The effect of strain rate on the impact strength of the high-Mn steel

In the paper, results of impact bending tests of a high-manganese steel of Fe – 30 wt.%, Mn – 9 wt.%, Al – 0,65 wt.%, C grade are presented. The tests were carried out using a flywheel machine, suitable for dynamic stretching and impact bending tests in the range of linear velocity of the forcing element from 5 ÷ 40 m/s. The obtained test results were compared with the results of impact resistance of the studied steel determined using Charpy machine. Structural investigations were carried out using scanning transmission electron microscopy. Surfaces of fractures formed in the break point during bending tests were analyzed, and they indicate a presence of mixed transcrystalline fractures with a predominance of plastic fractures

Comparison of Cu-Mg-Al-Ox and Cu/Al2O3 in selective catalytic oxidation of ammonia (NH3-SCO)

Copper-based materials are promising catalysts in the selective catalytic oxidation of ammonia into nitrogen and water vapour (NH 3 -SCO). Investigations under applied reaction conditions over such materials seem to be rare and a comprehensive understanding of the involved active copper oxide species could facilitate a knowledge-based catalyst optimization. In the present work, Cu-Mg-Al-O x mixed metal oxides and Cu/Al 2 O 3 active catalysts in NH 3 -SCO were investigated under NH 3 /O 2 /CO 2 /H 2 O/N 2 reaction conditions. Powder XRD, BET, NH 3 -TPD, H 2 -TPR and XAFS methods were used to characterize Cu-Mg-Al-O x (Cu/Mg/Al = 8/63/29, mol%) and 10 wt% Cu/Al 2 O 3 . Cu-Mg-Al-O x hydrotalcite derived mixed metal oxides were obtained by coprecipitation, while Cu/Al 2 O 3 was prepared by incipient wetness impregnation. A highly dispersed copper oxide species formed on Cu-Mg-Al-O x , while a mixture of highly dispersed (CuO x ) and bulk copper oxide species (CuO and CuAl 2 O 4 ) formed on Cu/Al 2 O 3 . The comparison of Cu-Mg-Al-O x and Cu/Al 2 O 3 in NH 3 -SCO provided good insight into the nature of the active species present in both copper-based catalysts. It was found that highly dispersed easily reducible copper oxide species and bulk copper oxide species appear as active species under NH 3 /O 2 /N 2 and NH 3 /O 2 /CO 2 /H 2 O/N 2 reaction conditions, respectively

MORALNOŚĆ W EDUKACJI WYCHOWANIA FIZYCZNEGO A EDUKACJA ZDROWOTNA

Sport i kultura fizyczna były już od zarania starożytności przedmiotem zainteresowań wielu uczonych. Liczni teoretycy zastanawiali się nad samą definicją kultury fizycznej, a także nad wzorem wychowanka jaki należałoby kształcić. Ten idealny wychowanek zarysowuje się już od czasów starożytnych. We wszystkich społeczeństwach zawsze ceniony był człowiek silny, zaradny, odporny. Wyrażany ideał zarysowuje się w kulturze rzymskiej, a także greckiej

Phylogenetic groups, virulence genes and quinolone resistance of integron-bearing Escherichia coli strains isolated from a wastewater treatment plant

We investigated phylogenetic affiliation, occurrence of virulence genes and quinolone resistance in 109 integron-containing strains of Escherichia coli isolated from a wastewater treatment plant. Selection for integron-bearing strains caused a shift toward phylogroup D, which was most numerous, followed by A, B1 and B2. Phylogroups D and B2, both of which are reported to include virulent extraintestinal pathotypes, made up 50.5% of all isolates and were present in every stage of wastewater treatment, including final effluent. Diarrheagenic pathotypes made up 21% of the strains. The average virulence factor genes score was low (1.40) and the range was from 0 to 5. Quinolone and fluoroquinolone resistance was observed in 56.0% and 50.4% of the strains, respectively; however, it was not associated with virulence factor score. Although the average virulence factor score was low, 17.4% of strains had three and more virulence genes. They were isolated mostly from raw sewage, but 30% of them were cultured from final effluent. Release of multiresistant integron-bearing E. coli strains with virulence traits into the environment may create potential threat and be of public health concern

Gaia Focused Product Release: Radial velocity time series of long-period variables

The third Gaia Data Release (DR3) provided photometric time series of more than 2 million long-period variable (LPV) candidates. Anticipating the publication of full radial-velocity (RV) in DR4, this Focused Product Release (FPR) provides RV time series for a selection of LPVs with high-quality observations. We describe the production and content of the Gaia catalog of LPV RV time series, and the methods used to compute variability parameters published in the Gaia FPR. Starting from the DR3 LPVs catalog, we applied filters to construct a sample of sources with high-quality RV measurements. We modeled their RV and photometric time series to derive their periods and amplitudes, and further refined the sample by requiring compatibility between the RV period and at least one of the $G$, $G_{\rm BP}$, or $G_{\rm RP}$ photometric periods. The catalog includes RV time series and variability parameters for 9\,614 sources in the magnitude range $6\lesssim G/{\rm mag}\lesssim 14$, including a flagged top-quality subsample of 6\,093 stars whose RV periods are fully compatible with the values derived from the $G$, $G_{\rm BP}$, and $G_{\rm RP}$ photometric time series. The RV time series contain a mean of 24 measurements per source taken unevenly over a duration of about three years. We identify the great most sources (88%) as genuine LPVs, with about half of them showing a pulsation period and the other half displaying a long secondary period. The remaining 12% consists of candidate ellipsoidal binaries. Quality checks against RVs available in the literature show excellent agreement. We provide illustrative examples and cautionary remarks. The publication of RV time series for almost 10\,000 LPVs constitutes, by far, the largest such database available to date in the literature. The availability of simultaneous photometric measurements gives a unique added value to the Gaia catalog (abridged)Comment: 36 pages, 38 figure