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Number of results: 7
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Abstract

The paper presents the results of experiments on the influence of the organic matter’s characteristics on the formation potential of water chlorination by-products – representatives of the following groups: trihalomethanes, haloacetonitriles, haloketones, chloral hydrate and chloropicrin. The products of water fractionation (the hydrophobic and hydrophilic acids, hydrophobic and hydrophilic bases, and hydrophobic and hydrophilic neutral fractions) were chlorinated with sodium hypochlorite. Its dose was adjusted to obtain a residual free chlorine concentration between 3 and 5 mg/dm3 after 24 h. After this time, the water chlorination by-products were analyzed with gas chromatography. The results’ analysis has defined the fractions, which have the highest potential to form particular groups of volatile organic water chlorination by-products.
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Abstract

Foam fractionation process for concentration of laccases from two Basidiomycete strains under different process conditions was investigated. Culture supernatants of Cerrena unicolor and Pleurotus sapidus containing active laccase were used with and without surfactant additives. Two surfactants: cationic cetrimonium bromide (CTAB) and non-ionic Polysorbate 80 were applied in the range from 0.2 mM to 1.5 mM. The pH levels ranging from 3 to 10 were examined with particular attention to pH=4, which is close to the pI of the enzymes. Results show that the source of the enzyme is significant in terms of partitioning efficiency in a foam fractionation process. Laccase from Cerrena unicolor showed the best activity partitioning coefficients between foamate and retentate of almost 200 with yields reaching 50% for pH 7.5 and concentration of CTAB cCTAB = 0.5 mM, whereas laccase from Pleurotus sapidus showed partitioning coefficients of up to 8 with 25% yield for pH 4 and cCTAB = 0.5 mM.
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Abstract

Antarctic krill carbohydrate content was followed during 1983—84 Eighth Polish Antarctic Expedition. The Admiralty Bay (King George Island) was th area of study. The following average values of three estimated fractions were obtained: 3.77 +- 1.51%, 0.47 +- 0.34% and 3.30 +- 1.33% for total, TCA-soluble and TCA-insoluble carbohydrates, respectively. Percentage contribution of the estimated fractions to dry weight varied seasonally (1.48—7.41%, 0.15—1.83%, and 1.28—6.28%, respectively). The carbohydrate content showed a clearcut cycle of changes over the calender year, with a minimum in autumn-winter and a maximum in spring-summer.
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Abstract

Changes in the amount of basic nitrogen fractions (total, protein and non-protein nitrogen) were studied in an annual cycle. Significant seasonal changes were noted, minima occurring in Antarctic winter and maxima during spring-summer season. These changes are due mainly to high fluctuations of water content in krill in the annual cycle.
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Abstract

The research aim was to determine the long-term impact of the mine waste stored at the coal waste dump Hałda Ruda on the content of heavy metals in the bottom sediments of the Bytomka River. It is a watercourse flowing along this coal waste dump and has been under its influence for over fifty years. The research also attempted to determine the seasonality of changes (2 years) and mobility of selected elements. The article presents total contents of Cr, Mn, Ni, Cu, Zn, As, Cd and Pb in the bottom sediments collected from the Bytomka River. It also focuses on the distribution of these elements in particular geochemical fractions determined with the Tessier's sequential chemical extraction procedure. Total element contents were determined with an EDPXRF (Energy Dispersive X-ray Fluorescence) technique. The extractants of particular Tessier's fractions were determined quantitatively with an ICP-MS (Inductively Coupled Plasma Mass Spectrometry) spectrometer. The research results show that the stored waste significantly influences the contents of heavy metals in the Bytomka River bottom sediments. The lowest concentration of heavy metals was observed at the B1 spot (above the dump), while the highest one was measured at the B3 spot (below the dump). Sequential chemical extraction of the bottom sediments indicates that the Zn content in the ion-exchange and carbonate fractions diminished within a year. Nevertheless, Zn bound to Fe and Mn oxides acted in the opposite way. Mn, Zn and Pb are the most dangerous elements from the viewpoint of environmental hazards, as their total concentrations were high. Moreover, their high contents were observed in the most mobile (ion-exchange and carbonate) fractions. Extremely toxic Cd was bound to the oxide fraction to the largest extent. Cu was mainly bound to the organic fraction while environmentally hazardous Cr was bound to the residual fraction.
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Abstract

The problem of of the use of fly ash still constitutes a research and exploration area for scientists. This is due to the fact that, 6,000,000 Mg of coal combustion by-products (CCB) are storage on landfills yearly in Poland alone. One of the potential directions of using fly ash is to use it as a substrate in hydrothermal syntheses of mesoporous materials (synthetic zeolites). Zeolites are aluminosilicates with a spatial structure. Due to their specific structure they are characterized by a number of specific properties among others molecular-sieve, ion-exchange and catalytic that can be used in engineering and environmental protection. So far, the synthesis has been carried out using coal combustion by-products such as fly ash or microsphere. The article analyzes whether separation from the fly ash of the appropriate fraction (below 63 μm) will affect the formation of zeolite grains. The syntheses were carried out using class F fly ash and the fraction separated from it, which was obtained by sieving the ash through a 63 μm sieve. Chemical (XRF) and mineralogical (XRD, SEM-EDS) analyzes were carried out for substrates as well as the obtained reaction products. In the case of substrates, the analysis did not show any significant differences between the ash and the separated fraction. However, in products after synthesis (Na-X zeolite with a small amount of Na-P1 zeolite, and small amounts of quartz and unreacted aluminosilicate glass - mullite) higher aluminum and sodium contents were observed from the separated fraction, with a lower calcium and potassium content. A small proportion of illite was observed on the diffraction curve of the zeolite from the fraction. Observations of grain morphology showed no differences in formation. Based on the conducted analyzes, it can be stated that, considering the economics of the synthesis process, the separation of fine fractions from the fly ash does not affect the quality of the synthesis process.
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Abstract

The paper discusses the modelling of magnetic coupling in ignition coils by fractional differential equations. The use of fractional-order coupling allows us to consider the losses caused by the non-linearity of the ferromagnetic core of the ignition coil and obtain the waveform of the ignition coil’s secondary voltage closest to the values obtained experimentally.
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