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Methodology for determining the relevant material characteristics of historical building materials for the restoration intervention
Slížková, Zuzana ; Frankeová, Dita ; Tišlová, R.
The aim of this metolodogy is to present a recommended list of material properties which have to be identified and evaluated within material survey of historical momuments.\n\n
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Plný tet: 0457225_2015_Slizkova_et_al_Metodika_urceni_rozhodnych_materialovych_charakteristik_historickych_stavebnich_materialu_pro_planovany_restauratorsky_zasah - Download fulltextPDF

Properties of Aerosol, Produced by Laser Ablation of Standard Materials for ICP-MS Analysis.
Holá, M. ; Nováková, H. ; Ondráček, Jakub ; Vojtíšek, M. ; Kanický, V.
Laser ablation (LA), together with inductively coupled plasma mass spectrometry (ICP-MS) as a detection system, has become a routine method for the direct analysis of various solid samples. The product of laser ablation contains a mixture of vapour, droplets and solid particles. All components are finally transported to a plasma by a carrier gas as a dry aerosol including mainly agglomerates of primary nanoparticles. In general, characterisation of aerosols by their particle size distribution (PSD) represents indispensable tool for fundamental studies of the interaction of laser radiation with various materials. The particle size distribution of dry aerosol originating from laser ablation of standard material was monitored by two aerosol spectrometers – Fast Mobility Particle Sizer (EEPS) and Scanning Mobility Particle Sizer (SMPS) simultaneously with laser ablation - ICP-MS analysis.\n
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Plný tet: SKMBT_C22016102412241 - Download fulltextPDF

Time lapse tomography of fracture progress in silicate-based composite subjected to the loading a combination with acoustic emission scanning
Kumpová, Ivana ; Kytýř, Daniel ; Fíla, Tomáš ; Veselý, V. ; Trčka, T. ; Vopálenský, Michal ; Vavřík, Daniel
The initiation and propagation of a fracture in quasi-brittle materials (such as silicatebased composite) is an increasingly discussed topic for which various methods of research have been developed/applied. As the quasi-brittle silicate-based composite compounds are very non-homogenous, the mechanism of the crack initiation and propagation can be very different even for samples with the\nidentical geometry. One possible approach to study the fracture mechanism in quasi-brittle materials is to use several different experimental techniques in a single experiment and perform detail analysis to identify generally valid fracture process phenomena. In this work, a simultaneous monitoring of fracture\nprocess zone formation and propagation by three different methods is presented and discussed. A three point bending test was performed on a notched silicate composite specimen. During the loading process, a highly accurate force displacement dependence was recorded accompanied with X-ray radiography,\nX-ray computed tomogra-phy and acoustic emission scanning.

Book of Abstracts of the 26th Joint Seminar Development of Materials Science in Research and Education
Kožíšek, Zdeněk ; Král, Robert ; Zemenová, Petra
Topics:\n- Trends in development of materials research\n- Education of materials science at the universities\n- Information about the research programmes of individual institutions\n- Information on equipment for preparation and characterisation of materials\n- Results of materials science research

Study of dielectrical properties of organic material thin films
Pospíšil, Jan ; Boušek, Jaroslav (referee) ; Mikula, Milan (referee) ; Zmeškal, Oldřich (advisor)
The dissertation is focused on the study of electric and especially dielectric properties of thin film organic materials with their huge potential for optoelectronics and other industrial sectors. The theoretical part deals with the use of organic materials in organic photovoltaic cells, the methods of deposition techniques and characterization. The theoretical knowledge of the dielectric spectroscopy, including methods for determining the physical properties and evaluation of experimental data are also described. The experimental part is devoted to the study of small molecule organic solar cells with bulk heterojunction composed of electron donor molecule of DPP(TBFu)2 and electron acceptor fullerene derivatives, such as PC60BM, PC70BM and TC60BM. The experimental part is divided into two main parts. The first part deals with the study of processes occurring at the interface between the active layer and the contact; the second part is focused on transport processes inside the structure of photovoltaic cells and also contains a study of perovskite solar cells.

Noise, Transport and Structural Properties of High Energy Radiation Detectors Based on CdTe
Šik, Ondřej ; Lazar, Josef (referee) ; Navrátil, Vladislav (referee) ; Grmela, Lubomír (advisor)
Poptávka ze strany vesmírného výzkumu, zdravotnictví a bezpečnostního průmyslu způsobila v posledních letech zvýšený zájem o vývoj materiálů pro detekci a zobrazování vysokoenergetického záření. CdTe a jeho slitina CdZnTe. jsou polovodiče umožnují detekci záření o energiích v rozsahu 10 keV až 500 keV. Šířka zakázaného pásma u CdTe / CdZnTe je 1.46 -1.6 eV, což umožňuje produkci krystalů o vysoké rezistivitě (10^10-10^11 cm), která je dostačující pro použití CdTe / CdZnTe při pokojové teplotě. V mé práci byly zkoumány detektory CdTe/CdZnTe v různých stádiích jejich poruchovosti. Byly použity velmi kvalitní spektroskopické detektory, materiál s nižší rezistivitou a výraznou polarizací, detektory s asymetrií elektrických parametrů kontaktů a teplotně degenerované vzorky. Z výsledků analýzy nízkofrekvenčního šumu je patrný obecný závěr, že zvýšená koncentrace defektů způsobí změnu povahy původně monotónního spektra typu 1/f na spektrum s výrazným vlivem generačně-rekombinačních procesů. Další výrazná vlastnost degenerovaných detektorů a detektorů nižší kvality je nárůst spektrální hustoty šumu typu 1/f se vzrůstajícím napájecím napětí se směrnicí výrazně vyšší než 2. Strukturální a chemické analýzy poukázaly, že teplotní generace detektorů způsobuje difuzi kovu použitého při kontaktování a stopových prvků hlouběji do objemu krystalu. Část mé práce je věnována modifikaci povrchu svazkem argonových iontů a jejímu vlivu na chemické složení a morfologii povrchu.

Deformation characteristics of chopped fibre composites subjected to quasi-static tensile loading
Šleichrt, J. ; Adorna, M. ; Neühauserová, M. ; Fenclová, N. ; Petráňová, Veronika
This work presents deformation behaviour of cost effective chopped fiber composites. Use of chopped fibre is advantageous for manufacturing however complex shape parts production technology could be challenging. Batches of samples with different fibres composition were subjected to uni-axial tensile loading to obtain overall materials properties and inspection of proper manufacturing based on local deformation inhomogeneities. Both crossbeam displacement and optical strain measurement were used for elastic characteristics evaluation. Deformation response was derived from full-field optical strain measurements based on digital image correlation method. Relatively large variation of mechanical properties testing of samples was found.

Determination of thermal response of Carrara and Sneznikovsky marble used as building material
Petráňová, Veronika ; Valach, Jaroslav ; Viani, Alberto ; Pérez-Estébanez, Marta
Physical weathering of marble, widely used as a cladding material on buildings, is one of the most common damaging mechanism caused by anisotropic thermal expansion of calcite grains. The extent of marble deterioration depends mainly on stone fabric and texture. Dry cuboids of Carrara marble and marble from Dolni Morava quarry were subjected to microscopic analysis and thermal cycling, to determine the thermal expansion related to stone fabric and predominant lattice orientation of grains (i.e. texture).

Identification of damaged zones in C/PPS specimens subjected to fatigue loading based on high-resolution thermography
Koudelka_ml., P. ; Kytýř, Daniel ; Fenclová, Nela ; Šperl, Martin
In this study high resolution thermography is used for identification of damaged zones in Carbon fiber/polyphenylene sulfide (C/PPS) long fiber composite specimens with induced impact damage subjected to tensile fatigue loading. Image processing techniques were applied on thermographs from all loading cases to obtain segmented images of the damaged location that were then used for\ncalculation of the heated area. Results show that the considered method can be used to identify heated area in the vicinity of damage with high confidence at low number of cycles where no significant fatigue effect is present in the material.

Doped DLC coatings for biomedical applications
Písařík, Petr
Nowadays there are materials having excellent properties for use in medicine (Diamond-like carbon, Hydroxyapatite, …). Diamond-like carbon (DLC) is a metastable form of amorphous carbon containing bonded carbon atoms of sp2 and sp3 hybridized orbital. DLC layers are semiconductors with high mechanical hardness, chemical inertness, low coefficient of friction, high thermal conductivity, good electrical and optical properties, biocompatibility and no cytotoxicity. All properties of the films are not always ideal, so it is necessary to modify the layer. One example of how to modify the properties of thin layers are dopations. The incorporation of dopants in films may lead to greater multifunctionality and much improved properties. Most modifications were made to modify contact angle and surface energy, to reduce internal stresses, to decrease surface roughness, coefficient of friction or wear....