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Měření hmotnostní koncentrace polétavého prachu v kabinách zemědělské techniky
MATĚJKA, Petr
This Bachelor thesis is focused on comparison of concentrations of particulate matter in cabins of combine harvesters. Fortschritt E 512, New Holland TX 66 and New Holland CX 880 were selected for the measurement. Literary research contains information about the history of combine harvesters and the basic concepts of dust. The results obtained were evaluated, plotted and compared.
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Size segregated atmospheric aerosol in selected workspaces of coal strip mine
Basslerová, Barbora ; Hovorka, Jan (advisor) ; Svoboda, Petr (referee)
The workers are exposed to aerosol particles in a coal strip mine. These particles are usually generated by the Bucket-wheel excavators which break the mined rock. The goal of the thesis thesis was to compare the concentrations of atmospheric aerosol particles - PM on the Bucket-wheel excavator Schrs 1320, the Stacker ZPDH 6300 and the Bucket- wheel excavator K 800/N2 in the coal quarry Doly Nástup Tušimice, and then to answer the questions what is the main cause of increased concentration PMx and whether the mining machines are different from each other. The measurement was realized stepwise on every mining machine in the time period from 12. 8. to 2. 9. 2016. The concentrations of PM1, PM2,5 and PM10 were measured by two portable laser nephelometers in the cab drivers and the outdoor walkway of the mining machines with the integration time of 1 minute. The air temperature and the relative humidity were monitored in both types of settings in every five minutes. The PMx concentrations variability is usually determined by the type of work and by the type of smoking. Consequently, PM concentrations on the mining machines were compared at the morning exchanges and evening exchanges, during the outdoor cleaning by sweeping, the indoor cleaning by hoovering and during the smoking. The highest...
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Proposal of ultrasonic trap
Bartoň, Petr ; Pavlů, Jiří (advisor) ; Vyšinka, Marek (referee)
Light scattering by dust grains is a complex problem when the size of the grain is about the wavelength of incident light. The Mie theory is often used to characterize such situtation, however, most of the materials lacks knowledge of neccessary material constants. Moreover, solution of Mie equations for general shapes is difficult and partly not known. Objective of this work is development of apparatus for light scattering measurements on small (micrometer ranged) ar- bitrary shaped dust grains levitating in the ultrasonic field. Trap parameters are obtained by survey of literature and by numeric simulations leading to design of reliable ultrasonic levitator including optical system. The results enable manu- facturing and completion of such apparatus. Eventually, this work can serve as guide "how to design ultrasonic levitator".
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Personal exposure to PM10 of selected workplaces in a coal strip mine determined by experiment
Basslerová, Barbora ; Hovorka, Jan (advisor) ; Hůnová, Iva (referee)
This thesis compares the experimentally determinated values of PM1, PM2,5, respirable fraction and PM10 between the cab drivers and the outdoor walkway of the bucket wheel excavator in the brown coal strip mine Doly Nástup Tušimice between March 16 and March 23, 2015. For the measurement of individual fractions, portable laser nephelometers were used. Superiority of coarse aerosol was confirmed outside from the total measurement time accounted for 82 %. PM10 fraction predominated outside and changed throughout the day depending on the activity carried out by a worker. Regular cleaning by sweeping stretches of dunes had an impact on PM10 concentrations. Fluctuations in the concentration of PM1 were detected in the driver cab due to smokers stay at this workplace. For these reasons there is a concentration difference between work shifts. Air temperature and relative humidity were also monitored in both types of work places. The air temperature average values reached over the range recommended for the optimal working environment in the driver cab. The thesis finds out personal exposure of a bucket-wheel excavator driver which is below the limit for the total concentration. Smaller fractions appears to be a potentially health risk. Powered by TCPDF (www.tcpdf.org)
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Solid Particle Emissions from AgroPellets Combustion
Svoboda, Marek ; Milčák, Pavel (referee) ; Lisý, Martin (advisor)
This thesis is divided into two parts. The first part deals with defining the main concepts, properties of biomass and pellets. Further, the procedures for measuring agropellets properties according to valid standards are mentioned. The following is a selection of the raw materials for the production of agropellet, with the determination of their properties. The theoretical part closes background research emissions from combustion and emission standards for a solid fuel boiler. The second part is an experimental one, which determines the formation of solid pollutants in combustion of four types of pellets made from alternative sources. Here are the graphs of the gaseous emissions of each of them. At last there will be a comparison of emissions agro pellets with more widespread wood pellets.
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Emise tuhých znečišťujících látek v chovech drůbeže
FARA, Radek
This bachelor thesis is focused to monitoring concentrations of the dust particles in the object of laying hens meat-type. Measurement took place in company international poultry testing based in Ustrasice. In this object was monitored fraction of particulate matter size PM10 . These particles can have a negative impact on worker's health and on breeding poultry. Own measurement was done by DUSTTRAK II 8530 Measurement was carried out continuously in a period of 24 hours with a recording interval every three seconds. After analyzing monitored values it was found that the values of dust particles from the housing meat-type hens were not in the hall in Ustrasice exceeded. It is desirable levels of dust particles to the maximum extent possible to eliminate.
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Laboratory Study of Field Ion Emission from Dust Grain
Jeřáb, Martin
Title: Laboratory study of field ion emission from dust grains Author: Martin Jeřáb Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc., KFPP Abstract: Dust particles are common objects in space environment. As a dust particles, we call objects with typical sizes of several atoms up to approximately 100 µm. However, a total mass of dust particles is only about 1% of total mass of our galaxy, the presence of dust particles significantly affects environment. The most interesting is dynamics of dust particles and attached dust charging processes. The presented thesis consists of two main parts. The first part deals with the experimental study of field ion emission. Our measurements have been performed using gold and carbon spherical dust grains. It has been found that during the charging of dust particle using ion gun are the primary ions implanted under the surface of the dust particle from where they are release in the form of neutral gas. This releasing of implanted ions affects field ion emission for several hours. The second part of the thesis describes a development of new experimental apparatus determined to the study of photoemission dust charging and con- sequently to the "true" field ion emission study. Keywords: dust, dusty plasmas, charging properties, field...
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Dust-UV interaction
Nouzák, Libor ; Pavlů, Jiří (advisor) ; Žilavý, Peter (referee)
Title: Dust - UV interaction Author: Libor Nouzak Department: Department of Surface and Plasma Science Supervisor: RNDr. Jiri Pavlu, Ph.D. Supervisor's e-mail address: jiri.pavlu@mff.cuni.cz Abstract: Micrometer objects (dust grains) are an integral part of the universe. As other objects in the plasma, these dust grains charge to potencial close to the potencial of the plasmas (in this case, interplanetary plasma). In the universe, the photoelectric charging dust grain dominantes all other charging processes. In general, the resulting charge of dust grain is given by a balance of all processes, which haven't been mostly jet theoretically described. In our laboratory, we are simulating space conditions and measure resulting charge and his changes on a single separated dust grain. This work is partly focused to UV source application and to finishing its electronics, and partly on test measurements and model calculations, connected with newly built experiment (e.g., to estimate effects of backgound currents, surfaces, and the geometry of the dust trap electrodes). The work is finished by the first measurements of glass grain charge under electron bombardment with provisional detection optics. Obtained results are compared with previous measurements on the same type of dust grains. Key words: dust, dusty plasma,...
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Resuspension chamber as a tool for determination of resuspendable fraction of soil and street dust
Civiš, Martin ; Hovorka, Jan (advisor) ; Ždímal, Vladimír (referee) ; Střižík, Michal (referee)
A purpose-built cylindrical resuspension chamber (V=0.437 m3 , S=0.35 m2 , S/V=8.38) was used for the dispersion of samples of soil and various kinds of dust. The samples were studied from the point of view of the number and mass distribution of aerosol particles which could affect the concentration of atmospheric aerosol. The samples were taken from lignite, power plant flue ash and from overburden soil in the North Bohemian surface mine Nastup. The individual samples were pneumatically dispersed inside the chamber under defined temperature-humidity conditions (20řC and relative humidity (RH) 50 %). An APS (Aerodynamic Particle Sizer) processing provided us with average size distributions of particle mass and number. Lignite and flue ash probably have the greatest potential impact on the concentration of atmospheric aerosol in the studied locality. The amount of the resuspended mass of the samples varied between 0.001 % (overburden soil) and 0.32 % (mine road). The lignite and flue ash samples were then analyzed by gravimetric methods using the HI (Harvard Impactor) and the SCI (Sioutas Cascade Impactor). The flue ash contained higher amounts of fine particles than the lignite. Subsequent chemical analysis by electron microscope of the filters with deposits of power plant flue ash showed that the PM2.5...
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