Electromagnetic Field Research Papers - Academia.edu (original) (raw)

We present both a computational and an experimental approach to the problem of biological aerosol characterization, joining the expertises reached in the field of theoretical optical scattering by complex, arbitrary shaped particles... more

We present both a computational and an experimental approach to the problem of biological aerosol characterization, joining the expertises reached in the field of theoretical optical scattering by complex, arbitrary shaped particles (multipole expansion of the electromagnetic fields ...

We report successful simulation of current-injection photonic crystal laser showing the spatial-temporal evolution of the electromagnetic field as well as carrier distribution using our dynamical semiconductor medium (DSM) FDTD model,... more

We report successful simulation of current-injection photonic crystal laser showing the spatial-temporal evolution of the electromagnetic field as well as carrier distribution using our dynamical semiconductor medium (DSM) FDTD model, showing its capability in dealing with complex electromagnetic structures and semiconductor carrier dynamics.

Radiating dipoles in photonic crystals. Kurt Busch 1,2 , Nipun Vats 1 , Sajeev John 1 , and Barry C. Sanders 3 1 Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, Canada M5S 1A7 2 Institut ...

In this article we discuss the realization of antenna gate structures for inductively coupled passive HF RFID systems. Antenna gates are currently used in several applications, from industrial tracking to access control: in these... more

In this article we discuss the realization of antenna gate structures for inductively coupled passive HF RFID systems. Antenna gates are currently used in several applications, from industrial tracking to access control: in these structures the identification process is realized with the use of more antennas disposed in a configuration that makes them similar to doors. Nowadays these structures can reach a maximum width of 1.50-1.60 meters due to the limitations deriving from the CEPT ERC Recommendation 70-03 annex 9 on electromagnetic emissions from electronic devices. Next to this, limitations also derive from the decrease of the electromagnetic field with the distance and from physical constrains due to the fact that the field strength is proportional to the dimensions of the antennas. The purpose of this article is to describe a possible optimum configuration of antennas allowing the detection of tags across a 2 meters wide gate reducing as much as possible its dimensions.

Remote measurements of the atmospheric state can be performed by radio occultation between satellites, a GPS satellite transmitting a radio signal to a receiving low Earth orbit (LEO) satellite, or between LEO satellites. The bending... more

Remote measurements of the atmospheric state can be performed by radio occultation between satellites, a GPS satellite transmitting a radio signal to a receiving low Earth orbit (LEO) satellite, or between LEO satellites. The bending angle of the traversing optical ray can be measured by detecting the Doppler shift of radio signals. The bending angle is an integrated measure of the refractive index in the atmosphere traversed by the optical ray. With a time series (profile) of the bending angle, it is possible to perform an inversion to obtain the refractive index. Various techniques for the retrieval of the bending profile already exist. The most recent methods have solved the problem of multipath, i.e., when the atmosphere allows several rays to exist simultaneously. The paper presents a new method for the reconstruction of bending angle as a single-valued function of impact parameter from complex radio occultation signal under multipath propagation conditions. The method utilizes the assumption of spherical symmetry of refractivity, i.e., n(?) = n(r), and the principle of synthetic aperture, thus allowing sub-Fresnel resolution. A distinctive feature of the method, as compared to previously known methods, is direct applicability for arbitrary orbits of transmitting and receiving satellites, without intermediate propagation of complex electromagnetic field to circle or straight line. This comes at the expense of impossibility to reduce the method to a FFT. The method can be useful for inverting radio occultation signals and for validation of other radio holographic methods.

Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar... more

Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar installations can elicit an aversive behavioural response in foraging bats. Four civil air traffic control (ATC) radar stations, three military ATC radars and three weather radars were selected, each surrounded by heterogeneous habitat. Three sampling points matched for habitat type and structure, dominant vegetation species, altitude and surrounding land class were located at increasing distances from each station. A portable electromagnetic field meter measured the field strength of the radar at three distances from the source: in close proximity (<200 m) with a high electromagnetic field (EMF) strength >2 volts/metre, an intermediate point within line of sight of the radar (200-400 m) and with an EMF strength <2 v/m, and a control site out of...

All the risks concerning the long lasting exposition to the asbestos, for instance diseases affecting the respiratory system, are known very well. In particular, it’s the friable asbestos the most dangerous element, above all as for the... more

All the risks concerning the long lasting exposition to the asbestos, for instance diseases affecting the respiratory system, are known very well. In particular, it’s the friable asbestos the most dangerous element, above all as for the easily dispersing fibres. Despite the above mentioned risks, the number of asbestos covered block is still high in many nations, in particular they are buildings characterized by eternit coverings (a mixture of cement and asbestos), certainly due to the features of materials and their low cost.Various legislations implement reclamation works on the asbestos roofs, but in several countries building farms keep on using such material, despite it’s forbidden to them. The present work has as objective one to supply a cheap tool for the automatic identifying with the buildings which do use for its covering of this very dangerous technology; they are taken back three alternative methodologies of development of the tool, everyone working on remote sensed images and of a procedure of specific classification for the problems in exam, skilled actually turned out to offer useful on the applicatory plan. In the specific one the three configurations melt their work on the comparison between the spectrum of a building, spatially considered well known, characterized by covering in cement-asbestos with the spectrum of the pure material obtained from laboratory measures.From such comparison it is generated, in the first two cases, the building and the implementation of a suitable operator that through the estimate of an opportune equalization coefficient (built respectively using the neural nets and the ionized plasma (electromagnetic fields)), it allows to identify in automatic way the present coverings on the territory and therefore proceed to the next phase of pixel-oriented classification of the whole image.The last methodology is responsible for making a comparison between the classifications obtained with the methodologies preceding (pixel-oriented) and that coming from the use of an object-oriented method consisting in a Nearest Neighbor classification tool following a multi-resolution segmentation worked on the whole scene.