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Ziemba R.,Rzeszow University of Technology | Maslowski G.,Rzeszow University of Technology | Baran K.,Higher Vocational State School in Kalisz
ICHVE 2014 - 2014 International Conference on High Voltage Engineering and Application | Year: 2014

The paper presents computer simulations of current distribution in lightning protection system (LPS) for a small residential structure. The primary objective was the theoretical examination of the current waveshapes in different parts of the circuit and the division of the injected impulse current between the grounding system of the LPS and remote ground. Two different approaches are adopted in modeling of impulse excitation. First, the simple current source described by double-exponential approximation is used. In the second approach the circuit model of the generator connected to the return path is implemented to ATP-EMTP simulation. Vertical and horizontal ground electrodes are modeled for specified parameter resulting from the geometrical configuration of the system and the measured soil resistivity. Computed currents show a good agreement with the experimental data obtained in 2013 using the impulse current generator at the test site in Poland. A significant influence of frequency dependent components of the system impedances on current waveshapes is noticed. The same as for measurements current waveshapes in the vertical ground electrodes differed from the injected current waveshapes and from the current waveshapes in other parts of the test system. © 2014 IEEE. Source

Czarny R.,Higher Vocational State School in Kalisz | Paszkowski M.,Wroclaw University of Technology | Knop P.,Wroclaw University of Technology
Journal of Tribology | Year: 2016

The results of the studies on the formation of surface and boundary layers in commercial lithium (LT4-S3) and calcium (STP) greases near the walls of six different materials are presented. Two elastomeric materials (nitrile-butadiene rubber (NBR), silicone rubber (MVQ/VMQ)), two thermoplastic materials (polyoxymethylene (POM), polyethylene (PE)), and two metal (copper C11000 and steel 304) alloys were used in the tests. The tests were carried out using a rotational rheometer operating in the plate/plate configuration. Structural viscosity-shear rate curves were determined and dynamic oscillatory tests were carried out. The tests have shown that the metal alloys have the highest capacity to adsorb grease thickener particles on their surface. The elastomeric materials have the smallest effect on the change in structural viscosity in the vicinity of the wall, which indicates their low capacity to form a surface layer in the tested commercial greases. © 2016 by ASME. Source

Bem H.,Higher Vocational State School in Kalisz | Plota U.,Higher Vocational State School in Kalisz | Staniszewska M.,Higher Vocational State School in Kalisz | Bem E.M.,Higher Vocational State School in Kalisz | Mazurek D.,Higher Vocational State School in Kalisz
Journal of Radioanalytical and Nuclear Chemistry | Year: 2014

Activity concentration of the 222Rn radionuclide was determined in drinking water samples from the Sothern Greater Poland region by liquid scintillation technique. The measured values ranged from 0.42 to 10.52 Bq/dm3 with the geometric mean value of 1.92 Bq/dm3. The calculated average annual effective doses from ingestion with water and inhalation of this radionuclide escaping from water were 1.15 and 11.8 μSv, respectively. Therefore, it should be underlined that, generally, it's not the ingestion of natural radionuclides with water but inhalation of the radon escaping from water which is a substantial part of the radiological hazard due to the presence of the natural radionuclides from the uranium and thorium series in the drinking water. © 2014 The Author(s). Source

Bem H.,Higher Vocational State School in Kalisz | Bem E.M.,Higher Vocational State School in Kalisz | Krawczyk J.,Higher Vocational State School in Kalisz | Plotek M.,Higher Vocational State School in Kalisz | And 2 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

Plastic PicoRad detectors with activated charcoal have been used for radon monitoring in local kindergartens and schools in two cities, Kalisz and Ostrów Wielkopolski, in the region of Greater Poland. Detectors were exposed for a standard time of 48 h during the autumn and winter of 2011 in 103 rooms (Kalisz) and 55 rooms (Ostrów Wlkp), respectively. The detectors were calibrated in the certified radon chamber of the Central Laboratory for Radiological Protection in Warsaw, Poland. The arithmetic and geometric means of indoor radon concentrations in the examined rooms were 46.0 and 30.3 Bq/m 3 for Kalisz and 48.9 and 29.8 Bq/m3 for Ostrów Wlkp, respectively. The measured levels of the indoor radon concentrations were relatively low, since the main source of indoor radon for these low storey (max. three storeys) buildings is radon escaping from the underlying soil with a low 226Ra concentration (~15 Bq/m3). Therefore, the calculated annual effective doses from that source for the children in Kalisz and Ostrów Wlkp were also low 0.35 mSv. © 2012 The Author(s). Source

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