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Effect of Morphology of Nanostructures to Filter Ultrafine Particles
Kimmer, D. ; Vincent, I. ; Fenyk, J. ; Petráš, D. ; Zatloukal, M. ; Sambaer, W. ; Ždímal, Vladimír
Selected procedures permitting to prepare homogeneous nanofibre structures of the desired morphology by employing a suitable combination of variables during the electrospinning process are presented. A comparison (at the same pressure drop) was made of filtration capabilities of planar polyurethane nanostructures formed exclusively by nanofibres and space nanostructures having bead spacers or structures formed by a combination of micro-and nanofibres, through which ultrafine particles of ammonium sulphate 20 - 400 nm in size were filtered. The structures studied were described using a new digital image analysis technique based on black and white images obtained by scanning electron microscopy.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22013111915280 - PDF
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Additive Group-Contribution Methods for Predicting Properties of Polymer Systems
Bogdanić, Grozdana
This overview presents group-contribution models for predicting properties of pure polymers, polymer/solvent and polymer/polymer mixtures. The state of art can be easily considered taking into account that polymer solutions and blends are complicated systems, with frequent occurrence of LLE in many forms (UCST, LCST, closed loop), significant effect of temperature and polymer molar mass in phase equilibrium, the free-volume effects, and other factors causing these difficulties. The choice of a suitable model depends on the actual problem and demands, especially on the following: type of mixture (solution or blend, binary or multicomponent), type of phase equilibrium (VLE, LLE, SLE), conditions (temperature, pressure, concentration), type of calculation (accuracy, speed, yes/no answer, or complete design). The performance of various models and their range of application will be discussed.
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Unique exposure system for the whole body inhalation experiments with small animals
Večeřa, Zbyněk ; Mikuška, Pavel ; Moravec, Pavel ; Smolík, Jiří
The especially inhalation chamber is constructed for chronic exposure studies of small animals to nanoparticles under strictly controlled conditions in frame of project „Study of transport of inhalated nano-sized particles (Pb, Cd) and their allocation in organs“. The inhalation chamber builds from a glass and stainless steel and makes possible long-term inhalation procedures (up to 60 days, 24 hours/day) with up to four discrete groups of mice population (up to 60 individuals each) or of rats population (up to 20 individuals each) under controlled illumination, temperature, relative humidity, doses (0.5 x 106 - 5 x 106 particles/cm3) and size (10-60 nm) of nano-sized particles which are synthesized via aerosol route in a hot wall tube flow reactor using metal organic precursors.
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Possible way to prepare nanoparticles from aerosols released at plasma deposition
Brožek, Vlastimil ; Mastný, L. ; Moravec, Pavel ; Ždímal, Vladimír
During plasma deposition of powdered metals or inorganic compounds using WSP® generator, they interact with the plasma having temperature between 25000 and 30000 K. As a result, they melt, evaporate, thermally decompose, get ionized and/or react chemically both with plasma-forming medium and with the surrounding atmosphere or carrier gas. An experimental apparatus was constructed enabling us to capture aerosol particles emitted from the surface of the free flying particles (FFP) heated in a stream of plasma. In this work we studied content, composition and size distribution of nanosized particles of Ag and oxides of Al, Ti, Cr and W, released during plasma deposition process. These particles were analyzed by dynamic light scattering - photon correlation spectroscopy using instrument MALVERN, and with aerosol spectrometers SMPS 3936 and APS 3321.Concentration of aerosols containing nanoparticles of silver or metal oxides with diameters below 100 nm was found to be in the range 85 to
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Preparation of Amide Derivatives of Oxidized Cellulose and Carboxymethylcellulose
Taubner, T. ; Synytsya, A. ; Sobek, Jiří ; Čopíková, J.
This work is focused on the preparation of amide derivatives of oxidized cellulose and carboxymethyl cellulose. Research involved the preparation of derivatives in two steps and the first preparation of a methyl ester of the starting polysaccharide, and then aminodealkyxilation with selected primary alkylamines, ethanolamine, ethylenediamine, hydrazine and hydroxylamine. Another part of the research included the direct amidation without intermediate steps starting polysaccharide preparation of methyl ester using the same reagents and support of microwave radiation. The obtained products were monitored by FT-IR spectroscopy and organic elemental analysis.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012043014260 - PDF
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