|
|
Utilization of interfacial rheology to study of biological systems
Kachlířová, Helena ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The aim of this bachalor thesis is to implement and optimization a relatively new method of interfacial rheology. The optimization of this method was realized on two types of interfaces, specifically liquid-liquid using immiscible systems water-chloroform and water-toluene, and water-air. The applicability of this method was tested by using real samples in form of surfactant septonex and biological system represented by protein (bovine serum albumin). The interfacial layers formed by septonex were purely viscous, where the rigidity of the layer increased slightly with concentration until reaching critical micellar concentration and then the rigidity decreased. In comparison with septonex, the interfacial film made of bovine serum albumin showed predominantly elastic behaviour.
|
|
|
Nickel coatings on magnesium alloys
Kosár, Petr ; Richtera, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This diploma thesis is focused to nickel coatings on magnesium alloys. At the introduction of this work is briefly commented phase composition of AZ91 alloy, which is followed by detailed description of five very different theories of Ni-P coatings formation. Theoretical part is ended by review aimed to current states of development in areas of chemical nickel coating, influence of AZ91 alloy microstructure to current less deposition and possibility of surfactants influence to decrease of surface roughness. In experimental part of this thesis was the morphology and composition of Ni-P coatings including interlayers dependence on chemical composition of nickel-plating bath and magnesium alloy surface pre-treatment investigated using scanning electron microscopy and inverted optical microscopy. Average phosphorus content was obtained using energy dispersive analysis. Closing part of experimental part was dedicated for mechanical properties of coatings by micro-indentation analysis.
|
|
|
Comparative study of interaction between surfactant and hyaluronan and different polyelectrolytes.
Stiborský, Filip ; Pravda,, Martin (referee) ; Pekař, Miloslav (advisor)
In this diploma thesis, the interactions between polyelectrolyte and surfactant at low and also at high concentration were studied. There was used pyrene as fluorescent probe during the fluorescence spectroscopy measurement, a cationic surfactant cetyltrimethylammonium bromide and as a main polyelectolyte has been chosen sodium polystyrene sulfonate at 1 MDa molecular size. In the medium containing 0.15 M NaCl we could observed a creation of the complexes – precipitates in the surrounding of CMC concentration and behind of this concentration. In the mixtures containing sodium polystyrene sulfonate and hyaluronan together, there was stronger tend to keep aggregation properties of sodium polystyrene sulfonate during difference concentration ratios. Beyond CMC concentration, hyaluronan starts to influence the aggregation properties of the system as well.
|
|
|
Study of optimizing thermoinsulation properties of rigid polyurethane foams
Eliáš, Filip ; Vojtová, Lucy (referee) ; Petrůj, Jaroslav (advisor)
The thesis deals with the processes that occur in the course of the manufacturing of rigid polyurethane-polyisocyanurate (PU-PIR) foams, their properties and technology. It deals above all with principles of foam nucleation and stability. The purpose of understanding these principles is their possible use for improving thermo-insulating properties of the material. The experimental part of the thesis studies the influence of additives and ultrasound on the PU-PIR foam properties. It has been found that low molecular weight compounds with perfluorinated chain leads to decreasing foam cell size and its lower thermal conductivity. The additives mentioned act probably on the surfactants principle by facilitating nucleation and stabilizing growing centres of bubbles. They probably form also part of blowing agents mixture inside the foam cells which cause lowering of thermal conductivity as well. Compounds with similar chemical structure have unique influence on the properties of rigid PU-PIR foams. Further research ought to be focused on cheaper modes of producing perfluorinated compounds.
|
|
|
Screening of biosurfactant production in selected thermophilic bacteria
Řeháková, Veronika ; Nováčková, Ivana (referee) ; Obruča, Stanislav (advisor)
The subject of the bachelor thesis is the production of biosurfactants by selected thermophilic bacteria. The theoretical part contains a general characterization of thermophilic bacteria, describes the structures and classification of biosurfactants, characterizes their properties and uses. The final part of the theoretical part deals with the production of biosurfactants by thermophilic bacteria. The experimental part deals with the screening of biosurfactant production by selected thermophilic bacteria. Thermophilic bacteria were obtained from composts and activated sludges. Isolation is not a subject of the thesis. In total 39 bacterial isolates were cultivated and their supernatants were tested by screening methods – emulsification capacity assay and solubilization of crystalline anthracene. Based on the results of these methods, 14 most promising producers were selected. These bacterial strains were re-cultured to obtain a new set of supernatants. For more detailed screening of production by selected thermophilic bacteria, in addition to determining the activity of the emulsion and solubilization of crystalline anthracene, other methods were added: direct surface tension measurement – Du-Noüy-Ring, drop pouring method and oil spreading method. The results were evaluated and the measurements were repeated for a new set of supernatants to verify the reproducibility of the production. The results of all the tests were compared and then three most reliable thermophilic bacterial producers were determined.
|
|
|
Study of the surfactants effect on polymer nanoparticle parameters
Moravcová, Katarína ; Holas, Ondřej (advisor) ; Šnejdrová, Eva (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Katarína Kostíková Title of thesis: Study of the surfactants effect on polymer nanoparticle parameters The main aim of this Diploma thesis was to examine whether the use of various stabilizers has any effect on the resultant size of prepared nanoparticles and to find out which type of stabilizer is the most appropriate in terms of preparation of the nanoparticles of the necessary size, adequate polydispersity and steadiness. The preparation of nanoparticles was based on the use of sodium cholate as a surfactant and polymer PLGA (poly (lactid-co-glycolic acid)) consisting of monomers of lactic and glycolic acids. Nanoparticles were prepared by means of nanoprecipitation method. Sodium cholate solution has always been prepared in water in different concentration: 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, and 5%. The following have been used as stabilizers: poloxamer 407, polyvinyl alcohol, cetrimonium-bromide (CTAB), and polysorbate 20, all of them in concentration of 0.1% and sorbitan-monostearate in concentration of 0.01%. Measurement of the size of created nanoparticles was performed using the device Zetasizer at the...
|
|
|
Study of the surfactants effect on polymer nanoparticle parameters
Kostíková, Katarína ; Holas, Ondřej (advisor) ; Šnejdrová, Eva (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Katarína Kostíková Title of thesis: Study of the surfactants effect on polymer nanoparticle parameters The main aim of this Diploma thesis was to examine whether the use of various stabilizers has any effect on the resultant size of prepared nanoparticles and to find out which type of stabilizer is the most appropriate in terms of preparation of the nanoparticles of the necessary size, adequate polydispersity and steadiness. The preparation of nanoparticles was based on the use of sodium cholate as a surfactant and polymer PLGA (poly (lactid-co-glycolic acid)) consisting of monomers of lactic and glycolic acids. Nanoparticles were prepared by means of nanoprecipitation method. Sodium cholate solution has always been prepared in water in different concentration: 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, and 5%. The following have been used as stabilizers: poloxamer 407, polyvinyl alcohol, cetrimonium-bromide (CTAB), and polysorbate 20, all of them in concentration of 0.1% and sorbitan-monostearate in concentration of 0.01%. Measurement of the size of created nanoparticles was performed using the device Zetasizer at the...
|
|
|
Screening of biosurfactant production in selected thermophilic bacteria
Řeháková, Veronika ; Nováčková, Ivana (referee) ; Obruča, Stanislav (advisor)
The subject of the bachelor thesis is the production of biosurfactants by selected thermophilic bacteria. The theoretical part contains a general characterization of thermophilic bacteria, describes the structures and classification of biosurfactants, characterizes their properties and uses. The final part of the theoretical part deals with the production of biosurfactants by thermophilic bacteria. The experimental part deals with the screening of biosurfactant production by selected thermophilic bacteria. Thermophilic bacteria were obtained from composts and activated sludges. Isolation is not a subject of the thesis. In total 39 bacterial isolates were cultivated and their supernatants were tested by screening methods – emulsification capacity assay and solubilization of crystalline anthracene. Based on the results of these methods, 14 most promising producers were selected. These bacterial strains were re-cultured to obtain a new set of supernatants. For more detailed screening of production by selected thermophilic bacteria, in addition to determining the activity of the emulsion and solubilization of crystalline anthracene, other methods were added: direct surface tension measurement – Du-Noüy-Ring, drop pouring method and oil spreading method. The results were evaluated and the measurements were repeated for a new set of supernatants to verify the reproducibility of the production. The results of all the tests were compared and then three most reliable thermophilic bacterial producers were determined.
|
|
|
Utilization of interfacial rheology to study of biological systems
Kachlířová, Helena ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The aim of this bachalor thesis is to implement and optimization a relatively new method of interfacial rheology. The optimization of this method was realized on two types of interfaces, specifically liquid-liquid using immiscible systems water-chloroform and water-toluene, and water-air. The applicability of this method was tested by using real samples in form of surfactant septonex and biological system represented by protein (bovine serum albumin). The interfacial layers formed by septonex were purely viscous, where the rigidity of the layer increased slightly with concentration until reaching critical micellar concentration and then the rigidity decreased. In comparison with septonex, the interfacial film made of bovine serum albumin showed predominantly elastic behaviour.
|
|
|
Surfactants in Surface and Waste Water
Štefka, Michal ; Vávrová, Milada (referee) ; Chýlková, Jaromíra (referee) ; Kráčmar, Stanislav (referee) ; Čáslavský, Josef (advisor)
This work is focused on the occurrence of surface-active substances in the environment. It deals with the development and optimization of methods for the determination of selected surfactants in samples from rivers and from influent and effluent of wastewater treatment plants. Representatives of anionic, nonionic and zwitterionic surfactants were selected as target compounds. Based on optimization of analytical methods and their pilot testing abroad on samples of surface water, the selection of analytes for the conditions in the Czech Republic were corrected and operatively expanded. For the final analysis liquid chromatography with mass spectrometry was used. Analysis of cationic surfactants was realized using liquid chromatograph with UV-VIS detector. This optimized method for analysis of anionic surfactants was applied to real samples. Samples of surface running water were from the River Thurso in Scotland and then from watercourses in the catchment area of Moravia river were collected. In addition to the grab sampling also continuous weekly sampling of water from Tvaroženský potok and Litava was realized. Waste water was collected at inflow and outflow of three wastewater treatment plants (WWTP) in South Moravia (Brno – Modřice, Břeclav and Hodonín).
|
guest ::
