05 (1999) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/38115
Procházet
19 výsledky
Search Results
Článek Otevřený přístup peer-reviewedpublished The application of derivatization and retention incides system for identification of alkylpolyethylene glycol ethers by capillary gas chromatography(Univerzita Pardubice, 2000) Komárek, Karel; Richter, PavelThis study deals with the possibility of GC analysis of individual alkylpolyethylene glycol ethers (APEGEs)C4-C10. The possibilities of derivatization reactions of these substances and the advantages of the derivative preparation are discussed. APEGEs were coverted into three types of derivatives: acetates, trifluoroacetates and trimethylsilyl ethers. The retention indices of individual oligomers of APEGEs and their derivaties for the column temperature programmed linearly were measured. The influence of an increase in the lenght of the chain in the alkyl orpolyoxyethylene glycol part of molecule of non-derivatized APEGEs and their derivatives on the retention indices was studied.Článek Otevřený přístup peer-reviewedpublished Influence of the fluidized bed flow regime on the permeate flux in ceramic membrane microfiltration(Univerzita Pardubice, 2000) Mikulášek, PetrThe influence of a fluized bed on permeate flux during the microfiltration of model disperrions on ceramic membranes has been studied. Following the description of the basic characteristic zirconium dioxide tubular membranes, model dispersions and spherical particles used, some comments about the experimental system, and experimental results for different microfiltration systems are presented. From analysis of experimental results it may be concluded the the use of a fluidized bed resulted in a significant increase of permeate flux in comparsion with results obtained in an empty tube system. This phenomenon is especially pronounced during the microfiltration of oil emulsion when the permeate flux in a fluidized bed system was nearly three times higher. Then, it was found that the optimum porosity of a fluidized bed during which maximal values of permeate flux were reached is in an interval around the value of 0.8. Experimental observations of the onset of aggregate (bubbling) behaviour in liquid fluidized beds are shown to agree with the predictions of a recently published model of the fluidization process. For a given liquid, the transition from particulate to aggregate fluidization process. For a given liquid, the transition from particulate to aggregate fluidization process. For a given liquid, the transition from particulate to aggregate fluidization depends on both the density and size of the fluidized particles.Článek Otevřený přístup peer-reviewedpublished Cationic surfactants as modifiers for carbon paste electrodesapplication to the determination of iodide(Univerzita Pardubice, 2000) Švancara, Ivan; Čermáková, Iva; Vytřas, Karel; Gössler, Walter; Kalcher, KurtThis article reports on applicability of carbon paste electrodes modified "in situ" with a surfactant in voltammetry to selected inorganic anions. A new method for the determination of iodide is proposed based on ion-pairing of iodide with 1-ethoxycarbonylpentadecyl-trimethylammonium bromide (Septonex). The procedure developed has been tested and verified by means of analyzing both model and real samples.Článek Otevřený přístup peer-reviewedpublished Approximative solution of the momentum transfer in incompressible Newtonian fluid-fluidized bed system(Univerzita Pardubice, 2000) Dolejš, Václav; Mikulášek, Petr; Doleček, PetrA method based on the dividing of the particle resistance into the frictional and shape components is suggested for the calculation of incompressible Newtonian fluid-fluidized bed system of spherical particles. This method led to the relationship which includes the general aspects of relationship of both the Richarson-Zaki and Wen-Yu types. The form of the dependence of a ratio of shape to frictional resistence on the Reynolds number has been determined experimentally. A comparison is made with a set of relationships given in the literature.Článek Otevřený přístup peer-reviewedpublished Properties of the stabilizate and possibilities of its utilization(Univerzita Pardubice, 2000) Bajer, Tomáš; Rusek, Vlastimil; Černohorský, Tomáš; Brunclík, Tomáš; Bečková, Veronika; Sákra, TomášThe paper is devoted to production of the stabilizate as a procedure for utilization of wates from coal burning and desulfurization process in heat power stations. This study completes the knowledge concerning the leachability of several metals (As, Al, Cr, V) and some properties of the stabilizate - pH and changes of conductance - in dependence on the method of stabilizate production and on the age of samples. The composition of the stabilizate presenting the best properties has been suggested. Future studies should focus on verification of these results during the longer time period.Článek Otevřený přístup peer-reviewedpublished Halftone dots segmentation in multicolour printing(Univerzita Pardubice, 2000) Fribert, MiroslavIn order to evaluate print characteristics from the samples of the printing sheets, the segmentation of halftone dots printed with process inks has to be done. Accuracy of the segmentation process influences significantly the following evaluation of print characteristics. This paper describes a suitable and verified method to achieve this aim. The segmentation method is based in the first step on the separation of individual process colours included in the print sample. The result of separation process is the monochromatic image, which is further processed by the threshold segmentation method with optimization of the threshold value.Článek Otevřený přístup peer-reviewedpublished Application of quantiles and pivots in evaluation of small sample sizes of data(Univerzita Pardubice, 2000) Dempír, JosefIn the present paper the use of quantiles and pivots in evaluation of small sample sizes of data is decribed. Formulae for computing mean value and standard deviation are derived. Some examples are given to illustrate the usefulness of this approach in the analytical practice.Článek Otevřený přístup peer-reviewedpublished Electrical properties of layered compounds derived from vanadyl phosphate dihydrate(Univerzita Pardubice, 2000) Kilián, MichalA set of layered compounds derived from vanadyl phosphate dihydrate in which a part of vanadyl groups is replaced with a trivalent metal (Fe, Mn, Cr, Al, Ga) was prepared. Electrical properties of the modified vanadyl phosphates were studied by total and electronic conductivities investigation in a wide temperature range as well as by thermoelectric power (Seebeck coefficient) measurements.Článek Otevřený přístup peer-reviewedpublished Effect of zeolite matrices on the redox and catalytic properties of the Cu ions in MFI zeolites(Univerzita Pardubice, 2000) Bulánek, Roman; Wichterlová, Blanka; Tichý, JosefThe aim of the paper is to bring insight into the relationship between the structure, redox properties and catalytic activity in propane oxidation of the Cu ions in high-silica zeolites. Previous studies revealed several defined Cu ion sites characteristic of high-silica zeolites, differing in coordination-siting, positive charges, and population depending on Cu concentration, and content of Al in the framework. It has been a highly important to relate this knowledge on the structure of Cu ion sites to the redox properties and oxidation catalytic activity of the Cu-high-silica zeolites. The reducibility and catalytic activity in propane oxidation was investigated for the Cu ions planted in zeolites of structural types ZSM-5 (MFI) with different Cu/Al/Si compositions, where NA(I) or H(I) ions were present as cocations, and Cu ions were exchanged at various conditions (concentration and pH). Reducibility of the CU(II) ions was investigated by temperature-programmed reduction (TPR) with hydrogen, and by vacuum and CO treatment of the zeolities; the relative concentration of the CU(I) ions was monitored by IR spectra of formed CU(I)-(CO)n complexes. Conversion of propane to CO and CO2 was studied in dependence on temperature in an integral through-flow reactor and evaluated in turn-over-frequency (TOF) values, representing the activity per one CO ion.Článek Otevřený přístup peer-reviewedpublished Investigation of cleaning effectivity of waste gases from an incinerator(Univerzita Pardubice, 2000) Sákra, Tomáš; Semerád, Pavel; Ťopek, MiroslavIncineration of wastes is supposed to be an effective way of liquidation particularly of those hazardous ones from the medical centers. Most are, therefore, equipped with a modern incinerator. Moreover, flue gases must be effectively cleaned to meet hygienical standards. This works is devoted to the investigation of some parameters characterizing the cleaning section of the Pardubice hospital incinerator. Because the measurement of concentration of some gaseous components in flue gases represents a legal duty of a company, optimization of the acid gases removal (HCl, CL2) and determination of composition of the dust particles was the aim of this first step of the work.