|
|
Viskozitní charakteristiky geologických suspenzí
Kulaviak, Lukáš ; Večeř, Marek ; Růžička, Marek ; Drahoš, Jiří ; Hladil, Jindřich
The system under study was real geological suspension – ground sedimentary rocks of different chemical composition (calcite, quartz, etc.) dispersed in water-glycerol solutions. The reference one-phase system was a Newtonian liquid (glycerine with water). It is problematic to measure the rheology of settling suspensions, so some specific tools must be used. We used the rotating vane rheometry, with the immersion viscometer Brookfield and two spindles V-71 and V-72. The basic rheological data of solid-liquid system are displayed as flow and effective viscosity curves. The obtained results on rheology were related to the settling behaviour of the geological mixtures, namely to the certain kind of the lateral instability.
|
|
| |
|
| |
|
| |
|
|
Vliv velikosti částic a smykového namáhání na tokové chování jemnozrnných suspenzí
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří
Non-Newtonian behaviour of high-concentrated sand and sand-kaolin slurries was observed. At low and medium velocities the flow resistance increases with the increasing concentration of solids, at high velocities the effect of the concentration can be opposite. An intensive turbulent and even long time laminar shearing result in a significant decreasing of the laminar/turbulent transition velocity and flow resistance in the laminar region. The effect of shearing is more significant for higher slurry concentration.
|
|
| |
|
|
Supermolecular arrangement in the development of pseudosynovial fluids
Štol, Miroslav ; Musil, Jan ; Pražák, Josef
Attention has been paid to sodium salt of carboxymethyl cellulose as a hyaluronic acid substitude. The latter substance has been modified by addition of some metalic ions. Measurements of dynamic viscosity of the NaCMC solutions revealed that bivalent metallic ions do not adequately crosslink polymer chains in an intermolecular fashion. On the other hand, some multivalent metallic ions (Mn or Ce) were active in crosslinking the polymer chains, thus forming their supermolecular arrangement.
|
|
|
Rheology and texture of multiphase emulsion systems
Štern, Petr ; Pokorný, J.
Sensory and texture analyses are important tools to characterise the acceptance of food products by consumers. The aim was to correlate the results of rheological and sensory analysis because they can directly an more easily be applied in production and quality control. As an example were chossen Tartar souces - emulsion of edible oil in an aqueous phase consisting of water, salts, vinegar, modified starch and other flavoring. Functional relations between rheological parameters of tartar souces and sensory characteristics were determined.
|
|
| |
|
|
Vliv .gamma.-záření na reologické vlastnosti tavenin ultravysokomolekulárního polyethylenu
Mikešová, Jana ; Nevoralová, Martina
Ultra-high molecular weight polyethylene is widely used as material in orthopaedic implants. Melt rheology was used to evaluate the result of simultaneous crosslinking and chain scission process in the polymer, .gamma.-irradiated in the solid state. The predominant mechanism in the process was strongly influenced by irradiation dose and dose-rate. An important result was obtained for the polymer irradiated with the sterilization dose 25 kGy and stored in nitrogen when no significant degradation of the polymer was observed.
|
guest ::
