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A Desktop Installation for Electrodiffusion Experiments
Wein, Ondřej; Tovčigrečko, Valentin; Slezák, Jiří; Sobolík, Václav
2010 - anglický
Klíčová slova:
electrodiffusion transient process; calibration operations
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
A Desktop Installation for Electrodiffusion Experiments
Separation Factors for Enrichment of Minor Components in Oils Extracted from Seeds with Supercritical CO2
Sovová, Helena
2010 - anglický
The present contribution shows that the same separation factors as for the oil fractionation in counter-current columns can be used to calculate the course of extraction of triacylglycerols and minor oil components in the initial period of fast extraction from crushed seed. Thus, the optimal conditions for minor component pre-concentration in extract or for removal of free fatty acids from the oil can be predicted. The values of separation factors for different minor components and for oils consisting mainly of C18 fatty acids are presented in dependence on the temperature, pressure, and CO2 density. The separation factors are based on both literature data and experimental data measured in our laboratory. The application of separation factors to calculate extraction yields of oil and its minor components in dependence on the amount of passed CO2 is presented, too.
Klíčová slova:
separation factors; extraction; oil
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Separation Factors for Enrichment of Minor Components in Oils Extracted from Seeds with Supercritical CO2
The present contribution shows that the same separation factors as for the oil fractionation in counter-current columns can be used to calculate the course of extraction of triacylglycerols and minor ...
Enrichment of Supercritical Extracts in beta-Sitosterol by Fractionation Process
Rochová, Kristina; Sovová, Helena; Sajfrtová, Marie; Bártlová, Milena
2010 - anglický
The aim of this contribution was to use the extraction with supercritical CO2 coupled with fractionation of extract for preparation of extracts rich in beta-sitosterol. Phytosterols have been proved to lower serum cholesterol levels in humans and to have other benefit for human health. Supercritical extraction is a green method to separate such compounds from plants. Sea buckthorn seeds and sunflower seeds were extracted and a mathematical model was applied to determine separation factor of beta-sitosterol as minor component of extract. According to the obtained results, conditions of fractionation were set up. The most important enrichment of a part of extract from seeds with beta-sitosterol was achieved with fractionation in two separators (first separator kept at 15MPa and 50°C) and subsequent fractionation in time at the output of the second separator.
Klíčová slova:
beta-sitosterol; fractionation process; supercritical extraction
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Enrichment of Supercritical Extracts in beta-Sitosterol by Fractionation Process
The aim of this contribution was to use the extraction with supercritical CO2 coupled with fractionation of extract for preparation of extracts rich in beta-sitosterol. Phytosterols have been proved ...
High-Pressure Measurements in Binary System Containing Supercritical CO2 and 1-Butanol
Sedláková, Zuzana; Bendová, Magdalena; Wagner, Zdeněk; Aim, Karel
2010 - anglický
The aim of this contribution is to test the Supercritical Phase Monitor apparatus by comparing solubility of ethanol or 1-butanol in supercritical CO2 to literature data. New experimental data were also obtained.
Klíčová slova:
experimental data; high pressure; supercritical CO2
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
High-Pressure Measurements in Binary System Containing Supercritical CO2 and 1-Butanol
The aim of this contribution is to test the Supercritical Phase Monitor apparatus by comparing solubility of ethanol or 1-butanol in supercritical CO2 to literature data. New experimental data were ...
Super/Subcritical Fluid Extractions for Synthesis of Porous Metal Oxides
Matějová, Lenka; Matěj, Z.; Cajthaml, Tomáš; Šolcová, Olga
2010 - anglický
In this study the influence of individual post-treatment steps on the crystallinity, purity and textural properties of prepared metal oxides - TiO2, ZrO2, TiO2-ZrO2 etc. in powdery form (aerogels) – has been studied. Titania and zirconia organogels were prepared as reaction semi-products of the sol-gel process controlled in reverse micellar solution of nonionic surfactant Triton X-114. in combination with a) subcritical fluid extractions (using water and subsequently methanol like pressurized solvents, SubWE/PFE) and b) calcination. The effect of various extraction conditions on textural and structural properties of metal oxides has been investigated. Besides that the reproducibility of these material properties has been also observed.
Klíčová slova:
metal oxide; supercritic fluid extraction; subcritic water extraction
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Super/Subcritical Fluid Extractions for Synthesis of Porous Metal Oxides
In this study the influence of individual post-treatment steps on the crystallinity, purity and textural properties of prepared metal oxides - TiO2, ZrO2, TiO2-ZrO2 etc. in powdery form (aerogels) – ...
Polybrominated Diphenyl Ethers –Design and Validation of Models for Photodegradation
Veselý, Martin; Žabová, Hana; Kaštánek, František; Ponec, Robert; Jiřičný, Vladimír
2010 - anglický
Presented study predict ways of PBDE degradation using different methods – photodegradation, degradation with zero-valent metal and electrochemical degradation. Thermodynamic properties of all congeners were evaluated for predicting the degradation behavior. These properties were in this study by quantum-chemical calculations, using a semi empirical method AM1. The PBDE properties from the quantum-chemical calculation were also used to predict the wavelength of maximum absorbance, the octanol-water distribution coefficient and the gas chromatography retention times of all PBDE congeners.
Klíčová slova:
polybrominated diphenyl ethers; degradation model; theoretical calculation
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Polybrominated Diphenyl Ethers –Design and Validation of Models for Photodegradation
Presented study predict ways of PBDE degradation using different methods – photodegradation, degradation with zero-valent metal and electrochemical degradation. Thermodynamic properties of all ...
Fluidized Bed Gasification of a Sub-Bituminous Coal, Biomass and Coal-Biomass Co-Gasification by a Gas Containing Oxygen-CO2 Mixtures
Svoboda, Karel; Pohořelý, Michael; Jeremiáš, Michal; Kameníková, Petra; Skoblia, Sergej; Šyc, Michal; Punčochář, Miroslav
2010 - anglický
Based on the above stated facts we concentrated in our study on FB gasification with higher concentrations of CO2 in gasification medium and on gasification of a reactive subbituminous German coal, biomass (wood) and a coal-biomass blend at temperatures between 800 oC and 900 oC. Out attention was particularly devoted to effects of CO2 concentrations and gasification temperature on producer gas heating value, energy yield, tar and BTX yields in comparison with FB gasification with steam-O2 mixtures.
Klíčová slova:
fluidized bed; gasification; goal
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Fluidized Bed Gasification of a Sub-Bituminous Coal, Biomass and Coal-Biomass Co-Gasification by a Gas Containing Oxygen-CO2 Mixtures
Based on the above stated facts we concentrated in our study on FB gasification with higher concentrations of CO2 in gasification medium and on gasification of a reactive subbituminous German coal, ...
Transition Metal Mixed Oxides from LDH Precursors and Their Activity in Total Ethanol Oxidation
Ludvíková, Jana; Jirátová, Květa; Kovanda, F.; Krúpa, L.; Sobek, Jiří
2010 - anglický
Klíčová slova:
catalytic total oxidation; volatile organic compounds; ldh precursor
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Transition Metal Mixed Oxides from LDH Precursors and Their Activity in Total Ethanol Oxidation
Voltage-step Transient in Redox Systems II. 1D Approximation (revisited)
Wein, Ondřej
2010 - anglický
Using the well-known Cottrell asymptote, voltage-step transient experiment could provide data on bulk concentration and diffusion coefficient of working depolarizer, essential in the liming-current techniques. However, the Cottrell asymptote is not directly applicable in an early stage of the voltage-step transient process,. There are three additional transport resistances that cannot be neglected at extremely high initial currents: Faradaic resistance at surface of working electrode, Ohmic losses in its intimate neighborhood, and the galvanometric constraint in the outer circuit (galvanometer, current follower, potentiostat). Non-linear effect of these additional transport resistances on the transient current is calculated in a 1D approximation, i.e. assuming uniform accessibility of the working electrode, for finite voltage steps.
Klíčová slova:
voltage-step transient; cottrell asymptote; ohmic loss
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Voltage-step Transient in Redox Systems II. 1D Approximation (revisited)
Using the well-known Cottrell asymptote, voltage-step transient experiment could provide data on bulk concentration and diffusion coefficient of working depolarizer, essential in the liming-current ...
The Next Flexible microPROCESSING Unit (FMU2) is Getting a Face
Maes, P.; Křišťál, Jiří
2010 - anglický
The report states the current status of the upgrade of the flexible microprocessing unit.
Klíčová slova:
microreactors; process intesification; SO2 oxidation
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The Next Flexible microPROCESSING Unit (FMU2) is Getting a Face
The report states the current status of the upgrade of the flexible microprocessing unit.
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