Selected ions and major and trace elements as contaminants in coal-waste dump water from the Lower and Upper Silesian Coal Basins (Poland)

Many temporary and permanent reservoirs of water occur on or near coal-waste dumps in the Lower-and Upper Silesian Coal Basins (Poland).Little or nothing is kno...     

Chromophore concentration effect on holographic grating formation efficiency in novel azobenzene‐functionalized polymers

Optically active photochromic poly(amideimide)s containing azobenzene side groups in the repeating unit were prepared. The polymers were designed and synthesized specifically for this work in order to evaluate chromophore concentration effect on holographic grating recording. The poly(amideimide)s with mono‐ and bis‐azobenzene moieties were obtained via direct high temperature polycondensation and compared with respect to their ability of diffraction grating formation due to the light‐induced optical anisotropy effects. Holographic gratings were fabricated in polymer films upon exposure to an interference pattern of two polarized Ar⁺ laser beams at 514.5 nm wavelength. Different geometries of laser beams polarization were applied. It should be emphasized that although the azobenzene moieties are rigidly connected to the polymers backbone, some of polymers exhibited the unusually high light diffraction efficiency of around 40%. The created surface relief gratings (SRGs) were successfully observed using the atomic force microscopy (AFM). AFM images show regularly defined and aligned grating structures. It should be stressed that the SRGs with maximum of relief height up to 260 nm in polyimide derivatives with side azobenzene group were observed for the first time. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Influence of cabbage juices on oxidative changes of rapeseed oil and lard

The influence of white cabbage on oxidative and thermooxidative changes of plant fats (rapeseed oil) and animal fats (lard) was determined by an array of standard tests. The fats were heated at 100 °C for 6 h in a model system mimicking normal cooking conditions in the presence or absence of fresh cabbage juice (FCJ) or sauerkraut juice (SJ). After thermal processing of fats in the presence of cabbage juices, regardless of the kind, the formation of oxidized triacylglycerols (TAG) was decreased by about 40% compared to fats heated alone. Juices also inhibited the formation of TAG dimers and polymers. Such parameters as peroxide value, extinction coefficient at 232 nm (E^1%_1cm), and losses of polyene fatty acids revealed the protective effect of cabbage juices as well; however, in this case FCJ displayed a much stronger antioxidant effect than SJ. The protection was more visible for lard which contains much lower amounts of natural antioxidants.     

Effect of lactic acid fermentation on antioxidant properties and phenolic acid contents of oyster (<Emphasis Type="Italic">Pleurotus ostreatus</Emphasis>) and chanterelle (<Emphasis Type="Italic">Cantharellus cibarius</Emphasis>) mushrooms

Fruiting bodies of Pleurotus ostreatus (oyster) and Cantharellus cibarius (chanterelle) mushrooms underwent acid fermentation using 3 strains of lactic acid bacteria (LAB) as starter cultures. Polyphenol contents, antioxidant activities, and phenolic acid contents in fresh, blanched, and fermented mushrooms were investigated. Fruiting bodies of oyster mushrooms exhibited higher total phenolic contents than chanterelle mushrooms. Blanching caused a decrease in polyphenol contents and antioxidant activities in both mushroom types. No important differences were observed in total phenolic compound contents (measured using Folin-Ciocalteau reagent) in mushrooms using different LAB strains. Lactobacillus plantarum was the most useful microorganism for lactic acid fermentation of fruiting bodies for reduction of the pH value. The highest concentrations of single phenolic acids: gallic, homogentisic, and ferulic acids were present in mushrooms fermented using L. plantarum.     

Structural changes in the surface layer of plastic as a result of sliding friction in a metal-thermoplastic system

Studies on structural changes in the surface layer of plastics during internal sliding friction (friction upon seizing) of metalthermoplastic systems have been carried out. These structural changes were carried out by means of polarized light microscopy, density measurements, X-ray diffraction and IR absorption spectroscopy (ATR). They were carried out for high density polyethylene (HDPE), polypropylene (PP) and nylon 6 (PA6). As a result it was found that the formation of completely different structures was caused by internal sliding friction.     

α‐Amino acids as initiators of ε‐caprolactone and L,L‐lactide polymerization

Biodegradable polymers/oligomers were successfully synthesized through a ring‐opening polymerization of ε‐caprolactone and L ,L ‐lactide, initiated by L ‐arginine and L ‐citrulline. The α‐amino acid initiators are natural, operationally simple, inexpensive, environmentally friendly and safe for human health. The polymerizations were performed with no solvents and without introducing any metal impurities. The chemical structures of the polymers obtained were elucidated using ¹H NMR, ¹³C NMR and Fourier transform infrared spectroscopies. In addition, incorporation of α‐amino acid molecules into the polymer chain was confirmed using matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. Due to the significant biological activity of L ‐arginine and L ‐citrulline, these α‐amino acid initiators may open a new route for the synthesis of functional polymers especially for pharmaceutical applications. Copyright © 2011 Society of Chemical Industry     

On the prevention of accidents and injuries : A comparative analysis of conceptual frameworks

The meaning of prevention has changed as new applications of the concept have appeared. Ideas presented in eleven different conceptual frameworks are compared. Identification of the frameworks took place through searches in databases and relevant literature. Five are general by nature, while six relate to injuries and accidents. All are supported by just a few parameters, the time dimension being the most prominent. Compatibility was established on three additional dimensions: level (individual, organizational or societal); direction (“bottom-up” or “top-down”); and in relation to the trichotomy “host-agent-environment”. An attempt to synthesize all these dimensions into one general model of accident and injury prevention is presented.     

Classification of parameter changes in a dynamic system with the use of wavelet analysis and neural networks

In this paper a neural detector of internal parameter changes in a stationary, non-linear SISO dynamic system is considered. A dynamic system is usually described by an input-output relation or by a set of state equations. Each change of parameter values creates a new non-nominal model of a dynamic system (sometimes with different values of parameters, sometimes with different structure and different values of parameters). Thus the detection of parameter changes can be formulated as a multi-model classification. The LVQ (Learning Vector Quantisation) neural network has been proposed as a classifier. Selected aggregated properties of discrete wavelet decomposition coefficients of the system output have been chosen as the inputs of the LVQ classifier. The output of the classifier points out the current model. The proposed approach to classification can be adopted as a fault detection method where faults are represented by changes of values of internal parameters of a system. The algorithm has been evaluated on the example of a non-linear fluid system with a non-ideal pipe which internal state is characterised by one value of a parameter, chosen from the known set.     

Phosphonated cross-linked polyethylenimine for selective removal of uranium ions from aqueous solutions

Among many remediation techniques for metal ion removal, polymeric adsorbents are efficient and widely applied. This has made them comparable with other remediation techniques in terms of technical and economic efficiency, feasibility as well as green technology. This study was dedicated to the development of an insoluble modified chelating polymer for use as an adsorbent for abstraction of uranium from wastewaters. Cross-linked polyethylenimine (CPEI) was phosphonated by phosphorous acid for selective removal of uranium ions. The binding affinity of the phosphonated cross-linked polyethylenimine (PCPEI) to uranium ions was assessed as well as its ability to be regenerated for reuse. It exhibited high removal percentage for uranium ions up to 99% with high selectivity even in the presence of competing ions (Mn, Ni, As). The Freundlich isotherm was found to be the best fit describing the adsorption process of uranyl ions onto the PCPEI. The pseudo-second-order equation was found to better explain the adsorption kinetics, implying chemisorption. The thermodynamic study of the adsorption revealed high activation energies which confirmed the chemisorption as the mechanism of adsorption.