Academic literature on the topic 'Vznik a transformace částic'

V posledních 30 letech prochází český vzdělávací systém řadou změn. Po delší době stagnace vzdělávacích přístupů, realizace jednotného školství a centralizace vzdělávání, založené na tzv. učebních osnovách, došlo v 90. letech k výrazné transformaci vzdělávací soustavy. Za jednu z nejvýznamnějších změn této transformace lze považovat vznik nových škol a postupné zvyšování autonomie škol díky uvolnění učebních osnov. V průběhu posledních 30 let lze také v českém prostředí pozorovat významnou proměnu paradigmatu přírodovědného vzdělávání, která je do značné míry dána otevřeností vzdělávacího systému k novým, globálním trendům ve vzdělávání. Cílem článku je zmapování vývoje paradigmatu přírodovědného vzdělávání v posledních 30 letech. Předmětem tematické kvalitativní analýzy budou relevantní strategické a koncepční dokumenty MŠMT (např. dlouhodobé záměry vzdělávání a rozvoje vzdělávací soustavy, vládní strategie v oblasti vzdělávání, i dílčí strategie související s přírodovědným vzděláváním) a další dokumenty tvořené organizacemi jakými jsou např. Výzkumný ústav pedagogický v Praze (nyní Národní ústav pro vzdělávání), či Česká školní inspekce. Na základě těchto dokumentů chceme demonstrovat širší kontext přírodovědného vzdělávání. V druhé části článku se na základě analýzy cílového zaměření kurikul v oblasti přírodovědného vzdělávání od roku 1989 chceme zaměřit na proměnu cílů v oblasti přírodovědného vzdělávání, soustředit se chceme také na promítání alternativních metod a postupů výuky do kurikul přírodních věd. Výběr vhodných dokumentů pro analýzu a jejich objektivní interpretace jsou do značné míry zaručeny týmem autorů, kteří se na řadě reformních kroků přímo nebo poradenstvím podíleli a mohou tak analýzu obohatit expertním pohledem na danou problematiku.

This diploma thesis is focused on study of physico-chemical influences on model surface-water treatment which contain humic compounds. From those factors were monitored especially the dose of destabilizing reagent, pH value, temperature, velocity gradient of mixing and time of its duration. As destabilizing reagents were used Al2(SO4)3 .18H2O a Fe2(SO4)3 . 9H2O.

Master´s thesis is focused to analyse the acoustic and electomagnetic emission signals. These signals generate external power applied on the material. This power put there plastic deformation and create cracks. Spectral analyse show that signals are non-stationary. Wavelet transformation was used to spectral analyse which informate about time-frequence vaules of the signal.

Title: Formation and transformation of atmospheric aerosol in boundary layer Author: Mgr. Adéla Holubová Šmejkalová Institute: Institute for Environmental Studies Supervisor: Ing. Vladimír Ždímal, Dr., Institute of Chemical Process Fundamen- tals of the CAS Training workplace: Institute of Chemical Process Fundamentals of the CAS Abstract: The experimental measurement of aerosol clusters from 1.17 nm in size was carried out from August 2016 till December 2018 at the National Atmospheric Observatory Košetice. Atmospheric conditions leading to aerosol clusters stabili- zation, fresh particles formation and particle growth were analyzed. Data of days with no new particle formation confrmed the connection between mixing layer height development and decrease of total aerosol number concentration together with lower gaseous pollutant concentrations. On the contrary, new particle for- mation process overcomes dilution of the atmosphere by increasing the number of freshly nucleated particles. Only decreasing gaseous pollutant concentrations were observed during these events. The atmospheric boundary layer was high du- ring new particle formation events that can mean enrichment of the atmosphere by other components transported by long-range transport or some transfer from the free troposphere. The measurement in...

This thesis is focused on biomass-containing topsoils from a highly contaminated semi-arid area in the vicinity of mining and smelting operations in Tsumeb and Kombat in the northern Namibia. The highest concentrations of inorganic contaminants were found in samples from Tsumeb and attained the following values (mg/kg): As 1920, Cd 81, Cu 5840, Hg 7,66, Pb 4880, Sb 266, Zn 3310. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA) have been used for determination of mineralogical composition of particulates adhering to surfaces of biomass and occurring in the heavy mineral fraction of topsoils. Quantitative partitioning of contaminants within individual mineral phases has been determined using autoSEM; contaminants were mainly bound in the slag glass (As: 16.7 %; Cu: 12.7 %; Pb: 26.2 %; Zn: 33.9 % of total concentration) and in metal(loid)-rich Fe-hydroxides (As: 14.4 %; Cu: 7.7 %; Pb: 21.6 %; Zn: 32.5 %). On biomass- rich topsoil samples, we have experimentally proved that bushfires can be responsible for transformation and re-mobilization of contaminants. Mercury is completely released at temperatures around 300 řC. In the same temperature range, also As anad Sb are released due to arsenolite (As2O3) thermal degradation. Cadmium is released...

1 ABSTRACT: This study is dedicated to the study of nucleation of sulphuric acid and water, which presents the key process associated with secondary aerosol formation via gas to particle conversion. We investigated the nucleation rates, new aerosol particles formation and growth dynamics of newly nucleated particles. These processes were explored in both laboratory and field experiments. In the laboratory measurements, we explored the H2SO4 - H2O nucleation rates and growth rates of newly formed particles under well-defined conditions and we also investigated the effect of experimental conditions on particle growth dynamics. Furthermore, we proposed a model, which predicts the particle growth and accounts for condensation of H2SO4, H2O and NH3. The comparison of experimental growth rates with atmospheric ones was made and resulting implications of the chemical nature of compounds involved in the early growth of nucleated particles is also presented. To investigate the atmospheric H2SO4 - H2O nucleation and new particle formation, we analysed a two-year long dataset of particle number size distributions, obtained from a urban background station in Prague Suchdol. A special attention was given to a recently reported special feature of particle growth dynamics - a particle shrinkage following previous new...

The diploma work "The birth and construction of myth and mythology of the cowboy character and the gay character in American cinematography and their transformation in the film Brokeback Mountain) focuses on historical trends in Westerns and films featuring gay characters, ending with Bokeback Mountain. Powered by TCPDF (www.tcpdf.org)

Due to its prevalence over large, densely populated areas, ammonium nitrate is an important chemical species in aerosol research. However, due to its volatility at ambient temperatures and over low temperature gradients, ammonium nitrate can be a difficult species to accurately measure. The volatility of ammonium nitrate is known to be dependent on temperature, relative humidity, the internal mixing state of the particle, and availability of the precursor gas constituents. The particle's physical state affects the equilibrium constant value of the ammonium nitrate - nitric acid / ammonia exchange and helps determine the dissociation rate. For indoor aerosol research, the outdoor originating aerosol particles' exposure to the new physical conditions indoors, such as changes in temperature, humidity, and particle-surface reactions within the microenvironment all accelerate ammonium nitrate dissociation. This increased rate of partitioning can generate artifacts on datasets, increase indoor particle formation, and accelerate the corrosion of cultural antiquities through acidification. The magnitude of these impacts is uncertain due to the current lack of knowledge on particle transformation processes when outdoor originating particles migrate indoors. To address this gap in knowledge, this thesis...