Statistical evaluation of research performance of young university scholars: A case study

The research performance of a small group of 49 young scholars, such as doctoral students, postdoctoral and junior researchers, working in different technical and scientific fields, was evaluated based on 11 types of research outputs. The scholars worked at a technical university in the fields of Civil Engineering, Ecology, Economics, Informatics, Materials Engineering, Mechanical Engineering, and Safety Engineering. Principal Component Analysis was used to statistically analyze the research outputs and its results were compared with factor and cluster analysis. The metrics of research productivity describing the types of research outputs included the number of papers, books and chapters published in books, the number of patents, utility models and function samples, and the number of research projects conducted. The metrics of citation impact included the number of citations and h-index. From these metrics -the variables -the principal component analysis extracted 4 main principal components. The 1st principal component characterized the cited publications in high-impact journals indexed by the Web of Science. The 2nd principal component represented the outputs of applied research and the 3rd and 4th principal components represented other kinds of publications. The results of the principal component analysis were compared with the hierarchical clustering using Ward's method. The scatter plots of the principal component analysis and the Mahalanobis distances were calculated from the 4 main principal component scores, which allowed us to statistically evaluate the research performance of individual scholars. Using variance analysis, no influence of the field of research on the overall research performance was found. Unlike the statistical analysis of individual research metrics, the approach based on the principal component analysis can provide a complex view of the research systems.Web of Science30217716

Urban water quality evaluation using multivariate analysis

A data set, obtained for the sake of drinking water quality monitoring, was analysed by multivariate methods. Principal component analysis (PCA) reduced the data dimensionality from 18 original physico-chemical and microbiological parameters determined in drinking water samples to 6 principal components explaining about 83 % of the data variability. These 6 components represented inorganic salts, nitrate/pH, iron, chlorine, nitrite/ammonium traces, and heterotrophic bacteria. Using the PCA scatter plot and the Ward's clustering of the samples characterized by the first and second principal components, three clusters were revealed. These clusters sorted drinking water samples according to their origin - ground and surface water. The PCA results were confirmed by the factor analysis and hierarchical clustering of the original data

Problems of Nitrogen at Central Municipal Water Works in Ostrava

Nitrogen is very important nutrient and must be removed during wastewater treatment process. The presented article describes the situation of nitrogen removal at the Central Municipal Water Works in Ostrava. At present, this biological sewage plant operates with only 45% nitrogen removal efficiency. The current three corridor denitrification-nitrification (D-N) system is planed to be reconstructed. One of several solution is modification of the activation tank into four step D-N system that could be completed by postdenitrification in the redundant clarifiers.In this paper the analytical methods, used for determination of nitrogen compounds in waste waters, are described as well. Only sufficiently precise and accurate methods must be selected and that is why the standardized or fully validated procedures are preferred. Laboratory results are used for monitoring of treatment process and for making of important technological decisions. For this purpose, introduction of the quality control and quality assurance system into laboratory practise is desired

Information entropy for evaluation of wastewater composition

The composition of wastewaters collected during one year was evaluated based on the Shannon information entropy. Eleven physico-chemical parameters, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), total suspended solids (TSS), total dissolved salts (TDS), pH, ammonium, phosphate, cyanide and phenol, were determined for their characterization. Entropy of the parameters calculated by means of their histograms decreased in the order: phosphate > ammonium > TDS > TN > pH > BOD > COD > TSS > TP > phenol > cyanide. Entropy weights of the parameters were calculated for the evaluation of wastewater composition by means of the entropy weighted index (EWI) defined according to the simple additive weighting (SAW) model. The EWI values were statistically processed by us to observe temporal wastewater composition changes and were verified by means of the principal component weighted index (PCWI). The EWI values were statistically analyzed by univariate statistics. The outlaying samples were also confirmed by multivariate analysis. The entropy-based approach allowed us to simply evaluate wastewater composition by means of one index instead of several parameters. The main advantage of EWI is the simple histogram-based calculation of entropy with no need of the normal distribution of the used parameters.Web of Science124art. no. 109

Empirical relationship between the number of review and research articles

In this contribution, an empirical relationship between the number of review and research articles published per year was searched. The simple idea based on proportionality (lin‑ earity) between the numbers of both kinds of articles was expressed in terms of a quad‑ ratic relationship, in which the quadratic member can refect negative or positive deviations from the assumed linearity. The quadratic relationship was able to describe beginning peri‑ ods of research felds as well as their mature phases and to detect the unpredictably high number of review articles. It was verifed by the articles published in 20 various research felds taken from the Web of Science during diferent time spans.Web of Science12842209220

Post-synthetic derivatization of graphitic carbon nitride with methanesulfonyl chloride: Synthesis, characterization and photocatalysis

Bulk graphitic carbon nitride (CN) was synthetized by heating of melamine at 550 degrees C, and the exfoliated CN (ExCN) was prepared by heating of CN at 500 degrees C. Sulfur-doped CN was synthesized by heating of thiourea (S-CN) and by a novel procedure based on the post-synthetic derivatization of CN with methanesulfonyl (CH3SO2-) chloride (Mes-CN and Mes-ExCN). The obtained nanomaterials were investigated by common characterization methods and their photocatalytic activity was tested by means of the decomposition of acetic orange 7 (AO7) under ultraviolet A (UVA) irradiation. The content of sulfur in the modified CN decreased in the sequence of Mes-ExCN > Mes-CN > S-CN. The absorption of light decreased in the opposite manner, but no influence on the band gap energies was observed. The methanesulfonyl (mesyl) groups connected to primary and secondary amine groups were confirmed by high resolution mass spectrometry (HRMS). The photocatalytic activity decreased in the sequence of Mes-ExCN > ExCN > CN approximate to Mes-CN > S-CN. The highest activity of Mes-ExCN and ExCN was explained by the highest amounts of adsorbed Acetic Orange 7 (AO7). In addition, in the case of Mes-ExCN, chloride ions incorporated in the CN lattice enhanced the photocatalytic activity as well.Web of Science102art. no. 19

Agglomeration of ZnS nanoparticles without capping additives at different temperatures

ZnS nanoparticles were precipitated in diluted aqueous solutions of zinc and sulphide ions without capping additives at a temperature interval of 0.5–20°C. ZnS nanoparticles were arranged in large flocs that were disaggregated into smaller agglomerates with hydrodynamic sizes of 70–150 nm depending on temperature. A linear relationship between hydrodynamic radius (R a ) and temperature (T) was theoretically derived as R a =652 - 2.11 T. The radii of 1.9–2.2 nm of individual ZnS nanoparticles were calculated on the basis of gap energies estimated from their UV absorption spectra. Low zeta potentials of these dispersions of −5.0 mV to −6.3 mV did not depend on temperature. Interactions between individual ZnS nanoparticles were modelled in the Material Studio environment. Water molecules were found to stabilize ZnS nanoparticles via electrostatic interactions.Web of Science12331731

Model of synthesis of ZnS nanoparticles stabilized by cetyltrimethylammonium bromide

A mathematical model of synthesis and stabilization of ZnS nanoparticles in aqueous solutions of cetyltrimethylammonium bromide (CTAB) is presented. ZnS nanoparticles precipitated by the reaction of sodium sulphide and zinc acetate are significantly influenced by CTAB both in a stage of nucleation and in a stage of growth and stabilization. The suggested model assumes a dominating influence of the nucleation stage on future properties of emerging ZnS nanoparticles. On the basis of a calculated nucleation rate depending on a degree of the ZnS supersaturation, the model adopts an approximate assumption that ZnS nuclei are formed all at one moment.Mathematical formulation of the nucleation model attempts to explain a recently observed relationship between ZnS nanoparticles radii and the CTAB concentration. The dependence of a surface tension of zinc acetate and CTAB aqueous solutions on the CTAB concentration was measured and further applied to obtain the relation between the CTAB monomer concentration and the CTAB total concentration. The nucleation model assumed a key role of CTAB monomers, which were considered as nucleation centres. The predicted radiiWeb of Science101039238

Zpráva o výsledcích vědecko-výzkumné a vývojové činnosti na VŠB-TU Ostrava za rok 2014 : určeno pro zasedání Vědecké rady VŠB-TUO dne 6. 3. 2015

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Zpráva o výsledcích vědecko-výzkumné a vývojové činnosti na VŠB-TU Ostrava za rok 2013 : určeno pro zasedání Vědecké rady VŠB-TUO dne 7. 3. 2014

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