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Dissertations / Theses on the topic 'Uhlíkový kompozit'
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1
Rubíček, Pavel. "Návrh palivového systému formulového vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231771.
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The fuel system is a very important part of the vehicle and the engine. The main function is to deliver the fuel- air mixture into the engine cylinder. This thesis describes the design of the Formula student car fuel system. The first part is an introduction to Formula Student competitions. The next section describes the options of the fuel systems structure and options for individual components. Those rules limit the possibilities for us FSAE that in the next chapter. The following parts are major chapters dealing with the actual design of the fuel system and analysis of selected components. The last part are chapters that deal with the production possibilities of parts and subsequent incorporation into the fuel system of the car.
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Bednár, Peter. "Návrh upravené technologie navíjení kompozitních trubek." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241838.
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This diploma thesis focuses on composite pipes production by winding of composite fibres soaked in resin binder and feeding with additional third type material simultaneously. It also describes the production machine FWMS180 and all of its additional devices necessary for the composites production by filament winding. The production process of composite pipes on the production machine FWMS180 is described in this paper as well as detailed description of the winding method. Furthermore, the technological bend and vibration tests procedures conducted on pipes of different material composition are discussed with related results and comparison. The thesis proves that presence of the third type material in composite pipes structure has different influence depending on observed and evaluated property.
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Vodička, Vít. "Interlaminární lomová houževnatost vláknových kompozitních materiálů s polymerní matricí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231461.
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Cílem této diplomové práce je lépe porozumět konceptu únavového poškození damage tolerance zmapováním všech možných vlivů na lomovou houževnatost vláknového kompozitu s polymerní matricí. Toho je dosaženo provedením zkoušek za různých podmínek (např. změna parametrů měření, mód zatížení, pořadí vrstev a materiál) a monitorováním odlišností v šíření trhliny. Na základě dat získaných během těchto testů je určena lomová houževnatost. Potenciální rozdíly jsou zkonzultovány a porovnány s ostatními vzorky.
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Kuběna, Martin. "Zpevnění polymerních kompozitů uhlíkovými nanotrubkami." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230848.
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This diploma thesis focuses on the influence of carbon nanotubes (CNTs) on the mechanical properties of a composite material with polyurethane (PU) matrix. The material was supplied in the form of thin films with thickness from 0.2 mm to 1.2 mm. The theoretical part of this thesis describes the production technology, properties and applications of composite materials PU/CNTs, and also deals with preparation technology and properties of both components of this composite material separately. The theoretical part also describes the principle of tensile testing of polymer materials. The experimental part of the thesis was primarily focused on comparing the tensile properties of a composite material PU/CNTs with tensile properties of pure PU. At first, tensile properties of pure PU were investigated, while the influence of various factors like strain rate, specimen thickness, heat treatment and aging was examined. In adition, stress relaxation tests and tests with strain rate jumps were performed on pure PU specimens. Then composite PU/CNTs was tested in tension and the results were compared with the results of tensile tests of pure PU. Composite material PU/CNTs was prepared with various concentrations, so it was possible to determine the effect of CNTs content on the tensile properties of the composite. The last part of this thesis deals with tensile tests of PU composite material with functionalized carbon nanotubes (PU/FCNTs), where the influence of surface modification (functionalization) of CNTs on the tensile properties composites was investigated. It was shown that the effect of both CNT and FCNT on mechanical properties of the composite is not significant. This conclusion was discussed on basis of the works of other authors, which do not unambiguously proved the positive effect of CNT or FCNT on mechanical properties of composites with polymer matrix.
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Přikryl, Pavel. "Technologie výroby uhlíkových kompozitů lisováním za tepla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402530.
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This master’s thesis deals with the composite materials and especially aims on the carbon and glass fiber composites. It points out different composition types and manufacturing methods which reflect in the different mechanical properties, final quality of the manufactured part and also in the manufacturing time. The practical part includes two particular manufacturing methods using prepregs, one cured in an autoclave and one by hot compression moulding.
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Michalička, Jan. "Lomová houževnatost kompozitu s Al-matricí a uhlíkovými vlákny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228117.
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Abstract The objective of this study was a values evaluation of fracture toughness of fiber-metal laminates (FML) compounded from carbon fibers in epoxy matrix and aluminium plates of lay-up 6/5. Samples with unidirectional and bidirectional orientation were tested experimentally. In the case of unidirectionally oriented samples an effect of moisture absorption to epoxy matrix on the values of fracture toughness was reviewed. A fracture toughness calculation was realized by COD method firstly. A bigger pop-ins in F – COD diagram as critical moments for "delta"c evaluation were considered; it was determined by 5% tangential line. It was found out, that results of this measurement weren’t in agreement with plane deformation condition and for this the results couldn’t be rated as fracture toughness "delta"Ic. A method of J integral for fracture toughness evaluation was used consequently. A test of elastic compliance changes before J integral calculation by all of samples was performed. Beginning of stable grow of crack was determined by this method. A critical forces Fc from beginnings were established, which were used for calculation of Jc. A functional dependence of elastic compliance on crack opening had specific waved shape before its linear (up to exponential) grow. It was observed in all cases. The critical forces Fc from the end of “wave” preceding the continual grow of compliance were determined. Equations stated in standards for J integral calculation were used, which are for metal materials normally used. Despite this was found out all of results of Jc were in good agreement with plane deformation condition and could be rated as fracture toughness JIc. In this study were found out these pieces of knowledge about fracture toughness of FML CARE: Unidirectional CARE had fracture toughness JIc about 76 kJ/m^2 and the same type but with bigger amount of absorbed moisture had JIc about 4 % higher. In this case negative moisture influences on CARE weren’t found. Bidirectional CARE had fracture toughness JIc about 31 kJ/m^2; it was about 65 % less then in the case of unidirectional CARE
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Genco, Ondřej. "Využití uhlíkových kompozitů k pasivnímu chlazení v oblasti kosmického průmyslu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417430.
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The content of the diploma thesis is evaluation of the usability of carbon composites in the space industry. The aim of this work is to assess whether carbon composites can find application in mechanical systems of passive thermal protection of artificial objects. Model examples demonstrate the principle of operation of selected passive thermal protection. The evaluation is realized based on the results of thermal analysis. Analytical formulas from field theory of heat transfer are used as a calculation method. The diploma thesis consists from two parts. The theoretical part briefly describes the mechanisms of heat transfer, selected types of passive thermal protection and properties and applications of carbon composites. The practical part consists of the assignment, calculation and evaluation of three examples. The results show that carbon composites can compete with commonly used materials for specific requirements.
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Šimko, Lukáš. "Vliv ohybového namáhání na elektrické vlastnosti alkalicky aktivovaných struskových kompozitů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372061.
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Ordinary concrete is the most commonly used building material, but nowadays the requirements for low energy consumption, durability of structures together with their easy diagnostics as well as ecological production raises. This thesis deals with cement and aluminosilicate composites with content of conductive fillers, which allows to monitor the change in electrical properties, most commonly electrical resistance in dependence on mechanical stress. In the experimental part of the thesis, test beams were produced based on alkali-activated slag with content of carbon nanotubes, graphite powder, carbon black and carbon fibre. The beams were subjected to flexural loading in a three-point bending configuration and the shift in electrical resistance was monitored.
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Míková, Maria. "Senzorické vlastnosti alkalicky aktivovaných struskových kompozitů při namáhání v tlaku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392329.
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Production of construction materials requires a large amount of energy. That can be decreased by using of waste materials. This thesis deals with the self-sensing properties of composites. It presents electrical properties of building materials and their measurement. In the experimental part, the influence of conductive fillers on the self-sensing properties of aluminosilicate composites was examined. Test cubes were made of alkali-activated slag with a content of graphite powder, carbon black, carbon fibers, steel fibers or carbon nanotubes. The fractional change in resistence during cyclic compressive loading was monitored.
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Misiurev, Denis. "Strukturální a elektrické vlastnosti PVDF-CNT kompozitu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442593.
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Electrospininig se osvědčil jako jeden z nejpopulárnějších a nejrozšířenějších způsobů výroby vysoce kvalitních vláken s požadovanými parametry. Kvalita a morfologie vyráběných vláken závisí na mnoha parametrů, jako je vlhkost, dávka materiálu, aplikované napětí atd. Omezení keramických piezomateriálů (křehkost, toxicita vzorků obsahujících olovo, obtížnost přípravy složitých tvarů atd.) vynutila výzkum v oblasti piezoelektrických polymerů. Jedním z nich je polyvinylidenfluorid (PVDF). polyvinylidenfluorid může by být připraven v různých formách: tenké filmy, objemové vzorky, vlákna. PVDF vlákna přitahují největší pozornost díky vysoké flexibilitě, nízké hmotnosti, mechanické stabilitě a chemické inertnosti. Vlastnosti PVDF vláken lze zlepšit pomocí doplňujících materiálů: keramické částice, kovové nanočástice, Graphicitové materiály jako jsou oxid Graphicenu nebo uhlíkové nanotrubičky (CNT).
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Škriniarová, Nina. "Mechanická odezva dlouhými vlákny vyztuženého polymerního kompozitu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217024.
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This diploma thesis is focused on monitoring of mechanical response of long-fiber reinforced polymer composite. Main part of this thesis was preparation of long-fiber reinforced composite specimens, on which matrix was reinforced by commercially sized glass fibers. For comparison of properties were prepared specimens reinforced by unsized glass fibers. Apart from preparing specimens reinforced by long glass fibers were prepared specimens contains long carbon fibers. For evaluation of mechanical response of the prepared composite specimen were used flexural test and short beam shear test. Mechanical response was evaluated with universal testing machine ZWICK Z010 and data were processed in OriginPro 8 program. Thanks to evaluation of the mechanical response of the prepared specimens was assessed adhesion to fiber-matrix interface. By examining the mechanical response or adhesion can be assessed efficiency of commercial fiber surface treatment and so standardize measurement to compare other options of surface treatments.
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Zbončák, Marek. "Termoplastické kompozity pro automobilové aplikace." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217008.
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Diplomová práca sa zaoberá prípravou teromplastických kompzoitov s PMMA a PC matricou s potenciálnym využitím v automobilovom priemysle. Ako výstuž boli použité krátke sklenené, uhlíkové a PBO (poly(p-fenylén benzobisoxazol)) vlákna známe pod obchodným názvom Zylon®. Práve do PBO vlákien boli vkladané veľké nádeje vzhľadom na ich ohromujúce mechanické vlastnosti. Vplyv objemového zlomku vlákien na modulu pružnosti, pevnosť a ťažnosť kompozitov bol skúmaný. Experimentálne zistený modul pružností bol porovnaný so semi-empirickým Halpin-Tsai modelom. Prídavok sklenených a uhlíkových vlákien viedol k značnému zvýšeniu modulu pružnosti. Ukázalo sa, že po istej hodnote objemového zlomku dochádza k poklesu pevností kompozitov v dôsledku zvyšujúceho sa počtu defektov. Prídavok PBO vlákien preukázal len nepatrný vystužujúci efekt. Viskoelastické vlastností kompozitov boli skúmané pomocou dynamicko mechanickej analýzy (DMA). Termogravimetrická analýza (TGA), konfokálna laserová rastrovacia mikroskopia (CLSM) a rastrovacia elektrónová mikroskopia (SEM) boli využité k štúdiu štruktúry kompozitov.
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Bartoška, Vojtěch. "Konstrukce rámu jízdního kola z uhlíkových vláken." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449781.
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This work aims to the design of a carbon fiber bicycle frame with production technology suitable for piece production. The work summarizes the methods of production of composite frames and important parameters that must be respected when designing the frame. A Gravel frame was chosen for the design. The frame was designed for production using stainless steel printed lugs with glued composite tubes. The proposed solution was strength tested. The work also contains a design of a production jig for the construction of bicycle frames.
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Pavlík, Ondřej. "Návrh kompozitní objímky rotoru vysokootáčkového rotačního stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382567.
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The diploma thesis focuses on manufacturing carbon fiber and epoxy composite material using filament winding method. Material properties of manufactured composite are ap-proximated using analytical and numerical homogenization models. Calculated material properties are applied to design and evaluate reserve factor of retaining sleeve for high speed brushless permanent magnet synchronous motor. Margin of safety of designed rotor is evaluated using composite failure criteria. Test stand for both static and dynamic testing is designed, static test stand is manufactured and assembled. Static strength test is carried out.
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Kupčák, Radim. "Využití kompozitních materiálů pro konstrukci sportovní optiky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402529.
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In Its first half this master's thesis describes composite materials with carbon fiber reinforced plastics being the main focus point. An overview of production technologies follows. The major objective of the second part of this master's thesis is to design and manufacture a simplified model of an optical device using prepregs.
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Odehnal, Ondřej. "Simulace průrazů kompozitních panelů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318146.
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This master thesis focuses on modelling and simulation of impact tests of composite panels. Simulations and analysis were made by using Finite Element Method in software MSC Patran and Dytran. The first part of the thesis deals with describing the properties of composite panels during impact testing and other cases of impacts on composite structures. Next part deals with the used models and results from Dytran. These results are compared with experimental data from real low-velocity impact tests. Part of the thesis is devoted to impact on panels with the stacking sequences which is supposed to be used for design of air duct for airplane Aero L-39NG.
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Pacltová, Klára. "Ověřování vlastností betonů s nanočásticemi." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392361.
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This diploma thesis deals with the influence of addition of carbon nanoparticles on cement composites. The theoretical part of the diploma thesis is focused on the research of information about carbon nanoparticles, more precisely about carbon nanotubes and graphene oxide. There are summarized methods of dispersing carbon nanotubes and their effects on cement composites. The practical part follows the theoretical part of the research. In the first phase, the correct technique of graphene oxide dispersion was verified. Subsequently, the effects of graphene oxide on the mechanical properties of cement mortars were verified. In the final phase of the diploma thesis, the knowledge gained from the previous part was verified on concrete samples.
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Žídek, Tomáš. "Návrh monokoku formulového vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231441.
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The diploma thesis describes the design of a carbon fiber monocoque Formula Student car according to current rules. The first part is focused on construction solutions of frames used in Formula Student cars. Following is a summary of the important rules for constructing composite monocoque. Subsequently are described composite materials and their properties. The main part of the thesis deals with the structural design of the CAD program and a computational model to simulate the load case in FEM program. The obtained results from the analysis of the monocoque are compared with the values allowed by the rules of Formula Student. In conclusion of this thesis is evaluated the proposed composite monocoque.
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Florián, Pavel. "Studium elektrických a dielektrických vlastností alkalicky aktivovaných aluminosilikátů se zvýšenou elektrickou vodivostí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-393991.
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This dissertation deals with the study of electric and dielectric properties of composite structures on the base of alkali-activated aluminosilicates with admixtures of various carbon particles. These materials fabricated from alkali-activated blast furnace slag, quarz sand, natrium water glass as alkali activator, water, dispersant and small amount of carbon admixture (carbon black, graphite powder, carbon fibers or carbon nanotubes) to increase electric conductivity may be used for example to construction of snow-melting, deicing and self-monitoring systems. Their current-voltage characteristics and impedance spectra were used for determination of electric and dielectric properties of these structures. The equivalent circuits were used for evaluation of impedance spectra. The results were correlated with thermal properties of these structures.
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Flašková, Veronika. "Komunitní centrum Petrovice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409993.
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The subject of diploma project is the design of complex of buildings using hemp lime composite, in English known as Hempcerete. Four detached houses are completed by building of facilities. Buildings have one to three floors. The composite fiercly reduces carbon footprint in building industry. The design is focused on different construction systems using hemp lime composite as a wall filling. Detached houses are made of load bearing timber frame with cast-in-situ hempcrete, building of facilities is made of reinforced concrete with precasted blocks. All buildings are cellarless. Detached houses are shed roofed, building of facilities is gable roofed.
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Začal, Jaroslav. "Mechanické vlastnosti vláknových uhlíkových kompozitů." Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-425060.
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Carbon fibre reinforced composites (CFRP) are construction material, which is viewed as a perspective for its ratio of mechanical properties to weight. In recent years the research was focused on implementing the carbon-based composites among smart materials. Nevertheless, extent and volume of use of these composites in technical practice is still not up to the potential, which this modern material offers. One of substantial reasons is the lack of adequate instruments for continuous manufacturing quality control and for mechanical condition monitoring of ready-made construction parts. For this reason the presented dissertation thesis is focused on effectiveness enhancement of detection of deformation response in composites subjected to mechanical loading with uniaxial tension with employment of passive acoustic emission (AE) detection, optical method for detection of surface deformation fields digital image correlation (DIC) and electron microscopy scanning electron microscopy (SEM). Combination of used methods proved as a robust instrument for identification and monitoring of entire degradation process in composite material in course of mechanical loading.
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Bergerová, Michaela. "Stanovení indikanu na uhlíkové pastové elektrodě a uhlíkové kompozitní elektrodě." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-356149.
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This thesis is focused on the application of two working electrodes of graphite suitable for determination of oxidizable tumour biomarkers. It deals with the study of electrochemical behavior of urinary indican. For the determination the technique of differential pulse voltammetry (DPV) was used on carbon paste electrode and film composite paste electrode in Britton-Robinson (BR) buffer. In the first step optimal conditions were determined to find the lowest limit of determination (LQ) of this substance. BR buffer of pH 3 was chosen as the optimum medium for determination on a carbon paste electrode and BR buffer of pH 2 was used as the optimum medium for the determinaton using a film composite electrode. Performance for both electrodes was observed in a concentration range of from 1 · 10-6 to 5 · 10-5 mol·l-1 . The limit of determination for measurements on a carbon paste electrode was 0.7 µmol·l-1 and the film composite electrode was 1.7 µmol·l-1 . Possibility of the acummulation of indican was examined in order to increase sensitivity and decrease of limit of quantification. However, after 5 minute sorption, no increase in response was observed and the accumulation step was not inserted. Developed method was tested on the determination of urinary indican in human urine matrix after solid phase...
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Jelínková, Vendula. "Vliv tepelné modifikace na mechanické vlastnosti kompozitu dřevo - uhlíková vlákna." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-90888.
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Pomp, Radek. "Analýza možností uplatnění kompozitního uhlíkového materiálu v nábytkářském průmyslu." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-88550.
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Vlach, Marek. "Hydrofoil pro kiteboarding -- návrh a výroba segmentu." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-361933.
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This work is about relation between material and technology for developing specific product used in field of sport equipment. Designed was mast or hydrofoil for kiteboarding. Basic part is about terminology, history, physical principle and actual market research. Next topic is related whit material selection, where is best choice carbon fiber reinforced composite. A description of composites goes from general information to specific steps in technology. Author describes practical experiences whit exclusive autoclave technology and also other methods. In practical part was prepared three prototypes whit deferent composition and technology. Core and moulds was made from wooden based materials which ware manufactured in three dimensions whit CNC machine. Fist prototype was laminated only on core, second used sandwich construction in mould and third combines these two methods.
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Bavol, Dmytro. "Prozkoumání možnosti využití uhlíkové kompozitní elektrody jako disposabilního senzoru při stanovení pesticidů." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-323437.
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In this master's thesis electrochemical determination of cymoxanil and famoxadone was performed on different types of electrodes. The work was focused on finding out optimal conditions for determination of these analytes in aqueous environments by differential pulse voltammetry (DPV) using a composite fiber rod electrode (CFRE), a glassy carbon electrode (GCE) and a capillary carbon paste electrode (CPE). Cymoxanil/famoxadone shows in aqueous environment BR buffer - methanol (9:1) single peak, whose position and height depends on the pH. As pH optimum for CFRE in the cathodic potential range for cymoxanil, pH 4 was chosen, the GCE was chosen pH 7 in the anodic area for famoxadone monitored by the GCE was chosen pH 4, pH 2 was chosen for the CPE. Under the optimal conditions, repeatability in oxidation and reduction area was verified. The optimum conditions of cymoxanil determination on CFRE and famoxadone determination on CPE were utilized for the measurement of the calibration curves. The second set of calibration curves was measured with addition of cymoxanil/famoxadone. Newly developed voltammetric methods were used for the determination of cymoxanil and famoxadone in samples of river water and soil.
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Marek, Michal. "Vývoj a analýza kombinovaného vrstveného materiálu." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-428016.
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The diploma work is focused on the development and analysis of plywood material reinforced by means of synthetic fibers, namely on its mechanical properties in a three – point bend in compliance with the CSN EN 310 Standard in comparison with the conventional plywood. At first, the mechanical properties of the material were simulated with the aid of a computer-aided model on the basis of the classical laminate theory and then compared to the real measured values. In addition to it, the influence of preloaded fibers on the mechanical properties of the composite was examined. To preload the fibers, two simple fixtures were manufactured. The analysis of variance and the Tukey’s test of multiple comparison demonstrated important differences in the resistance and rigidity of the plywood material both with the reinforcement and without it. The highest resistance proved the plywood samples without any reinforcement (at an average of 153.9 MPa), the highest rigidity was achieved in samples with reinforcement without any preloading (at an average of 29374.4 MPa).
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Němeček, Václav. "Monitoring degradačních vlastností karbonu." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-430267.
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In the diploma thesis there was made an attempt to compare the samples of carbon fiber composite materials (carbon). The teoretical part presents knowledge of the composition of composite material. Next, there is described the production and possible use of carbon composite materials in various technological branches. In the practical part the thesis focuses on the testing of composite materials made of carbon fiber with different orientation and weights of fibers. There is performed a tensile test and simultaneous monitoring of the course of the tensile test by acoustic emission. Finally, the statistical processing of the measured values occurs.
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Libánský, Milan. "Konstrukce měřící cely s elektrodou na bázi uhlíkového filmu." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-330713.
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This Thesis deals with the construction of an electrochemical cell with two types of integrated composite electrodes based on carbon films. Using these electrodes, the voltammetric behavior of environmental pollutant triclosan (5-chlor-2-(2,4- dichlorophenoxy)phenol) was studied. For the construction of composite electrodes, graphite and glassy carbon were used as conductive microparticles. Several types of polymers served as the nonconductive binder. For the measurements, combinations of graphite with polystyrene and graphite with polycarbonate were selected as optimum materials. From the dependence of peak heights on solution composition, a mixture of a buffer of pH 7 and methanol (1:9, V/V) was selected as the optimum medium. In this medium, concentration dependences were measured; calculated triclosan detection limit were 0,49 µmol dm-3 for carbon polystyrene composite electrode and 0,25 µmol dm-3 for carbon polycarbonate composite electrode, respectively. The possibility of further increasing the sensitivity of the determination by the accumulation step was studied. Accumulation of triclosan on carbon polystyrene composite electrode was observed, but the increase in response was connected with the loss of repeatability. Accumulation of triclosan on carbon polycarbonate composite electrode was...
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Libánský, Milan. "Testování nových elektrodových uspořádání pro monitorování elektrochemicky oxidovatelných biologicky aktivních organických látek." Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-354366.
Full textAbstract:
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...