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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂

Wyrwas, Richard Ben, Jr. 22 November 2004 (has links)
Early transition metal oxide clusters have been a focus of study for several years. The production of vanadium oxide cluster anions in a pulsed helium flow reactor provides a relatively precise way of introducing defect sites and controlling the oxidation state of the vanadium atoms. The composition of the clusters can be changed from the V2O5 stoichiometry, where the vanadium atom is in a +5 oxidation state, to more reduced stoichiometries yielding a mixture of oxidation states containing atoms in the +2 oxidation state. The subsequent addition of reactant gases such as H2O and SO2 yields very intense adsorption reactions as well as a demonstration of the robustness of particular defect free clusters. For example, the cluster has been identified as a defect free cluster where all vanadium atoms are in the +5 oxidation state and all oxygen atoms are predicted to be in the 2- state. The cluster has been shown to not adsorb SO2- while clusters in a reduced oxidation state, such as and readily adsorb one or more SO2 molecules. The adsorption process has been shown to be size dependent, with the smallest monovanadium oxide anions being the most reactive.
22

Návrh parní odběrové kondenzační turbíny v Precheza, a.s. / Design of an extraction steam condensing turbine in the Precheza company.

Pavelka, Tomáš January 2009 (has links)
This diploma thesis is concerned with the design of the machinery with an extraction steam condensing turbine in Precheza corp. The theoretical part of this thesis describes the energetical situation in the company and the primary consideration about recovery of the heat, released at sulphuric acid production, for electrical power production. There is also presented brief description of the sulphuric acid production and the fundamental principles of the steam production at this process. In the practical part of this thesis there is performed the calculation of the heat-flow diagram of the steam turbine and the calculation of heat and producted electrical power at the basic operational states. There is presented the source code for the calculation of the heat-flow diagram using Matlab software. In the end there is mentioned the economical evaluation of the whole project, using the fundamental economical methods, such as net present value method, or profitability index, including the calculation of the pay-back period.

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