|
|
Reactivity-mapping studies on biopolymers in hydrogel forms
Smilek, Jiří ; Kislinger, Jiří (referee) ; Sedláček, Petr (advisor)
The diploma thesis is focused on the study of interactions between biopolymers and model probes in a hydrogel media utilizing diffusion processes. The main aim was to test and to optimize selected combination of diffusion methods (diffusion cells and unsteady diffusion) in study of interactions between biopolymers and organic dyes. Anionic (humic acids) and cationic (chitosan) representatives of biopolymers were utilized and methylene blue and methylene orange were used as a reactivity probe in the case of humic acids and chitosan, respectively. Another appreciable part of the work is represented by in-depth characterization of applied biopolymers and hydrogel samples by a wide range of analytical and physico-chemical methods (rheometry, UV-VIS, FT-IR etc.). Besides particular experimental results on studied systems, the diploma thesis provides both theoretical and practical background for subsequent applications of the innovative and full-automated method for reactivity mapping of biopolymers.
|
|
|
Study of intercalation properties of electrode materials based on naturla graphite
Bílek, Lukáš ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This diploma thesis deals with the issue of lithium-ion accumulators. The thesis focuses on the negative electrode of lithium-ion accumulators made of natural graphite. The first part of this thesis points to the issue of electrochemical cells. In the theoretical part the thesis deals with the SEI layer, advantages, disadvantages, characteristics, operating principle and the use of lithium-ion accumulators. The practical part focuses on the electrochemical properties of negative electrode, especially the determination of the diffusion coefficient. Thesis also deals with electrochemical impedance spectroscopy (EIS) and its use in determining the equivalent replacement circuit and calculating the diffusion coefficient.
|
|
|
Measurement of Dialyser-Membrane Diffusion Coefficient
Kašák, Pavel ; Bartoš, Michal (referee) ; Jiřík, Radovan (advisor)
This thesis focuses on the measurement of diffusion coefficient of dialysis membrane. The first part describes possibilities of membrane modelling. Basic models, which allow us to determine the basic characteristics of dialysis membranes like permeability and diffusion coefficient, are described. Next chapter deals with basic types and properties of membranes. The main part focuses on making the experimental installation, which is used to simulate permeance of contrast agent, used in DCE-MRI, through dialysis membrane. The last theoretical chapter describes calculations used to estimate diffusion coefficient. Practical part of this thesis uses a designed experimental installation for estimation of diffusion coefficient for two contrast agents Gadovist® and Multihance®.
|
|
|
Design and Measurement of Parameters of Acoustic Diffusors
Burda, Jan ; Vrba, Kamil (referee) ; Schimmel, Jiří (advisor)
This work focuses on the issue of acoustic diffusers. The introductory chapter describes the necessary theory of the sound distribution through enclosed space. Acoustic fields are also described. A description of the different diffusion element types and theirs design methods follows. It focuses mainly on design, which uses pseudo-random mathematical sequences. The aim of the work is to produce several types of acoustic diffusors and to verify their diffusion properties by means of measurements. The work uses the AFMG Reflex to simulate the diffusion properties of the proposed elements. Further, the thesis contains a description of the diffusion properties measurement process by the boundary plane method and the process of evaluating the measured data using the Matlab program.
|
|
|
Study of gel electrolytes properties by MR methods
Mrnka, Michal ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
Theoretical part of the work deals with explanation of nuclear magnetic resonance phenomenon, relaxation processes in system of nuclear spins, basic techniques for measurement of relaxation times. There are described diffusion and techniques for diffusion coefficient measurement including method for suppressing the background gradient. Experimental part describes preparation of gel electrolytes samples and measurement of relaxation times. Sodium salt was used as a conductive agent. There is interpreted dependence of relaxation times on polymerization times and on concentration of conductive agent in gels.
|
|
|
Diffusion of dyes in biopolymeric hydrogels
Vyroubal, David ; Mravec, Filip (referee) ; Klučáková, Martina (advisor)
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.
|
|
|
Study of intercalation properties of negative electrode materials
Minda, Jozef ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
The bachelor thesis deals with the research of intercalating properties of negative electrode materials for lithium-ion and sodium-ion accumulators. The main focus of this work is on the kinetic aspects associated with the diffusion processes of lithium in graphitic negative electrode material and sodium in titanates materials in relation to the electrochemical parameters. By comparing the materials in terms of kinetic properties expressed by the diffusion coefficient with using of electrochemical impedance spectroscopy in the state of the base material and after creating the passive layer on the electrode, it is possible to determine the application possibilities of the materials and the dependence on the electrochemical parameters. In the thesis is designed a procedure for electrodes preparation, measurement and evaluation of monitored parameters. Within the experimental part, the structural and electrochemical parameters and diffusion coefficients of the studied materials are determined by the proposed method.
|
|
|
DLS microrheology to study gelation of polymer
Píšová, Denisa ; Smilek, Jiří (referee) ; Hnyluchová, Zuzana (advisor)
This bachelor thesis deals with the study of gelation process on model polymer through DLS microrheology. As the model polymer was used agarose and for microrheological measurement were used polystyrene particles. Agarose samples of various mass concentrations were studied through dynamic light scattering. Measured data were used to create graphs of MSD against time which were compared to MSD curves and error bars. The values of diffusion coefficients for all samples and each temperature were also compared.
|
|
| |
|
|
Assessment of diffusion coefficient
Mikeš, Petr ; Schimmel, Jiří (referee) ; Míča, Ivan (advisor)
Most acoustic measurements and parameters provided by a manufacturer of acoustic elements, which are offering additional solutions to room acoustics as well as acoustic construction works, are mainly limited to the parameters associated with absorption of individual elements. Until now, these diffusional elements have been neglected. Diffusi- onal panels are used to e.g. eliminate direct reflection of sound waves to the listener or reflection of sound waves concentrated at one point. Combination of absorptive acoustic panels and diffusion elements results in a space that is customised to the submitter’s needs.
|
guest ::
