Detection of Signed Homonuclear Couplings between Low Abundant Nuclei
Blechta, Vratislav; Schraml, Jan
2011 - English The subject of this lecture is a modification of CSEc method for detection of signed homonuclear couplings. The new sequence is neither trivial nor simple application of the CSEc but some tricks are used to design broadband pulse sequence without selective pulses. The sequence was proved on a few samples by measuring carbon-carbon two- and three-bond couplings. For the first time signs of 2J(Si-O-Si) couplings were measured on a set of siloxane oligomers with different bond maps. The results will be presented. Keywords: signed coupling; linear spin system; sign of J(C,C) Available at various institutes of the ASCR Detection of Signed Homonuclear Couplings between Low Abundant Nuclei

The subject of this lecture is a modification of CSEc method for detection of signed homonuclear couplings. The new sequence is neither trivial nor simple application of the CSEc but some tricks are ...

Blechta, Vratislav; Schraml, Jan
Ústav chemických procesů, 2011

The Accuracy of a Monofiber Optical Probe
Vejražka, Jiří; Orvalho, Sandra; Večeř, M.; Sechet, P.; Cartellier, A.
2010 - English In this contribution, the accuracy of optical probe in a bubbly flow is deduced from high-speed imaging of bubble probe interaction. A dimensionless criterion useful for the estimation of the error of indicated void fraction is developed. It is also observed that the probe deformability may significantly decrease the probe accuracy. Keywords: opticle probe; bubble-fiber interaction; measurement accuracy Available at various institutes of the ASCR The Accuracy of a Monofiber Optical Probe

In this contribution, the accuracy of optical probe in a bubbly flow is deduced from high-speed imaging of bubble probe interaction. A dimensionless criterion useful for the estimation of the error of ...

Vejražka, Jiří; Orvalho, Sandra; Večeř, M.; Sechet, P.; Cartellier, A.
Ústav chemických procesů, 2010

Photo-Electrochemical Properties of Hierarchical Nanocomposite Structure: Carbon Nanofibers/TiO2/ZnO Thin Films
Hubička, Zdeněk; Kment, Štěpán; Gregora, Ivan; Čada, Martin; Olejníček, Jiří; Klusoň, Petr; Petras, D.; Krýsa, J.; Jastrabík, Lubomír; Dytrych, Pavel
2010 - English In this contribution we report on photoelectrochemical functionality of the multilayers system consisting of CNF's/photoactive anatase TiO2/ conductive ZnO thin films. Recently the thin phthalocyanines films has been prepared and studied individually. Keywords: phthalocyanines films; multi-layers systems; photovoltaics Available at various institutes of the ASCR Photo-Electrochemical Properties of Hierarchical Nanocomposite Structure: Carbon Nanofibers/TiO2/ZnO Thin Films

In this contribution we report on photoelectrochemical functionality of the multilayers system consisting of CNF's/photoactive anatase TiO2/ conductive ZnO thin films. Recently the thin ...

Hubička, Zdeněk; Kment, Štěpán; Gregora, Ivan; Čada, Martin; Olejníček, Jiří; Klusoň, Petr; Petras, D.; Krýsa, J.; Jastrabík, Lubomír; Dytrych, Pavel
Ústav chemických procesů, 2010

Formation Of Sn-Ag-C and Sn-Au-C Nanoalloys Through Ir Laser Ablation OF Ag and Au Target and Simultaneous Decomposition of TMT in the Gas Phase
Křenek, Tomáš; Murafa, Nataliya; Bezdička, Petr; Šubrt, Jan; Pola, Josef
2010 - English IR laser ablation of Ag or Au in dielectric breakdown of tetramethyltin leads to nanostructured films composed of nanograins of Sn and amorphous Au-C or Ag-C phases. Keywords: tetramethyltin; ir laser; ablation Available at various institutes of the ASCR Formation Of Sn-Ag-C and Sn-Au-C Nanoalloys Through Ir Laser Ablation OF Ag and Au Target and Simultaneous Decomposition of TMT in the Gas Phase

IR laser ablation of Ag or Au in dielectric breakdown of tetramethyltin leads to nanostructured films composed of nanograins of Sn and amorphous Au-C or Ag-C phases.

Křenek, Tomáš; Murafa, Nataliya; Bezdička, Petr; Šubrt, Jan; Pola, Josef
Ústav chemických procesů, 2010

Calcined Transition Metal Layered Double Hydroxides, Their Characterization and Activity in Total Oxidation of Ethanol
Jirátová, Květa; Kovanda, F.; Ludvíková, Jana; Klempa, Jan
2010 - English Keywords: catalytic activity; ethanol; chemical analysis Available at various institutes of the ASCR Calcined Transition Metal Layered Double Hydroxides, Their Characterization and Activity in Total Oxidation of Ethanol

Jirátová, Květa; Kovanda, F.; Ludvíková, Jana; Klempa, Jan
Ústav chemických procesů, 2010

Correlations for the Prediction of NTU and Mass Transfer Coefficient for a VPE
Rathilal, S.; Čárský, M.; Heyberger, Aleš; Rousková, Milena
2010 - English Liquid-liquid extraction is the separation of the constituents of a liquid solution by contact with another insoluble liquid and belongs to the class of countercurrent diffusional separation processes, where it ranks second in importance to distillation. There are many different types of columns that are available for liquid-liquid extraction and the reciprocating column and vibrating plate column are two types of mechanically aided columns. This paper aims at developing appropriate correlations for the prediction of NTU/HETS and the mass transfer coefficient, kox for the VPE based on the agitation level of the plates (af – the product of frequency and amplitude of the plate motion), the plate spacing and the flow rates which will allow for the simplification in the design of this type of column. Keywords: mass transfer coefficient; liquid-liquid extraction; acetone-toluene-water system Available at various institutes of the ASCR Correlations for the Prediction of NTU and Mass Transfer Coefficient for a VPE

Liquid-liquid extraction is the separation of the constituents of a liquid solution by contact with another insoluble liquid and belongs to the class of countercurrent diffusional separation ...

Rathilal, S.; Čárský, M.; Heyberger, Aleš; Rousková, Milena
Ústav chemických procesů, 2010

Reconstructed 3D Microstructure and Effective Diffusivity of a Zeolite-Polyimide Mixed Matrix Membrane
Čapek, P.; Hejtmánek, Vladimír; Fryčová, M.; Sysel, P.; Kočiřík, Milan; Brabec, Libor; Zikánová, Arlette; Bernauer, B.; Fíla, V.
2010 - English In our work we focused on a two-phase system consisting of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride (6FDA) and 4,4’-oxydianiline (ODA), and silicalite-1 [3, 4]. Its microstructure on the scale capturing the morphology of silicalite particles was reproduced by means of stochastic reconstruction. Then, effective diffusivity of an arbitrary fluid in the reconstructed composite material was determined by exploiting random walk simulation. Resulting values were compared with the corresponding values obtained using two traditional correlations for conductivity of composite materials. Image processing and analysis as the first step of stochastic reconstruction was a bit inexact in terms of an estimation of the volume fractions of both phases. Keywords: simulation; effective diffusivity; membrane Available at various institutes of the ASCR Reconstructed 3D Microstructure and Effective Diffusivity of a Zeolite-Polyimide Mixed Matrix Membrane

In our work we focused on a two-phase system consisting of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride (6FDA) and 4,4’-oxydianiline (ODA), ...

Čapek, P.; Hejtmánek, Vladimír; Fryčová, M.; Sysel, P.; Kočiřík, Milan; Brabec, Libor; Zikánová, Arlette; Bernauer, B.; Fíla, V.
Ústav chemických procesů, 2010

Experimental Study of Bubble Interactions with the Solid Surface
Zedníková, Mária; Vobecká, Lucie; Vejražka, Jiří; Růžička, Marek
2010 - English The experiments were carried out in a rectangular vessel equipped with a device generating the bubbles of defined size ranging from 0.4 to 2.0 mm (Vejrazka et al., 2008). Cleaned glass was used as a hydrophilic surface and polypropylene, polyethylene and Teflon were used as hydrophobic surfaces. Deionised water with addition of sodium dodecyl sulphate was used as liquid. The collision and attachment process was observed by means of high speed camera. The following quantities were evaluated from the image sequences: impact and rebound velocities of a bubble, maximal bubble deformation during the contact with the surface and the time required for three-phase contact line formation. The experimental results were compared with our previous investigations (Fujasova-Zednikova et al., 2009). Keywords: bubble attachment; surfactants; floation Available at various institutes of the ASCR Experimental Study of Bubble Interactions with the Solid Surface

The experiments were carried out in a rectangular vessel equipped with a device generating the bubbles of defined size ranging from 0.4 to 2.0 mm (Vejrazka et al., 2008). Cleaned glass was used as a ...

Zedníková, Mária; Vobecká, Lucie; Vejražka, Jiří; Růžička, Marek
Ústav chemických procesů, 2010

Volumetric Mass Transfer Coefficient and Gas Holdup in Solution of Electrolyte in Different Flow Regimes in Bubble Column
Fialová, Marie; Orvalho, Sandra; Zedníková, Mária; Drahoš, Jiří; Růžička, Marek
2010 - English Volumetric mass transfer coefficient, kLaL and gas holdup, εG were measured in distilled water and in solutions of Na2SO4 (both coalescent solutions and solutions with suppressed coalescence), under homogeneous and heterogeneous bubbling conditions in bubble column. Dynamic pressure step method was used for kLaL measurement. The gas holdup, εG was measured by the bed expansion method. Keywords: gas holdup; volumetric mass transfer; bubble column Available at various institutes of the ASCR Volumetric Mass Transfer Coefficient and Gas Holdup in Solution of Electrolyte in Different Flow Regimes in Bubble Column

Volumetric mass transfer coefficient, kLaL and gas holdup, εG were measured in distilled water and in solutions of Na2SO4 (both coalescent solutions and solutions with suppressed coalescence), under ...

Fialová, Marie; Orvalho, Sandra; Zedníková, Mária; Drahoš, Jiří; Růžička, Marek
Ústav chemických procesů, 2010

Effect of Velocity on the Coalescence of Bubbles
Orvalho, Sandra; Cachaza, E.M.; Abadie, T.; Drahoš, Jiří; Růžička, Marek
2010 - English The present work is focused only on the effect of the velocity of approach between the interfaces of two identical bubbles, that are brought into contact in liquids known to be either coalescent (pure water) or non-coalescent (surfactant solutions). Keywords: effect of velocity; coalescence of bubbles Available at various institutes of the ASCR Effect of Velocity on the Coalescence of Bubbles

The present work is focused only on the effect of the velocity of approach between the interfaces of two identical bubbles, that are brought into contact in liquids known to be either coalescent (pure ...

Orvalho, Sandra; Cachaza, E.M.; Abadie, T.; Drahoš, Jiří; Růžička, Marek
Ústav chemických procesů, 2010