Electrochemical characterization of alternate conducting carbazole-bisthiophene units

An electrochemical and theoretical character of alternate copolymer of carbazole and bithiophene units was investigated. Polymerization is processed as two steps bielectronic oxidation of molecule. With monoelectronic oxidation is connected stable radical cation with spin located mainly on carbazole. The electrochemical properties of polymer are dependent on thickness of film deposited on electrode. In case of the thin layers one it is observed characteristic redox couple of carbazole oxidation to radical cation. Analysis of polymer behavior and results of spectrochemical measurements indicate on mixed type of electroconductivity.Molecular structures, HOMO-LUMO gaps and nature of highest occupied and lowest unoccupied molecular orbitals were also studied in presented work for oligomers ranging from monomer to octamer. The studies applied density functional theory (DFT).     

A heuristic approach to the reinforcement-learning control of the one-dimensional model of an HTR core

Results of calculations are presented, which are concerned with applications of the heuristic linear reinforcement systems to the control of pebble-bed HTRs with the OTTO-loading scheme. Control results of three types of systems applications are presented and discussed. The systems were found to be satisfactory for control of the complex physical plants.     

A model of smoothing slide ball-burnishing and an analysis of the parameter interaction

The paper analyses a model of smoothing ball-burnishing which takes into account the mechanical properties of the workpiece, the geometry of the workpiece-tool contact area as well as the stereometry of the machined surface. It allows the determination of the dependence of the tip displacement of the machined surface asperities on the burnishing tool pressure. In the model-based research the effect of the particular parameters of the burnishing process on the tip displacement was defined. The optimum value of the displacement and the pressure it takes under various burnishing conditions were calculated. The analysis results were verified experimentally.     

Effect of processing on the content of glucobrassicin and its degradation products in broccoli and cauliflower

The influence of thermal treatment, pickling and fermentation on the content of glucobrassicin and its selected breakdown products in broccoli and cauliflower was investigated. The highest content of glucobrassicin and the lowest content of its breakdown products were found in vegetables which underwent thermal treatment such as boiling and steam cooking. The lowest content of glucobrassicin and the highest content of its breakdown products were present in raw, pickled and fermented vegetables in which the myrosinase remained active. Ascrobigen was the major glucobrassicin breakdown product and its content was negatively correlated with glucobrassicin content in broccoli and cauliflower. After heating of vegetables in 60 °C for 20 min (causing thermal deactivation of epithiospecific protein) no presence of indole-3-acetonitrile was found.     

The effect of ethanol on carbon-catalysed decomposition of methane

Because of its ecological character, the reaction of catalytic decomposition of methane (CDM) is expected to be an important future method of hydrogen generation. However, the main drawback of this technology is a relatively fast deactivation of the catalyst used, as a consequence of its pores blocking by the low-active methane-originated carbon deposit. This paper reports on an attempt of restricting the catalyst deactivation by introducing into the reaction system ethyl alcohol capable of forming in situ a potentially active in this reaction carbonaceous deposit. The catalyst used was activated carbon obtained from the waste material (hazelnut shells). The reactions of methane and ethanol decomposition were performed by the alternate method (for certain time methane was introduced into the reactor, and then it was replaced by ethanol). Three temperatures of the reactions were applied (750, 850 or 950 °C) and another variable was the duration of the ethanol decomposition. As follows from the results, an addition of ethanol has diverse effect on the catalytic activity of activated carbon and the amount of hydrogen formed depends on the temperatures of methane and ethanol decompositions and on the time of the reagent dosing.     

Hydrogen production by propylene-assisted decomposition of methane over activated carbon catalysts

Catalytic decomposition of methane (CDM) permits obtaining hydrogen in high yields and – what is essential – it does not lead to release of CO₂. Unfortunately, most of the catalysts used in this process undergo fast deactivation. Their possible regeneration, consisting in the removal of pore blocking carbonaceous deposit of low catalytic activity, leads to generation of undesirable carbon dioxide. An alternative solution for maintaining high catalyst activity in the CDM reaction can be generation of the catalytically active carbonaceous deposit on its surface. Such a deposit can be obtained by decomposition of different organic substances. This paper reports on methane decomposition carried out in the presence of propylene (used in the concentration of 10 or 20%). The reaction was performed at three temperatures of 750 °C, 850 °C or 950 °C. Three types of activated carbon were tested as catalysts: the first one was obtained by activation of pine wood biomass with Na₂CO₃, whereas the second and third ones were commercial carbons (WG-12 and Norit RX3 Extra). According to the results, the addition of propylene to the CDM system effectively reduces deactivation of the activated carbon catalysts and permits fast stabilisation of their catalytic activity at a high level.     

Characterization 0f solid-liquid adsorption systems by using Gaussian energy distribution

Theoretical foundations of the isotherm equations derived for adsorption from binary liquid mixtures composed of molecules of different sizes on heterogeneous surfaces characterized by Gaussian energy distribution are discussed. On the basis of numerical simulation studies the correlation between adsorption parameters of the equations in question and the parameters of the Gaussian energy distribution are established. These studies allow characterization of the Gaussian-type adsorbents on the basis of excess adsorption data.     

Friction welding of ductile iron with stainless steel

The study of mechanical properties and microstructure of friction welded coupe of ductile iron with stainless steel are presented. Scanning electron microscopy (SEM) was used for investigation of the fracture morphology and phase transformations taking place during friction welding process. It was concluded that in case of bainitic ductile iron (BDI) the fracture precedes mainly trough the cleavage planes. Moreover, the distribution of selected elements on both side of the joining interface was studied using EDS line and maps spectrometry. The EDS spectrometry showed some enrichment of ductile iron with Cr and Ni atoms close to the joint. The depth of Cr atoms penetration reached 50 μm. The heat generated locally by friction increased the temperature in the area close to the interface even over the melting point of ductile iron. This was confirmed by metallography which revealed the carbide eutectic enriched with Cr in ductile iron.