Diploma thesis main goal is to obtain new pieces of knowledge about relationship between hydrogel structures and its flow and transport properties. Thesis is mainly focusing on combining pertinent biopolymers into model hydrogels based on agarose. Then perform correlation of results obtained by diffusion methods, and by rheologic measurements on macroscopic and microscopic level. Properties of hydrogels were measured by selected rheologic measurements, dynamic light scattering method, and correlative fluorescence spectroscopy. From these methods various parameters (MSD modules, values of complex viscosity) were obtained. Afterwards transport properties of prepared hydrogels were studied by observing Rhodamine 6G diffusion. Here two different approaches were used. From macroscopic perspective, simple principles of mass diffusion from dye solution to cuvettes filled with hydrogels containing individual biopolymers were used. From microscopic perspective, dye was added during the sample preparation and then the mass diffusion was investigated using FCS. Based on evaluated results it was discovered that added biopolymers don’t influence properties of carrier medium, in this case agarose hydrogels. During the study of prepared hydrogels’ reactivity and barrier properties some differences were observed. Charge of biopolymer and its charge density were discovered as main factors influencing transport of charged solutes into prepared hydrogels.

Title: Anomalous diffusion of plasma in tokamak edge region Author: Jakub Seidl Tutoring institution: Institute of Plasma Physics AS CR, v.v.i. Supervisor: Doc. Ing. Ladislav Krlín, DrSc., IPP AS CR Consultant: RNDr. Radomír Pánek, Ph.D., IPP AS CR Abstract: This work provides brief introduction to the topic of plasma turbu- lence in tokamak edge region and several aspects of anomalous plasma diffusion are discussed. We use numerical code ESEL to model interchange turbulence and investigate properties of turbulent structures in different regimes of parallel trans- port. Means of experimental verification of the results are discussed. Results of the modelling are then used to interpret unexpected results experimentally obtained by electrostatic ball-pen probes on tokamak ASDEX Upgrade, mainly appearance of a 'bump' in power spectra of measured plasma potential. Next, we explain be- haviour of cross-correlation function of density signals measured by two spatially separated Langmuir probes in the vicinity of magnetic separatrix and we point out an ambiguity in interpretation of results of vorticity measurement made by set of floating Langmuir probes. In the last part, transport of plasma impurities by electrostatic turbulent potential is modelled. We identify reversal of radial particle velocity for particles with...

ermal desorption spectroscopy (TDS) is a common method for surface analysis of adsorbed molecules. In chapter 1 the work deals with the theoretical background of this method and shows the principles of a desorption process influenced by subsurface diffusion. Chapter 2 first shows application of TDS for detection of surface molecules and determination of binding energy.Experiments were mainly focused on ditermination of surface adsorbents and impurities on Si wafers. The second part of chapter 2 describes desorption of atoms of a Ga layer on Si surface and their subsurface diffusion. A Ga diffusion process was also observed by with secondary ion mass spectrometry (SIMS) and numerically simulated.

Název: Hyperkapnie a difuse plynů ve sněhové lavině - (Změny funkčních parametrů jedinců v krizové situaci) Cíle práce: Cílem studie bylo kontinuální sledování kompenzačních mechanismů, zejména změn ventilačně-respiračních ukazatelů, v simulované sněhové lavině. Metoda: K získání dat byl použit experiment a nestandardizovaný dotazník. Výběr souboru byl vzhledem ke sledované problematice přísně selektivní. Výzkumu se účastnilo 22 probandů, ale po analýze dat bylo pro nesplnění požadovaných kritérií 11 osob vyřazeno. Soubor tedy tvořilo 11 zdravých mužů průměrného věku 25,3 let. Před vlastním experimentem byla pomocí osobního spirometru testována senzitivita na hyperkapnii a hypoxii (výdrž v apnoi) a dechová zdatnost (vitální kapacita plic s usilovným výdechem). Experimentální situaci představovalo jak dýchání do uzavřeného objemu (8 l), tak do vytvořené vzduchové kapsy ve sněhu (400 ml). Kontinuální záznamy oběhových funkcí (srdeční frekvence, krevní tlak) a ventilačně-respiračních parametrů (dechová frekvence, dechový objem, minutová ventilace, obsah O2 a CO2 ve vdechovaném a vydechovaném vzduchu, odpor při výdechu a saturace krve kyslíkem) byly snímány pacientským monitorem DATEX Ohmeda. Vzhledem k charakteru dat byla využita analýza rozptylu při opakovaném měření se dvěma faktory (dvoucestná...

Mesophyll conductance is (together with stomatal conductance) a crucial component of diffusion limitations of photosynthesis and it is important to understand the mechanisms of CO2 fluxes through the leaves. Here I tested a new technique for estimation of drawdown in CO2 concentration across hypostomatous leaves based on carbon isotope composition (13C) of leaf cuticle and cuticular waxes isolated from opposite leaf sides.

This thesis is focused on diffusion of dyes in biopolymer-based hydrogels. These hydrogels are based on interaction between biopolymer-like electrolytes with oppositely charged surfactants. When polyelectrolytes interact with oppositely charged surfactants, micelle-like nano-containers can be formed. These nano-containers are able of binding hydrophobic compounds. In this study, combination of modified dextran (diethylaminoethyl dextran) with positive charge and oppositely charged sodium dodecylsulphate as surfactant was used for preparation of hydrogels. Next type of hydrogel was based on hyaluronan and positive charged surfactant Septonex (carbethoxypendecinium bromide). As a diffusion probes in hydrogels dyes Nile red and ATTO 488 were used. The diffusion of these dyes from aqeous solutions of NaCl or surfactants into hydrogels was monitored in time. Transport of dyes into structure of hydrogels was characterized by diffusion coefficients and structural parameters of hydrogels.

Ultrasound imaging is widely used in medical examination. However, the interpretation of images is not trivial and requires much experience. In this thesis, various techniques for enhancement of visual quality of ultrasound images are presented. Several basic and advanced methods that may simplify the visual diagnosis are described. Finally, an interactive application is designed and implemented for simple usage of presented methods.

The thermal stability of p-type CdTe crystals by using conductivity and Hall-effect measurements have been studied at room and slightly increased temperatures. It was observed that thermal changes often implicate an anomalous behavior of the hole density characterized by reversible decrease/increase in a heating/cooling regime. This anomaly was explained by a transfer of fast diffusing donors between Te inclusions and the bulk of the sample. Sodium and potassium were determined by the Secondary Ion Mass Spectroscopy (SIMS) as the most probable diffusing species. To verify this behavior samples were also treated in saturated NaCl solution for different time intervals in order to examine the influence of the oxide layer and sodium on the surface of the sample. To determine the structure of the surface the sample was characterized by ellipsometric and X-ray photoelectron spectroscopy (XPS) and SIMS. Very low determined diffusion coefficient of Na was explained by trapping of Na in Cd sublattice

This diploma thesis describes the origins of harm reduction (HR) in the Czech drug policy. It focuses on the role of HR in national strategies and the development of syringe and needle program and substitution treatment. The aim of the thesis is to describe and explain how the HR approach was developed in the Czech environment. Using the framework of policy diffusion, the author explains the mechanisms by which harm reduction was transferred from abroad. Thesis describes the history of drug policy and the development of the harm reduction approach in the world. This information forms the context in which the author advocates HR development in the Czech Republic's drug policy after 1989. By analysing expert texts and expert interviews she explains how the first national strategies were formed in which HR has been included since 1993. Similarly, it deals with the beginnings of syringe exchange, which has been in operation since 1986, and substitution treatment that was first used in 1992 and has been officially operational since 1997. The mechanisms of diffusion of HR from abroad to the Czech Republic are defined. In all three areas, the mechanism of learning is defined. Substitution treatment and national strategies are also defined by the mechanism of emulation. To a lesser extent, a mechanism of...

Title: Numerical analysis of approximation of nonpolygonal domains for discon- tinuous Galerkin method Author: Filip Klouda Department: Department of Numerical Mathematics Supervisor: prof. RNDr. Vít Dolejší, Ph.D., DSc., KNM MFF UK Abstract: In this work we use the discontinuous Galerkin finite element method for the semidiscretization of a nonlinear nonstationary convection-diffusion pro- blem defined on a nonpolygonal two-dimensional domain. Using so called appro- ximating curved elements we define a piecewise polynomial approximation of the boundary of the domain and a space on which we search for a solution. We study the convergence of the method considering a symmetric as well as nonsymmetric discretization of diffusion terms and with the interior and boundary penalty. The obtained results allow us to derive an error estimate for the Discontinuous Galer- kin method employing the approximating curved elements. This estimate depends on the order of the approximation of the solution and also on the order of the approximation of the boundary. We describe one possibility of the construction of the approximating curved elements with the aid of a polynomial mapping given by an interpolation of points on the boundary. We present numerical experiments. Keywords: nonlinear convection-diffusion equation, discontinuous...