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Wyszukujesz frazę "causes of transformations" wg kryterium: Wszystkie pola


Wyświetlanie 1-2 z 2
Tytuł:
Vegetation Transformations of Kujawy-Pomerania Region in the Last Twenty Years Period
Autorzy:
Załuski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/765031.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
causes of transformations
ecological processes
plant communities
vegetation dynamics
Opis:
This paper contents dynamic tendencies analysis results of Kujawy-Pomerania region (N Poland) for a 20-year time period. Acreage changes as well as structure and species composition transformations of forest and shrub vegetation (associations) and non-forest vegetation (alliances) were evaluated. Main factors influencing on regressive and progressive changes were set out. Analysis was relied on results of geobotanical research and observations of selected objects. Regressive changes were noted for i.a. thermophilous oak forests, dry and fresh coniferous forests, aquatic, halophytic, pasture vegetation, vegetation of Molinion and Cnidion meadows, heaths and xerothermic grasslands. Whereas progressive were observed in case of mixed coniferous forests, mesophytic shrubs, rush and tall herbs vegetation, fresh meadows and some ruderal communities.
Źródło:
Acta Universitatis Lodziensis. Folia Biologica et Oecologica; 2011, 7; 75-98
1730-2366
2083-8484
Pojawia się w:
Acta Universitatis Lodziensis. Folia Biologica et Oecologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the Causes of Cracking of Pipes Derived from Recirculated Polyethylene
Autorzy:
Samujło, Bronisław
Longwic, Filip
Lavorgna, Marino
Powiązania:
https://bibliotekanauki.pl/articles/2181748.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
polyethylene recyclate
pipes
fatigue crack
phase transformations
Opis:
The objectives of the research was to determine the causes of cracks in pipes made of high-density polyethylene (HDPE) regranulate during their storage. A visual assessment of the cracks was carried out and their fatigue nature was found. Due to the insufficient information on the composition and properties of the processed regranulate, tests were carried out on the density distribution and mass flow rate of plastic samples taken from various areas of the pipe wall. Comparative tests were performed using infrared spectrophotometry of a plastic sample taken from a pipe, commercial HDPE and commercial polypropylene (PP) by attenuated total reflection/Fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetry (TG) and differencial scaning calorimetry (DSC) method. There were differences in density and flow rate depending on the distance from the outer surface of the pipe, reaching several percent. Based on the conducted spectroscopic, thermogravimetric and differential scanning calorimetry studies, none of the expected plastics contamination, mostly PP, has been found in recirculated polyethylene. Futhermore, the expected decrease in the temperature of phase transformations and the beginning of decomposition of polyethylene (PE) after recycling, compared to the original one, were visible. Possible causes of cracks were considered to be differences in the PE structure in the pipe wall and the occurrence of possible porous structures, which when storing pipes in variable load and temperature conditions could cause the propagation of microcracks.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 2; 19--25
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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