|
|
Dynamic viscosity of asphalt binders
Broďák, Marek ; Coufalík, Pavel (referee) ; Dašek, Ondřej (advisor)
The bachelor thesis describes a laboratory characteristics of bituminous binders. The principle, procedure of meansurment and comparison of test results of dynamic viscosity, needle penetration and softening point by ring and ball method will be described. The tests will be performed on samples of the bituminous binders with different degree of modification.
|
|
|
Magnetorheological fluid response time in shear mode
Válek, Josef ; Vimmr, Jan (referee) ; Kubík, Michal (advisor)
Magnetorheological fluids (MRF) are suspensions of (commonly) oils and carbonyl iron powder. Under magnetic field, apparent viscosity of suspension changes in short time. This so-called response time can’t be neglected in modern MR devices. Multiple response times are distinguished based on load mode. Rheological response time (MRF under shear rate) will be affected by load and composition of MRF. In this thesis, these influencing parameters are investigated, which was allowed by developing rheometer with minimal hardware response time and methodology. Gained data shows, that most affecting parameter is ratio of inner forces, described e.g., Mason number. Model of Mason number was verified for larger values, but in lower values, significant difference was observed (probably caused by different shear stress mechanism in MRF). After other investigation and clarification of model, precise prediction of MRF and MR devices behaviour will be possible, which can lead to improving their function and e.g., road safety.
|
|
|
Magnetorheological fluid response time in shear mode
Válek, Josef ; Vimmr, Jan (referee) ; Kubík, Michal (advisor)
Magnetorheological fluids (MRF) are suspensions of (commonly) oils and carbonyl iron powder. Under magnetic field, apparent viscosity of suspension changes in short time. This so-called response time can’t be neglected in modern MR devices. Multiple response times are distinguished based on load mode. Rheological response time (MRF under shear rate) will be affected by load and composition of MRF. In this thesis, these influencing parameters are investigated, which was allowed by developing rheometer with minimal hardware response time and methodology. Gained data shows, that most affecting parameter is ratio of inner forces, described e.g., Mason number. Model of Mason number was verified for larger values, but in lower values, significant difference was observed (probably caused by different shear stress mechanism in MRF). After other investigation and clarification of model, precise prediction of MRF and MR devices behaviour will be possible, which can lead to improving their function and e.g., road safety.
|
|
|
Influence of organic matter on the character of aggregates formed during coagulation/flocculation process in dringing water treatment
Filipenská, Monika ; Pivokonská, Lenka ; Vašatová, Petra ; Pivokonský, Martin
Characteristics of aggregates (size, shape, density and porosity) affect separation efficiency. These characteristics come from properties of impurities (molecular weight and structure, charge density, affinity to water, etc.), coagulation parameters (pH, type and concentration of coagulants, etc.) and by physical conditions (shear rate and time of mixing). In this work, we describe relations between the size of aggregates and shear rate and moreover dependency on the characteristics of coagulated compounds. In order to understand dependency on compounds, flocs formed by kaolinite, Algal Organic Matter (AOM) and a mixture of the same were studied. There was found aggregates are bigger and more porous when AOM is present. The most striking result is that aggregates size changes in dependence on shear rate are not smooth in progress. A rapid change for the kaolinite-coagulant suspension and two rapid changes for the suspensions containing AOM were observed. These were attributed to various intermolecular interactions between floc components participating in coagulation at the different shear rate.
|
|
|
Dynamic viscosity of asphalt binders
Broďák, Marek ; Coufalík, Pavel (referee) ; Dašek, Ondřej (advisor)
The bachelor thesis describes a laboratory characteristics of bituminous binders. The principle, procedure of meansurment and comparison of test results of dynamic viscosity, needle penetration and softening point by ring and ball method will be described. The tests will be performed on samples of the bituminous binders with different degree of modification.
|
guest ::
