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Latex Modified Cement Composites
Kunc, Michal ; Rovnaníková, Pavla (referee) ; Kuřitka, Ivo (referee) ; Havlica, Jaromír (advisor)
The subject of dissertation is a study of physic-mechanical properties and development of self-leveling polymer-cement composite of the ternary binder system PC-CAC-CS modified with chemical additives and polymeric substances. The dissertation systematically describes a four-step optimalization of the composite considering its key properties. Experimental part has been focused on monitoring the impact of composite components on selected final properties. Basic physico-mechanical, structural properties and its relations (compressive strength, porosity, flow abilities, setting times) have been analyzed for deeper understanding of the effects of individual composite components. Methods which quantify the existence of the newly formed hydration product – ettringite (XRD, SEM with EDS, calorimetry, dilatometry) has been chosen as additional study methods on selected combinations. A working prototype of self-leveling polymer-cement composite was successfully developed based on systematic process and using of testing procedures and measuring methods.
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Spectrophotometric determination of phosphate in ternary systems with dyes
Novotný, Radek ; Komendová, Renata (referee) ; Sommer, Lumír (advisor)
The theoretical part of this master’s thesis is focused on the characteristics and forms of phosphorus, occurrence in natural waters and the problems associated with higher phosphorus concentrations, especially in the development of cyanobacteria and algae. There are also described the possibilities of determining the degree of pollution of natural waters by nutrients and the effects of eutrophication. There are also described methods for the determination of phosphates, especially spectrophotometric determination in ternary systems with dyes. Like other methods are mentioned AAS, ion chromatography, electrophoresis and izotachophoresis, electrochemical methods or enzymatic methods. In the experimental part of this work deals with the selection and optimalization of suitable ternary system with organic dyes for spectrophotometric determination of orthophosphates. The system with phosphovanadomolybdic acid is studied too. For analytical procedure with malachite green oxalate, which was found to be most useful, were studied interfering ions, commonly occurring in natural waters . The chosen procedure was finally tested on real water samples.
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Microstructure and mechanical properties of the potentially biodegradable ternary system Zn-Mg0. 8-Ca0.2
Pinc, Jan ; Čapek, Jaroslav ; Kubásek, J. ; Veřtát, Petr ; Hosová, K.
Zinc and zinc alloys exhibit suitable corrosion properties for biodegradable implants. Insufficient mechanical properties (for some applications) or low biocompatible Zn2+ concentrations can be modified by the alloying by essential elements like magnesium, calcium or strontium. The alloying elements also enhance the biocompatibility of zinc due to a decrease of Zn2+ release which could be toxic in a concentration exceeding 100 µM. In this study, the microstructure and hardness of a potentially biodegradable alloy ZnMg0.8Ca0.2 were observed in relation to different cooling rates. It was found that zinc dendrites, Mg2Zn11 (MgZn2) and CaZn13 phases occur in the material structure. The micro-hardness measurements revealed constant hardness of the particular phases, however, the macro-harness slightly decreased with the decreasing cooling rate due to changes in phase sizes and distribution.
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Latex Modified Cement Composites
Kunc, Michal ; Rovnaníková, Pavla (referee) ; Kuřitka, Ivo (referee) ; Havlica, Jaromír (advisor)
The subject of dissertation is a study of physic-mechanical properties and development of self-leveling polymer-cement composite of the ternary binder system PC-CAC-CS modified with chemical additives and polymeric substances. The dissertation systematically describes a four-step optimalization of the composite considering its key properties. Experimental part has been focused on monitoring the impact of composite components on selected final properties. Basic physico-mechanical, structural properties and its relations (compressive strength, porosity, flow abilities, setting times) have been analyzed for deeper understanding of the effects of individual composite components. Methods which quantify the existence of the newly formed hydration product – ettringite (XRD, SEM with EDS, calorimetry, dilatometry) has been chosen as additional study methods on selected combinations. A working prototype of self-leveling polymer-cement composite was successfully developed based on systematic process and using of testing procedures and measuring methods.
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Spectrophotometric determination of phosphate in ternary systems with dyes
Novotný, Radek ; Komendová, Renata (referee) ; Sommer, Lumír (advisor)
The theoretical part of this master’s thesis is focused on the characteristics and forms of phosphorus, occurrence in natural waters and the problems associated with higher phosphorus concentrations, especially in the development of cyanobacteria and algae. There are also described the possibilities of determining the degree of pollution of natural waters by nutrients and the effects of eutrophication. There are also described methods for the determination of phosphates, especially spectrophotometric determination in ternary systems with dyes. Like other methods are mentioned AAS, ion chromatography, electrophoresis and izotachophoresis, electrochemical methods or enzymatic methods. In the experimental part of this work deals with the selection and optimalization of suitable ternary system with organic dyes for spectrophotometric determination of orthophosphates. The system with phosphovanadomolybdic acid is studied too. For analytical procedure with malachite green oxalate, which was found to be most useful, were studied interfering ions, commonly occurring in natural waters . The chosen procedure was finally tested on real water samples.
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Termodynamické re-modelování systému Cu-Ni-Sn
Zemanová, Adéla ; Kroupa, Aleš
The Cu-Ni-Sn system is an important alloy system in lead-free soldering. In the scope project COST 531 the binary data for the Ni-Sn system required modification. The high temperature form of Ni3Sn, which has a DO3 structure, was modeled as BCC_A2 in the COST 531 thermodynamic database for compatibility with Cu-Sn system. The reassessment of this phase was carried out with the help of Parrot module in the ThermoCalc software and very good agreement was reached comparing the partial quantities from previous data and new model of this phase. Nevertheless it was also necessary to remodel the description of the Cu-Ni-Sn ternary system. The reassessment was based on the work of Miettinen who was primarily concerned with copper-rich compositions and experimental data for lower temperature.
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