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Wyszukujesz frazę "Bujňáková, P." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
Analysis of brittle failure of prestressed bridge in the north of Slovakia
Autorzy:
Moravčík, M.
Bujňáková, P.
Powiązania:
https://bibliotekanauki.pl/articles/131510.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Komisja Inżynierii Budowlanej PAN Oddział w Katowicach
Tematy:
post-tensioned girder
brittle failure
precast girder
corrosion
dźwigar kablobetonowy
uszkodzenie
dźwigar prefabrykowany
korozja
Opis:
This paper is focused on the primary causes of failures and collapse state of the concrete bridge superstructure located in the north of Slovakia. It is situated on the international route I/59 connecting Slovakia with Poland and registered at No. 59-090. Dangerous structural defects of brittle character were found in four girders of the bridge structure during the routine inspection in 2015. Subsequently, it was declared as being in the emergency status and immediately closed for the traffic at the end of 2015. This bridge was built in 1956 as a bridge of the first generation of the precast and prestressed structures in Czechoslovakia.
Źródło:
Roczniki Inżynierii Budowlanej; 2017, 17; 27-34
1505-8425
Pojawia się w:
Roczniki Inżynierii Budowlanej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physico-Chemical and Biological Properties of Arsenic Sulfide ($As_{55}S_{45}$) Nanosuspension Prepared by Milling
Autorzy:
Bujňáková, Z.
Shpotyuk, O.
Sedlák, J.
Pastorek, M.
Turianicová, E.
Baláž, P.
Ingram, A.
Powiązania:
https://bibliotekanauki.pl/articles/1375164.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Wk
81.05.Kf
81.07.-b
Opis:
Nanosuspension based on melt-quenched arsenic sulfide of nominal $As_{55}S_{45}$ composition was prepared by nanomilling and tested as potential anticancer drug. Polyvinylpyrrolidone was used as steric stabilizer and inhibitor of agglomeration. Individual nanoparticles had average size of 192 nm (determined by photon cross-correlation spectroscopy) and had several times better dissolution ability in comparison with bulk $As_{55}S_{45}$. Effect of nanomilling is shown to be associated with formation of arsenic sulfide crystalline nanoparticles and free-volume entities located at the interface between nanoparticles and surrounding matrix as it follows from positron annihilation measurements. Cytotoxicity tests were performed using human melanoma cell line Bowes and confirmed high toxicity of the studied nanosuspension.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 902-906
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of Solid-State Synthesis of Quaternary Cu₂FeSnS₄ (Stannite) Nanocrystals for Solar Energy Applications
Autorzy:
Baláž, P.
Baláž, M.
Zorkovská, A.
Škorvánek, I.
Bujňáková, Z.
Trajić, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032135.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.05.Hd
61.46.Hk
Opis:
In this study we demonstrate the use of elemental precursors (Cu, Fe, Sn, S) to obtain stannite forms by a solid-state one-pot mechanochemical synthesis. In the processing route, we report the kinetics of the synthesis. For the characterization of the unique nanostructures, X-ray diffraction, specific surface area measurements and SQUID magnetometry methods were applied. CFTS polymorphs with the tetragonal body-centered structure with the average crystallite size 18-19 nm were obtained. The weak ferromagnetic properties of the quaternary nanocrystals after maximum milling time were also documented.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1153-1155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Sorption Activity of Mechanically Activated Magnetite $Fe_3O_4$
Autorzy:
Baláž, P.
Timko, M.
Kováč, J.
Bujňáková, Z.
Ďurišin, J.
Myndyk, M.
Šepelák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1535173.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
61.05.cp
76.80.+y
Opis:
It is known that the action of mechanical forces on solids (mechanical activation and/or mechanochemistry) leads to changes of their properties and reactivity. We have studied the physico-chemical and sorption properties of magnetite $Fe_3O_4$ (Kiruna, Sweden) mechanically activated in a planetary mill. Several methods such as X-ray diffractometry, Mössbauer spectroscopy, magnetometry, specific surface area measurement as well as arsenic sorption tests have been applied. By X-ray diffractometry strong amorphisation of magnetite has been evidenced. In parallel, specific surface area increased from 0.1 $m^2//g$ for the reference (non-milled) sample to the values 0.5-6.1 $m^2//g$ for milled samples. The Mössbauer spectrum of the reference sample is well fitted with two subspectra corresponding to tetrahedrally (A) and octahedrally (B) coordinated iron cations in the spinel structure of $Fe_3O_4$. In mechanically activated samples (B)-site subspectrum becomes asymmetric, while (A)-site spectrum remains more or less unchanged. The more covalent character of the Fe(A)-O bond compared to the Fe(B)-O bond can explain qualitatively why the spin-density transfer from (A) to (B) in the spinel structure is more effective than vice versa. The value of the saturation magnetization at room temperature was 67.4 ≈ 43.6 emu/g which is significantly lower than that of the bulk particles 92 emu/g. This reduction may be attributed to the surface disorder or spin canting at the particle surface. During the milling process the coercivity value increases from 150 Oe up to 460 Oe with milling time. This increase can be related to the fact that magnetic anisotropy may increase when particle size decreases. The sorption activity of $Fe_3O_4$ was enhanced as a consequence of its disordering: 88% of $As^{3+}$ was captured for the mechanically activated sample in comparison with 0% for the non-milled one.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1005-1007
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemistry of Solids: New Prospects for Extractive Metallurgy, Materials Science and Medicine
Autorzy:
Baláž, P.
Baláž, M.
Achimovičová, M.
Bujňáková, Z.
Dutková, E.
Powiązania:
https://bibliotekanauki.pl/articles/1375090.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Dz
81.20.Wk
81.07.Bc
Opis:
In this review paper recent advances in chalcogene mechanochemistry are described. Three selected areas are being covered, i.e. metallurgy, materials science, and medicine. In extractive metallurgy, the processing of copper arsenic mineral enargite ($Cu_3AsS_4$) with the aim of its dearsenification and subsequent preparation of a new anticancer drug ($Na_3AsS_4$) and of copper in nanocrystalline state ( ≈ 20 nm) illustrate the non-traditional prospect of ore treatment. In material science, the new nanocrystalline semiconductors were synthesized mechanochemically, e.g. selenides of zinc and lead (ZnSe, PbSe) and bismuth sulphide ($Bi_2S_3$). Metal and chalcogene were applied as reaction precursors. In some cases, the amino acids (cystine, cysteine) were applied as sulphur precursor, in order to provide reactive sites on synthesized solid (PbS) for bioconjugation and to prevent agglomeration. The concept of nanomilling is described as a way to prepare effective substances for cancer treatment in medicine. In vitro activity of realgar ($As_4S_4$) as an example is described. In all three areas the focus is aimed also on industrial applications where suitable large-scale mills are described. The described examples represent the contemporary aim of mechanochemists - to prepare substances with the desired properties in a reproducible way under easy-operating, environmentally friendly and essentially waste-free conditions.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 879-883
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical Dechlorination of PVC by Utilizing Eggshell Waste
Autorzy:
Baláž, M.
Baláž, P.
Bujňáková, Z.
Pap, Z.
Kupka, D.
Zorkovská, A.
Powiązania:
https://bibliotekanauki.pl/articles/1375093.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Lg
81.20.Wk
88.20.dr
Opis:
Within this work, the dechlorination of polyvinylchloride (PVC) chemical as a model by co-milling with eggshell was performed in a planetary ball mill in order to show that mechanochemistry can be utilized for the simultaneous treatment of two wastes, while the products of the treatment can be used in further applications. The products of the reaction are water-soluble calcium chloride ($CaCl_2$), which can be used e.g. for de-icing of roads in winter and organic residue on the basis of ethylene, which can be recovered as energy source. The highest dechlorination yield (almost 97%) was achieved under following milling conditions: molar ratio between Ca and Cl: 2.34, ball-to-powder ratio: 65, rotation speed of the planet carrier: 550 rpm, milling time: 4 h and material of milling media: tungsten carbide. The optimum conditions were then applied for the removal of chlorine from industrial waste - the abandoned PVC window parapet. In this case, 95% dechlorination was evidenced.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 884-887
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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