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Number of results: 16
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Abstract

Hard bitumens are used in the construction industry primarily in it’s unmodified form, for instance for the production of the so-called traditional roofing felt. Due to the low price of these types of membranes, the use of a popular but expensive modifying agent, SBS copolymer, is not justified economically. Research carried out by the authors has shown that chemical organic compounds belonging to a group of imidazolines may potentially be used as much cheaper bitumen modifier. It was demonstrated that a new type of modifier based on oleic imidazoline, developed by the authors, has a significant impact on improving the physical properties of bitumen. The use of this modifier results in a significant increase in the bitumen plasticity range, both before and after laboratory ageing .In addition, there was a considerable increase of bitumen’s resistance to aging. Its use can help improve the quality and durability of popular waterproofing products manufactured with the use of hard bitumen.
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Abstract

The phase composition of the cement paste phase of concrete containing fly ash from circulating fluidized bed combustion (CFBC) was studied. The motivation was to broaden the knowledge concerning the microstructure and the durability of concrete containing new by-products from the power industry. Several air-entrained concrete mixes were designed with constant water to binder ratio and with substitution of a part of the cement by CFBC fly ash (20%, 30% or 40% by weight). X-ray diffraction tests and thermal analysis (DTG, DTA and TG) were performed on cement paste specimens taken from concrete either stored in water at 18° C or subjected to aggressive freeze-thaw cyclic action. The evaluation of the phase composition as a function of CFBC fly ash content revealed significant changes in portlandite content and only slight changes in the content of ettringite. The cyclic freeze-thaw exposure did not have any significant influence on the phase composition of concrete with and without the CFBC fly ash.
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Abstract

W obliczu rewolucji technologii informatycznych badacze nauk społecznych mają przed sobą nie lada wyzwanie. Oto bowiem wraz ze zwiększającą się popularnością Internetu pojawiły się ogromne ilości danych zawierających opinie, poglądy i zainteresowania jego użytkowników. Chociaż analiza tych danych stawia przed badaczami poważne problemy metodologiczne, za ich użyciem przemawia fascynujący materiał powstający bez ingerencji badaczy. Dużą część tego materiału stanowią dane z najpopularniejszej na świecie wyszukiwarki Google. Co minutę jej użytkownicy ze wszystkich miejsc na świecie zadają ponad 3 miliony zapytań, które są następnie klasyfikowane i udostępniane za pomocą aktualizowanych na bieżąco narzędzi. W artykule tym omówione są próby adaptacji tych danych do potrzeb nauk społecznych, a także dotychczasowe badania na ten temat. Omówione są także praktyczne aspekty pracy z narzędziami Google’a: Google Trends oraz Google Keyword Planner. Artykuł jest przeznaczony przede wszystkim dla badaczy nauk społecznych zainteresowanych internetowymi źródłami Big Data oraz wykorzystaniem tych danych w pracy naukowej.
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Abstract

This paper presents the method for determination of the time of further safe service for welded joints of boiler components after exceeding the design work time. The evaluation of the life of the parent material and its welded joints was performed. Microstructure investigations using a scanning electron microscope, investigations of strength properties, impact testing, hardness measurements and abridged creep tests of the basic material and welded joints were carried out. The investigations described in this paper allowed the time of further safe service of the examined components made of 13CrMo4-5 steel to be determined. The method for determination of the time of safe service of boiler components working under creep conditions allows their operation beyond the design service life. The obtained results of investigations are part of the materials database developed by the Institute for Ferrous Metallurgy.
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