by an acceleration in the process of wound healing. Since this process is physiologically accompanied by a large modification in the structural organization of actin and focal adhesions, we analyzed the rearrangement of some cytoskeleton elements demonstrating a major reorganization of the fibres and of the focal adhesion complexes after …

animal structuresCytoskeleton organizationPhysiologyAngiogenesisBiophysicsNeovascularization PhysiologicBiologyRadiation DosageFocal adhesionElectromagnetic FieldsEndothelial cellElectricityHumansRadiology Nuclear Medicine and imagingTherapeutic angiogenesisCytoskeletonCells CulturedEndothelial CellsDose-Response Relationship RadiationGeneral MedicineCell biologyEndothelial stem cellAngiogenesiSignal transductionWound healingExtremely low frequency electromagnetic fieldsBioelectromagnetics
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Innovative and Applied Research in Biology: Proceedings, Vol.1

2019

Projekti: ZD2016/AZ81 & ZD2016/AZ107

bio textilessurface waters quality:FORESTRY AGRICULTURAL SCIENCES and LANDSCAPE PLANNING [Research Subject Categories]waterbirdsred beetroot juicenature conservationprotected landscape areagenetic diversitylitter decompositionurban environmentbioindicationlow frequency electromagnetic fields:NATURAL SCIENCES [Research Subject Categories]ecology
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