Michal Kosterec

Ticks and radio-frequency signals: behavioural response of ticks ( Dermacentor reticulatus ) in a 900 MHz electromagnetic field

Abstract The electromagnetic field (EMF) is present in the environment throughout the world and encompasses both natural and human-made sources of electromagnetic fields. It has been shown that EMF influences a variety of biological systems, including the behavioural responses of both vertebrates and invertebrates. As such, determining the effects of the EMF on the ecosystem in detail may be important for understanding the ecology and biology of organisms, particularly those, such as ticks, that are important in disease transmission. Our main goal was to determine if the tick, Dermacentor reticulatus, interacts with the EMF. An experimental behavioural test of tick sensitivity to radio frequency power radiation was performed under laboratory conditions. Tests were performed in an electromagnetic compatibility laboratory in a radio frequency electromagnetic field (RF-EMF) anechoic chamber. Ticks were irradiated using a Double-Ridged Waveguide Horn Antenna with 900 MHz RF-EMF. The applied radio-frequency power was tuned below the proposed limit for public exposure to mobile phone base stations. We found that exposure induces an immediate tick locomotor response manifested either in a previously unreported jerking movement of the whole body or in jerking of the first pair of legs. Overall, ticks exhibited significantly greater movement in the presence of the RF-EMF. Significant sex differences relative to RF-EMF exposure were observed in both response variables. In the presence of RF-EMF, body jerking by females was greater than in males and vice versa for leg jerks. This study represents the first experimental evidence of a behavioural response of D. reticulatus ticks to exposure to RF-EMF.

Breakdown voltage of polypropylene film during C and thermal ageing

This paper investigates the electrical breakdown of biaxially oriented polypropylene (BOPP) film during accelerated DC and thermal ageing. The DC breakdown voltage of 6.5 μm thick capacitor grade polypropylene (PP) films was measured. Two types of films with different crystallinity were tested. 88 breakdowns per sample were collected. The scale and shape parameter of the Weibull distribution were fitted to the data. The scale parameter values obtained vary between 713 and 804 V. Results indicate that during ageing procedure the film crystallinity is an influencing factor of their breakdown voltages.

Solution of transient phenomena during the connection of the photovoltaic power plants

This paper deals with the solution of transient phenomena during the connection of the photovoltaic power plants. There was investigated the impact of the failure of current protection for renewable energy sources during the network disconnection. There was verified the possibility of network operation during the islanding operation. Failure of network protection represents the significant hazard for employees of distribution system operator so it is necessary to solve the accurate current and voltage values during the connection of particular renewable energy sources.

The impact of electromagnetic radiation on the dielectric properties of magnetic nanofluids

Presented article discusses the impact of electromagnetic radiation on dielectric properties of magnetic fluids based on transformer oil ITO 100. For measurements and evaluation of the samples we used the PDC analysis. The measurements were performed in two variants, specifically when individual samples were irradiated and were not irradiated with the external magnetic field. To minimize undesired electromagnetic fields, the measurements were realized in the anechoic EMC chamber. The main objective of this experiment was to determine if the electromagnetic radiation can change properties of magnetic liquid. Used samples of magnetic fluids were with different concentrations of magnetic nanoparticles. In the experiment was generated electromagnetic field, used to charge and discharge streams, of which are indicative of the state of the insulation system. For comparison of the results the samples were analyzed before irradiation with EM field and after irradiation with EM field.

Thermal degradation of transformer pressboard impregnated with magnetic nanofluid based on transformer oil

In this paper, the thermal ageing of pressboard impregnated with two kinds of insulation liquids is studied by means of frequency domain spectroscopy which involves the measurement of real and imaginary part of complex permittivity as function of frequency. The magnetic nanofluid was composed by mineral transformer oil as carrier liquid, nanoparticles of magnetite and surfactant. The thermal aging test was performed at the temperature 90°C for 1000 hours. Each sample had two variations, with and without copper, which has function catalyst. Then frequency domain spectroscopy was investigated at 40°C for restriction of moisture influence from surrounding. From the data and curves, it can be shown that the undried samples are dried with the aging time and cooper considerably getting worse the imaginary part of complex permittivity. In case of magnetic nanofluid, the colloidal suspension was unstable after 800 hours of the thermal ageing. There was found much more resistance of moisture at the nanofluids than in case of mineral oil impregnated pressboard.

Experimental observation of interaction between radiofrequency electromagnetic field and blood tissue

The exposition of biological and technical systems to electromagnetic radiation has increased with the rapid development of wireless data transfer. Recent studies are incrementally aiming at electromagnetic compatibility between electromagnetic radiation sources and biological and technical systems. No source of electromagnetic radiation should affect operation of other technical systems and endanger biological systems. Studies show that biological organism reacts to electromagnetic fields. This paper is focused on experimental observation of interaction between electromagnetic radiation and biological samples in the form of blood preparations. Results of interaction of radiofrequency electromagnetic radiation produced by mobile phone and biological tissue are presented. Samples of animal blood were used. The first part is focused at actual research in the world. In the second part there is presented workplace setup for exposing biological tissues to non-ionizing electromagnetic field. Results of this exposure are presented in the end.

Influence of electromagnetic interference on time-domain spectroscopy of magnetic nanofluids

The article deals about magnetic fluids based on a transformer ITO100 oil and about behaviour of these fluids under influence of permanent magnetic field represented by time-current characteristics. The measurements were performed in an anechoic EMC chamber and outside the chamber for comparing the results on the same samples. The main objective was to determine how much is the measurement influenced by external electromagnetic fields that generate around electrical equipment and the impact of higher harmonics in the power supply voltage. The measurement is dependent from orientation of actuating magnetic field, this behaviour mainly shows the effect of nanoparticles structuring during exposition of specimen by magnetic field. These particles also changes polarization processes in fluid influence of nanoparticles concentration contained in the fluid.