|
| |
|
|
Viscosity study of liquid materials
Januš, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Bachelor thesis focuses on the study of viscosity of liquid materials. Its aim is to study the mathematical and physical fundamentals of dynamic viscosity. The thesis presents a correlation between conductivity and viscosity of liquid insulators called Walden rule. Further part of work is a review of methods for measuring viscosity of liquids and classification of insulating liquids. The last section is the practical part in which it is verified Walden rule for available insulating liquids.
|
|
|
Hydraulic efficiency of multi-chamber septic tanks based on mathematical modelling
Hradilová, Iva ; Hyánková, Eva (referee) ; Kriška-Dunajský, Michal (advisor)
The submitted diploma thesis is focused on finding optimal inside arrangement of multi-chamber septic tank using the conductive method. The diploma thesis brings detailed description and measuring results, including the testing of several different arrangements of the standard circular three chamber septic tank in the project TAČR with the working title "Anasep" and newly developed four-chamber septic tank with several innovative features. The results are then categorized according to own terminology for ease application in the practice. The described method may be a suitable alternative for other technically and economically less available methods. The method shows very clearly whether the inner space of the septic tank sufficient use its volume to the velocity field distribution which has a direct impact on the rate of sedimentation of suspended solids and therefore affect the life of the downstream filtration equipment. Measured data processing and graphical outputs were processed in the programme Minitab. Graphical display of all variants of septic tanks was carried out using SketchUp. Visualization of a septic tank in 2D and 3D space plane was solved in COMSOL Multiphysic with the application of CFD module. The conclusion is based on achievements discussed the applicability of the described method and it presented hydraulically efficient multi-chamber septic tank, which is currently copyrighted solution, developed by a team of solvers in the project ANASEP.
|
|
|
Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
|
|
|
Measurement of conductivity of liquids
Mašláň, Stanislav ; Havránek, Zdeněk (referee) ; Beneš, Petr (advisor)
The first part of thesis is theoretical and it is the introduction into conductometry. It defines the essential terms of this field as well as contact and contactless methods of measurement of fluid conductivity and also the influential parasitic phenomena and possibilities of their elimination. The second part is dealing with design of the contactless transformer conductivity probe. The characteristics of designed probe are verified in the practical part of the thesis. The final part of the thesis is dealing with measurement according to the defined points in the assignment. The characteristics of several contact probes are verified and also the characteristic of the contactless transformer probe, which was implemented according to the design from the second part. Outcomes of these measurements establish the suitable power supply frequencies and currents for all these probes.
|
|
|
Plasma diagnostics of electric discharges generated in selected configurations in liquids
Vašíček, Michal ; Bartlová, Milada (referee) ; Kozáková, Zdenka (advisor)
My diploma thesis is focused on a comparison of direct-current and high frequency (15-80 kHz) electric discharge, which generates non-thermal plasma in water solution of sodium chloride. Mainly current-voltage and Lissajous charts are discussed in the first part of this thesis. These charts describe different discharge phases: electrolysis, bubble formation, discharge breakdown and discharge regular operation in a pin-hole of a dielectric barrier. Influence of frequency, electrolyte conductivity, thickness of the diaphragm (or length of the capillary) and pin-hole diameter on discharge breakdown and bubble generation was studied, too. Measurements were realized in a polycarbonate reactor with total volume of 110 ml, which was divided by a changeable polyacetal insulating wall. This wall divided the reactor into two approximately equal spaces with one stainless steel planar electrode in each part. The Shapal-MTM ceramic discs (thickness of 0.3–1.5 mm and diameter of the central pin-hole of 0.3-0.9 mm) were mounted in the centre of the insulating wall. Initial conductivity of sodium chloride solution was chosen within the interval of 100900 S/cm. The second part of my thesis compares an influence of the direct-current (DC) and high frequency (HF) power sources on physical solution properties (conductivity, pH and temperature) and generation of hydrogen peroxide. A plasma reactor with total volume of 4 l and with mixing set up was divided into two equal spaces with one planar platinum electrode in each part. Diaphragm with thickness of 0.6 mm and pin-hole diameter of 0.6 mm was installed in the middle of the separating wall. Experiment was held at discharge operation of 45 W for 40 minutes with both power sources. Detection of hydrogen peroxide was realised by using a titanium reagent forming a yellow complex, which was analysed by absorption spectroscopy. If HF discharge power is plotted as a function of applied frequency, exponential decrease of frequency with increasing power can be observed. Higher breakdown voltage is necessary for thicker dielectric barriers, on the other hand for bigger diameter of the pin-hole lower breakdown voltage and higher power is needed in DC as well as in HF regime. Breakdown voltage is decreased by the increasing conductivity in both regimes; due to more charge carriers in the higher conductivity lower breakdown voltage is needed. However frequency in HF regime and DC discharge power increases. HF discharge power is decreased by the increasing conductivity. Solution conductivity and temperature are increased by initial conductivity value in both discharge regimes. Solution pH drops to acidic conditions when HF or DC positive regime is applied due to the generation of reactive species and electrolysis (in DC regime). However solution becomes alkaline when DC negative regime is applied. Concentration of hydrogen peroxide is produced linearly when HF or DC negative regime is applied and it depends on initial solution conductivity.
|
|
|
Puccinelia distans and Digitaria sanguinalis as a phenomenon of road verges
LAXOVÁ, Lenka
The main subject of this bachelor thesis is establishment the main phenological phases of two grass species Puccinelia distans and Digitaria sanguinalis, which occur in vegetation bands along the roads. It also deals with change of their dominance during one with higher soil salinity along roads near the town České Budějovice. The soil conductivity on road verges was measured, too. Collected information and field data from certain localities were proccesed into tables, diagrams and summary resuls. The tendency in phenological phases exchange confirmed propagation and existence of theese two species on joint area during thge spring and summer seasons. It shows an adaptation of both plants into salt contaminated soil. Soil conductivity shows fluctuating trend in soil salinity during the year on road verges
|
|
|
Kontrola kvality vod Bílého potoka
Brychtová, Jana
This work is focused on monitoring the water quality of the White Creek and basic information characterizing the selected site. Samples were collected from October 2012 to September 2013 monthly to capture the changes in the seasons. I measured the conductivity and pH of samples taken from three locations using the multimeter. Two measured sections were chosen in the natural park of the White Creek Valley third grader segment is outside the Valley of the White Creek near the source of the White Creek. Measurements should prove fluctuations pH and conductivity in the case of larger tributary waters from rainfall or melting snow. The paper further describes the natural park of the White Valley Creek with regard to protected species occurring plants and animals. There are also described methods, principles and importance of pH and conductivity. The work is made of the laws governing water quality and flow distribution. In conclusion is emphasized influence of pH on aquatic life and the importance of measuring these indicators. The aim of the work was the monitoring of selected sections of the stream flow White Creek using selected methods (pH, conductometry).
|
|
| |
|
| |
guest ::
