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8:30
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Bc.
Viet Tomáš
Nguyen
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M1
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Ing. Edyta Paula Adrián, Ph.D.
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Mikroskopické strukturování povrchů pro tkáňové inženýrství/Microscopic surface patterning for tissue engineering applications
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detail
Mikroskopické strukturování povrchů pro tkáňové inženýrství/Microscopic surface patterning for tissue engineering applications
With the rapid advancement of technologies and studies of different kinds, humankind has been able to benefit from such progress. One of the most prominent examples of this progress would be the improvement of living standards and medical treatments that enable one to live a longer and healthier life compared to what was only a few decades ago. However, not even modern medicine has solutions for diseases that damage organs to such an extent, that the only way to save a patient is to have the affected organs replaced by transplanting a new organ, from a donor.
To tackle the shortage of organs and tissues from donors, many have been putting their hopes into tissue engineering. As all of the tissue engineering applications require a vast number of healthy cells, numerous studies regarding cell culture have been conducted in order to improve their quality, viability and functionality. Generally, cells are cultivated on flat petri dishes and laboratory flasks. Nonetheless, it has been proven that cells show better proliferation on substrates with surface patterning.
Thusly, this work focuses on preparation of surfaces with microscopic surface patterning enhancing cell proliferation and differentiation.
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8:50
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Bc.
Tetyana
Zheleznyak
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M2
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prof. Ing. Petr Kočí, Ph.D.
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Modeling of PNA-SCR system with heat exchanger for abatement of NOx emissions during cold start
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detail
Modeling of PNA-SCR system with heat exchanger for abatement of NOx emissions during cold start
Combined exhaust aftertreatment systems including a passive NOx adsorber (PNA) followed by a catalyst for selective catalytic reduction of NOx (SCR) provide a promising solution for meeting the upcoming strict NOx emission limits for Diesel engines. The basic idea is that PNA adsorbs NOx during the cold start and releases it when the downstream SCR (including the urea injection unit) reaches its operating temperature. However, the NOx desorption from PNA may occur earlier than the SCR unit is heated up, resulting in an undesired NOx slip.
In this contribution I present a simulation study exploring the cold-start performance of a PNA–SCR system extended with a counter-current heat exchanger (HEX). The heat recuperation accelerates the SCR heat-up while slowing down the increase of the PNA temperature, which effectively delays the NOx desorption peak from the PNA and increases the chances that the desorbed NOx are completely reduced in the SCR. Three different PNA formulations are considered: Pd/BEA zeolite (BEA-PNA), Pd/SSZ-13 zeolite (SSZ13-PNA), and PtPd/ceria-zirconia-alumina (CZA-PNA). These adsorbers are studied in combination with two different SCR formulations: V2O5/WO3/TiO2 (V-SCR) and Cu/SSZ-13 (Cu-SCR). A new 1D model is developed for the heat exchanger device.
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9:10
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Gwendal
Tardivel
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B3
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prof. Dr. Ing. Tomáš Moucha
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Hydrodynamics measurements in multiple impeller pilot-plant reactor
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detail
Hydrodynamics measurements in multiple impeller pilot-plant reactor
Mass transfer is one of the fundamental phenomena of the process industry, adopted in chemical processes worldwide. The mass transfer processes are often carried out in stirred tank reactors due to the ability easily vary operational conditions. One of the purposes of mechanical agitation is to disperse the gas phase in the liquid. The finer the dispersion, the more interfacial air will increase and therefore the more material transfer is promoted. The advantage of using an agitated vessel as a reactor type is that it is more efficient when high liquid retention is required. To intensify the contact between a small amount of gas and a large amount of liquid, we often use mechanically agitated gas-liquid reactors with single or multiple impeller configurations on common shaft. The fact to have more than one impeller allows having a better hydrodynamic properties such as distribution of shear stress, energy dissipation, improved liquid circulation and better gas distribution. This work aims to measure residence time distribution, which is an important parameter for the evaluation of exchange flows between impeller sections, i.e. for individual impeller regions. This is gained by probes measuring conductivity.
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9:30
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Colin
Fauchadour
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M2
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prof. Ing. Petr Kočí, Ph.D.
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Filtration of particulate matter in exhaust aftertreatment filters
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detail
Filtration of particulate matter in exhaust aftertreatment filters
Particulate matter emitted from combustion engines consists of elemental carbon particles which agglomerate and adsorb other compounds. The soot particles have a negative impact on the environment and thus must be removed. This can be done using ceramic particulate filters composed of parallel channels that are alternately plugged at one end. Exhaust gas is forced to pass through the porous wall and soot is trapped on the walls. The captured soot is then oxidized, and the filter is regenerated. Mathematical modeling is an important part of the filter design targeting on high filtration efficiency and reasonably low pressure drop.
The soot size distribution allows for two types of filtration: deep filtration and cake filtration. The applied model assumes three mechanisms: interception, inertial impaction and Brownian diffusion. It can predict the filtration of particulate matter along the reactor but also the soot oxidation reactions into CO and CO2.
In this work, the developed model is verified by performing multiple simulations of filtration and regeneration under various operating conditions and filter configurations.
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9:50
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Bc.
Terezie
Císařová
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M1
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Mgr. Jaroslav Hanuš, Ph.D.
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Computational stalking of hypothetical ladderane membrane behaviour
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Computational stalking of hypothetical ladderane membrane behaviour
Molecular dynamics (MD) as a prediction tool has been used for molecular systems ranging from a bunch of atoms to the whole biosystems. It permits us to observe the configuration development of the system in time and to compute various descriptive data just with the knowledge of a few parameters and initial system configuration.
This work is engaged in predicting the behaviour of the ladderane-phospholipid bilayer by MD methods. A Ladderane phospholipid is a structure with possibly beneficial influence when integrated into the liposome membrane. Liposomes are spherical nanocapsules used as drug carriers that facilitate the drug distribution in organism. However, they often suffer from spontaneous leakage of encapsulated drugs. The permeability of liposomes at different temperatures is given by their phospholipid composition. Thus, we want to predict the potential extraordinary behaviour of liposomes with incorporated ladderanes. By MD methods, we can obtain data like area per lipid, thickness of the bilayer, lateral diffusion etc. Results are then used to interpret experimental data. With both approaches, it may be predicted whether liposomal structures such as ladderanes are suitable for liposome creation and possibly explain their so-far unknown purpose in annamox bacteria.
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10:30
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Jan
Sochor
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B2
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prof. Ing. František Štěpánek, Ph.D.
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Stabilization of suspension produced by anti-solvent precipitation in spray dried matrix
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detail
Stabilization of suspension produced by anti-solvent precipitation in spray dried matrix
Spray drying is a method of turning liquid material into dry powder of fine particle size. Thanks to its scalability, simplicity, and cost efficiency it is widely used in pharmaceutical industry as a method of improving bioavailability of drugs and as a step to tableting. The somewhat novel “three-fluid nozzle” uses two different inlet feeds, which get combined in the nozzle tip and subsequently atomized. The aim of my work is combining spray drying with in-situ anti-solvent precipitation, a common particle size reduction method, using different parameters (such as solvent/anti-solvent ratio, temperature…) with the three-fluid nozzle to make the powder that is easier to handle, due to improved flow properties and further improve bioavailability of drugs, which can be achieved by improved wettability and dispersibility of the powder and low drug particle size.
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10:50
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Bc.
Lucie
Kubíčková
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M2
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Ing. Martin Isoz, Ph.D.
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Affordable turbulence modelling with immersed boundary method
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detail
Affordable turbulence modelling with immersed boundary method
Immersed boundary method (IBM) is a simulation approach used in computational fluid dynamics. The core idea is that the simulated part geometry is not directly represented via a complex conforming computational domain, but it is projected onto a simple domain by a scalar field (λ) and adjustment of governing equations. Thus, the time spent on mesh generation is substantially reduced. It is advantageous to use the IBM in geometry optimizations, where having a single mesh and updating only the scalar field allows for a massive optimization speed-up. Nonetheless, there is a problem with simulation of the fluid behavior in the boundary layer near the immersed walls. In general, this problem can be solved by a mesh refinement close to the IB. However, this destroys the mesh independence on the specific geometry. Moreover, the more turbulent the flow is the finer mesh is required and the simulation time rapidly increases making any optimization unaffordable. Hence, in this work, we aim to avoid this problem by using established turbulence models where the turbulent behavior is approximated using closure variables and specific boundary conditions, wall functions (WFs). The main contribution of the work lies in design and implementation of the wall functions into our custom IBM variant.
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11:10
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Bc.
David
Horký
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M2
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prof. Dr. Ing. Juraj Kosek
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Triboelectric separation of plastic waste: how to get from batch to continuous process?
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detail
Triboelectric separation of plastic waste: how to get from batch to continuous process?
Electrostatic charging of material surfaces during mutual friction is a well-known phenomenon. It occurs not only in industry but also in everyday life, and it causes various problems, such as undesired discharges that may ignite fires or cause explosions. However, static electricity can be useful in many processes, for example, in a triboelectric separator of plastic waste.A crucial step towards using the separator on an industrial scale is transforming it from a batch to a continuous process. This transformation's main issue lies in the not-fully understood mechanism of triboelectric charging. It may be influenced by various factors, such as atmospheric humidity, chemical additives on the surface of the charged materials, or even an external electric field. These factors influence the resulting polarity and absolute value of surface charge, and thus it is necessary to satisfyingly understand them to make the process effective.
In our experiments, the effect of an external electric field and its direction on the resulting saturation charge was studied. Additionally, conductive polymers were used as charging materials and their influence on the charging mechanism was examined.
Knowledge gained in this research may help to transfer triboelectric separation to a continuous process.
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11:30
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Bc.
Zuzana
Hlavačková
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M2
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prof. Ing. František Štěpánek, Ph.D.
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Manufacturing of multi-drug personalized medicine by solvent impregnation
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detail
Manufacturing of multi-drug personalized medicine by solvent impregnation
The current ways of drug manufacture are based on large-scale production with a few dosage strength variations. The dosage strength often differs from the patient-specific needs, which leads to the patient being constantly slightly underdosed or overdosed. Patients often get drugs prescribed in various combinations with other drugs. This results in low compliance of the patients. The aim of personalized medicine is to create drugs that are tailored to each patient using patient-specific information. Promising ways of creating such medicine are minitablets or drop-on-demand (DoD) technique and others. The tablets in this work were prepared, using the DoD technique, by layer-by-layer precise droplet loading from a solution of the desired active pharmaceutical ingredient (API). Placebo tablets containing a high amount of mesoporous silica were used as a substrate. The pores of mesoporous silica are big enough to capture the API and small enough to prevent the API from recrystallisation. Therefore, the API remains in its amorphous form. The aim of this work was to study the dissolution profiles from tablets containing combinations of two and three APIs prepared by the DoD method and to study the interactions of APIs between each other.
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11:50
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Bc.
Zbyněk
Tomiška
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M2
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Ing. Alexandr Zubov, Ph.D.
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Cahn-Hilliard modelling of hollow fibers morphogenesis
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detail
Cahn-Hilliard modelling of hollow fibers morphogenesis
Hollow fibers are one of the most popular membrane materials used for a gas separation. The advantage of hollow fibers, in comparison to different membrane materials, is their large membrane surface per module volume. The problem studied in this work is mathematical modelling of a formation of the hollow fiber. The mechanism of the morphogenesis is that two concentric streams of polymer solution and antisolvent are gushed from two concentric nozzles. During the downward fall, the two streams are mixed and consequently form thin tube of porous polymer with the hole inside originating from the inner nozzle. The developed dynamic, spatially 2D simulation describing morphogenesis of the hollow fiber is based on Cahn-Hilliard model of spontaneous phase separation. The primary goal of this work is an extension of Cahn-Hilliard model with balance of momentum, i.e. description of convective flow, which should allow us to predict morphological features (e.g. finger-like pores) that cannot be captured by purely diffusion-based model.
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