Repozytorium Uniwersytetu Śląskiego RE-BUŚ
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Geographical drivers of geochemical and mineralogical evolution of Motianling peatland (Northeast China) exposed to different sources of rare earth elements and Pb, Nd, and Sr isotopes
Full text linkGeochemical shifts triggered by surface runoff and atmospheric fallout in a Chinese peatland were investigated
by using Pb, Sr, and Nd, REE and by SEMmineralogical analysis.Motianling peatland (Northeast China) is located
at 1670ma.s.l., near the China–Mongolia border. Based on division of profile into two phases of different trophy,
the totalΣREE value determined for the minerotrophic part of the profile (from 62 to 46 cm) varied from 67 to
31 mg·kg−1 and mineralogical analysis revealed the occurrence ofweathered volcanic rocks, supported by a high
εNd value (−3.26). After the transition from minerotrophic to more ombrotrophic conditions, the peatland became
independent of the local bedrock weathering, which was manifested by a much lower concentration of
REE (7–20 mg·kg−1) and lower εNd values (−7.37; −8.11). Moreover, PAAS-normalized pattern of REE distribution
in the bottom part revealed the highest Eu/Eu* value (1.24), as well as a slight enrichment in Eu. The anthropogenic
effect was visible from 1964, during which period the spheroidal aluminosilicate particles (SAP),
produced by coal-fired power-plant activity, appeared for the first time, followed by an abrupt decrease in
206Pb/207Pb isotopic signature to 1.167. The dimensions of SAP (~1.5 μm), as well as the time of first appearance,
indicated long-range transport. The REE ratios obtained in this study are characteristic of the eolian deposition
signature, which is like the Gobi and northern Chinese deserts. The anthropogenic activity was manifested by a
slight enrichment in Gd during reduced delivery of natural dust. Both, North Chinese and Asian part of the
Russian industry supply anthropogenic dust. Topography, wind direction, and patterns of precipitation, as well
as the initial phases of Asian industrial development, are the most important drivers promoting the deposition
of chemical elements
Catalytic Removal of NOx on Ceramic Foam-Supported ZnO and TiO2 Nanorods Ornamented with W and V Oxides
Full text linkEnergy consumption steadily increases and energy production is associated with many
environmental risks, e.g., generating the largest share of greenhouse gas emissions. The primary gas
pollution concern is CO2, CH4, and nitrogen oxides (NOx). Environmental catalysis plays a pivotal
role in NOx mitigation (DeNOx). This study investigated, for the first time, a collection of ceramic
foams as potential catalyst support for selective catalytic NOx reduction (SCR). Ceramic foams could
be an attractive support option for NOx removal. However, we should functionalize the surface of
raw foams for such applications. A library of ceramic SiC, Al2O3, and ZrO2 foams ornamented with
nanorod ZnO and TiO2 asWand V oxide support was obtained for the first time. We characterized
the surface layer coating structure using the XPS, XRF and SEM, and TEM microscopy to optimize
the W to V molar ratio and examine NO2 mitigation as the SCR model, which was tested only
very rarely. Comparing TiO2 and ZnO systems reveals that the SCR conversion on ZnO appeared
superior vs. the conversion on TiO2, while the SiC-supported catalysts were less efficient than Al2O3
and ZrO2-supported catalysts. The energy bands in optical spectra correlate with the observed
activity rank
Procedural Generation of Artistic Patterns Using a Modified Orbit Trap Method
Full text linkIn the literature, we can find various methods for generating artistic patterns. One of the methods is the orbit trap method. In this paper, we propose various modifications of a variant of the orbit trap method that generates patterns with wallpaper symmetry. The first modification relies on replacing the Picard iteration (used in the original method) with the S-iteration known from the fixed point theory. Moreover, we extend the parameters in the S-iteration from scalar to vector ones. In the second modification, we replace the Euclidean metric used in the orbit traps with other metrics. Finally, we propose three new orbit traps. The presented examples show that using the proposed method, we are able to obtain a great variety of interesting patterns. Moreover, we show that a proper selection of the orbit traps and the mapping used by the method can lead to patterns that possess a local fractal structure.Natural Science Foundation of China grant number 6206204
The usefulness of X-ray diffraction and thermal analysis to study dietary supplements containing iron
Full text linkX-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/
derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully
used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary
supplements or drugs. In this work, 31 dietary supplements available on the Polish market that
contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate,
were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as
food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed
by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron
(II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements.
Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the
formulation, it was possible to identify this compound in the tested supplements. For amorphous
iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have
characteristic diffraction lines. Food supplements containing crystalline iron compounds have a
melting point close to the melting point of pure iron compounds. The presence of excipients was
found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic
peaks and changes in their position were observed, as well as exothermic peaks indicating
crystallization of amorphous compounds. Weight loss was determined for all dietary supplements
tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements
takes place in several steps. The results obtained by a combination of both simple, relatively fast and
reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical
abnormalities or by detecting the presence of the correct polymorphic form
Synthesis and Characterisation of Cobalt Ferrite Coatings for Oxygen Evolution Reaction
Full text linkIn this paper, two novel procedures based on powder sedimentation, thermal treatment, and galvanostatic deposition were proposed for the preparation of porous cobalt ferrite (CoFe2O4) coatings with a metallic and organic binder for use as catalysts in the oxygen evolution reaction (OER). The electrochemical properties of the obtained electrode materials were determined as well, using both dc and ac methods. It was found that cobalt ferrite coatings show excellent electrocatalytic properties towards the oxygen evolution reaction (OER) with overpotential measured at a current density of 10 mAcm−2 from 287 to 295 mV and a Tafel slope of 35–45 mVdec−1. It was shown that the increase in the apparent activity of the CoFe2O4 coatings with an organic binder results mainly from a large electrochemically active area. Incorporation of the nickel binder between the CoFe2O4 particles causes an increase in both the conductivity and the electrochemically active area. The Tafel slopes indicate that the same rate-determining step controls the OER for all obtained coatings. Furthermore, it was shown that the CoFe2O4 electrodes exhibit no significant activity decrease after 28 h of oxygen evolution. The proposed coating preparation procedures open a new path to develop high-performance OER electrocatalysts
Correlation between the Dendritic Structure and Lattice Parameter of γ′- Phase in Single-Crystalline Turbine Blades Made of Superalloys
Full text linkThe dendritic structure and the distribution of the γ′-phase lattice parameter (aγ′) along selected lines of the longitudinal section in a model single-crystalline blade made of CMSX-4® nickel-based superalloy were studied. It was established that there is a correlation between the value of the aγ′ and the predomination of initial or ending fragments of the secondary dendrite arms. It is most noticed for the areas where the dendrite growth conditions are similar to steady. They are located in the center and near the root’s selector extension (SE) area. The correlation has been related to the dendritic segregation mechanism. It was shown that in the single-crystalline blades obtained by the directional crystallization using a spiral selector, the “walls” of the primary dendrite arms that grow at a low angle to the blade axis are created. It was found for the first time that the value of the lattice parameter aγ′ is decreased near such “walls”. Additionally, it was found that competitive growth of the dendrites may occur at a distance of even several millimeters from the bottom surface of the root. The first-time applied X-ray diffraction measurements of aγ′ made in a single-pass along the line allow the analysis of the dendritic segregation in the whole blade cast
Synthesis and Photoluminescence Properties of Pr3+-Doped Ba0.5Ca0.5TixZr(1-x)O3 Perovskite Diphasic Ceramics Obtained by the Modified Pechini Method
Full text linkThe Pr3+-doped solid solutions from (Ba,Ca)(Ti,Zr)O3 (BCTZO) system were successfully synthesized using an efficient and low-energy consuming route—the Pechini method combined with the sintering at relatively low temperature (1450 °C). The obtained materials were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were systematically studied. The Pr3+-doped BCTZO diphasic material generates intense and broad red photoluminescence (PL) emission at room temperature. The optical properties were significantly improved with the Ti4+ substitution by Zr4+ ions. As a result, the Pr3+-doped (Ba,Ca)(Ti,Zr)O3 ceramics is a promising candidate for environmentally friendly, multifunctional material by combining good dielectric and photoluminescent properties with prognosis for the manifestation of strong photoluminescent and mechanoluminescent effects
Bachelard and Psychoanalysis / Bachelard et la Psychanalyses / Bachelard e la Psicoanalisi - [bibliografia]
Full text linkSpis bibliograficzny nt. Bachelard i psychoanaliz
Tuning the electronic properties of a clean TiO2(1 1 0) surface via repeated sputtering and annealing: A KPFM and LC-AFM study
Full text linkRepeated sputtering and annealing are standard preparation methods for obtaining a stoichiometric TiO2(110) surface for surface science experiments. However,
both processes result in a reduction in TiO2 crystal when used separately, leading to the modification of the physical and chemical properties of oxide materials. Our
investigation aims to determine how these two processes affect the electronic properties of the surface and subsurface regions at the nanometer scale. To accomplish
this goal, we utilized local microscopy (Kelvin probe force microscopy and local-conductivity atomic force microscopy) and spectroscopy methods (X-ray photoelectron
spectroscopy and secondary ion mass spectrometry). We found that repeated sputtering and annealing does, in fact, affect both the conductivity and work
function of the surface. The work function, as well as conductivity, increase with increasing number of cycles, but then reach a plateau. Furthermore, we show that
the way the surface is prepared, using multiple cycles or one cycle of equivalent ion-beam fluence, matters. We attribute the differences in the crystal properties to the
dynamics of stoichiometric changes during sputtering and subsequent annealing which we illustrate using secondary ion mass spectroscopy, which shows that after
multiple cycles the subsurface layer is modified, even though XPS shows a stoichiometric surface
Aromaticity Effect on Supramolecular Aggregation. Aromatic vs. Cyclic Monohydroxy Alcohols
Full text linkIn this paper, the steric hindrance effect related to the presence of either an aromatic or cyclic
ring on the self-association process in the series of monohydroxy alcohols (MAs), from
cyclohexanemethanol to 4-cyclohexyl-1-butanol and from benzyl alcohol to 4-phenyl-1-
butanol, was studied using X-Ray Diffraction (XRD), Differential Scanning Calorimetry
(DSC), Fourier Transform Infrared (FTIR) spectroscopy, Broadband Dielectric Spectroscopy
(BDS) and the Pendant Drop (PD) methods. Based on FTIR results, it was shown that phenyl
alcohol (PhA) and cyclohexyl alcohol (CA) derivatives reveal substantial differences in the
association degree, the activation energy of dissociation, and the homogeneous distribution of
supramolecular nanoassociates suggesting that the phenyl ring exerts a stronger steric impact
on the self-assembling of molecules than cyclohexyl one. Additionally, XRD data revealed
that phenyl moiety introduces more heterogeneity in the organization of molecules compared
to the cyclic one. The changes in the self-association process of alcohols were also reflected
in differences in the molecular dynamics of the H-bonded aggregates, as well as in the
Kirkwood factor, defining the long-range correlation between dipoles, which were slightly
higher for CAs with respect to those determined for PhAs. Unexpectedly it was also found
that the surface layers of PhAs were more organized than those formed by CAs. Thus, these
findings provided insight into the impact of aromaticity on the self–assembly process, Hbonding
pattern, supramolecular structure, and intermolecular dynamics of the studied
alcohols