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Analysis of ash from fireplace
Drápela, Jakub ; Špiláček, Michal (referee) ; Hrnčířová, Michaela (advisor)
This bachelor thesis should familiarize readers with the size of analysis of ashes of fireplace inset. The work is posssible to divide into two parts, when the first one is devoted to a description of fireplace insets, fuels and subsequent processes during burning in fireplace insets and to individual methods used for size analysis of particles.The other part is focused on practical measurements of individual samples of ashes and subsequent evaluation.
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Device and methods for testing clean rooms
Bojanovský, Tomáš ; Kolbábek, Antonín (referee) ; Štětina, Josef (advisor)
In the introduction of the thesis there is described main information about clean rooms that influences the way of measurement and evaluation of these rooms. Then there is a summary of instruments that are used with testing and controlling mentioned rooms. It is primarily a case of device for measurement of concentration of particles in the air that are produced by several firms nowadays. Lighthouse Worldwide Solutions is mentioned as the main producer of these devices. Its three basic types are described in the work. In the next chapter there is the list of other firms occupying this technology and their products. Finally, particular instruments are compared with the regard of different requirements that are placed on them.
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Determination of eutrophication potential of particles in rivers and waterbody sediments
JAN, Jiří
Extraction solutions were assessed to find the most appropriate method for characterisation of particles in the context of release or uptake phosphorus in non-calcareous regions. Advantages and limitations of methods for determination of different phosphorus (P) forms and its important binding components iron and aluminium (hydr)oxides, were pointed out. Characterisations of these forms, that show highly different behaviour under changing environmental conditions, were used for the assessment of particles saturation with respect to P. Sorption/desorption behaviour of soil particles susceptible to erosion and their content of plant available P was tested. Strong correlation, which is dependent on P saturation ratio, was used to propose a method for the determination of soil erosion impact to supply dissolved P in stream waters of variable dissolved P concentration.
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The Effects of Agitated Beds Homogenization on Stirrer Geometry and Bed Depth via DEM
Kohout, M. ; Trávníčková, Tereza ; Havlica, Jaromír
In this contribution open source DEM particle simulation software LIGGGHTS was studied and tested. Collision forces are there modelled by the softsphere approach with the Hertzian collision model. As an application we studied agitated particle beds (packed from glass spherical particles of two colours – packed vertically and horizontally) mixed by different types of agitators. Dependence of degree of homogenization on particle diameter, particle properties (Young’s modulus), and on geometrical aspects (bed depth, agitator position, etc.) will be also discussed.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22014090110404 - PDF
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Improvements of saltation model
Kharlamova, Irina ; Vlasák, Pavel
The present paper introduces a new model of a bed-load transport. The model simulates a particle motion in the channel with turbulent flow and rough bed. The effects of mutual interaction of conveyed particles with carrier liquid, with bed particles, and also with other conveyed particles are taken into account. The model predicts average saltation characteristics, e.g. saltation length and height, particles distribution in vertical direction, and mass rate of conveyed particles per unit area of channel bed.
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Coarse-grained particles conveying along a pipe bed
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří ; Kysela, Bohuš
The paper describes the results of a flow visualisation of model coarse-grained fully stratified particle-water mixtures. Investigation was focussed on study of the particle behaviour and carrier liquid and conveyed particles local velocities. Glass balls and washed graded pebble gravel of mean diameter of 6 mm were conveyed by water in a horizontal smooth pipe loop with a transparent pipe viewing section of inner diameter 40 mm. Particle movement along the pipe invert and particulate stationary bed, created by two layers of spherical particles of the same size as the conveyed particles, was studied. The effect of stationary bed on local velocity values of the carrier liquid and conveyed particles were determined. It was conducted that the maximum liquid velocity is significantly shifted from pipe centre to a higher position in the flow pattern with stationary bed.
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Komplexní charakterizace prachových frakcí ve volném ovzduší (AirToxPM)
Masarykova univerzita, Brno ; Klánová, Jana
Stručný popis prací v rámci projektu, jehož cílem je snaha co nejlépe charakterizovat fyzikální, chemické a toxikologické vlastnosti prachových částic. Projekt zahrnuje výzkum a identifikaci jejich primárního zdroje, charakterizuje jejich sorpční potenciál. Zabývá se modelováním chování, studiem jejich dalšího osudu, délkou setrvání v atmosféře a toxikologickými efekty. Byly vyhodnoceny analytické výsledky, které umožnily stanovení míry rizik plynoucích z expozice prachovým částicím pocházejících z různých zdrojů a různých velikostí. Je připravena metodika hodnocení vlivu polétavého prachu pro regionální a lokální studie. Jsou uvedeny citace publikačních výstupů i vlastní texty článků.
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Synthesis of Heterostructure Particles by CVD Method in a Tube Flow Reactor
Moravec, Pavel ; Smolík, Jiří ; Levdansky, V.V. ; Keskinen, H.
Powders of mixed or heterostructure fine particles are of even greater value than the single component ones. During last decade we prepared single component fine particles of silica, alumina, titania and zirconia by decomposition of organoelement precursors in an externally heated tube flow reactor. On the basis of experience with the synthesis of single component particles we prepared mixed or coated multicomponent particles Al2O3-SiO2, TiO2-SiO2 and ZrO2SiO2 by simultaneous decomposition of two precursors in one reactor.
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