National Repository of Grey Literature 24 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Transport and Catalytic Properties of Polymeric Nanofibrous Layers Prepared by Electrospinning
Soukup, Karel ; Topka, Pavel ; Petráš, D. ; Šolcová, Olga
This work has been focused on the electrospinning generation of nanofibrous membranes from polystyrene, polyurethane and polyphenylene oxide (poly(2,6-dimethyl-1,4-phenyleneoxide) – PPO), on their texture and transport properties determination and catalytic activity of the platinum catalyst supported on PPO membrane.
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Modeling of Partial Oxidation of Biomass Oil Suspension
Tukač, V. ; Hanika, Jiří ; Veselý, Václav ; Kovač, D. ; Lederer, J.
Mathematical modeling of complex chemical equilibrium during biowaste oil suspension gasification in pilot plant reactor was aimed in the study. Simulation results were compared with pilot plant experiments using rape meal suspension in high boiling hydrocarbons. Application for reactor design and process scale up could be realistic.
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Modular Microsystems for Novel Processes Research
Křišťál, Jiří ; Jiřičný, Vladimír ; Hanika, Jiří
Paper summarises results of ICPF AS CR team in application of micro-devices including microreactors for research of novel chemical processes. Experiences were reached during the international projects IMPULSE and F3 FACTORY solved in the 6th and 7th Framework Program EU. Novel chemical processes development for chemical specialties supports their higher purity. This trend represents great challenge for chemical engineers. The piece of knowledge was applied also during discussions on Strategic Research Agenda and Implementation Action Plan formulations by the Czech Technology Platform for Sustainable Chemistry founded at the Association of Chemical Industry of the Czech Republic.
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A Simplified Calculation of a Continuous Flow Packed Contactor with Help of Characteristic Times
Sovová, Helena
The proposed approach is illustrated on several examples of supercritical fluid extraction kinetics. Simple expressions for the calculation of characteristic times of both extraction and individual extraction steps are derived from mass balance equations and applied on experimental data from typical extractions from plants with supercritical CO2, as the extraction of oils from seeds or the extraction of essential oils from aromatic plants.
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Semi-Empirical Model of Toluene Transport in Polyethylene Membrane Based on the Data of New Type of Apparatus for Gas Permeability, Diffusivity and Solubility
Setničková, Kateřina ; Wagner, Zdeněk ; Noble, R.D. ; Uchytil, Petr
Solubility, diffusivity and permeability of toluene vapors in a low-density polyethylene (LDPE) membrane were measured using new type of permeation apparatus. The simple semi-empirical model of toluene transport in a polyethylene membrane based on relation between experimentally obtained effective diffusion coefficients and concentration dependent diffusion coefficients evaluated from experiments on new permeation apparatus was proposed.
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Effect of Conditions of Supercritical Fluid Extraction on Insecticidal Activity of Isolates from Rue
Sajfrtová, Marie ; Pavela, R. ; Karban, Jindřich
The aim of this study was to find optimal operating conditions of SFE from rue to obtain extract with maximal insecticidal activity. Several types of extracts were prepared using the benefit of variable solvent power of supercritical carbon dioxide. The extracts rich in volatile oil or oleoresin were obtained at 40 °C and 12 or 28 MPa, respectively. The extract enriched with polar components was extracted at pressure of 28 MPa and temperature of 40 °C with acetone added to CO2 as modifier (2.5 – 10 wt. %).
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Mass Transport Simulation in Replicas of Porous Material: Effective Transport Properties Estimation
Čapek, P. ; Veselý, M. ; Kolafa, J. ; Hejtmánek, Vladimír ; Brabec, Libor
The purpose of this study was calculation of transport properties of the replicas of some macroporous materials. These trasport parameters such as the effective permeation or diffusion coefficient, respectively, were compared with their experimentally measured counterparts.
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A New Look on the Nernst Model in Electrochemistry
Wein, Ondřej
The present paper is inspired by the electrodiffusion (ED) flow measurement, utilizing the limiting-diffusion regime (LDR) in two-electrode ED cells. The electrochemical testing and calibrations of the ED cells is based on two standard electrochemical techniques - quasi-steady voltammetry and voltage-step transient. Recently published theory of the voltage-step transient under simultaneous effect of Faradaic and Ohmic resistances is based on a suitably extended Nernst model. An analogous theory of the voltammetric experiment is presented here.
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AWS Viscosimetry of Microdispersions - Detection of Apparent Wall Slip
Pěnkavová, Věra ; Večeř, M. ; Wein, Ondřej
The rheometric data measured using three various sensor geometries (PP60, ZZ40DIN and KK-sensor) are compared in this contribution at the case of water solution of polymer welan. The KK-sensor, constructed at our department, combines advantages of geometry both plate-plate and concentric cylinder geometry. It is shown that KK-sensor is comparable to commercial sensors. It is presented for water kaolin dispersions that apparent wall slip does not disappeared neither for low consistent dispersions. The values of slip coefficients are even higher in the case of less consistent samples.
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