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Experimental and computer modeling diffusion of low-molecular solutes in gel – based carriers
Masár, Lukáš ; Gregorová, Eva (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on combination of experimental study and computer modelling of diffusion processes in gel phases. The aim of experimental part of the diploma thesis was to test and optimize the setting of the diffusion coefficient in gel medium by using the method of horizontal diffusion cells, commonly used for study of diffusion processes through membranes. Specific description of experiments was to determinate the impact of presence of reactive component in inert hydro-gel carrier on final value of diffusion coefficient of low-molecular model diffusion probe. The defined dependencies were subsequently combined with computer simulation of diffusion process in a properly designed model in order to determinate the experimentally unavailable system parameters. The stated combination of both approaches was proved to be an appropriate instrument for studying of hydro-gels with a wide potential especially in the field of preparation of hydro-gel carriers with controlled release of active substances.
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Planar transmission line on semiconductro substrate
Chára, Pavel ; Harwot, Ondřej (referee) ; Pokorný, Michal (advisor)
The aim of this thesis is to acquaint with the various types of the planar transmission lines and discuss their properties. Subsequently, the development of the real models of selected lines and verification their properties by simulations using COMSOL Multiphysics. The second part deals with the modeling of the semiconductor substrate, which replacing the dielectric substrate used for the transmission lines in the first part. The final part deals with the verification of calculation results in a specialized program TiberCAD.
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Optimization of method for susceptibility measurement
Jeništa, Petr ; Marcoň, Petr (referee) ; Bartušek, Karel (advisor)
The aim of this thesis is measure the specimens placed in field of MR tomograph, the measured data to evaluace the process and measurement errors. The theoretical part is focused on describing basic parameters of magnetic field, commissioning some older methods of measurement and design methods for the measurement of samples not issuing MR signal. There is performed modeling for the proposed Metod and the 1D, 2D and 3D environments using COMSOL Multiphysics. The practical part is the measurements samples in the tomograph the Institute of Scientific Instruments Academy of Science in Brno. The measured data are processed in Marevisi and Matlab programs. The MATLAB program is written for processing, analysis and data evaluation, after which it is possible to determine the value of the magnetic susceptibility of the selected samples. In conclusion of the work is the quantification accuracy of measurements.
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Modeling migration of pharmaceuticals
Osipenko, Ivan ; Závodská, Petra (referee) ; Klučáková, Martina (advisor)
The presented bachelor thesis deals with the problem of the possibility of sulfapyridine diffusion in soil systems. The main objective of this thesis is to propose a simple mathematical model to calculate and explain the possibility of drug migration in soil systems using the example of diffusion in agar gel in the presence of humic substances as the main component of organic matter in soil. In the present bachelor thesis, simulations of sulfapyridine diffusion in porous media, influenced by chemical side reactions of different series, were carried out. For these calculations COMSOL Multiphysics software and the corresponding packages "Chemistry" and "Transport of diluted species in porous media" were used, allowing simulations of real processes. The modelling results showed that the addition of reactive components to the hydrogel have an effect on the migration of sulfapyridine due to the interactions taking place during the diffusion. Reactions of different orders, including back reactions, were added successively to the simulations in inert media. The results obtained showed that the probable sum interaction mechanism has less influence on migration than the interaction of other mechanisms.
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Thermal Mass Flowmeter
Mlčoch, Albert ; Kunz, Jan (referee) ; Beneš, Petr (advisor)
The thesis deals with the design of a mathematical model and practical implementation of a flowmeter based on the thermal principle. The range of the proposed flowmeter is from units of kilograms per hour to lower hundreds of kilograms per hour. The design of the flowmeter is non-invasive to the flow channel, the heating element is located outside the pipe. In this paper, the flowmeter parameters are identified and a temperature regulator is proposed. Measurements are made on a test bench. The results of the measurements are discussed. Modifications to the existing hardware are suggested.
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Influence Of Piezoelectric Material Properties On Impedance Characteristic And Improvements Of Calibration Equipment
Krejčí, Jakub
This paper deals with finite element simulations of impedance characteristics piezoelecticelements utilized in sensors of acoustic emission (AE). Coefficients of piezoelectric material arechanged to evaluate the sensitivity to their variation in case they are not known precisely, so to whichextent can they influence the sensitivity of the sensor. Result showed sensitivity on coefficient inc-matrix, mainly to coefficients c11 and c13. Second investigated topic is issue with test stand for calibrationof AE sensors, where output of force sensor was affected by parasite signal. By contactlessmeasurement with laser interferometer was discovered the parasite signal is caused by mechanic ofthe system and it is no threat for the measuring chain.
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Simulations And Measurement Of Acoustic Emission Effects
Krejčí, Jakub
This paper deals with issue of method of acoustic emission and performed measurements of acoustic emission signals and simulation of this phenomenon. Main interest is given into measurement of acoustic emission transducer displacement to verify homogeneity on its surface in time and simulations by finite element method. Performed simulations deal with displacement calculation of calibration block after a capillary break, calculation of impedance characteristics of piezoelectric sensing element and their comparison with analytic solution or measurement.
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Modelling of particle thermal motion
Orság, Miroslav ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
The goal of this thesis was to get familiar with the basics of mathematical description of the thermal motion of particles in a given media, and with other possibilities of the software package COMSOL Multiphysics. A model for viscous and viscoelastic environments was created, a uniform and user friendly system for simulation and calculation of MSD and system for data conversion from FCS to MSD. Furthermore, the possibilities of the model for use in microrheology were assessed and another procedure in the implementation of the COMSOL program in the characterization of gels was proposed.
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