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Number of results: 5
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Abstract

The purpose of this paper is to focus on the loss separation of non-grain-oriented electrical steels used for speed-variable rotating electrical machines. The impact of laser-cutting, used in prototype manufacturing and of flux density harmonics, occurring locally in the lamination, on the loss distribution is studied in detail. Iron losses occurring under operation can physically be separated in different loss components. In this paper, a frequency-based loss model with parameters identified for single-sheet tester specimens, cut in strips of different widths, is therefore used. Moreover, a time-domain approach considers loss distributions occurring from higher harmonics. Hysteresis losses having high sensitivity to cut edge effects are calculated by the well-known Jiles-Atherton model adapting the frequency-based loss parameters. The model is validated by free-curve measurements at a single-sheet tester. It has been shown that the studied elliptical hysteresis model becomes inaccurate particularly for specimens with small strip widths with similar dimensions as teeth of electrical machine laminations. The incorrect mapping of losses occurring from minor hysteresis loops due to higher harmonics is concluded. The results showconsequently that both, the impact of a cut edge effect and local distributions of flux density harmonics need to be considered in terms of accurate iron loss prediction of electrical machine design.

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Authors and Affiliations

Christoph Mülder
Silas Elfgen
Kay Hameyer
ORCID: ORCID
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Abstract

Generalized Rademacher functions, constructed as a sequence of elements of Galois fields are intended to find the spectral representation of signals with levels. These functions form a complete basis on the interval corresponding to -1 discrete time intervals and for passing into the classical Rademacher functions. The advantage of such spectra obtained using Galois Fields Fourier Transform is that the range of variation of the spectrum amplitudes remains the same as the range of variation of the original signal, which is modeled on discrete time functions taking values in the Galois field.
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Authors and Affiliations

Elizaveta S. Vitulyova
1
Dinara K. Matrassulova
2
Ibragim E. Suleimenov
3

  1. Almaty University of Power Engineering and Telecommunications named after Gumarbek Daukeyev, Almaty, Republic of Kazakhstan
  2. Almaty Universityof Power Engineering and Telecommunications named after GumarbekDaukeyev, Almaty, Republic of Kazakhstan
  3. National Engineering Academy of Republic of Kazakhstan, Almaty, Kazakhstan
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Abstract

An important aspect in assessing noise in urban agglomerations is the subjective one, which takes into account the sensitivity and specific reactions of residents to the noise in their living environment. This paper presents results of a sociological study initiated to determine the population awareness, regarding the urban acoustic environment and estimation of effects and disturbance. The survey was conducted in a Romanian city, to complement the information provided by the strategic noise map of the area. This approach allows the estimation of specific local patterns of reaction and response to urban noise of the exposed population and provides the information, needed to develop action plans and to set proper solutions for urban area planning.

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Authors and Affiliations

Diana Popescu
Iuliana Moholea
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Abstract

A drachm of Trajan struck in 98 AD in the mint in Lycia was uncovered at a settlement of the Przeworsk culture at Łęki Majątek (Kutno district). The coin was found in a pit house dated at the beginning of phase C2 of the Late Roman Period (c. 260--c. 280 AD). A good state of preservation of the coin indicates that most of the time it remained hidden in a hoard.
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Authors and Affiliations

Mateusz Bogucki
Beata Jurkiewicz
Henryk Machajewski
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Abstract

The next issue of the Dictionary of folk stereotypes and symbols, published in Lublin under the editorship of Prof. E. Bartminski, is dedicated to the theme Flowers. Unlike many types of plants, whose cultural semantics "superimpose" on their practical significance in human life, flowers have an almost exclusively symbolic function – they serve as a decoration of the home space and a means of marking persons and objects that perform special ceremonial roles.

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Authors and Affiliations

Светлана М. Толстая
ORCID: ORCID

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