Browsing by Author "Pokorný, Pavel"
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- ItemAnalýza procesu elektrostatického zvlákňování a možnosti jeho řízení(Technická Univerzita v Liberci, ) Pokorný, Pavel
- ItemAutomatizovaný sběr dat při elektrostatickém zvlákňování(Technická Univerzita v Liberci, 2012) Hřebíček, Tomáš; Pokorný, PavelThis thesis is focused on preparing a work place for data collecting from high voltage DC electrospinning. Protection of measuring circuit from destructive effects of this process. It contains galvanic problem solution of sending a measured. All measurements were measured on Poly-vinyl-alkohol.
- ItemFabrication of dual-functional composite yarns with a nanofibrous envelope using high throughput AC needleless and collectorless electrospinning(NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND, 2019-02-12) Valtera, Jan; Kalous, Tomáš; Pokorný, Pavel; Baťka, Ondřej; Bílek, Martin; Chvojka, Jiří; Mikeš, Petr; Kuželová Košťáková, Eva; Žabka, Petr; Ornstová, Jana; Beran, Jaroslav; Stanishevsky, Andrei; Lukáš, DavidNanotechnologies allow the production of yarns containing nanofibres for use in composites, membranes and biomedical materials. Composite yarns with a conventional thread core for mechanical strength and a nanofibrous envelope for functionality, e.g. biological, catalytic, have many advantages. Until now, the production of such yarns has been technologically difficult. Here, we show an approach to composite yarn production whereby a plume of nanofibers generated by high throughput AC needleless and collectorless electrospinning is wound around a classic thread. In the resulting yarn, nanofibres can form up to 80% of its weight. Our yarn production speed was 10 m/min; testing showed this can be increased to 60 m/min. After the yarn was embedded into knitwear, scanning electron microscope images revealed an intact nanofibrous envelope of the composite yarn. Our results indicate that this production method could lead to the widespread production and use of composite nanofibrous yarns on an industrial scale.
- ItemLiberecký zajatecký tábor v první světové válcePokorný, PavelThe focus of this study is the prisoner of war camp in Liberec, which was located in Liberec-Ostašov and Růžodol in 1914–1918. It was one of the first prisoner of war camps of the Great War in Austria-Hungary. At a certain time, it was by far the largest prisoner of war camp in the entire monarchy, and due to its size, it also made a major impact on the life of the city. Extensive anthropological research, which took place here during the war, then gave it supra-regional significance. In this text, I analyze its history since its foundation, through its operation and its impact on the pop ulation till its termination.
- ItemPraktické a teoretické aspekty elektrického zvlákňování nanovlákenPokorný, PavelPráce je rozdělena do dvou částí. V první části jsou uvedeny vybrané teoretické a praktické aspekty elektrického zvlákňování. Ve druhé části jsou uvedeny vybrané patenty a užitné vzory, které vznikly na základě pozorování a závěrů ze zkoumání elektrického zvlákňování. The work is divided into two parts. The first section describes selected theoretical and practical aspects of electrospinning. In the second part are selected patents and utility models that originated on the basis of the observations and conclusions of the investigation of electrospinning.
- ItemProduction of poly (epsilon-caprolactone) Antimicrobial Nanofibers by Needleless Alternating Current Electrospinning(2019) Manikandan, Sivan; Divyabharathi, Madheswaran; Lukáš, David; Pokorný, PavelThe present study is focused on the fabrication of antimicrobial polycaprolactone (PCL) nanofibers using uncommon needleless and collector less alternating current (AC) electrospinning. The PCL polymeric solutions (6 & 12 wt.%) were prepared using 1:1 acetic acid and formic acid. The antimicrobial agent chlorhexidine (CHX) was added to the PCL precursor solution at 1 wt%. The PCL/CHX solutions (6 & 12 wt.%) were electrospinnable at the applied AC potential of 25kV and 35kV rms. The surface morphological investigation of PCL/CHX antimicrobial nanofibers confirmed that smooth beadless nanofibers have been obtained. Fiber diameter and viscosity were increasing with respect to PCL/CHX concentrations.
- ItemStudie využitelnosti nanomateriálů při konstrukci a výrobě sportovních míčů(Technická Univerzita v Liberci, 2013) Burgetová, Zuzana; Pokorný, PavelDiplomová práce se zabývá studií využitelnosti nanomateriálů při konstrukci a výrobě sportovních míčů společnosti GALA a.s. V teoretické části je proveden průzkum dané problematiky, který zahrnuje analýzu výrobního procesu volejbalových a nohejbalových míčů, definici parametrů volejbalových a nohejbalových míčů. V této části diplomové práci je podrobně zhotovena literární a patentová rešerše na téma: Nano v míči a Nano ve sportovních potřebách využívaných po celém světě. Praktická část obsahuje popis a výsledky zkoušek prováděných s použitím nanomateriálů při výrobě volejbalových a nohejbalových míčů. Na základě porovnání výsledků experimentu s poznatky získanými v teoretické části, jsou v samotném závěru práce navrhnuta možná teoretická východiska daného řešeného problému.
- ItemStudy of polycaprolactone wet electrospinning process(Budapest Univ Technol & Econ, 2014) Košťáková, Eva; Seps, M.; Pokorný, Pavel; Lukáš, DavidWet electrospinning is a useful method for 3-dimensional structure control of nanofibrous materials. This innovative technology uses a liquid collector instead of the metal one commonly used for standard electrospinning. The article compares the internal structural features of polycaprolactone (PCL) nanofibrous materials prepared by both technologies. We analyze the influence of different water/ethanol compositions used as a liquid collector on the morphology of the resultant polycaprolactone nanofibrous materials. Scanning electron micro-photographs have revealed a bimodal structure in the wet electrospun materials composed of micro and nanofibers uniformly distributed across the sample bulk. We have shown that the full-faced, twofold fiber distribution is due to the solvent composition and is induced and enhanced by increasing the ethanol weight ratio. Moreover, the comparison of fibrous layers morphology obtained by wet and dry spinning have revealed that beads that frequently appeared in dry spun materials are created by Plateau-Rayleigh instability of the fraction of thicker fibers. Theoretical conditions for spontaneous and complete immersion of cylindrical fibers into a liquid collector are also derived here.