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Abstract

The aim of the paper is to study the effect of zinc addition on the corrosion behavior of Ca65–xMg17.5Zn17.5+x (x = 0, 2.5, 5 at.%) alloys in simulated physiological fluids at 37°C. The electrochemical measurements allowed to determine a corrosion potential, which showed a positive shift from –1.60 V for Ca65Mg17.5Zn17.5 alloy to –1.58 V for Ca60Mg17.5Zn22.5 alloy, adequately. The more significant decrease of hydrogen evolution was noticed for Ca60Mg17.5Zn22.5 alloy (22.4 ml/cm2) than for Ca62.5Mg17.5Zn20 and Ca65Mg17.5Zn17.5 samples (29.9 ml/cm2 and 46.4 ml/cm2), consequently. The corrosion products after immersion tests in Ringer’s solution during 1 h were identified by X-ray diffraction and X-ray photoelectron spectroscopy as calcium, magnesium oxides, carbonates, hydroxides and calcium hydrate.

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Authors and Affiliations

R. Babilas
P. Wojciechowski
A. Bajorek
P. Sakiewicz
K. Cesarz-Andraczke
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Abstract

In this paper cation arrangement in two samples of aluminoceladonite, emerald‑green and dark-green were studied by Mössbauer, Raman and X-ray photoelectron spectroscopies. The X-ray photoelectron spectroscopy (XPS) spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p, and O1s core levels provided information, for the first time highlighting a route to identify the position of Si, Al, K, and Fe cations in a structure of layered silicates. The XPS analysis showed the presence of Al in tetrahedral and octahedral coordination while the K2p line indicated the possibility of K+ substitution by other cations in interlayer sites. Mössbauer spectroscopy provided information about crystal chemistry with respect to the local electronic and geometric environment around the Fe atom and to distortions of the polyhedra. It turned out that iron was located mostly in the cis-octahedra position wherein about 75% of iron appeared in the form of Fe 3+. The most preferred cation combinations around Fe corresponded to 3Fe 3+ ions and MgFe 2+Fe 3+/2MgFe 3+. Raman spectroscopy illustrated aluminium substitution in silicon and iron positions wherein the concentration of the aluminium determined the degree of structural distortion within the layered system. These isomorphic substitutions implied a typical band arrangement in the hydroxyl region, which has not been observed in celadonites so far.
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Authors and Affiliations

Mariola Kądziołka-Gaweł
1
Mateusz Dulski
2
Maria Czaja
3
Tomasz Krzykawski
3
Magdalena Szubka
1

  1. Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland
  2. Institute of Material Science, University of Silesia, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
  3. Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland
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Abstract

The surface properties of particles emitted from six selected coal-fired power and heating plants in Poland have been studied in this work for the first time. Samples were collected beyond the control systems. Surface composition of the size-distributed particles was obtained by photoelectron spectroscopy (XPS).

The reflection of the smallest, submicron particles was also measured to calculate their specific/mass absorption. The surface layer of the emitted particles was clearly dominated by oxygen, followed by silicon and carbon. The sum of the relative concentration of these elements was between 85.1% and 91.1% for coarse particles and 71.8–93.4% for fine/submicron particles. Aluminum was typically the fourth or fifth, or at least the sixth most common element. The mass absorption of the submicron particles emitted from the studied plants ranged from 0.02 m2g-1 to 0.03 m2g-1. Only specific absorption obtained for the “Nowy Wirek” heating plant was significantly higher than in other studied plants probably because the obsolete fire grate is used in this heating plant.

The obtained results suggest that the power/heating-plant-emitted fine particles contain less carbonaceous material/elemental carbon on their surfaces than those that are typical in urban air.

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Authors and Affiliations

Józef S. Pastuszka
Jan Konieczyński
Ewa Talik
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Abstract

The paper presents results of investigations carried out in 2005 at six crossroads in Zabrze. The investigations comprised determinations of vehicular traffic intensity, observations of meteorological conditions and, as a main subject, determinations of concentrations of PM2.5 and PM 10 at all observed sites. Structure of ambient aerosol in the vicinity of crossroads was compared with the structure of aerosol at a reference measuring point, located beyond effects of vehicular traffic, by determining a share of PM2.5 in PM 10 for cach site. At a selected crossroad the measurements lasted 11 days and the sampled dust was analyzed for chemical composition of surface of its particles with the use of the X-ray photoelectron spectroscopy (XPS). Both the most abundant and trace elements in the surface layer of dust sampled at the crossroads were identified.
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Authors and Affiliations

Wioletta Rogula
Józef S. Pastuszka
Ewa Talik

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