Contamination and Ecological Risk Assessment of Long-Term Polluted Sediments with Heavy Metals in Small Hydropower Cascade

The identification of contamination level and ecological risks, associated with heavy metal pollution of sediments in small hydropower cascade was done on the base of index analyses approach. The concentration of As, Cd, Cu, Hg, Pb, Zn, total organic carbon and percentage of fines were determined in sediments of two habitats in cascade sequence – river and dam. Correlation and multivariate analyses suggest that As, Cu, Pb and Zn are associated with similar anthropogenic source. Cadmium and mercury originate from different source and have specific moving. Based on the contamination and background indices the sediments in Middle Iskar cascade are moderate contaminated at least and are subject of intensive hydrological and technological mixing. The potential ecological risk index (PERI) classifies the sediments in dam site with the higher risk level. Suitable indicators for express assessment of metal pollution in “river” sediments are contamination/enrichment indices which are more sensitive for local concentration increase of less toxic metals. In “dam” sites the process of sedimentation affects strongly the degree of metals accumulation and differences in toxicity are clearly presented – PER/PERI in combination with content of fine sediment fractions and TOC have a potential for rapid identification of sediment-associated risks.     

A multiple narrative approach to information systems failure: a successful system that failed

We discuss the introduction of an information system where the dominant coalition claimed project success. While the key users did not use the system as intended and the project goals were not achieved, the project committee reported success to the top management board. Using a multi-methodological approach, we can follow how different stakeholders attributed different meanings to the system introduced over time. The rhetorical tools used are analysed using a narrative methodology. We draw on the social construction of technology and use the concept of relevant social groups to understand the different interests influencing the organisational dynamics. We complement this approach by employing the concepts of organisational power and cultural fit between the new system and the different subcultures. We found that this multiple approach explains well how the acceptance of the new software processes was interpreted differently within the organisation, and also by the software supplier. Although limited, our case study reveals the process of socially constructing the success or failure of an information system using this multiple research approach. We compare our results with the literature on IS failures and we consider the value of combining constructionist and critical approaches through a narrative methodology.     

Characteristics of testing conditions for constitutive models in metal plasticity

We propose a method of identifying constitutive models and material parameters in engineering applications. The presented method is used in the setting of optimal experimental design and is based on successive optimization of a finite set of possible material models. The goal is, for an initially unknown material, to define an optimal test bed based on a given set of constitutive models and a range of possible parameters. As a result of the algorithm, suitable observation operators and external loads are identified. These are then the optimal experimental conditions under which the parameters of the unknown material are tested.     

Screening of elemental impurities in commercial detonation nanodiamond using sector field inductively coupled plasma-mass spectrometry

The quantitation of 55 elemental impurities in 15 commercial samples of detonation nanodiamond (DND), micron-sized diamond of high pressure/high temperature synthesis and detonation synthesis soot (DS) was achieved using a direct sector field ICP-MS analytical method. A set of 23 elements contributing more than 99.8 mass % of all impurities was selected and used as markers for the evaluation of DND purity. Obtained data were evaluated to identify important information on possible sources of nanodiamond contamination during purification, disaggregation, solubilisation or stabilisation of suspensions. Distinctive groups of elements (including Cr, Mn and S; Mo, W, V and Ti; Na, B and Si; Ca and Mg) occurring at elevated levels in DND can be readily visualised using radar plots, and can be related to the detonation synthesis (construction materials of explosion chamber, admixture in coolant, detonator type) and/or purification processes (type of oxidation process and reagents). The contaminant profile for each respective DND can be also considered as a fingerprint, characteristic for every producer and technology used. Results obtained also highlight how DND can be considered as effective collectors of various inorganic impurities from chemical reagents, glassware, sonotrode and other materials used during processing, including disaggregation and stabilisation of suspensions.     

Capturing device mismatch in analog and mixed-signal designs

As feature size goes below 70 nm, process variation introduced device mismatch may cause over 40% performance variations and circuit failures especially for analog/mixed-signal designs. The location dependent correlations among devices and the large number of devices in some practical designs make it difficult to predict performance corners accurately and efficiently. This paper aims to provide an overview of possible methodologies and approaches that model and analyze device mismatch. In particular, the paper describes a new finite point device modeling technique that can speed up the analysis procedure, a new parametric reduction method and a novel Chebyshev Affine Arithmetic (CAA) based performance bound estimation approach.     

Liquid Chromatography Orbitrap Mass Spectrometry Method for Analysis of Homocysteine and Related Aminothiols in Cereal Products

Liquid chromatography Orbitrap mass spectrometry method for quantification of biological aminothiols (cysteine, homocysteine, and glutathione) in cereal products has been developed. The assay is based on preliminary derivatization with N-(2-acridonyl)maleimide and high resolution accurate mass spectrometry with utilization of dl-Homocystine-3,3,3′,3′,4,4,4′,4′-d₈ (homocystine-d₈) as internal standard. The limits of quantification for homocysteine, cysteine, and glutathione are 19.44, 40.78, and 338.93 pg, respectively, per 10 μl injection. Intra- and inter-day precision expressed as relative standard deviations are in the range of 1.76 to 2.94 % and 1.06 to 4.13 %, respectively. The average recoveries were 98 % for Hcy, 87 % for Cys, and 92 % for GSH. Wheat, maize, and bakery products with different origin were analyzed. The content of Hcy in the investigated samples was found to be in range of 9–436 μg/100 g, Cys in range of 29–6,895 μg/100 g and GSH in range of 259–14,795 μg/100 g.     

Classification of Ferrospinel Structures and Textures

The nomenclature and classification of ferrospinel structures and textures are presented. Conditions for their formation are described. In this respect, the classification suggested may be used both as a basis for closer investigation and as a means of obtaining ferrites with the desired structure.