National Repository of Grey Literature 67 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Electroassisted photocatalysis
Filipská, Markéta ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This thesis is focused on fotoelectrochemical cells, where as photocathode is used titanium dioxide coated on conductive FTO glass and as counter electrode is used gold electrode. Thesis is also focused on relationship between intensity of irradiation and Faradaic efficiency and also influence of the overvoltage to the rate of degradation od the model pollutant, in this case Acid Orange 7. Electrical properties were measured by recording values of photocurrent. The aim of this thesis was to study influence material composition of photoanode and connection with intensity of irradiation, rate of degradation proces of model pollutant and current.
Printed insulating interlayrs
Olejníková, Marie ; Zmeškal, Oldřich (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with preparation and study of printed insulating interlayers based on barium titanate. The composition of ink formulation and method of deposition were investigated. The composition was optimised with the type of added binder. The printing was made using a screen printing method. Characterisation of prepared layers was made using contact profilometry and optical microscopy. Dielectric properties of layers were subsequently analysed using the impedance spektroskopy method.
Fabrication of conductive paths by electroless plating of printed precursors
Kováčová, Silvia ; Zita, Jiří (referee) ; Dzik, Petr (advisor)
The subject of this bachelor thesis is the preparation of conductive tracks by electroless plating of printed precursors. The experimental part deals with the preparation of standard samples based on the length of immersion time in the coppering bath. The precursor layers were applied with a technical pen to ceramic corundum substrates. The individual precursor layer substrates were immersed in the coppering bath in various time intervals. The structure of the grown copper layers was observed by an optical microscope and their thickness was determined by a profilometer.
Hybrid biopolymer composites for 3D printing applications
Menčík, Přemysl ; Bakoš, Dušan (referee) ; Dzik, Petr (referee) ; Jančář, Josef (advisor)
This dissertation work deals with the thermic and the mechanical behavior of plasticized bio-plastics and bio-composites for the 3D printing applications. The influence of plasticizer chemical structure on thermic and mechanical properties of plasticized polymeric blends from the poly-3-hydroxybutyrate and the poly lactic acid was investigated. Used plasticizers are based on derivative of citric acid. The influence of plasticizers on polymeric matrix and their compatibility was estimated by gear torque rate of melt mixer, respectively rate of plasticizer migration from the material during higher temperature. The plasticizer structure influence on the glass transition temperature and on the kinetics of crystallization of plasticized material was investigated by modulated differential scanning calorimetry. The behavior of material during 3D printing was also observed. Mechanical properties of printed samples, especially their elongation at break, were determined by tensile tests. The largest softening effect was observed using tributylcitrate plasticizer, where the glass temperature decreased by 35 °C and elongation at break increased by 150% compared to non-plasticized reference material. This plasticized polymeric blend showed also sufficient 3D printing properties and was used as the matrix for composites in the next part of this work. Composites were filled by kaolin, limestone, halloysit, fumed silica, talc, magnesium hydroxide and chopped flax fibers. Particle distribution in composites in dependence of used surface treatment of filler was observed by scanning electron microscopy. The influence of composite filler on rheological properties, crystallization kinetics and thermal stability of composites, was observed by viscometry and differential scanning calorimetry. Their mechanical properties and heat deflection temperature were observed on samples prepared by 3D print. Kaolin in composite material showed homogeneous particle distribution and insignificant nucleation effect and influence on thermic stability. Composite filled by kaolin also showed 18% smaller warping during 3D printing compared to non-filled reference. Consequently kaolin was evaluated as suitable inorganic filler for bioplastic composite intended for 3D print and this composite was used in the following part of this thesis. Method of mathematical prediction of Young's modulus was described for composite samples prepared by 3D print. Composites filled by one type of filler – kaolin, or limestone, resp. by combination of both fillers were investigated on the basis of the micromechanic Halpin-Tsai model modified by the semiempiric multiparametric Cerny's equation. Additive and combinational method of Young's modulus evaluation is used for composites with hybrid filling. Deflection of measured and theoretical Young's modulus value of composite filled with kaolin was decreased by established correction from 21% to 1% and for composites filled with limestone from 13% to 9%. In this manner it is possible to predict the Young's modulus of the samples prepared by 3D print.
Printed UV senor based on photoelectrochemical cell
Vičarová, Monika ; Drbohlavová, Jana (referee) ; Dzik, Petr (advisor)
This thesis deals with the construction of a photoelectrochemical cell, which is used for detection of ultraviolet radiation by means of generated photocurrent in dependence on the intensity of incident radiation. The cell construction is based on a carbon electrode system with a titanium dioxide sensory layer and a UV curable electrolyte. Printing techniques such as screen printing, inkjet printing and pad printing were used to deposit individual layers. Carbon electrodes with sensory layer were studied through profilometric analysis, optical microscopy, and four-point probes. The viscosity of the liquid formulation of uncured electrolyte was characterized by rheometric measurement. Photoelectrochemical properties of the prepared cell for use as a UV sensor were investigated by cyclic voltammetry and chronoamperometry.
Fabrication and characterization of oxidic conductive layers
Bartoš, Radim ; Gemeiner,, Pavol (referee) ; Dzik, Petr (advisor)
Liquid composition for antimony doped tin oxide solgel deposition was prepared. Anorganic precursors of tin and antimony were used (tin(IV) chloride, antimony(III) chloride). ATO nanoparticles were dispergated in composition. This composition was used for spincoating deposition of thin films. Composition was analyzed by thermal analysis TGA and DSC. Sheet resistence of prepared samples were examined by four probe sensing. RMS roughness and thickness was measured by profilometry. Samples were analyzed by scan electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Transmittance and haze were measured and calculated by UV-VIS spektrometry with integration sphere.
The influence of titania morphology on the physico-chemical properties of photocatalytic coatings
Saňák, Tomáš ; Cihlář, Jaroslav (referee) ; Dzik, Petr (advisor)
This bachelor thesis examines two variously milled liquid dispersions containing titanium dioxide and coatings made by them. First dispersion was provided by partners from COC s.r.o. Pardubice and was prepared by high-energy milling. Second disperzion was milled in improvised ball-mill. Coatings prepared from these disperzions were applied on two various substrates (microscopic glass, FTO glass) and were characterized by three analytical methods (profilometry, haze measuring, electrochemical measuring). Profilometry and haze measuring reported about decreasing properties of layers according to milling time. Electrochemical measuring used to explore photocatalytic properties showed us that photocatalytic activity requiere optimal milling time.
Accelerated testing of lightfastness of indoor furniture coatings
Kulhánková, Michaela ; Drábková, Klára (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with the study of the current methods of testing and evaluation of lightfastness of interior paints. Their fading is caused mainly by the influence of solar radiation. The first part provides the basic information needed to understand the experiment. In the second part, wood samples with various white varnishes and coatings were subjected to accelerated testing of lightfastness. The experiment was performed by exposing these samples to xenon lamp through the window glass filter in the solar chamber. Changes in the color of the samples were evaluated based on the measurement of the reflection spectra from which the colorimetric quantities were calculated and then displayed in the color space CIE 1976 L*a*b*. The conclusion was focused on the final real life of the samples, their mutual comparison and evaluation of the most suitable materials.
Synthesis and properties of tungsten tioxide layers originating from colloid dispersions
Papák, Jiří ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with preparation and characterization of tungsten oxide thin layers originating from colloid dispersions. Thin layers were prepared from a commercially available precursor by spin coating or on a material printer Dimatix. The properties of the prepared layers were monitored by profilometry, scanning electron microscope (SEM), X-ray crystallography (XRD) and electrochemical measurements.
The influence of material composition and spatial arrangement on the properties of photoelectrochemical cells
Pachovská, Martina ; Krystyník, Pavel (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with photoelectrochemical cells containing photoactive titanium dioxide anode and their use for photocatalytic degradation of organic compound from water solutions. The electrical properties of the produced photoelectrochemical cells were determined by the use of voltamperometric characteristics, the oxidation ability of the cells was monitored by measuring the fluorescence of the oxidative intermediates. To study these reactions, benzoic acid was used as the fluorescence probe for OH˙ radicals. The aim of the study was to study the influence of material composition and spatial arrangement of the cathode and the relationship between irradiation, current and rate of electrode processes.

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