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Charakterizace karagenanu densitometrií
Poledňáková, Halina ; Krouská, Jitka (oponent) ; Hurčíková, Andrea (vedoucí práce)
Denzitometricky byla zkoumána hustota roztoků karagenanu v závislosti na koncentraci a teplotě roztoků. Následně byla zkoumána ultrazvuková rychlost rovněž denzitometricky a pomocí ultrazvukové spektroskopie s vysokým rozlišením (HRUS). Na měření byly použity vzorky karagenanu ve vodě a v chloridu sodném o široké škále koncentrací. Experimentálně bylo zjištěno, že vzorky karagenanu nepodléhají nevratným změnám hustoty a ultrazvukové rychlosti v závislosti na teplotě a koncentraci. Dále bylo prokázáno, že karagenan je v obou prostředích stabilní, nedochází k degradaci a změnám vlastností působením iontové síly.
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Humic Substances Characterization Employing High Resolution Ultrasonic Spectroscopy
Drastík, Martin ; Franců, Juraj (oponent) ; Janoš, Pavel (oponent) ; Pekař, Miloslav (vedoucí práce)
This doctoral thesis deals with the application of high resolution ultrasonic spectroscopy (HRUS) on studying of humic substances (HS). The goal is to obtain deeper insight to the field of relations between primary characteristics (elemental composition and distribution of carbon in functional groups) and aggregation properties. In the literature review the contemporary information about HS and HRUS are presented. Furthermore, basic information about fractal analysis as well as its application on data obtained by various techniques is mentioned. In the first section of the experimental part of this thesis the advantageous application of HRUS in the research of HS is discussed. International Humic Substances Society (IHSS) standards were selected to represent wide spectrum of samples, both humates and fulvates were used. To determine the influence of sodium counterion also fulvic acids in their protonized form were used. Power-based fitting was applied on all samples data and gained empirical parameters were correlated with primary characteristics. Fractal analysis method was developed and applied on the HRUS data. An alternative approach was applied on data gained by HRUS. From a global point of view, the dependency of ultrasonic velocity on concentration shows a linear trend and therefore a linear regression method can be applied. The second purpose of this thesis is to find information about thermal stability of HS aggregates (IHSS standards). Samples at four different concentrations were treated by temperature gradients and aggregation behavior was assessed and discussed. In the third part of thesis the concentration dependencies of the samples were studied. Unlike the first goal, samples originating mainly from locations unaffected by anthropogenic activity were used. Power-based fitting and fractal analysis were applied and acquired parameters were correlated with primary characteristics. To elucidate the extent of hydration shells, the high precision density measurements were performed. As the state-of-the-art research shows, the aggregation properties of humic biomolecules may play an important role in the future designing of humic substances applications, mainly in the agriculture and environmental protection, but even also in medicine.
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Humic Substances Characterization Employing High Resolution Ultrasonic Spectroscopy
Drastík, Martin ; Franců, Juraj (oponent) ; Janoš, Pavel (oponent) ; Pekař, Miloslav (vedoucí práce)
This doctoral thesis deals with the application of high resolution ultrasonic spectroscopy (HRUS) on studying of humic substances (HS). The goal is to obtain deeper insight to the field of relations between primary characteristics (elemental composition and distribution of carbon in functional groups) and aggregation properties. In the literature review the contemporary information about HS and HRUS are presented. Furthermore, basic information about fractal analysis as well as its application on data obtained by various techniques is mentioned. In the first section of the experimental part of this thesis the advantageous application of HRUS in the research of HS is discussed. International Humic Substances Society (IHSS) standards were selected to represent wide spectrum of samples, both humates and fulvates were used. To determine the influence of sodium counterion also fulvic acids in their protonized form were used. Power-based fitting was applied on all samples data and gained empirical parameters were correlated with primary characteristics. Fractal analysis method was developed and applied on the HRUS data. An alternative approach was applied on data gained by HRUS. From a global point of view, the dependency of ultrasonic velocity on concentration shows a linear trend and therefore a linear regression method can be applied. The second purpose of this thesis is to find information about thermal stability of HS aggregates (IHSS standards). Samples at four different concentrations were treated by temperature gradients and aggregation behavior was assessed and discussed. In the third part of thesis the concentration dependencies of the samples were studied. Unlike the first goal, samples originating mainly from locations unaffected by anthropogenic activity were used. Power-based fitting and fractal analysis were applied and acquired parameters were correlated with primary characteristics. To elucidate the extent of hydration shells, the high precision density measurements were performed. As the state-of-the-art research shows, the aggregation properties of humic biomolecules may play an important role in the future designing of humic substances applications, mainly in the agriculture and environmental protection, but even also in medicine.
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Charakterizace karagenanu densitometrií
Poledňáková, Halina ; Krouská, Jitka (oponent) ; Hurčíková, Andrea (vedoucí práce)
Denzitometricky byla zkoumána hustota roztoků karagenanu v závislosti na koncentraci a teplotě roztoků. Následně byla zkoumána ultrazvuková rychlost rovněž denzitometricky a pomocí ultrazvukové spektroskopie s vysokým rozlišením (HRUS). Na měření byly použity vzorky karagenanu ve vodě a v chloridu sodném o široké škále koncentrací. Experimentálně bylo zjištěno, že vzorky karagenanu nepodléhají nevratným změnám hustoty a ultrazvukové rychlosti v závislosti na teplotě a koncentraci. Dále bylo prokázáno, že karagenan je v obou prostředích stabilní, nedochází k degradaci a změnám vlastností působením iontové síly.
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