Silesian University of Technology
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1101 research outputs found
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Deformativnìst' krivolìnìjnoï dvobalkovoï nerozrìznoï zalìzobetonnoï progonovoï budovi mosta dlâ skladnih umov budìvnictva pri zmìnì ìï statičnoï shemi
No full texts. 11-1
Multielectrochromism of redox states of thin electropolymerised films of poly(3-dodecylpyrrole) involving a black coloured state
No full textThin films of poly(3-dodecylpyrrole) have been found to yield multi-electrochromic characteristics. Optimisation of the polymer electrodeposition process enabled fabrication of layers exhibiting three distinct colourations at different oxidation levels. Coupled EPR-UV-Vis-NIR spectroelectrochemistry enabled cor-relation of these colour changes with the formation and decay of polaron and bipolaron charge carriers, offering an insight into the mechanism of doping/dedoping processes taking place in this polymer. The ionisation potential of the polymer was found to be very low, with valence band edge located at -3.7 eV, explaining the relative oxidation ease of the polymer and accounting for an ample number of spins presentin the electrochemically dedoped polymer film. Maximum optical contrast of up to 15% and a visible light range averaged one of 10% was observed. Dynamic colour switching contrast of 10% is attainable at 5 s switching time, while switching steps as short as 0.5 s afford 6% contrast value. The fully oxidised polymer features broad UV-Vis absorption, making the system an interesting candidate for transmissive-to-black electrochromic devices
Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4 thiadiazole and 1,2,4-triazole
No full textA new synthetic approach towards the preparation of functionalised, soluble, donor–acceptor (DA) alkylbithiophene derivatives of oxadiazole, thiadiazole and triazole is reported. Taking advantage of the Fiesselmann reaction, reactive bithiophene synthons having alkyl or alkoxy substituents at designated positions are prepared. Following a synthetic strategy, featuring the bottom-up approach, sequential structural elements are built, starting from a simple thiophene compound, until the target molecule is obtained, all in good yield. Supplementing the well established methods of oxadiazole and thiadiazole synthesis, efficient ring closure reaction affording a 4H-1,2,4-triazole unit is presented. All target ambipolar compounds display strong photoluminescence with measured quantum yields up to 0.59. Modification of the demonstrated synthetic routes may be exploited for the preparation of longer, specifically functionalised oligothiophenes, coupled to other heteroaromatic cores
Metody badania stabilności układów LTV
No full textIn this paper the selected method for determining the stability conditions of the systems with non-periodically variable parameters have been presentedW artykule omówiono wybrane i wykorzystywane w bada-niach nad układami o zmiennych w czasie parametrach LTV (ang. linear time varying) metody wyznaczania warunków stabilności tych układów
The use of fuzzy logic in the enterprises operating risk assessment on the example of coal mining companie
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Określenie przewodności cieplnej stali P60
No full textPublished data that concerns steels for rail wheels usually contains their mechanical properties. However visible lack of their thermal properties data can be noticed. In the current work an apparatus for heat conductance of metals measuring was built. It enables determination of the heat conductance with Angström method. Measurements for the P60 steel used for wheel tyres of locomotives manufacturing were carried out.W literaturze dotyczącej stali stosowanych na obręcze kół kolejowych najczęściej podawane są ich własności mechaniczne. Natomiast zauważalny jest brak danych dotyczących własności cieplnych tych stali. W pracy zbudowano stanowisko do wyznaczania przewodności cieplnej metali metodą Angströma i wykonano na nim pomiary dla stali gatunku P60 stosowanej na obręcze kół lokomotyw
The optimal current in the non-ideal three-phase system with unsteady parameters
No full textThis paper presents a description of three-phase system with unsteady parameters. The changes of loads represent potential changes resulting from their physical properties i.e. for arc furnaces. The changes of non-ideal source parameters can represent fluctuations of voltage and changes of source impedances resulting from switching in electrical networks. Parameters of the considered system are described as fuzzy numbers, and the main aim of the paper is to apply the optimisation technique called as fuzzy mathematical programming in order to determine the optimal currents of the system with minimal RMS values and to minimize power lossesPosterW artykule został przedstawiony opis układu trójfazowego o niestałych parametrach. Zmiany odbiorników reprezentują sobą potencjalne zmiany wynikające z ich fizycznych właściwości np. dla pieców łukowych. Zmiany parametrów nieidealnego źródła mogą reprezentować sobą fluktuacje napięcia i zmiany impedancji źródła wynikające z przełączeń w sieci elektrycznej. Parametry rozpatrywanego układu są opisywane jako liczby rozmyte a głównym celem artykułu jest zastosowanie techniki optymalizacyjnej nazywanej rozmytym programowaniem matematycznym do wyznaczenia prądu optymalnego układu z minimalną wartością skuteczną i minimalizacja strat mocy.Plakat naukow