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Abstract

The main purpose of the present paper is to distinguish water located in various types of pores contained within cement paste. The water sorption isotherm is the starting point of the experimental analysis. The investigation was conducted employing the conventional gravimetric method on cement paste composed with w/c=0.5. The investigation was conducted for the following relative humidity values: 11%, 54%, 75%, 84%, 93%, 97% and 100%. Once samples reached the equilibrium water content they were investigated by means of differential scanning calorimetry (DSC), which enabled us to record exothermic peaks corresponding to the crystallization of different water portions. Moreover, we intended to investigate the thermodynamic characteristics of the liquid phase confined within cementitious materials. Hence, the artificial pore solution was prepared. In order to determine the phase transition temperature and the amount of formed ice, the solution was used to saturate silica gel, which is a chemically passive material. Then the thermal analysis was conducted.
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Authors and Affiliations

Marcin Koniorczyk
1
ORCID: ORCID
Dalia Bednarska
2
ORCID: ORCID
Alicja Wieczorek
2
ORCID: ORCID
Piotr Konca
2
ORCID: ORCID

  1. DSc., PhD., Eng., Lodz University of Technology, Department of Building Physics and Building Materials, 90 - 924 Al. Politechniki 6, Poland
  2. PhD., Eng., Lodz University of Technology, Department of Building Physics and Building Materials, 90 - 924 Al. Politechniki 6, Poland
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Abstract

The one-dimension frequency analysis based on DFT (Discrete FT) is sufficient in many cases in detecting power disturbances and evaluating power quality (PQ). To illustrate in a more comprehensive manner the character of the signal, time-frequency analyses are performed. The most common known time-frequency representations (TFR) are spectrogram (SPEC) and Gabor Transform (GT). However, the method has a relatively low time-frequency resolution. The other TFR: Discreet Dyadic Wavelet Transform (DDWT), Smoothed Pseudo Wigner-Ville Distribution (SPWVD) and new Gabor-Wigner Transform (GWT) are described in the paper. The main features of the transforms, on the basis of testing signals, are presented.

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Authors and Affiliations

Janusz Mroczka
Mirosław Szmajda
Krzysztof Górecki
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Abstract

Five species of Tardigrada were found in two moss samples collected from the Hornsund area (Ariekammen, Spitsbergen) including one new to science. The new species, Isohypsibius karenae sp. n., differs from the other similar congeners mainly by having a different type of cuticular sculpture, a different macroplacoid length sequence, by the presence of lunules and cuticular bars under claws as well as by some morphometric characters. The current study increases the number of Isohypsibius species known from Svalbard to thirteen.
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Authors and Affiliations

Krzysztof Zawierucha

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