Browsing by Author "Lukáš, David"
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- ItemA 2-Dimensional Model Of The Mechanical-Properties Of Textiles(Textile Inst Intl Headquarters, 1993-01-01) Jirsák, Oldřich; Lukáš, David; Charvát, RichardA two-dimensional model of the mechanical properties of textiles is constructed, and the relations between model parameters and model behaviour are studied. The influence of the number of bonding sites in the model on stress-strain curves, on the CPU time consumption, and on the stability of model outputs is described. The methodology of computer-simulation methods in the study of textile mechanics is discussed.
- Item3rd Workshop on Mechanics of Nanomaterials – Nanomaterials, Electrospinning Processes; Theory and Application(2022-12-13) Lukáš, DavidSborník s názvem „3rd Worshop on Mechanics on Nanomaterials—Nanomaterials, Electrospinning Processes; Theory and Application“ obsahuje 13 příspěvků, které byly prosloveny na setkání v Kryštofově Údolí dnech 15 - 16 června 2022. Setkání se konalo pod záštitou České společnosti pro mechaniku (expertní skupina mechaniky nanomateriálů), University of Alabama at Birmingham a Technické univerzity v Liberci. Příspěvky ve sborníku je možné rozdělit do následujících skupin: Vývoj nanomateriálů včetně jejich testování, studie mechanismů produkce nanovlákenných materiálů a vývoj technologií a zařízení pro výrobu nanomateriálů. Annotation: Thirteen contributions were addressed at the meeting in Kryštof Valley on June the 15th – 16th, 2022. They are involved in the proceedings entitled “3rd Worshop on Mechanics on Nanomaterials—Nanomaterials, Electrospinning Processes; Theory and Application ". The workshop was held under the auspices of the Czech Society for Mechanics (expert group - Mechanics of Nanomaterials), Uni-versity of Alabama at Birmingham and Technical University of Liberec. The contributions can be divided into the following groups: development of nanomaterials including their testing, description of phenomena related to the production of nanofibrous materials and development of technologies and equipment for the production of nanomaterials.
- ItemAktualizace dlouhodobého záměru Technické univerzity v Liberci pro rok 2001(Technická univerzita v Liberci, 2000-01-01) Lukáš, David; Rektorát TUL
- ItemAktualizace dlouhodobého záměru Technické univerzity v Liberci pro rok 2002(Technická univerzita v Liberci, 2001-01-01) Lukáš, David; Rektorát TUL
- ItemAktualizace dlouhodobého záměru Technické univerzity v Liberci pro rok 2003(Technická univerzita v Liberci, 2002-01-01) Lukáš, David; Rektorát TUL
- ItemBiochemical and biophysical aspects of collagen nanostructure in the extracellular matrix(Technická Univerzita v Liberci, 2007-01-01) Koláčná, Lucie; Bakešová, J.; Varga, Ferdinand; Košťáková Kuželova, Eva; Plánka, Ladislav; Nečas, Alois; Lukáš, David; Amler, Evžen; Pelouch, VáclavECM is composed of different collagenous and non-collagenous proteins. Collagen nanofibers play a dominant role in maintaining the biological and structural integrity of various tissues and organs, including bone, skin, tendon, blood vessels, and cartilage. Artificial collagen nanofibers are increasingly significant in numerous tissue engineering applications and seem to be ideal scaffolds for cell growth and proliferation. The modern tissue engineering task is to develop three-dimensional scaffolds of appropriate biological and biomechanical properties, at the same time mimicking the natural extracellular matrix and promoting tissue regeneration. Furthermore, it should be biodegradable, bioresorbable and non-inflammatory, should provide sufficient nutrient supply and have appropriate viscoelasticity and strength. Attributed to collagen features mentioned above, collagen fibers represent an obvious appropriate material for tissue engineering scaffolds. The aim of this minireview is, besides encapsulation of the basic biochemical and biophysical properties of collagen, to summarize the most promising modern methods and technologies for production of collagen nanofibers and scaffolds for artificial tissue development. © 2007 Institute of Physiology, v. v. i., Academy of Sciences of the Czech Republic.
- ItemBiofyzika I(2020-01-01) Lukáš, David; Trčka, Michal; Kuželová Košťáková, Eva; Jenčová, Věra; Asatiani, NikiforCílem projektu je vytvoření učebního textu (skript) k novému předmětu Biofyzika v rámci nově akreditovaného SP Bioinženýrství.
- ItemComputer simulation of liquid wetting dynamics in fiber structures using the Ising model(Textile Inst, Manchester, United Kingdom, 1997-01-01) Lukáš, David; Glazyrina, Elena; Pan, NingWe present in this paper a method which applies the so-called Ising model and Kawasakithermodynamics, combined Mith the Monte Carlo computer simulation technique to studythe liquid-Hber interaction and the wetting behavior of Tiber networks.The various types of interactions occurrin;^ during a wetting process in a fiber mass areanalyzed, and their individual contributions towards the Hamiltonian system are derived.The criterion for energy state exchange between the Ising spin variables is given as the criticalstep for the wetting simulation.The procedures of the simulation algorithm are provided. Various predictions of the wettingprocess including wetting of a fiber network, the spreading of a liquid drop on a single Tiberas well as a brief parametric study are included in this paper
- ItemCrystallinity of Electrospun and centrifugal spun polycaprolactone fibers: A Comparative Study(HINDAWI LTD, ADAM HOUSE, 3RD FLR, 1 FITZROY SQ, LONDON, W1T 5HF, ENGLAND, 2017-01-01) Kuželová Košťáková, Eva; Blažková, Lenka; Lukáš, David; Mašková, GabrielaCrystalline properties of semicrystalline polymers are very important parameters that can influence the application area. The internal structure, like the mentioned crystalline properties, of polymers can be influenced by the production technology itself and by changing technology parameters. The present work is devoted to testing of electrospun and centrifugal spun fibrous and nanofibrous materials and compare them to foils and granules made from the same raw polymer. The test setup reveals the structural differences caused by the production technology. Effects of average molecular weight are also exhibited. The applied biodegradable and biocompatible polymer is polycaprolactone (PCL) as it is a widespread material for medical purposes. The crystallinity of PCL has significant effect on rate of degradation that is an important parameter for a biodegradable material and determines the applicability. The results of differential scanning calorimetry (DSC) showed that, at the degree of crystallinity, there is a minor difference between the electrospun and centrifugal spun fibrous materials. However, the significant influence of polymer molecular weight was exhibited. The morphology of the fibrous materials, represented by fiber diameter, also did not demonstrate any connection to final measured crystallinity degree of the tested materials.
- ItemDlouhodobý záměr Technické univerzity v Liberci 1999 - 2005(Technická univerzita v Liberci, 2000-01-01) Lukáš, David; Rektorát TUL
- ItemElectrospun starch-polymer scaffolds for tissue engineering: a brief review(Technická univerzita v Liberci, Česká republika, 2010-01-01) Nugroho, Robertus WN; Lukáš, DavidRůzné biopolymery, například takové, které obsahují škrob nebo acetylovaný škrob, jsou slibnými materiály pro tkáňové inženýrství. Elektrostatické zvlákňování je jedinečnou technologií pro výrobu trojrozměrných biopolymerních tkáňových nosičů. Tkáňové nosiče obsahující směs polymeru a modifikovaného škrobu podporují buněčnou aktivitu, která je důležitá pro aplikaci v regenerativní medicíně.
- ItemElektrostatické zvlákňování na dvoustranném spineru(Technická Univerzita v Liberci, 2007-01-01) Buranská, Mária; Lukáš, DavidThis work is focused on electrostatic field between electrodes of bilateral spinner and is basic on works of Zeleny and Taylor, ....
- ItemElektrostaticky zvlákňované nosiče ze směsí polymerů a škrobů(Technická Univerzita v Liberci, 2013-12-20) Nugroho, Robertus Wahyu Nayan; Lukáš, David
- ItemExperimental fortification of intestinal anastomoses with nanofibrous materials in a large animal model(Nature Research, 2020-01-01) Rosendorf, Jáchym; Horáková, Jana; Klíčová, Markéta; Pálek, Richard; Červenková, Lenka; Kural, Tomáš; Hošek, Petr; Kříž, Tomáš; Tégl, Václav; Moulisová, Vladimíra; Tonar, Zbyněk; Treska, Vladislav; Lukáš, David; Liska, VáclavAnastomotic leakage is a severe complication in gastrointestinal surgery. It is often a reason for reoperation together with intestinal passage blockage due to formation of peritoneal adhesions. Different materials as local prevention of these complications have been studied, none of which are nowadays routinely used in clinical practice. Nanofabrics created proved to promote healing with their structure similar to extracellular matrix. We decided to study their impact on anastomotic healing and formation of peritoneal adhesions. We performed an experiment on 24 piglets. We constructed 3 hand sutured end-to-end anastomoses on the small intestine of each pig. We covered the anastomoses with a sheet of polycaprolactone nanomaterial in the first experimental group, with a sheet of copolymer of polylactic acid with polycaprolactone in the second one and no fortifying material was used in the Control group. The animals were sacrificed after 3 weeks of observation. Clinical, biochemical and macroscopic signs of anastomotic leakage or intestinal obstruction were monitored, the quality of the scar tissue was assessed histologically, and a newly developed scoring system was employed to evaluate the presence of adhesions. The material is easy to manipulate with. There was no mortality or major morbidity in our groups. No statistical difference was found inbetween the groups in the matter of level of peritoneal adhesions or the quality of the anastomoses. We created a new adhesion scoring system. The material appears to be safe however needs to be studied further to prove itsʹ positive effects.
- 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.
- ItemFyzika polymerů(2013-01-01) Lukáš, David; Raab, Miroslav; Vysloužilová, Lucie; Košťáková, Eva; Mikeš, Petr
- ItemFyzikální principy tvorby nanovláken I(2015-01-01) Mikeš, Petr; Lukáš, David
- ItemJehlové koaxiální elektrostatické zvlákňování(Technická Univerzita v Liberci, 2012-01-01) Baláž, Ladislav; Lukáš, DavidThe thesis deals with the production of nanofibres through coaxial electrospinning. The theoretical part of the work focuses on the description of the issue. First, the principle of coaxial electrospinning is clarifid, lastly material and technological conditions of the process are described. The next part focuses on finding the appropriate analytical methods for the evaluation of nanofibrous structures. Experimental part concerates on the production of core/shell nanofibres using coaxial electrospinning. For these purposes has been designed and tested zvlákňovací equipment for surface coaxial electrostatic melt spinning.
- ItemKoaxiální zařízení pro elektrostatické zvlákňování a jeho uplatnění pro vývoj tkáňových nosičů(Technická Univerzita v Liberci, 2009-01-01) Michalová, Adriána; Lukáš, DavidThis final work deals with a research of coaxial electrostatic spinning and his connection with use nanofibers in tissue engineering. The first part of the final work describes basic theoretical findings associated with the existing subject. The experimental part of this thesis is focused with the construction of coaxial electrospinning and further on, it is oriented on the production of bi-component nanofibers by using electrostatic coaxial electrospinning
- ItemModeling liquid transport in fibrous structures: An multi-scale approach(Technická Univerzita v Liberci, 2006-01-01) Zhong, Wen; Pan, Ning; Lukáš, DavidThe Ising model combined with Kawasaki dynamics is applied in modeling liquid transport in fibrous materials. This meso-scale approach is especially useful in the study of materials with characteristic length scale in the range of nano- and micrometers, where conventional continuum mechanics approach is no longer valid. The technique presented in this paper represents an attempt for cross-scale modeling of physical phenomena to bridge the gap between macro behavior of a heterogeneous material system and those of its basic constituent particles. The transition from one scale to another is carried out by the so called "hand-shaking strategy." Copyright © 2006 American Scientific Publishers All rights reserved.
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