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Design of optoelectronic sensor for biological tissues
Balík, Zdeněk ; Bartlová, Milada (referee) ; Tománek, Pavel (advisor)
Biological tissues are optically inhomogeneous and absorbent materials. They are comprised of various structures such as cells, cell organelles, and various fiber structures. Due to these structures leads to different interactions with the light and phenomena such as absorption, scattering and polarization of light. Different ultrasonic, electromagnetic, electrical and optical methods are used for meat ageing detection. Muscles are turbid anisotropic media, they exhibit changes in electrical and optical properties according to the direction of the electrical and optical fields in the sample. The diploma work assesses the feasibility of impedance measurements for meat ageing detection and their comparison with optical measurement of scattered polarized light. Two different sample were used: pork chop slices and chicken breasts were used for their relative homogeneity. The electrical method is a promising method due to the possibility of getting much information and realizing cheap and fast enough measurement systems. The proposed optical method allows measure the rotation of polarization plane with meat ageing in the range of 95 degrees within considered period. Through the first promising results obtained in this thesis, a further work has to be provided to determine closer relationship between optical scattering characteristics, electrical anisotropy in ageing-related tissue structural properties.
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Mixed lipids and their interaction with biopolymers
Cigánková, Hana ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This thesis focuses on the study of interactions between hyaluronan and lipid DOTAP and its mixtures with DPPC in water. First, the aggregation behavior of the lipid itself and its mixtures was measured, afterwards the influence of hyaluronan in different concentration was studied. Further the fluorescence anisotropy of fluorescence probe DPH in these mixtures and influence of cholesterol was measured. These properties were investigated by fluorescence spectoscopy using pyrene and DPH as fluorescence probes. The measurements revealed that the addition of hyaluronan has observable influence on the aggregation behavior of the lipid DOTAP and its mixtures with DPPC and that cholesterol influences liposomes fluidity.
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Microviscosity probes in study of aggregation in a biopolymer-surfactant system.
Vašíčková, Kamila ; Vala, Martin (referee) ; Mravec, Filip (advisor)
The effect of cationic surfactant concentration and ionic strength on anisotropy of fluorescence of probes diphenylhexatrien and fluorescein has been investigated in the system of cationic surfactant and in the system of cationic surfactant and hyaluronan. The investigation has been done by fluorescence emission spectroscopy. Obtained anisotropy gives information about microviscosity of investigated systems. Subsequently the system of cationic surfactant and hyaluronan has been investigated by 9-(2-carboxy-2cyanovinyl)julolidine, 4-(dicyanovinyl)julolidine and 1,3-bispyrenylpropane probes. The information about the microviscosity of the system gives the integral under the emission curve of 9-(2-carboxy2-cyanovinyl)julolidine and 4-(dicyanovinyl)julolidine and the ratio between excimer and monomer of 1,3-bispyrenylpropane. It has been discovered that the ionic strength influences the anisotropy of diphenylhexatrien and fluorescein only in the fist addition of salt (concentration 0,025 mol dm-3) and that addition of hyaluronan influences the anisotropy of diphenylhexatrien and fluorescein only in samples without addition of salt. Results of measurment with 9-(2-carboxy2-cyanovinyl)julolidine and 4(dicyanovinyl)julolidine describe the formation of aggregates of catinoc surfactant with hyaluronan and characterize these aggregates from the point of microviscosity.
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Numerical solutions of EMC problems of small airplanes
Šeděnka, Vladimír ; Dědková, Jarmila (referee) ; Mazánek, Miloš (referee) ; Raida, Zbyněk (advisor)
Disertace popisuje současné problémy v certifikaci malých letadel, které by se měly v budoucnu řešit numerickým modelováním. Tento postup má zefektivnit návrh a zlevnit certifikaci letadel. Práce je úzce spjata s projektem HIRF-SE, který se problematikou certifikace letadel numerickými metodami zabývá. Podstatná část práce je věnována popisu dvou modulů pro platformu HIRF-SE: řešič BUTFE založený na metodě konečných prvků v časové oblasti a budicí nástroj BUTFE_EXC. Práce popisuje řešení pohlcujících okrajových podmínek, modelování disperzních a anizotropních materiálů a aproximaci tenkých drátů. Speciální pozornost je věnována řešení aproximace tenkých drátů s ostrými ohyby, jejíž současná formulace způsobuje překryvy mezi jednotlivými segmenty drátu.
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Interaction of negatively charged vesicular systems based on ionic amphiphilic pairs with polycations
Fardová, Lucie ; Venerová, Tereza (referee) ; Mravec, Filip (advisor)
This work is focused on the preparation of negatively charged vesicular systems from amphiphilic pairs deprived of counterions and their interaction with the polycation. First, vesicular systems were prepared from the surfactants sodium dodecyl sulfate and cetyltrimethylammonium bromide. The addition of cholesterol and phosphatidic acid stabilized and at the same time gained a negative charge. Subsequently, there was an interaction with the polycation diethylaminoethyl-dextran hydrochloride. The systems were investigated by the measuring of particle size, zeta potential, generalized polarization and anisotropy. The measurement of generalized polarization was enabled with the laurdan probe and measurement of anisotropy was performed with the introduction of the 1,6-diphenyl-1,3,5-hexatriene probe. The results indicate the successful preparation of stable, negatively charged systems that interacted with positive diethylaminoethyl-dextran hydrochloride, which affected the behavior of the outer membrane but not the inner. The systems were still stable.
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Computational Modelling of Mechanical Behaviour of "Elastomer-Steel Fibre" Composite
Lasota, Tomáš ; Okrouhlík,, Miloslav (referee) ; Nováček,, Vít (referee) ; Burša, Jiří (advisor)
Tato práce se zabývá výpočtovými simulacemi zkoušek jednoosým tahem a tříbodovým ohybem kompozitního vzorku složeného z elastomerové matrice a ocelových výztužných vláken orientovaných pod různými úhly, jakož i jejich experimentální verifikací. Simulace byly provedeny pomocí dvou různých modelů - bimateriálového a unimateriálového výpočtového modelu. Při použití bimateriálového modelu, který detailně zohledňuje strukturu kompozitu, tzn. pracuje s matricí a jednotlivými vlákny, je zapotřebí vytvořit model každého vlákna obsaženého v kompozitu, což přináší řadu nevýhod (pracná tvorba výpočtového modelu, řádově větší množství elementů potřebných k diskretizaci v MKP systémech a delší výpočetní časy). Na druhé straně v unimateriálovém modelu se nerozlišují jednotlivá vlákna, pracuje se pouze s kompozitem jako celkem tvořeným homogenním materiálem a výztužný účinek vláken je zahrnut v měrné deformační energii. Porovnání experimentů se simulacemi ukázalo, že bimateriálový model je v dobré shodě s experimenty, na rozdíl od unimateriálového modelu, který je schopen poskytnou odpovídající výsledky pouze v případě tahového namáhání. Z tohoto důvodu byl hledán způsob, který by umožnil rozšířit unimateriálový model o ohybovou tuhost výztužných vláken. V roce 2007 Spencer a Soldatos publikovali rozšířený unimateriálový model, který je schopen pracovat nejen s tahovou, ale i ohybovou tuhostí vlákna. Představený obecný model je však založen na Cosseratově teorii kontinua a jeho praktické využití je pro jeho složitost nemožné. Proto byl vytvořen zjednodušený model (částečně podle Spencera a Soldatose) s vlastní navrženou formou měrné deformační energie. Za účelem ověření nového unimateriálového modelu s ohybovou tuhostí vláken byly odvozeny všechny potřebné rovnice a byl napsán vlastní konečno-prvkový řešič. Tento řešič je založen na Cosseratově teorii kontinua a obsahuje zmíněný anizotropní hyperelastický unimateriálový model zahrnující ohybovou tuhost vláken. Vzhledem k tomu, že v případě Cosseratovy teorie jsou při výpočtu potřebné i druhé derivace posuvů, bylo nutné použít tzv. C1 prvky, které mají spojité jak pole posuvů, tak jejich prvních derivací. Nakonec byly provedeny nové simulace s využitím vlastního řešiče, které ukazují, že tuhost vláken lze u nového unimateriálového modelu řídit odpovídající materiálovou konstantou. V závěru práce je pak diskutováno, zda je nový unimateriálový model s ohybovou tuhostí schopen poskytnout stejné výsledky jako model bimateriálový, a to jak při tahovém tak i ohybovém namáhání kompozitního vzorku.
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Quality of hydrophobic domains in polyelectrolyte-surfactant system
Holínková, Petra ; Vala, Martin (referee) ; Mravec, Filip (advisor)
In this bachelor thesis were studied the photophysical properties of four fluorescent probes depending on the viscosity of their surroundings by the fluorescence spectroscopy. For probes DPH, DPB a perylene was determinated dependence of fluorescence anisotropy and for P3P dependence of ratio excimer/monomer on the viscosity of the sample. Anisotropy probes DPH and perylene were also used to study interaction between hyaluronan and cationic surfactant CTAB (concentration below CMC) in aqueous solution and 0,15 M NaCl. Information about forming hydrophobic domains were obtained by measurement of fluorescence intensity and anisotropy depending on the concentration of CTAB in the sample. It was found that in an aqueuos solution, after the initial addition of CTAB to hyaluronan formed small hydrophobic domains linked to chain of hyaluronan. Increasing concentration of CTAB leads to the formation of gel and phase separation. After addition of NaCl leads to reorganization of this system and probably the formation of free micelles in the solution with higher concentration of CTAB.
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Static analysis of the timber roof structure
Sedlák, Petr ; Gratza, Roman (referee) ; Kytýr, Jiří (advisor)
This thesis with the numerical modeling and assessment has been carried timber roof structure of the gymnasium hall of the elementary school TGM at Bílovec. The study was realized in program system ANSYS. They are created a variety 2D and 3D numerical models which are assessed according to current normative regulations.
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Characterization of migmatite fracturing using ultrasonic methods
Petružálek, Matěj ; Vilhelm, Jan (advisor) ; Vavryčuk, Václav (referee) ; Koktavý, Pavel (referee)
Submitted PHD thesis is focused on fracturing process of migmatite, which is a low porosity anisotropic rock. Migmatite, from a locality Skalka, was chosen as a suitable experimental material, namely due to its macroscopically visible, plane-parallel structure (foliation). The fracturing was studied by means of uniaxial loading experiments on cylindrical samples with different dip of migmatite foliation: 13ř (subhorizontal), 81ř (subvertical) and oblique (47ř and 67ř). The net of eight piezoceramic transducers was employed for ultrasonic sounding (US) measurement and acoustic emission (AE) monitoring during the loading experiments. Realized study of migmatite fracturing is based on the interpretation of both mentioned ultrasonic methods. Part of this work was a software development, including its testing for processing and interpretation of measured AE and US data. Methodical part of the thesis consists of: development and testing of algorithms for automatic P wave arrival detection; introduction of anisotropic velocity model to describe magnitude and orientation of velocity anisotropy, as well as to localize AE events in anisotropic velocity field; determination of crack initiation stress using first arrival amplitude of US. Based on the interpretation of AE and US data, there was found a...
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Modeling of anisotropic viscoelastic fluids
Šípka, Martin ; Tůma, Karel (advisor) ; Průša, Vít (referee)
In this thesis, we aim to create a framework for the derivation of thermodynamically consistent anisotropic viscoelastic models. As an example we propose simple models extending the isotropic Oldroyd-B and Giesekus models to illustrate the models' behavior and the process of finding the correct equations. We show what behavior in sheer we can expect and continue with a 3D simulation inspired by the experiment on a real liquid crystal mixture. Finally, we compare the simulation and the experiment to find similarities and possible further research topics.
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