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- Author or Editor: J. Kozlowski x
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Abstract
The inherited disciplinary structure of the science of post-communist countries of CEE carries a strong common features of its past. The communist heritage is present in: a) a relatively homogeneous research profile among post-communist countries; b) the similar structure of disciplinary comparative advantages of post-communist countries; c) the unbalanced and concentrated disciplinary structure of comparative advantages. The analysis is based on ISI databases and uses statistics on papers and citations for the 1992–1997 period for all central and eastern European countries as well as for other world regions. In the conclusions we discuss the relevance of the results for the restructuring of science in the countries of Central and Eastern Europe.
Abstract
The influence of oxidation of coal, performed with different oxidising agents, on the sulphur species was studied. Conversions of the sulphur species were investigated by the Atmospheric Pressure-Temperature Programmed Reduction method (AP-TPR). The removal of pyrite proved to be advantageous for AP-TPR analysis. It was found that non-thiophene sulphur species undergo easier oxidation by different agent then thiophenic structures.
Abstract
The paper gives a short overview of application of polymer inclusion membranes (PIMs) for separation and removal of metal ions. Investigation of the selective removal of toxic metal ions, i.e. Cr(VI), Cd(II), Zn(II) from acidic chloride aqueous solutions, as well as trace radionuclides, i.e., 137Cs, 90Sr and 60Co from wastewaters using transport across polymer inclusion membranes was studied. The carriers, i.e., tri-n-octylamine for anionic metal species, as well as dibenzo-21-crown-7, tertbutyl-dibenzo-21-crown-7, and dinonylnaphtalenesulfonic acid for metal cations were incorporated into polymer inclusion membranes composed of cellulose triacetate as a support and o-nitrophenyl pentyl ether as a plasticizer. Selective transport of chromium(VI) over zinc(II) and cadmium(II) chloride complexes through PIMs was observed. Competitive transport of trace radionuclide ions, i.e., 137Cs, 90Sr, and 60Co from NaNO3 aqueous solutions across polymer inclusion membranes containing a mixture of dinonylnaphtalenesulfonic acid, and dibenzo-21-crown-7 as the carrier provide the selectivity order Cs(I)>Sr(II)>Co(II).
Abstract
Competitive alkali metal cation transport across polymer inclusion membranes (PIMs) containing sym-(alkyl)dibenzo-16-crown-5-oxyacetic acid carriers provides excellent selectivity for Na+ transport with the total fluxes being strongly influenced by the length of the alkyl chain that is attached geminal to the functional side arm in the lariat ether. Removal of chromium(VI) anions by PIMs from acidic aqueous phases was also investigated. Using tri-n-octylamine (TOA) as the ion carrier, Cr(VI) was removed by a PIM to decrease the source phase metal concentration from 1.0 to 0.010 ppm after 30 hours of transport. Competitive transport of Cr(VI) and Cr(III) ions from acidic source phases through PIMs and supported liquid membranes (SLMs) containing TOA and tri-n-octylphosphine oxide (TOPO) as carriers was evaluated and a very high Cr(VI)/Cr(III) separation ratio of 4800 was achieved with a PIM containing TOA. Competitive transport of Zn(II), Cd(II), and Cr(VI) from acidic aqueous solutions through PIMs containing TOA was investigated. The selectivity order for metal ion transport was: HCrO4 –>CdCl4 2–+CdCl3 –>ZnCl4 2–+ ZnCl3 –. Non-contact atomic force microscopy was used to obtain images of the pores in cellulose triacetate membranes containing a plasticizer.
Abstract
Carbonaceous films containing Pd nanocrystals can be applied as active layers in gas sensor applications. In this article we show results of studies of C-Pd films, obtained with two different methods: (1) physical and (2) physical + chemical deposition. First type of film prepared by physical vapor deposition (PVD) process was composed of fullerenes, amorphous carbon, and palladium nanograins. In the second method PVD film was modified in chemical vapor deposition (CVD) process forming a foam-like structure. Both types of films were studied by SEM, TEM, TGA, and electrical characterization (measurement of resistivity versus composition of gaseous hydrocarbons mixture).
Abstract
A facile and benign route to N-heterocycles, including triazoles and triazolopyrimidines, has been developed. Using continuous-flow microreactor technology, organic azides are prepared in situ and reacted with cyanoacetamide in a [3+2] cycloaddition to produce a variety of substituted 1,2,3-triazoles, which can be elaborated into useful building blocks. A benzyl-substituted triazole was further functionalized to an analog of the core structure of the antiplatelet agent Brilinta®. The methodology lends itself well to flow chemistry, where reaction volumes are minimized, heating and mixing are consistent, and the need for intermediate azide isolation bypassed. The scope of the process is wide, and the efficiency is high, suggesting this as a practical, green route for the production of triazolo-based heterocycles.
