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Characterization of optical fiber after surface modification
Anuj Shukla; vedoucí práce Rajesh Mishra
2012 - English
Optical fibers have been used principally for data transmission, since it offers fast connectivity, low cost, and high resistance to damage. The purpose of this research was not to evaluate the data capabilities of plastic optical fibers (POF) which transmits axially, but rather to exploit the ability of the fiber emit light through the side of the fiber.The uses of side emitting fibers in textile would prove to beneficial in several ways, few of them being the flexibility of the fiber for integration into fabrics, and possibly to mask this fiber like all others, with the aid of classical textile dyeing methods. The POF, with trade name Flexi was used in this case, because of its flexibility, and variation in diameters available on the market.Flexi cores were stripped from its cladding, and were dyed using a disperse dye, under various conditions including changing in dye concentration and dye time. Samples were then analysed for side emission of light with the use of Prototype 1, which was an instrument specifically designed for the measurement of this nature. The results showed that the dye penetration is dependent on the dye time, if dye concentration and temperature are kept constant. After 40minutes of dyeing, the fiber core showed an increase in side emission, with lower loss due to attenuation. Also excessive time in the hot conditions degraded the fiber, such that the fiber became very stiff and brittle.Fibers were also subjected to heat, in the form of boiling water bath, for selected periods of time, and it was found that the effect was similar to that of the prior experiments.Surface treatment of Flexi fibers were carried out using ethyl acetate as an etching agent, to possibly accept more disperse dye on the fibers surface. The results after dyeing showed a more than significant improvement in both side emission and attenuation of light. The influence of the illuminating source of the fiber also proved to be important, such that the side emission is dependent on the temperature of light from the source.
Keywords:
optická vlákna; barviva; barvení textilií
Available to registered users in the Library of TUL
Characterization of optical fiber after surface modification
Optical fibers have been used principally for data transmission, since it offers fast connectivity, low cost, and high resistance to damage. The purpose of this research was not to evaluate the data ...
Effects of temperature on sorption process using nanofibrous membrane
Paul Sicelo Ngcobo; vedoucí práce Jakub Wiener
2012 - English
The release of dyes into the environment only contributes a small proportion of water pollution but due to dye brilliance, they are visible even in very small quantities such that the control of water pollution has become of high importance nowadays. Government legislations are therefore forcing dye using industries to treat their effluent to high standards. Colour removal by conventional treatment methods such as ozonation, bleaching, hydrogen peroxide/UV, electrochemical techniques are not adequate due to the fact that most textile dyes have complex aromatic molecular structures that resist degradation. The research has shown that the use of membrane filtration can be an alternative for low cost treatment methods. In this study membrane made of electrospun polyamide 6 nanofibres is used in order to investigate the effects of increasing temperature on dye removal (sorption) using sorption filtration method. C.I Acid blue 41, C.I Acid yellow 42 and C.I Acid blue 78 were used to determine the accumulated mass of each on the electrospun polyamide 6 nanofibre membrane, using the temperatures of between 20 °C and 60 °C. The accumulated mass could decrease with the increase in temperature till the glass transition temperature of the membrane such that above this temperature the accumulation of dye was increased. All the results were based on spectrophotometric analysis and also the SEM was used for image analysis in order to analyze the effects of increasing temperature on the surface of the membrane. All the dyes tested could follow the Langmuir isotherm such that the curves for the experiments and the ones for Langmuir isotherm were comparable with very small differences. The results also show that C.I Acid Blue 41 had the highest values of sorption capacity compared to Acid Blue 78 and Acid Yellow 42, this was because of the highest saturation value (S) compared to the other two. Determination of sorption capacity at equilibrium was tested after a period of 10 days with increasing mass of fibre from 1 piece up to 10 pieces of 30mm x 30mm nanofibrous membrane with constant concentration and volume of solutions used.
Keywords:
textilní chemie; nanovlákna; nanotechnologie; elektrostatické zvlákňování; spektrofotometrie
Available to registered users in the Library of TUL
Effects of temperature on sorption process using nanofibrous membrane
The release of dyes into the environment only contributes a small proportion of water pollution but due to dye brilliance, they are visible even in very small quantities such that the control of water ...
Biotechnology in Textile Pre-treatment
Siviwe Artwell Mfuywa; vedoucí práce Michal Vik
2011 - English
The cellulases of the soft-rot fungus. Trichoderma reesei are the most studied and understood of all cellulolytic systems. Cellulases are used for modification of cellulosic fibres and fabrics, e.g. cotton, viscose and lyocell, yielding properties such as stonewashing, peach-skin and biofinishing effects. Cellulases are usually applied as multi-component enzyme systems and most of the commercial cellulases contain a variety of different activities. The cellulolytic system of T. reesei is composed of two cellobiohydrolases (CBHI and CBHII), at least six endoglucanases and two -glucosidases. Cellulases are known to act synergistically in the hydrolysis of crystalline cellulose. Endoglucanases randomly attack the amorphous regions in cellulosic substrates, whereas cellobiohydrolases can also act the crystalline regions of cellulose, releasing cellobiose from the ends of cellulose chain. In the present investigation, purified T. reesei cellulases CBHI, CBHII, EGI and EG II were used to treat different types of cotton fabrics in order to evaluate the effects of individual mono-component cellulases on cotton properties. By comparing the impact of mono-component cellulases on cotton twill and poplin woven fabrics and interlock knitted fabric; it became apparent that cellobiohydrolases and endoglucanases have different effects on the tested fabrics.
Keywords:
textilní chemie; biotechnologie
Available to registered users in the Library of TUL
Biotechnology in Textile Pre-treatment
The cellulases of the soft-rot fungus. Trichoderma reesei are the most studied and understood of all cellulolytic systems. Cellulases are used for modification of cellulosic fibres and fabrics, e.g. ...
Sorption processes in nanofibres
Sihle Ntaka; vedoucí práce Jana Šašková
2011 - English
With the increasing concern of colour removal from wastewater before discharging it to the environmental rivers and with the knowledge of sorption process as being the only process so far which can remove dyes effectively on wastewater, however the current sorbent materials used in this process are expensive. This yield attention in finding cheaper sorbent material that would be able to solve the current latter. Recently there has been much attention paid to nanofibers as alternative sorbents because of the high surface area they propound. In this study electrospun polyamide 6 nanofibers were used as the sorbent material to remove colour of dyes in the simulated wastewater concentration of textile industries, using sorption-filtration method which was able to remove dye in relatively short time since the system was under vacuum pressure and the sorbent thickness by adding more nanofiber layers was tested, where it was concluded that the percentage of dye removal increases if the thickness (more nanofiber layers) of sorbent was increased. The presented process has more potential in dye removal studies because the sorbent (nanofilter) was protected from mechanical damage and it possible to perform many experiments in short time.The sorption properties of nanofibers were also tested by kinetics experiments and equilibrium experiments where two substrate of polyamide 6 (standard fibres and nanofibers) were compared in both experiments. The Cegarra-Punte was the best fit theoretical model to describe kinetics experiments, where Langmuir isotherm was the best model for describing equilibrium experiments. With Langmuir saturation constant S it was concluded based on the obtained result that nanofibers had 10 time higher saturation value when compared to standard fibres which was explained by the high surface area that nanofibers offer. The diffusion coefficient was also used to further study the sorption properties of the two substrates.
Keywords:
textilní chemie; nanotechnologie; nanovlákna
Available to registered users in the Library of TUL
Sorption processes in nanofibres
With the increasing concern of colour removal from wastewater before discharging it to the environmental rivers and with the knowledge of sorption process as being the only process so far which can ...
Finishing of basalt fibres
Nkululeko Muzi Patrick Dlamini; vedoucí práce Jakub Wiener
2011 - English
Basalt fibre (BF) is a material made from extremely fine fibres of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. It is almost similar to its mineral fibre counterparts, like carbon fibre and glass fibre, having better physical mechanical properties than glass fibre, but being significantly cheaper than carbon fibre. In this study a series of investigations are conducted, to explore and develop other techniques which could be useful for basalt fibre finishing. The first investigation is piloted by qualitatively analysing the atomic element(s) composition of basalt fibre, with a use of Laser-Induced Breakdown Spectroscopy (LIBS). The inter-facial interaction relationship between basalt fibre, acids and alkalis is also explored as a means to determine the degree of BF resistance against corrosion. An attempt to modify BF surface properties is conducted by means of IR laser (CO2 laser) irradiation. A degree of BF surface damage due to different CO2 laser beam intensity levels is classified accordingly. An attempt to deposit carbon on BF surface, by IR laser method is explored. Lastly, a carbon matrix (C-matrix) is prepared from different concentrates of sucrose solution. This C-matrix is then used as a binding resin for BF reinforced composite material. Porous carbon composites rods (carbon electrode) are produced and tested for electrical conductivity, mechanical properties and thermo stability. To assess and evaluate properties of the specimens prepared, the following instruments are used: Scanning Electron microscopy (SEM), Tera 2300 mechanical tester, X-ray florescence (XRF), and Dynamic mechanical analyser (DMA).
Keywords:
textilní chemie; chemická technologie
Available to registered users in the Library of TUL
Finishing of basalt fibres
Basalt fibre (BF) is a material made from extremely fine fibres of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. It is almost similar to its mineral fibre counterparts, ...
Rozvoj komunikační kompetence prostřednictvím vhodných jazykových podnětů
Radim Rybáček; vedoucí práce Renata Šimůnková
2011 - English
Mnoho učitelů cizího jazyka zasvětilo své životy honbě za ideálním přístupem nebo metodologií k výuce cizího jazyka. Mezi lingvisty proběhla živá diskuze, jestli je možné osvojení cizího jazyka, podobně jako je osvojen jazyk mateřský. Současné kurikulární dokumenty, například Společný evropský referenční rámec,schvalují, s určitými omezeními, myšlenku osvojení a popisují jazyk jako sadu kompetencí, které mohou a mají být využity pro uskutečnění komunikačních úkolů. Tato práce obsahuje tvrzení, že odpovídající jazykové podněty mohou použité pro rozvoj komunikačních kompetencí mohou do značné míry nahradit formální jazykové instrukce a vědomé učení. Tento projekt, který pracoval s takovými faktory jako je afektivní filtr, motivace nebo jazykové portfolio potvrdil na základě reflexí a vyhodnocení jazykového portfolia a psaných a mluvených výstupů, že komunikativní kompetence může být osvojena, když jsou poskytnuty odpovídající jazykové podněty. Role formálních jazykových instrukcí a vědomého učení se dá omezit.
Keywords:
komunikační dovednosti; jazyková výuka; angličtina
Available to registered users in the Library of TUL
Rozvoj komunikační kompetence prostřednictvím vhodných jazykových podnětů
Mnoho učitelů cizího jazyka zasvětilo své životy honbě za ideálním přístupem nebo metodologií k výuce cizího jazyka. Mezi lingvisty proběhla živá diskuze, jestli je možné osvojení cizího jazyka, ...
Experimental model of electromechanical unit of vehicle driving direction
Dumitru Bambuleac; vedoucí práce Elias Tomeh
2011 - English
Daná diplomová práce se zaobírá úpravou stávající jednotky řízení vozu a vytvořením matematického modelu pro její ovládání, včetně následného měření parametrů. Jde o konstrukční úlohu, jejíž výsledky mohou být následně použity pro další vývoj v oblasti experimentálních systémů řízení vozidla.
Keywords:
elektrické pohony; elektrické motory
Available to registered users in the Library of TUL
Experimental model of electromechanical unit of vehicle driving direction
Daná diplomová práce se zaobírá úpravou stávající jednotky řízení vozu a vytvořením matematického modelu pro její ovládání, včetně následného měření parametrů. Jde o konstrukční úlohu, jejíž výsledky ...
Language and Content Learning Integration in Lower - Secondary EFL Classes
Hana Dujčáková; vedoucí práce Zuzana Šaffková
2011 - English
Tato diplomová práce se zabývá vlivem integrace obsahového a jazykového vzdělávání (Content and Language Integrated Learning - CLIL) na motivaci žáků druhého stupně. Cílem je dokázat, že zařazení CLILu do výuky na druhém stupni pozitivně ovlivňuje přístup žáků k jazykové výuce angličtiny, aniž by negativně ovlivnil efektivitu obsahové výuky.Poznatky z teoretické oblasti této práce byly aplikovány v praktickém výzkumu, do kterého bylo zapojeno 21 žáků šesté a 12 žáků deváté třídy. V praktickém šetření byla gramatika a slovní zásoba anglického jazyka vyučována na základě vybraných témat z občanské výchovy a zároveň poznatky z občanské výchovy byly uvedeny i upevňovány v anglickém jazyce. Tento způsob výuky, založený na logické integraci obsahu a jazyka, představuje alternativu k tradičnímu přístupu k výuce a poskytuje žákům možnost poznat smysluplný a podnětný způsob učení.Výsledky získané ve výzkumu jsou založeny na analýze dat z dotazníku, pozorování a na ústní zpětné vazbě od zúčastněných žáků. Tyto výsledky dokazují, že CLIL má pozitivní vliv na motivaci a tím i na aktivní přístup k výuce žáků druhého stupně. Také efektivita CLILu byla potvrzena.
Keywords:
jazyková výuka; angličtina
Available to registered users in the Library of TUL
Language and Content Learning Integration in Lower - Secondary EFL Classes
Tato diplomová práce se zabývá vlivem integrace obsahového a jazykového vzdělávání (Content and Language Integrated Learning - CLIL) na motivaci žáků druhého stupně. Cílem je dokázat, že zařazení ...
Využití aktivit zařazených do úvodní části hodiny ke zlepšení výuky anglického jazyka
Veronika Machová; vedoucí práce Marcela Malá
2011 - English
Diplomová práce "Využití aktivit zařazených do úvodní části hodiny ke zlepšení výuky anglického jazyka" se zabývá zahřívacími aktivitami v hodinách anglického jazyka s cílem rozvíjet motivaci a koncentraci studentů, a tak zlepšit proces učení. V teoretické části je zahřívací aktivita představena jako mocný nástroj ve výuce anglického jazyka. V této části se také podrobně pojednává o motivaci a koncentraci. V praktické části je představeno pět učebních plánů se zahřívacími aktivitami. Z výsledků založených na analýze odučených hodin vyplývá, že dobře připravená zahřívací aktivita může vyvolat motivaci, upoutat pozornost žáků, a tudíž vede k lepším výsledkům v procesu učení.
Keywords:
angličtina; jazyková výuka
Available to registered users in the Library of TUL
Využití aktivit zařazených do úvodní části hodiny ke zlepšení výuky anglického jazyka
Diplomová práce "Využití aktivit zařazených do úvodní části hodiny ke zlepšení výuky anglického jazyka" se zabývá zahřívacími aktivitami v hodinách anglického jazyka s cílem rozvíjet motivaci a ...
Laser light treatment of glass fibres
Makabongwe Mkhululi Goba; vedoucí práce Jakub Wiener
2011 - English
Glass fibres have many industrial applications such as filtration media and composite materials. Glass fibre applications are generally based on the type of glass fibre, constitutional composition, and the structural ordering of the glass fibres in the final structure, such as nonwoven glass fibre mats used as filtration media. Nonwoven glass fibre mats may be available in variable thickness dimensions. Glass fibre is a dielectric material and is therefore able to absorb energy from a carbon dioxide laser light beam. The carbon dioxide laser produces many watts in a single spatial mode that is then concentrated on a small area. The energy produced is in the thermal infrared region at approximately 10.6?m. When glass fibres absorb heat energy from the carbon dioxide laser beam they heat up, melt and then change definition, depending on the amount, rate and how the energy is applied. The main objective of this research was to determine the thermal effects caused by the laser light beam produced by the carbon dioxide laser on the glass fibre mat, and to determine incorporation of metal oxides during laser light beam treatment
Keywords:
textilní chemie; chemická technologie; lasery; skleněná vlákna
Available to registered users in the Library of TUL
Laser light treatment of glass fibres
Glass fibres have many industrial applications such as filtration media and composite materials. Glass fibre applications are generally based on the type of glass fibre, constitutional composition, ...
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