Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Microstructure-related properties of explosively welded multi-layer Ti/Al composites after rolling and annealing

Solecka Monika, Mróz Sebastian, Petrzak Paweł, Mania Izabela, Szota Piotr, Stefanik Andrzej, Garstka Tomasz, Paul Henryk

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 1

art. no. e39, 2023

The processes of rolling and annealing of explosively welded multi-layered plates significantly affect the functional properties of the composite. In current research, fifteen-layered composite plates were fabricated using a single-shot explosive welding technique. The composites were then rolled up to 72% to reduce layer thickness, followed by annealing at 625 °C for varying times up to 100 h. Microstructure evolution and chemical composition changes were investigated using scanning electron microscopy equipped with energy-dispersive spectroscopy. The mechanical properties of the composite were evaluated by tensile testing, while the strengths of individual layers near the interface were evaluated by micro-hardness measurements. After explosive welding, the wavy interfaces were always formed between the top layers of the composite and the wave parameters decreasing as the bottom layers approach. Due to the rolling process, the thickness of Ti and Al layers decreases, and the waviness of top interfaces disappeared. Simultaneously, the necking and fracture of some Ti layers were observed. During annealing, the thickness of layers with chemical composition corresponding to the Al3Ti phase increased with annealing time. A study of growth kinetic shows that growth is controlled by chemical reaction and diffusion. The results of micro-hardness tests showed that after annealing, a fourfold increase of hardness can be observed in the reaction layers in relation to the Ti, while in relation to Al, the increase of hardness is even 15 times greater.

Study on activated sludge flocs morphology and composition in a full-scale wastewater treatment plant in Poland

Liwarska-Bizukojc Ewa, Andrzejczak Olga, Solecka Monika

Environment Protection Engineering

2019

Vol. 45, nr 2

69--82

This work is a comprehensive study of a full-scale municipal wastewater treatment plant (WWTP) in the city of Zgierz (Poland) aiming at the estimation of the impact of seasonal changes of temperature on flocs morphology, biomass concentration, quantity of filamentous bacteria, content of polyhydroxybutyrate (PHB) and composition of microinvertebrates in the activated sludge system. Two short-term measurement campaigns, in winter and in summer, were carried out under dry weather conditions. It occurred that lower temperatures (11.1–14.6 °C) had hardly any effect on flocs size or concentration of activated sludge biomass in the full-scale activated sludge system treating municipal wastewater. They did not aggravate the biosynthesis of PHB either. However, decreasing temperature favored the growth of filamentous bacteria and led to the elevation of the sludge volume index (SVI). In spite of this, it did not induce any bulking events. Irrespective of the season, the groups of crawling ciliates, attached ciliates and testate amoebae, indicating good performance of the full-scale plant tested, were predominant.