http://hdl.handle.net/10195/38116 2013-05-24T00:48:48Z http://hdl.handle.net/10195/32768 Title: Ligand field model for bent (C(2v))d1 metallocene complexes Authors: Pavlík, Ivan; Fiedler, Josef; Vinklárek, Jaromír; Pavlišta, Martin Abstract: Ligand field calculations, excluding spin-orbit soupling, have been carried out for bent d1 metallocene complexes in C2v symmetry. The application of the results to the interpretation of the d-d electronic spectrum of the representative d1 complex vanadocene dichloride is discussed with particular reference to the relative energy of the five d orbitals. 2000-01-01T00:00:00Z http://hdl.handle.net/10195/32759 Title: Cost modelling in chemical production Authors: Machač, Otakar; Böhmová, Simona Abstract: The paper deals with costs and their models as one of instruments for revitalization in chemical companies. The first part treats the construction of the technological production and consumption functions and their transformation into the cost and revenue functions. Then these functions are used for optimizing the economic results of a particular production. The technological functions are obtained usually by experimental measurements or by derivation from the regularities of chemical reactions. The cost and revenue functions and their parameters are then derived by simulation and/or regression analysis. In the second part, possibilities of utilization of the cost input-output models for creation the system and dynamic cost calculations in chemical multistep production are described. Two examples taken from practice are given as an illustration of the indicated possibilities. 2000-01-01T00:00:00Z http://hdl.handle.net/10195/32752 Title: Reaction of 2-naphthol with activated sludge Authors: Komers, Karel Abstract: In a batch stirred isothermal reactor the biochemical reaction has been studied of water solution of 2-naphthol (BN) and activated sludge (AS) adapted to BN at aerobic conditions in the BN concentration range S(0) = 0.5 - 2 mmol dm -3, AS concentration range (wxpressed as the weight of dry biomass in the unit of the reaction volume) X0 = 0.1 - 4 g dm -3 and temperature range 11 - 40 °C. The decomposition of BN in the reaction mixture can be described as a reaction of zero order in BN and probably 1st order in AS if the ratio of initial concentrations p = X0/S0 is greater than 0.6 g AS per mmol BN. At lower p values the reaction order in BN fluctuated between 0 and 2. The concentration of AS was practically constant during every experiment, the concentration of oxygen dissolved in the raction mixture decreased by a reaction of zero order. In addition to the decomposition of BN a red dinaphthol derivative is formed as a side product. Its concentration increases at higher temperature and smaller p. The rate constant of the BN decomposition increased from k=0.23 at 11°C to k = 0.68 mmol S g-1 Xh-1 at 30°C. In this temperature interval the Arrhenius equation between k and temperature is fulfilled. The temperature above 40°C denaturates AS and stops the decomposition of BN. 2000-01-01T00:00:00Z http://hdl.handle.net/10195/32746 Title: Influence of two-phase gas-liquid flow on permeate flux and cake characteristics in ceramic membrane crossflow microfiltration Authors: Mikulášek, Petr; Pospíšil, Petr Abstract: The convection promotion within an aluminium oxide tubular membrane using the gas-liquid two-phase flow was studied for microfiltration of aqueous titanium dioxide dispersions. The influence of gas flow velocity and that of periodical gas flow is also presented. The results of experiments show that a constant gas-liquid two-phase flow has a positive impact on the flux. From analysis of experimental results it may be concluded that two-phase flow seems to expand the particle cake as it increases both cake porosity and thickness, thus allowing higher fluxes. For the periodical gas flow it was found that the improvement of the permeate flux is less. However, this phenomenon depends on the periodical gas flow mode and on the concentration of the dispersion used. The most important consideration is that for all the concentrations in the range tested, an enhancement of the permeate flux because of the air injection is always observed. There is no concentration for which air enjection has no effect on the permeate flux. 2000-01-01T00:00:00Z