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Glinicki M.A.,Instytut Podstawowych Problemow Techniki PAN
Cement, Wapno, Beton | Year: 2014

In the paper the qualitative and quantitative methods of concrete air entrainment were presented, not only these which are in standard, but also behind them. From the last ones the foam index, foam stability and the method applying buoyancy rule of particles migration were described and their drawbacks as well as the good points are given. Detailed discussion is devoted to microscopic method of pores structure determination and the drawback of standard lack is underlined. Also the Danish, German and Canadian Standard are discussed, the last one especially in the case of roads construction. © 2014, Foundation Cement, Lime, Concrete. All rights reserved. Source

Zurek Z.H.,Silesian University of Technology | Kukla D.,Instytut Podstawowych Problemow Techniki PAN | Kurzydlowski K.J.,Warsaw University of Technology
Przeglad Elektrotechniczny | Year: 2012

The fatigue degradation of ferromagnetic steels proceeds with the changes of electrical (γ) and/or magnetic (μ) parameters. The article presents some selected issues of research into correlations between the magnetic parameters and the material fatigue degree, in operating conditions as well as quantitatively controlled in laboratory conditions. In order to identify and assess the effects of fatigue, a methodology of quantitative description of material defect degree was developed. According to the developed methodology, a set of standard samples with specified value of their defect degree was prepared. There were tested and analyzed the microstructural aspects of degradation process taking place in the operating conditions under the influence of variable mechanical, thermal and environmental loads, and also in the conditions of single-variable loads performed in the laboratory. Source

Moranda H.,Poznan University of Technology | Ranachowski P.,Instytut Podstawowych Problemow Techniki PAN | Moscicka-Grzesiak H.,Poznan University of Technology
Przeglad Elektrotechniczny | Year: 2010

The article describes results of the attempt to find out the correlation between porosity of porcelain and selected parameters describing partial discharges generated under AC voltage. The study shows that there is a correlation between the percentage of different sizes pores and the frequency of PD pulse occurrence. Source

Ranachowski P.,Instytut Podstawowych Problemow Techniki PAN | Rejmund F.,Instytut Podstawowych Problemow Techniki PAN | Ranachowski Z.,Instytut Podstawowych Problemow Techniki PAN | Pawelek A.,Instytut Metalurgii i Inzynierii Materialowej PAN | And 2 more authors.
Przeglad Elektrotechniczny | Year: 2014

The paper presents the microscopic and mechanoacoustic study of degradation processes of the porcelain material C 110 type. Smallsized samples, derived from the low voltage insulator, were subjected to a slow, quasi-static compression, with simultaneous recording of acoustic emission descriptors. There were distinguished consecutive stages of the material degradation. Obtained results were compared with the images of the microstructure of low-voltage insulator materials after many years of operation. On this basis, there were distinguished the factors determinant of the short-term strength of porcelain and its resistance to ageing processes under operating conditions. © 2014, Wydawnictwo SIGMA - N O T Sp. z o.o. All rights reserved. Source

Dabrowski M.,Instytut Podstawowych Problemow Techniki PAN | Glinicki M.,Instytut Podstawowych Problemow Techniki PAN
Road and Bridges - Drogi i Mosty | Year: 2013

The paper presents results of the investigation of the air void characteristics and the resistance to cyclic freezing and thawing of air-entrained concrete containing calcareous fly ash. The frost resistance was tested also under the presence of de-icing salts to check the resistance to frost-salt scaling and without de-icing salts. The range of investigation included air entrained concrete mixes with the specified water-binder ratio of w/b=0.45 with addition of calcareous fly ash or made using blended cements with calcareous fly ash (W), and also siliceous fly ash (V) and ground granulated blast-furnace slag (S). The coarse aggregates used were crushed granodiorite and crushed limestone. The air-void system parameters were determined by microscopic image analysis and the effect of addition of calcareous fly ash was assessed. The effect of concrete age and presence of fly ash W on the strength and freeze-thaw resistance was also studied. The tests have shown that the use of calcareous fly ash as one of the main constituents of blended cements does not affect the frost salt scaling resistance nor the resistance to internal frost damage provided that the air void system is adequate. Source

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