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Department of Chemical Engineering

List of available PhD theses

Acidorezistant forms of prazols for more effective treatment of stomach ulcers

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Study programme: Drugs and Biomaterials

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Prazols are a group of pharmaceutical compounds, which block the production of hydrochloric acid in the stomach through proton pump inhibition. They are the drug of first choice for the treatment of peptic ulcers and other gastrointestinal diseases. However, the molecules are unstable at low pH (such as in stomach), so now, they must be coated in an acidorezistant protective layer that only dissolves at the higher pH of the intestine. The goal of this work will be to prepare novel multicomponent solid forms of prazols with pH-controlled solubility. Through the preparation of salts, cocrystals, coamorphs and solid dispersions, we aim to create solid forms that will have lower solubility in acidic conditions than in basic ones, therefore negating the need for the acidorezistant coating. Samples will be prepared by crystallization or grinding. The properties of the prepared materials will be evaluated regarding purity, stability, crystallinity (XRPD, SEM, DSC, NMR) and pH-dependant solubility.

Anomalies of aqueous solutions of simple alcohols and their consequences for industrial applications

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Short-chain alcohols (C1-C3) are used as solvents, co-solvents or co-surfactants in many industrial, biotechnological and pharmaceutical applications and, at the same time, they are of great interest due to their atypical physico-chemical properties over a broad range of composition. They exhibit anomalous behaviour when mixed with water, which has been proven to be a result of the ordered formation of water and alcohol molecules. The result is a significant drop in surface tension, multiple increases in viscosity and a dramatic change in bubble surface mobility and bubble coalescence. In these systems, additional added surfactants do not behave in the common manner. At the moment there are only few studies of the overlap of the mentioned anomalies into real chemical or biological processes. The aim of this project is study the behaviour of ethanol-water and propanol-water mixtures in aerated systems. The basis will be the visualization of processes (high-speed camera) and measurement of surface tension, coalescence and interphase viscosity. In three-phase systems, bubble adhesion and droplet spreading will be studied.

Anomalies of aqueous solutions of simple alcohols and their consequences for industrial applications

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Short-chain alcohols (C1-C3) are used as solvents, co-solvents or co-surfactants in many industrial, biotechnological and pharmaceutical applications and, at the same time, they are of great interest due to their atypical physico-chemical properties over a broad range of composition. They exhibit anomalous behaviour when mixed with water, which has been proven to be a result of the ordered formation of water and alcohol molecules. The result is a significant drop in surface tension, multiple increases in viscosity and a dramatic change in bubble surface mobility and bubble coalescence. In these systems, additional added surfactants do not behave in the common manner. At the moment there are only few studies of the overlap of the mentioned anomalies into real chemical or biological processes. The aim of this project is study the behaviour of ethanol-water and propanol-water mixtures in aerated systems. The basis will be the visualization of processes (high-speed camera) and measurement of surface tension, coalescence and interphase viscosity. In three-phase systems, bubble adhesion and droplet spreading will be studied.

Bioengineering and pharmaceutical application of liposomes and their composites

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Study programme: Drugs and Biomaterials

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Liposomes and related particles (exosomes, supported lipid bi-layers, magneto-liposomes, liposome aggregates) have many intetesting applications especially in drug encapsulation and drug delivery. The aim of this project is to explore liposome-based systems as miniature reactors for remotely controlled drug delivery and drug synthesis from pro-drugs. The encapuslation of multiple actives or their precursors, characterisation of release kinetics, stability, interaction with biological substrates in vitro and in vivo will be investigated. In particular, the incorporation of magnetic nanoparticles into liposome structures for sensing and remote control capability, and the embedding of mesoporous silica particles into liposomes in order to increase the drug loading capacity, will be explored along with processes for their fabrication. As a novel method of permeability control, the incoporation of ladderanes into liposomes will be investigated.

Controlling drug crystals properties during crystallization and their impact on consequent unit operations

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Active Pharmaceutical Ingredients (APIs) are commonly small molecules, which are prepared by crystallization process. Properties of prepared crystals (i.e. physico-chemical but also formulation properties) are strongly dependent on the used drug solid form, their size and crystal morphology. Therefore, the focus of this project is to study impact of crystallization process parameters and post-processing step on the prepared drug crystals with respect to size, morphology and polymorphism. Temperature modulated batch crystallization will be combined with wet-milling process to control the shape as well as flow properties of prepared drug crystals. Crystallization step will be combined with following steps, i.e. filtration and drying, to evaluate the impact of the crystal size and shape on the efficiency of these unit operations. In parallel, we will also study impact of washing step on the amount of remaining solvent and the polymorphic stability of the final product. While pharmaceutical industry is typically using batch operation, as a part of this project we will investigate the possibility to prepare same drug crystals as studied in batch mode in a continuous process. Process analytical technology capable to measure crystal size, shape and morphology com will analysis of composition via Raman spectroscopy will be used to ensure constant product quality. On-line measurement will be supported by off-line measurement via SEM, IR spectroscopy, XRD and NMR. Student will be also involved in the scale up of developed process.

Design of high performance flexible supercapacitors based on cellulose nanofibrils and conductive materials

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

Development of 3D cell cultures for the evaluation of drug delivery systems

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

Development of nanoparticles for sonotherapy

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Main focus of this project is to synthesize multifunctional vesicles loaded with hydrophilic and hydrophobic drugs and inorganic nanoparticles (iron and gold) as the novel nano carrier for photoacoustic imaging and ultrasound mediated delivery into cancer cells. Student will study the impact of vesicle composition (primary system will be surfactant and cholesterol forming niosomes) and method of preparation on the size and properties of the formed nano carriers as well as drug encapsulation efficiency. Furthermore, to tune drug release kinetics gold nanoparticles with various sizes and shapes will be synthesized and incorporated either in the core or in the shell of niosomes. Once drug will be loaded into niosomes its release will be measured as a function of ultrasound intensity and duration as well as upon exposure to the light irradiation. In vitro experiments are planned to be used to test uptake by the cells. Using theoretical and experimental approaches, interactions between the drugs and niosomes will be studied to understand the possible mechanisms for their incorporation allowing to optimize the long-term formulation stability. Quality of the prepared samples will be characterized by combination of analytical techniques including 3D modulated DLS, Depolarized dynamic light scattering, static light scattering, optical video microscopy combined with image analysis, XRD, UV/VIS and Raman spectroscopy and cryo-TEM.

Development of scaling-up methods of industrial mechanically agitated reactors

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Dr. Ing. Tomáš Moucha

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Fermenters or, in general, mechanically agitated aerated vessels are frequently used in industry for the intensification of gas-liquid mass transfer, especially in the case of a low gas to liquid volume ratio. Industrial processes as aerobic fermentations, hydrogenations and chlorinations can serve as examples of their application. In many processes the gas-liquid interfacial mass transfer becomes the rate determining step, so the volumetric mass transfer coefficient becomes the key parameter in the design. Mass transfer laboratory pays many year effort to gas-liquid mass transfer measurement in mechanically agitated gas-liquid dispersions with the aim to formulate the scaling-up rules for industrial vessels design. In the frame of this research an extensive experimental work has been done using various batch types (coalescent, non-coalescent, viscous) and for various impeller types (from purely axially pumping to purely radially pumping ones) and their combinations. After collecting large data series in laboratory scale vessels, experimental work continues using pilot-plant vessel equipped with a modern computer controlled regulation and data acquisition system in the form used also in industry. The aim of the PhD work is to collect the transport characteristics (impeller power, gas hold-up and volumetric mass transfer coefficient, kLa) measured in the pilot-plant vessel using various types of impellers (e.g., Rushton Turbine, Lightnin, Techmix, Pitched Blade impellers). The experimental research will be now focused to the transport characteristics in viscous batch and in the presence of solid particles. Both high viscosity and solid particles presence are typical features of industrial fermentation broths. Based both on the laboratory data and on the pilot-plant data the scaling-up rules will be formulated, which will be employable for industrial gas-liquid contactors design. A PhD student will get acquainted with the design methods of other gas-liquid and vapour-liquid processes as well, because he/she will work in the team dealing also with the absorption columns, distillation columns and ejector bubble columns design. More info: Tomáš Moucha, UCT building B, ground floor, room No. T02a, phone: 220 443 299, e-mail: mouchat@vscht.cz

Diagnostics of two-phase flows in microchannels

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Jaroslav Tihon, CSc.

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The aim of this project is an experimental investigation of the character of two-phase flow (gas/liquid) in microchannels. The mapping of different flow regimes will be carried out for various microchannel configurations (e.g. channel crossing, T-junction, sudden expansion) and different model liquids (Newtonian, viscoelastic, pseudoplastic). The electrodiffusion method, an original experimental technique developed in our department, will be used to determine the near-wall flow and to detect the characteristics of translating bubbles. The visualization experiments using a top-level high-speed camera (Redlake) and the velocity field measurements by mPIV technique (Dantec) will bring additional information on the flow structure in microchannels. The candidate should have a M.Sc. degree in chemical engineering or in a similar applied science field. He/she should possess experimental skill for a laboratory work and some basic knowledge of hydrodynamics. However, the enthusiasm for independent scientific work is the first principal requirement. The candidate will surely profit from our long-time experience in experimental (computer-controlled measurements with subsequent data processing in LabView) and theoretical (solving the complex hydrodynamic problems in MatLab or Mathematica) fluid mechanics.

Dynamics of multi-phase systems: gas-liquid-solid

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Multiphase systems are all around us, in nature and in industry technologies and applications (sedimentation, fluidization, bubble columns, flotation apparatuses, etc.). Due to the complexity and applicability of these systems, it is seriously worth to study their hydrodynamic aspects. The present PhD research will focus on the experimental and theoretical description of processes controlling multiphase dispersions at microscale level (like bubble coalescence, bubble-particle collision) and their consequences on the flow regimes at the macroscale level (bubble columns, flotation apparatus, etc.). The obtained results will be valuable in many industrial applications (chemical and oil industry, food processing, metallurgy, pharmaceutical and environmental industry).

Effect of interfacial properties on dynamics of bubbles and drops

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Multiphase systems consisting of a gas phase or a liquid phase dispersed in a liquid environment, such as foams, emulsions, are omnipresent in nature and in living systems, as well as in industrial products of high added value as in pharmaceutical and cosmetical applications. The presence of surfactants (SAS) alters the behavior of many multiphase processes, and for systems in motion, the characterization of the interface only by surface tension is not enough and less conventional measurements of surface rheology and SAS adsorption/desorption characteristics are crucial. The aim of this work is to experimentally determine the influence of SAS on the dynamics of processes with bubbles and drops (movement, dissolution, breakup, coalescence, etc.) and to characterize selected SASs by measuring relevant physico-chemical and transport properties. The typical work will include measurements of interfacial rheology, observations of bubble/drop dynamics by high-speed camera, but also building single-purpose experimental equipment and physical interpretation of results.

Electrochemical energy storage based on metal-air chemistry

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Dr. Ing. Juraj Kosek

Enzyme-catalyzed reaction of vegetable oils in supercritical CO2

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Marie Sajfrtová, Ph.D.

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Enzymatic reactions in supercritical carbon dioxide (scCO2), combining advantages of enzyme specificity, fast diffusion in supercritical fluids, and non-toxic scCO2, are a relatively new and promising field of research. In the present project, they are applied to enrich the products of vegetable oil reactions with w-3 a w-6 polyunsaturated (essential) fatty acids, necessary in nutrition. The reactions catalyzed by a regiospecific enzyme and methods for separation of the fraction enriched in essential fatty acids from reaction mixture will be studied. The aim is to propose a “green” way to prepare enriched vegetable oils, which will integrate the extraction of oil from seeds, its reaction, and fractionation of reaction mixture and will be based on the application of scCO2

Experimental and modelling study of diffusion and relaxation processes in polymers

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Dr. Ing. Juraj Kosek

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Diffusion and sorption of species in polymeric materials is essential in many applications: membrane separation, food protection, controlled ripening, degassing of polymers, production of polymers in reactors, coating by polymer latexes. Better understanding of diffusion in polymer is limited by scarce systematic experimental studies. Moreover, many theoretical models of penetrant diffusion in polymers were introduced, but the quality and adequcy of these approaches are often not well assessed. This PhD project aims to contribute first to systematic experimental studies of diffusion, sorption and related processes. The working horses are going to be differential pressure decay, confocal Raman in pressure cell and TD-NMR apparatuses and the results will be accompanied by systematic sorption equilibria and swelling studies, SAXS, micro-CT, DSC, GPC and AFM. The purpose of these studies is to provide comprehensive characterization of polymer samples including their semi-crystalline morphology and relaxation dynamics of polymer chains. Theoretical concept describing diffusion are usually based on Fickian-like models, models employing the free-volume theory and model with driving force described consistenty with thermodynamics by the gradient of chemical potential. Moreover, semi-crystalline morphology is usually introduced just empirically into the models. Moreover, physical chemistry offers molecular dynamics simulations, which are somehow limited by the available computation power. All these models will be assessed with respect to the database of high-quality diffusion data. The main goal is to establish predictive models of diffusion in polyolefin materials. Such well validated models are currently not available. The situation is complicated also by the non-isotropic nature of diffusion in many materials with the history of their thermal processing affecting semi-crystalline morphology. Prospective PhD student shall be involved in activities contributing to his/her personal development including the construction of new apparatuses and participation on grants and industrial projects. Prospective PhD student is expected to spend a term in some European laboratory with similar research interests and to take some responsibility for the contractual industrial research. Info: phone +420 220 44 3296, office B-145, e-mail jkk@vscht.cz, web http://kosekgroup.cz

Fabrication of hierarchical structures and their interaction with a living cell

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Study programme: Chemical Engineering
Theses supervisor: Ing. Viola Tokárová, Ph.D.

Flow-through milifluidic systems for investigation of electromembrane separation processes

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Ing. Zdeněk Slouka, Ph.D.

Fluid bed processing of nanosuspensions

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

Formation of Microstructured Materials through Self-Assembly

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: RNDr. Ivan Řehoř, Ph.D.

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Self-assembly is a spontaneous arrangement of individual units - building blocks - into an ordered structure. The ordered structure has the lowest energy from all accessible building block arrangements, which drives the assembly process. The arrangement of the ordered structure is defined by the properties of the building blocks, such as their shape, material anisotropy or magnetic interaction with external field. Tailoring these properties to achieve desired structure can be considered 'programming' and may represent viable alternative to other ways of constructing micro and nanostructured materials. The question of lengthscales is crucial in self-assembly. When building blocks are small enough (We recently demonstrated, that we can assemble anisotropic hydrogel microparticles on solid liquid interface to form ordered 2D structures. We introduced novel mechanisms to control orientation of the building blocks during the self-assembly process and, thus, to not freeze in the disorderedd state. Ordered microparticles can be subsequently covalently bound together. The resulting structure - sheet - has complex mechanical properties i.e. ability to buckle in a preprogrammed way determined by the shape, size and material composition of the building blocks. The goal of the project is to find new approaches to the self-assembly of hydrogel microparticles and combine them with directed asembly methods using mobile microrobots developed in our team (https://www.youtube.com/watch?v=PQOXS7f9rDg). Resulting structures will find application in the preparation of metamaterials, microrobotics or tissue engineering.

Formation of drug colloids in gastrointestinal tract and their characterization

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Many active pharmaceutical ingredients (APIs) have low solubility in water, which causes their low bioavailability. To improve this negative effect it is common to prepare metastable forms of APIs, which are characterized by enhanced solubility. However, this often results in their low stability during dissolution which is manifested by APIs precipitation. In this project we will investigate conditions leading to the formation of colloidal particles composed of API, which can be considered as APIs reservoirs. Impact of common excipients used as nucleation or growth inhibitors will be combined with naturally occurring surfactants in the GI fluids. Combination of several analytical techniques, i.e. DLS, SLS, optical video microscopy combined with image analysis, surface tension measurements, DSC, XRD, UV/VIS, Raman spectroscopy SEM/TEM combined with elemental analysis and NMR will be used to identify size, shape and composition of the formed colloids. Specific experiments mimicking mass transfer through the intestine membrane will be used to study the dynamic of drug colloids and their capability to maintain API super saturation. Experiments performed in our laboratory will be combined with measurement of mass transport in simulated GI tract setup provided by our academic collaborator.

Hydrogel microparticles mimicking red blood cells

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: RNDr. Ivan Řehoř, Ph.D.

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Red blood cell has a discoidal shape around 10 μm in diameter and circulates effortlessly through the bloodstream, although the capillaries are as thin as 5 μm. This unique ability is given by their shape, mechanical properties and surface. The aim of this project is to synthesize hydrogel microparticles that mimic these red blood cells properties. Stop-flow lithografy will be used for synthesis of blood cell-shaped hydrogels from biodegradable polymers of such composition, that the mechanical propperties of the particles will be similar to the real red blood cells. In the followup of this project, the ability of hydrogels to circulate in the bloodstream will be investigated. The ultimate goal of the project is to incorporate chemical fluorescent sensor monitoring medically relevant parameter (e.g. pH) into the microparticle and read its signal remotely through the skin using a detector placed outside the patients body.

Hydrogels and their nanocomposites

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Jaroslav Tihon, CSc.

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Hydrogels are cross-linked polymers containing a large amount of water. They can be used, for instance, in medicine (contact lens, wound dressing materials, tissue engineering), and in vaste water treatment (they exhibit high adsorption ability for organic dyes). When suitable nanoparticles (mostly anorganic) are incorporated into a hydrogel structure, hydrogel nanocomposites are formed. They often exhibit even better physicaly-chemical properties than original hydrogels – typically their rigidity increases, and water swelling, pollutants adsorption or drug releasing ability changes. In this project, the preparation of novel hydrogel nanocomposites, their physicaly-chemical properties and potential using in the field of medicine and environmental engineering will be studied. The candidate should have a M.Sc. degree in chemical engineering, physical chemistry, or in a similar applied science field. Some experimental skill is appreciated. However, the enthusiasm for scientific work is only the principal requirement.

Impact of protein properties on its aggregation behavior and stability during lyophilisation

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Protein stability and formation of aggregates is of paramount importance when considering intravenous delivery route. Therefore, this project will be covering al key steps in formation of injectable protein dosage. In collaboration with our university partner we will start from production of proteins with precisely defined modifications of amino acid sequence. In this way we will be able to prepare peptides or proteins with hydrophilic and hydrophobic moieties. Consequently we will study their colloidal behavior under various conditions by varying protein concentration, ionic strength, type or ions, presence of stabilizing agents etc. In the next step we will perform lyophilisation of prepared samples under various conditions with or without cryo protective agents and controlled freezing step followed by the analysis of reconstituted product. Analysis will be done by several techniques including dynamic and static light scattering, XRD, SAXS NMR, TEM, calorimetry and circular dichroism. Gained knowledge will be used in optimization of conditions for preparation of injectable protein products.

Matematické modelování mikrofluidních separátorů pro dělení racemických směsí

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Microfluidic devices are characterized by a large ratio of interfacial area to internal volume. This can be used in chemical separations by extraction or membrane processes. Separation of optically active substances, often important pharmaceutical or food products, at membranes or sorbents with anchored chiral selectors represents a great challenge for chemical engineers. Mathematical modeling can lead to a better understanding of complex processes in such devices and consequently to the design of efficient microfluidic separators. The main objectives of the PhD project are: Based on preliminary and available experimental data, a mathematical-physical description of mass and momentum transport in microfluidic devices with anchored chiral selectors will be developed. Mathematical models of processes on different spatial scales will be created. They will include description of transport of the separated chemicals by diffusion, convection and electromigration. Models will be analyzed numerically. Parameter values that ensure high separation efficiency and high productivity of the microfluidic system will be searched in the parameter space. The lab is equipped with modern computers. The participation of the doctoral student in grant projects and active participation in international scientific conferences is expected.

Mathematical Modelling of Electrochemical Cells

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Dr. Ing. Juraj Kosek

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The advancement of renewable energy sources (wind turbines and photovoltaics) as well as electric cars poses challenging requirements on the storage of electric energy either in stationary distributed storage systems or in batteries with high specific energy providing sufficient power. The development of technically, ecologically and economically acceptable solutions for the above mentioned applications is mostly empiric. The objective of this project is the development of models of electrochemical cells that will improve our understanding of practical limitations of various cells, enable the testing of various hypotheses and enable the systematic development of improved cells. This Ph.D. project is connected with the experimental research and development in our laboratories. By solutions of modeling equations we are going to obtain concentration and electric potential profiles as well as load and discharging characteristics of various batteries. We shall concentrate on following electrochemical systems: (i) redox-flow batteries, (ii) classical lead cells, and (iii) zinc-air secondary batteries and fuel cells. Mathematical modeling will employ also meso-scale spatially 3D models developed by former Ph.D. students. For example, we shall simulate oxygen transport and reduction in the porous air electrode of zinc-air battery or the dendritic deposition of zinc. The prospective Ph.D. student will become familiar not only with advanced 3D modeling techniques but also with thermodynamics of concentrated electrolytes, transport of ions, description of porous and pasted electrodes, effects of partial solubility of species in electrochemical cells, phase changes at electrode surfaces etc. The student will closely cooperate not only with colleagues from our laboratories but also with partners from companies and other universities.

Mathematical modeling of microfluidic devices for separation of racemic mixtures

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Microfluidic devices are characterized by a large ratio of interfacial area to internal volume. This can be used in chemical separations by extraction or membrane processes. Separation of optically active substances, often important pharmaceutical or food products, at membranes or sorbents with anchored chiral selectors represents a great challenge for chemical engineers. Mathematical modeling can lead to a better understanding of complex processes in such devices and consequently to the design of efficient microfluidic separators. The main objectives of the PhD project are: Based on preliminary and available experimental data, a mathematical-physical description of mass and momentum transport in microfluidic devices with anchored chiral selectors will be developed. Mathematical models of processes on different spatial scales will be created. They will include description of transport of the separated chemicals by diffusion, convection and electromigration. Models will be analyzed numerically. Parameter values that ensure high separation efficiency and high productivity of the microfluidic system will be searched in the parameter space. The lab is equipped with modern computers. The participation of the doctoral student in grant projects and active participation in international scientific conferences is expected.

Membrane separation of fermentation primary products

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Dr. Ing. Tomáš Moucha

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In biotechnologies, batch processes are often used, in which living cultures/biomass are used. Metabolites produced by culture are often poisonous and can damage the culture itself, as an example of which can serve ethanol fermentation. In periodic processes, the initial periods including sterilizing, nutrient dosing, etc., used to be time consuming, financially burdening. Therefore, it is desirable to dedicate an effort to develope continuous performance of such processes. One of the operations ensuring the process continualization can be membrane separation. This case brings the necessity of two membranes modules: i) microfiltration to separate solid particles-biomass and ii) pervaporation to separate primary product of fermentation, e.g., ethanol, as mentioned above. The goal of this work is to experimentally develop two step membarne separation technique, including microfiltration and pervaporation, to be prepared for an interconnection with a fermenter. THe development will be conducted from the viewpoint of chemical engineering. The reached separation parameters (selectivity, permeability) will be investigated in dependency on the process parameters (pressure, flowrate, temperature, feed composition). Chemical engineering quantities (membrain polarization module, mass transfer coefficient,...) will be used to describe these dependencies. At the workplace the new membrane modules are available, which were purchased for the purpose of this development. The PhD student will get familier both with industrial membrane module and with the custom made one. In addition to being familiar with modern technologies introduced in industry, the PhD student will also work in the team of students and academic staff who are experienced in industrial cooperation. PhD study will prepare the student to obtain either qualified working position in industry or to be able systematically conduct further research from the viewpoint of qualified chemical engineer. Further information Assoc. Prof. Tomáš Moucha, UCT Prague, building B, room T02, email: tomas.mooucha@vscht.cz

Microfluidic systems for the synthesis and separation of optically active chemicals

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Microfluidic reactors and separators are modern devices that represent an alternative to conventional batch and flow systems used in biotechnology. The small spatial scale ensures reproducible reaction conditions and intensive mass and heat transfer. Microfluidic devices generally lack moving parts and allow easy combination of many unit operations such as mixers, separators, reactors. The main objectives of the PhD project are: Study of kinetics of selected enzymatic reactions, which lead to production of optically active chemicals that are used in pharmacy, food industry or synthesis of chemical specialties. Design and fabrication of microfluidic separators with embedded membrane or sorbents with attached chiral selectors for separation of racemic mixtures. Testing of manufactured microfluidic devices for selective separation of selected optically active compounds. Evaluation of the possibility of accelerated transport of optically active substances through membranes by means of an imposed electric field. The lab is equipped with technologies for the production of microfluidic systems, modern measuring instruments and powerful computers. The participation of the doctoral student in grant projects and active participation in international scientific conferences is expected.

Mikrofluidní systémy pro syntézu a separaci opticky aktivních látek

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Microfluidic reactors and separators are modern devices that represent an alternative to conventional batch and flow systems used in biotechnology. The small spatial scale ensures reproducible reaction conditions and intensive mass and heat transfer. Microfluidic devices generally lack moving parts and allow easy combination of many unit operations such as mixers, separators, reactors. The main objectives of the PhD project are: Study of kinetics of selected enzymatic reactions, which lead to production of optically active chemicals that are used in pharmacy, food industry or synthesis of chemical specialties. Design and fabrication of microfluidic separators with embedded membrane or sorbents with attached chiral selectors for separation of racemic mixtures. Testing of manufactured microfluidic devices for selective separation of selected optically active compounds. Evaluation of the possibility of accelerated transport of optically active substances through membranes by means of an imposed electric field. The lab is equipped with technologies for the production of microfluidic systems, modern measuring instruments and powerful computers. The participation of the doctoral student in grant projects and active participation in international scientific conferences is expected.

Modeling of thermal degradation of wood materials in fire

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Dr. Ing. Milan Jahoda

Modelling of gas flow in apparatus of chemical technology

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Ing. Dalimil Šnita, CSc.

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Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows. Computers are used to perform the calculations required to simulate the flow of the fluid, and the interaction of the fluid with surfaces defined by boundary conditions. Initial validation of such software is typically performed using experimental apparatus or pilot and industrial data. The work will be focused on the comparison between more and less approximated mathematical models in the form of case studies. Work will be concerned with several chosen devices, e.g. laminar boxes or electric furnaces with forced or natural convection. The results of modelling will be validated with the available experimental data.

Modular Hydrogel Microrobots

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: RNDr. Ivan Řehoř, Ph.D.

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Miniturization of robots to the sizes of tens of microns will allow their application in new, currently inacccesible areas, such as controlled drug delivery or microsurgery. In order to simplify the mechatronic design of such microrobots, novel approaches have been adopted for their operation and control, exploiting soft materials, actuating through deformation, such as responsive polymers. These advanced materials, together with development of their processing in microscales gave rise to soft microrobots capable of independent untethered motion or manipulation with other objects . In our group, we have recently developed hydrogel microrobots, crawling over surfaces, powered by light (https://www.youtube.com/watch?v=PQOXS7f9rDg). Many of the visionary real-life applications of microrobots foresee their ability to autonomously cooperate and connect into greater structures, that will perform tasks, inaccessible to the individual robots. Modular connectivity of macroscopic locomotive robots has been tackled experimentaly, demonstrating the extended application of such robot assemblies, compared to the individual robots. The connective mechanisms and the organization of the individual robots into the assembly however remains a complex and challenging task. This project aims to probe potential pathways for the connection of crawling hydrogel microrobots into actuating millimeter-sized structures, capable of performing mechanical work.

Nové systémy pro doručování steroidních léčiv

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Steroids represent a promising class of drugs for a range of diseases including chronic pain and various neurological disorders. However, many potentially promising lead structures suffer from poor aqueous solubility, which complicates their pre-clinical evaluation. The use of incompatible formulations such as DMSO solutions at the cell culture level, o/w emulsions for parenteral administration during small animal studies, and solid dosage forms for oral administration at the stage of larger animal studies, complicates the understanding and correct translation of results. The aim of this project is to come up with a common formulation platform that would be applicable for pre-clinical testing at all stages. The project will involve the comparison of several formulation approaches, namely liposomes, lipid-coated nanocrystals, mini-emulsions, and impregnation to porous micro- or nano-particles. The feasibility of these formulation platforms will be compared both in vitro and in vivo using several drug substances from the steroid family, both currently known and newly discovered. This project will suit a person with background in chemistry or pharmacy. The project will be carried out in colloaboration with Dr. Eva Kudova, IOCB.

Oleogely jako systémy pro doručování léčiv

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Oleogels, like hydrogels, are semi-solid materials that can contain up to 99 % of a liquid, which is solidified by a three-dimensional polymer network. While hydrogels contain as the liquid and the polymers are hydrophilic, oleogels contain oil and an oleophilic polymer network. Many APIs that are poorly soluble in water could potentially be formulated using oleogels and be either directly dissolved in the oil phase or form a particle depot that would dissolve in the oil gradually and act as a longer-lasting reservoir. The aim of this project is to evaluate the suitablitity of selected oleogel formulations for drug delivery applications from the point of view of manufacturability, drug release kinetics, drug stability, and biological compatibility. The application of oleogels will be demonstrated using several selected APIs both in vitro and in vivo.

Platforma pro současné disoluční a permeační testování formulačních prototypů

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Supersaturating drug delivery systems such as amorphous solid dispersions or amorphous drugs loaded to mesoporous carriers can significantly increase the dissolution rate of poorly soluble APIs. However, in order to translate this into increased bioavailability, the API must be absorbed from the GI tract. The aim of this project is to develop methodology for the simultaneous measurement of dissolution and permeation under biorelevant conditions, and so enable early-stage evaluation of formulation prototypes that minimized false positives as well as false negatives. Permeation methods based on model lipid layers, cell cultures and co-cultures, and hollow fibre based modules will be compared and their predictions compared from the results of in vivo studies for several chosen molecules from the BCS class II and class IV category.

Pokrocile formulace za použití mikročástic z přírodních zdrojů

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Nature provides numerous examples of microparticles with a diversity of sizes and shapes that are available in abundant quantities. These include pollen, various single-cell microorganisms and their spores, the silica skeletons of diatoms, yeast, extracellular vesicles of both plant and animal origin, but also sub-cellular compartments such as vacuoles and other organnelles. The biological origin of these particles can provide several interesting application properties such as biodegradability, biocompatibility, slight immunogenicity which could enable specific targeting (e.g. to macrophages or to the lymphatic system), resistence against environmental factors such as moisture or oxygen diffusion, resistance to digestive enzymes which could prove useful for oral delivery, or the presence of specific surface moieties that could enable very specifc targeting (e.g. extracellular vesicles). The aim of this project is to explore the use potential use of selected categories for the formulation of bioactive substances (mainly pharmaceutics) which are challenging in traditional formulation approaches. This includes poorly soluble drugs, highly lipophilic drugs, or peptides. The project will consider processes for the harvesting of natural particles, their physico-cehmical characterisation, drug encapsulation methods, investigation of release kinetics, and evaluation of application potential by both in vitro and in vivo studies.

Pokročilé metody formulace léčiv pro topické podání

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Study programme: Drugs and Biomaterials

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Although skin appears to be a macroscopically homogeneous and biologically passive structure, it is exactly the opposite: it is incredibly heterogeneous both chemically and structurally, and it is host to a diversity of active cells such as macrophages and bacteria. Traditional approaches to topical delivery have relied on relatively simple systems such as passive diffusion from water- or oil-based solutions or creams/gels. The aim of this project is to investigate bioactive transport as a mechanism for topical delivery and find a solution to such molecules as therapeutic peptides, which are known to be extremely challenging to formulate and delivery to the body. This project will explore the use of drug delivery systems that are actively phagocytised for targeting macrophages residing in the skin. These drug delivery systems will include naturally sourced polysaccharide shells or lipidic vesicles obtained from single-cell organisms. Their mild immunogenicity, biocompatibility and ability to encapsulate a broad range of molecules will be utilized for the formulation of APIs that have proven to be challenging by traditional means.

Polymer-based membranes for highly selective removal of CO2 from biogas

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Ing. Zdeněk Slouka, Ph.D.

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Membrane-based gas separation technology has contributed significantly to the development of energy-efficient systems for natural gas purification. Also CO2 removal from biogas, with CO2 contents exceeding 40% has more recently known rapid growth and development. Major challenge of polymer membranes for gas separation is related to their susceptibility to plasticization at high CO2 partial pressures. CO2 excessively swells the polymer and eases the permeation of CH4, thus reducing the selectivity. Membrane crosslinking is one of the best ways to prevent the plasticization. Mixed matrix membranes (MMMs), consisting of fillers homogeneously dispersed in a polymeric matrix aim at combining the processibility of polymers and the superior separation properties of the porous fillers. Metal-organic frameworks (MOFs) are such materials which have attracted considerable attention due to their tailorable functionality, well-defined pore size, pore tunability and breathing effects. MMMs for biogas upgrading will be prepared with increased permeabilities by choosing proper MOF/polymer combinations and modifying the thermal treatment, employing core-shell MOF materials with high bulk porosity and a selective shell layer.

Preparation and characterization of porous materials for photo-catalytic conversion of CO2

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Increasing amount of CO2 Application of enzymes for preparation of various biomolecules is ever growing field. This is due to low energy demand and high specificity of the catalyzed reactions. Significant disadvantage of this technology is loss of enzyme activity and removal of the enzyme from the reaction system. Solution for these problems is enzyme immobilization on a suitable support. In this project we will use recently developed technology of reactive gelation suitable for buildup of 3D porous material with tunable porosity and pore size distribution combined with covalent bonding of enzymes to the surface of prepare material. To understand impact of enzyme-surface interactions we plan to use various building blocks made out of polymers or silica combined with different spacer molecules placed between porous material and enzyme anchoring group. In this way we will be able to study impact of these interaction on the enzyme activity and yield of reaction. Once the system will be established, we will further investigate effect of process conditions (dispersed porous aggregates vs. packed bed), effect of ionic strength, pH, substrate concentration etc., on the yield and selectivity of the performed enzymatic reaction. In the last part of the project, the system will be extended towards multiple consequent enzymatically catalyzed reactions. Student will be involved in the preparation of porous material and its characterization as well as in the surface functionalization with suitable enzyme anchoring moieties. Consequently, student will be responsible for enzyme attachment and testing of its activity and yield.

Preparation of co-amorphous solid forms of drug substances

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Low solubility of drugs represent significant drawback in development of new drug products. Possibility to improve this limitation is formulation of drug molecules in amorphous forms, e.g. using polymers formulated in hot-melt extrusion process, precipitation from solution or via spray drying. Despite significant improvement of drug dissolution characteristics, commonly there is a limited amount of drug, which can be solubilized within a polymeric matrix and thus prevent drug molecule to recrystallize. New approach to prepare amorphous drugs is to use small molecules, which can form co-amorphous solid forms. In this thesis, we will investigate possibility to prepare co-amorphous solid forms for selected drug molecules. Student will start with the screening process where various small molecule excipients will be tested using ball mill technique. Prepared solid forms will be characterized by XRD and DSC. For suitable candidates we will measure long-term stability under elevated temperature and humidity as well as measure their dissolution kinetics. In the last part of the project, student will be responsible for process scale-up and testing of process robustness.

Preparation of drug delivery carriers for treatment of rheumatoid arthritis

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Study programme: Drugs and Biomaterials

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Rheumatoid arthritis (RA) is a chronic autoimmune disorder, mainly affecting joints that are identified by inflammation and swelling of the synovium of the joint. Today, apart from the conventional synthetic disease-modifying antirheumatic drugs (DMARDs), a number of biological DMARDs have been approved. Recently the first targeted synthetic DMARD has also been approved, while other targeted compounds are in the development phase. Particularly interesting is group of drugs which are based on gold complexes. Despite their promising properties, these drugs has low solubility in water and thus low bioavailability. Therefore, within this project we plan to investigate possibility to prepare more soluble compounds of gold complexes using crystal engineering approach as well as formulate these drugs into various nanocarriers. Combination of various preparation and analytical techniques will be used to investigate stability of gold complexes. In the next step we will investigate the impact of encapsulation matrix or complexation partner on the dissolution characteristics of gold complexes.

Preparation of porous materials for enzyme immobilization and their application in biocatalysis

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Application of enzymes for preparation of various biomolecules is ever growing field. This is due to low energy demand and high specificity of the catalyzed reactions. Significant disadvantage of this technology is loss of enzyme activity and removal of the enzyme from the reaction system. Possible solution for these problems is enzyme immobilization onto a suitable support. In this project we will use recently developed technology of reactive gelation suitable for synthesis of 3D porous material with tunable porosity and pore size distribution combined with covalent attachment of enzymes to the surface of prepare material. To understand impact of enzyme-surface interactions we plan to use various building blocks made out of polymers or silica combined with different spacer molecules placed between porous material and enzyme. In this way we will be able to study impact of these interactions on the enzyme activity and yield of biocatalytic reaction. Once the system will be established, we will further investigate effect of process conditions (dispersed porous aggregates vs. packed bed), effect of ionic strength, pH, substrate concentration etc., on the yield and selectivity of the performed enzymatic reaction. In the last part of the project, the system will be extended towards multiple consequent enzymatically catalyzed reactions. Student will be involved in the preparation of porous material and its characterization as well as in the surface functionalization with suitable enzyme anchoring moieties. Consequently, student will be responsible for enzyme attachment and testing of its activity and yield. Combination of several analytical techniques including SEM, light scattering, BET measurement, Hg porosimetry, XPS, HPLC etc., will be used to characterize material properties and test behavior of immobilized enzymes.

Preparation of porous materials using phase inversion approach

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Dr. Ing. Juraj Kosek

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The aim of this PhD project is a study of preparation of porous (bio)polymeric materials with well-defined microstructure of pores suitable for various applications, such as membrane separations or scaffolds in tissue engineering. Principal method used for the fabrication of porous materials explored in this project is the phase inversion, which consists of several steps: (i) formation of homogeneous solvent-polymer mixture, (ii) externally induced change in system Gibbs free energy of mixing leading to phase separation, (iii) removal of the solvent from the “frozen” porous polymer matrix. The alteration in Gibbs free energy of mixing can be done in various ways, for instance by addition of immiscible species (nonsolvent) to the system (nonsolvent induced phase separation, NIPS), or by rapid decrease of thermal energy (thermally induced phase separation, TIPS). This work will focus on testing both NIPS and TIPS, as well as their combination (N-TIPS). As a primary experimental project, it involves screening for suitable polymer-solvent(-nonsolvent) combinations (considering also potential biocompatibility of the prepared tissue scaffold), thermodynamic characterization of the system (including its theoretical description), construction of the apparatus for material fabrication, preparation of the porous material and characterization of its morphology and technical properties (e.g. separation performance, dynamics of biodegradation, mechanical properties). There are two ultimate goals of this project: (i) experimental mapping between the phase separation physical conditions and final morphology of the prepared material, and (ii) process scale-up proposition, and optimisation of the material production method, including solvent removal. The project will therefore contribute to the understanding of hetero-phase material morphogenesis during phase separation process, and will offer new classes of materials suitable for real life applications. The student will work with both traditional polymers and with newly emerging biodegradable materials, and will get opportunity to use state-of-the-art methods of morphological characterization, including scanning electron microscopy (SEM), atomic force microscopy (AFM), 3D computed micro-tomography (mCT), confocal Raman microscopy and others. The project will be carried out in close cooperation with Czech company MemBrain, Central European Institute of Technology (CEITEC), and Process Engineering for Sustainable Systems Section of Katholieke Universiteit Leuven (KU Leuven). Contact: Prof. Juraj Kosek, PhD UCT Prague, Technicka 5, 166 28 Praha 6, Czech Republic E-mail:Juraj.Kosek@vscht.cz Phone: +420 220 44 3296

Programovatelné uvolňování léčiv z vícejednotkových lékových forem

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Multi-unit pellet systems (MUPS) are dosage forms composed of smaller sub-units, typically pellets or mini-tablets, combined into a single larger tablet or capsule. Traditionally, the sub-units are all identical. However, by mixing sub-units of different properties such as particle size, disintegration rate, composition, or coating thickness, it is theoretically possible to fine-tune the drug release from the MUPS almost arbitrarily. The aim of this project is to explore the possibility to achieve precise control over drug release from MUPS by programmed mixing of different grades of sub-units. The project will involve the formulation of individual sub-units for a selected set of drugs, their production by fluid-bed coating or multi-tip tablet compression, their individual characterization and finally their controlled combination into MUPS with a pre-defined release profile. The project will suit a person with a background in pharmaceutical sciences or chemical engineering.

Rate-based model of multi-component distillation. Experimental verification.

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc.Ing. František Rejl, Ph.D.

Reaction-transport processes in ion-exchange systems

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Ing. Zdeněk Slouka, Ph.D.

Robotická linka pro kontinuální výrobu personalizovaných formulací

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Currently, approximately 10 % of the whole population and 30 % of adults aged 65+ take five or more different prescription medications each day. Low prescription compliance due to the complexity of the prescription regime is a major problem, responsible for an estimated 125,000 deaths per year and 10 % of all hospitalizations in the USA alone. Therefore, it would be beneficial if each patient could take only 1 pill per day that would contain the required drug combination while being bioequivalent with the single-drug dosage forms. The aim of this project is to design and assemble an automatic manufacturing line that would enable the production of patient-specific batches based on their electronic prescription for a given period of time, e.g. 30 days. The line will be based on the well-established process of pharmaceutical compounding. However, instead of manual compounding by a live person, this process will be autonomous and rely on robotics. The project will involve the selection and validation of individual compounding sub-stations and their connection to a fully automatic bench-scale manufacturing line. This project would best suit a person with a background in engineering (chemical, mechanical, electrical).

Separation of racemic mixtures by membrane processes

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Pavel Izák, Ph.D. DSc.

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The aim of the doctoral thesis is the separation of racemic mixtures by membrane separation processes. The racemic mixtures contain the same amount of L and D enantiomers. The individual enantiomers have the same physicochemical properties in the achiral environment and therefore it is very difficult to separate them. However, in the human body, the L and D enantiomers have different effects and the D enantiomers may be detrimental to health. Ph.D. work will focus on the development of new membranes and separation techniques for the selective separation of enantiomers from racemic mixtures with practical applications, especially in the pharmaceutical, food or agrochemical industries.
The doctoral candidate will be required to work out a detailed search of international literature on the subject (need for active English knowledge), independent measurement and results processing, and in co-operation with the supervisor writing publications to international journals.

Solvent and pH stable membranes with ultra-sharp molecular weight cut-off values

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Ing. Zdeněk Slouka, Ph.D.

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Membrane-based separations currently offer the best strategy to decrease energy requirements and environmental footprint through newly developed solvent resistant nanofiltration (SRNF) or solvent-tolerant nanofiltration (STNF). So-called solvent activation of polymeric membranes involves treatment of an existing membrane by contacting it with solvents or solvent mixtures, which is hypothesized to restructure the membrane polymer through solvatation, increase polymer chain flexibility and organization into suitable structures. This will be verified by systematically treating membranes with different solvents and testing them for the separation of synthetic liquid streams. A high-throughput set-up will be used. Fundamental physico-chemical characterisations of the membranes before and after the treatments will provide insight in the changes at molecular level. The characterization techniques include gas and liquid uptake experiments (diffusivity), PALS (positron annihilation lifetime spectroscopy, to determine free volume element distributions), ERD (elastic recoil scattering, providing elemental analysis in membrane depth profiles), solid state NMR (nuclear magnetic resonance), TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry).

Stabilization and controlled release of a drug by coating of drug particles with polymers

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Current active pharmaceutical ingredients (API) commonly have very low bioavailability, which is in most cases caused by their low water solubility. One of the possibility to improve this situation is to prepare metastable polymorphic forms, which are having intrinsically higher water solubility. However, this often results in their low chemical or physical stability, which limits their application. The main goal of this project is to investigate the possibility to coat surface of metastable API particles by suitable polymeric compound to generate protective layer. In addition, such layer might also provide other functionality, which is controlled release of API during dissolution. Therefore, student will be involved in the testing of various methods to coat API particles by various polymers. As promising method is milling as this method is commonly used for preparation of metastable forms of APIs followed by attachment of the polymer on the surface of metastable forms of API. Small-scale apparatus will be used to test various operating conditions as well as combination of API and various polymers. Prepared API particles coated with polymer will be consequently characterized by several techniques including SEM, XRD, DSC etc., combined with the measurement of API dissolution kinetics. Here time evolution of the API concentration in the used media together with size and morphology of particles will be followed by UV/VIS and Raman spectroscopy (both API concentration), FBRM (particle size) and optical video microscopy (particle size and shape). In the last stage of the project student will be responsible for the scale up of this process to illustrate possibility to prepare larger amount of coated API particles. Simulated impact of normal and tangential forces similar to those occurring during formulation, i.e. granulation and tableting, will provide information about the mechanical robustness of developed coating.

Strength and fluidity of granular media

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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Mechanics of granular media (sand, clay, silt, debris, etc.) is central to many problems in geology and technology. Natural hazards such as earthquakes or landslides are triggered by mechanical instability of embedded granular gauges. On the other hand, conditions leading to good fluidity of granular media are often sought in civil engineering, pharmacy, and chemical technology. Therefore, understanding of mechanisms controlling the strength of granular media is of high importance. The student will run computer simulations of a shearing granular layer and will study conditions leading to flow. The resulting theoretical picture should enlighten mechanisms that are most effective in degrading mechanical strength. In particular, the effect of pore fluid and oscillations of boundaries will be studied in detail.

Study of bubble and drop interactions with a turbulent vortex

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Jaroslav Tihon, CSc.

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Gas-liquid or liquid-liquid dispersions are encountered in numerous technological and biotechnological processes. The fluid particles (bubbles or droplets) break in the turbulent liquid flow and form a complex multiphase system. Understanding the particle breakup mechanism at turbulent flow conditions is important because theoretical models describing this mechanism are essential for the numerical modeling of complex multiphase systems. The postgraduate project will be focused on the experimental study of dynamic behavior of bubbles and drops after their interaction with a turbulent vortex in order to determine the breakup rate of original particles and the size distribution of newly formed particles. The breakage mechanism will be studied in dependence on various hydrodynamic and physico-chemical conditions of the studied system. Department is well equipped for the study of bubble/drop breakup in turbulent flow. Cells for controlled generation of bubble, toroidal vortices and intense turbulent flow are available, as well as all the control and evaluation software. Requirements for the applicant: master degree in chemical or mechanical engineering; ability to teamwork; systematic and creative approach to scientific problems; interest in experimental work.

Study of transport characteristics in various types of bioreactors

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Dr. Ing. Tomáš Moucha

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The production of new biotechnology and pharmaceutical products is based on a bioreactor design. The choice of a suitable type of bioreactor is crucial with respect to maximum yield, but it is also limited by the lifetime of the microorganisms present. The aim of the doctoral study is to compare design parameters (transport characteristics) of three types of the most commonly used bioreactors. The results will be used to characterize the differences and similarities of specific types of bioreactors in terms of gas distribution, mass transfer and mixing depending on the total energy supplied to the system. Transport characteristics will be obtained experimentally for model batches, which will be designed based on physical properties of real broths. Both cooperating departments are well equipped and have all the three types of bioreactors i) mechanically stirred reactor, ii) bubbled column and iii) air-lift reactor. All bioreactors are adapted to measure transport characteristics by the same methods, therefore the results will be comparable. Requirements for applicant: master degree in chemical or mechanical engineering, organic technology, biotechnology etc.; ability for teamwork; systematic and creative approach to scientific problems; interest in experimental work Further information: Assoc. Prof. Tomáš Moucha, building B of UCT Prague, room T02, e-mail: tomas.moucha@vscht.cz

Synthesis and characterisation of particles with immuno-adhesive properties

Department: Department of Chemical Engineering, Faculty of Chemical Engineering

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The specificity of adhesion to the target cells or tissues in a physiological envirionment is a key requisite for the successful implementation of drug delivery systems (DDS). The aim of this work is to explore DDS based on immunoliposomes and their composites (e.g. with magnetic nanoparticles) using surface modification by antibody fragments and other suitable targeting moieties. The immunoliposomes will be tested both in vitro and in vivo in terms of specificity of adhesion, pharmacokinetics, and ability do encapsulate and delivery drugs or pro-drugs.

Transformations of aerosol particles due to changes in gaseous environment

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: Ing. Vladimír Ždímal, Dr.

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The aerosol particles are omnipresent in the atmosphere, influencing many processes on the Earth starting from the global warming to health effects. They tend to be both in physical and chemical equilibrium with their gaseous environment, but due to dynamic changes in the atmosphere or during their transport to human lungs, the particles change during their lifetime. Therefore, it is necessary to study their answers to these changes to be able to predict their fate and effects after their release to or formation in the atmosphere. The study will be carried out using a newly developed system of laminar flow reactors enabling to control ambient conditions of particle neighborhood. The doctoral student is supposed to study these phenomena using advanced methods of aerosol instrumentation including on-line chemical and physical characterization of particles by aerosol mass spectrometry.

Triboelectric routes enabling plastic waste separation and recycling

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: prof. Dr. Ing. Juraj Kosek

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Recycling is the most beneficial and eco-friendly way to treat large amount of plastic waste. However, conversely to a public belief, the majority of plastic waste is burned in incineration plants or stored in landfills instead of being recycled. The bottleneck of the plastic waste treatment originates in the pre-separation, as only precisely separated waste can be recycled. Even the incineration process requires the pre-separation of plastics, mainly the removal of polymers containing halogens that could otherwise form harmful gases during combustion. Current methods like manual separation, IR spectroscopy or methods based on density differences aren’t sufficiently effective. The new promising technique, triboelectric separation, is based on the idea that each plastic material reaches different electrostatic charge by tribocharging (charging by friction) and therefore charged plastic mixtures can be separated in electric field. The objective of this Ph.D. project is the establishment of experimental bases (systematic series of data) related to charging and discharging dynamics in powders, which will provide integrated description of these phenomena. The student will also investigate opportunities for control of surface charge and subsequent separation of dielectrics in electric field. The student shall challenge several open problems: (i) relation between ESC and mechanical/chemical properties of materials, (ii) electric charge dissipation, (iii) charging of powders under the conditions simulating real industrial production of industrially important powders, (iv) the effect of charge on fouling, (v) charging for separation and recycling of plastic materials. The project is a pioneering work which is desperately needed and is sufficiently challenging for a student with interest in physico-chemical fundamentals of previously described processes. The student will work with highly qualified Ph. D. students and postdocs in our research group and will also cooperate with our European partners. Our laboratory is well prepared for the research of electrostatic processes (Faraday cup, corona charging, high-voltage separator) and characterization of powder texture and material properties (micro-tomography, atomic force microscopy – AFM). Info: phone 220 44 3296, office B-145, e-mailjkk@vscht.cz, web http://kosekgroup.cz

Virtual design and testing of porous catalysts and filters aided by multi-scale mathematical models

Department: Department of Chemical Engineering, Faculty of Chemical Engineering
Theses supervisor: doc. Ing. Petr Kočí, Ph.D.

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The work focuses on the development of advanced mathematical models of porous catalysts and filters for purification of exhaust gases that can be utilized in virtual design of such a device. The models are developed in the CFD environment OpenFOAM and focus on the processes both during the catalytic filter preparation (influence of parameters during the washcoating of catalyst suspension into prous substrate and subsequent drying) as well as on the impact of the resulting structure on the functional properties of the device (simulations of flow, diffusion, catalytic reaction and filtration for prediction of pressure loss, conversion and filtration efficiency). The studied processes are modelled in detail on the level of wall pores and individual particles and also on the level of channels in the entire reactor. The 3D structure of porous materials is reconstructed using X-ray tomography (XRT) and electron microscopy images. The model results are verified with the available experimental data from lab reactor.


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