|
|
A comparative study of the total mercury determination in highly contaminated soils by AAS and RNAA methods
Sysalová, J. ; Kučera, Jan ; Zvěřina, O.
High total mercury (T-Hg) contents in soils, up to 25 mg kg−1, were determined by two independent methods: a one-purpose atomic absorption spectrometer AMA-254 (Advanced Mercury Analyser) with direct solid sampling, and radiochemical neutron activation analysis (RNAA), using sample masses of 10 mg to 25 mg and about 150 mg, respectively. An excellent agreement between results of both methods was obtained. For quality control (QC) purposes, NIST SRM 2711 Montana Soil and NIST SRM 2711a were analysed by both methods using the above sample masses. The results obtained were compared with the NIST certified values within the uncertainty margins, thus proving the accuracy of the procedures employed. It has been found that the cryogenic grinding used provided sufficiently representative and homogeneous samples. A test in which HgS was analysed by RNAA showed that even mercury present in sulfide form would be fully recovered using the procedures employed. For contents of T-Hg above the upper limit of the AMA-254 working range (500 ng), samples were firstly diluted with sea sand in the ratio 1:10 and homogenised well to get RSD below 5%. The dilution procedure was verified using the certified reference material ERM-CC580 Estuarine Sediment.
|
|
|
Determination of reference values of element contents in certified reference material SWCNT-1 by INAA a PGAA
Kučera, Jan ; Sturgeon, R. E. ; Grinberg, P. ; Oflaz, R. ; Paul, R. L. ; Bennett, J. W. ; De Nadai Fernandes, E. A. ; Kubešová, Marie ; Bacchi, M. A. ; Stopic, A. J.
Instrumental neutron activation analysis with both relative and k-0 standardization was used in four experienced laboratories to determine element mass fractions in single-wall carbon nanotube certified reference material (CRM) SWCNT-1. Results obtained were evaluated using the NIST “Type B On Bias” approach and yielded consensus values in agreement with NRCC certified values for Fe, Co, Ni and Mo and provided mass fraction values for thirteen additional elements, namely Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Br, La, W and Au. In addition, prompt gamma neutron activation analysis was employed to determine mass fractions of H, B, Co, Ni, and Mo. Results of this work provide a basis for the establishment of reference values of element mass fractions in CRM SWCNT-1, thus expanding its usability for more accurate characterization and benchmarking of similar nanotechnology materials.
|
|
|
Revitalization study for 4th order catchment
KUČERA, Jiří
This diploma thesis examines the state of the Lisov stream and its basin. It also suggests the way of revitalization of the whole riverbed in given places. For better solution of this problem, the stream was divided into several sections, which are analysed both separately and as a whole. The basic information for the purposes of this diploma thesis were gained primarily from the survey of the given area. The evaluation was realized according to the findings and other maps which are freely available on the Internet. Thereafter there is a suggestion of the revitalization works which was made together with individual revitalization objects. This suggestion includes also the possible way of financing all these revitalization actions. There were several slopes set in the basin and the soil removals caused by water erosion were calculated for these slopes. The reason for including these data is that this diploma thesis puts emphasis also on the river sediments which are forming the riverbed of the stream too. At the same time there was another survey completed. It is related to the flood protection and the suggestion how to build up these necessary flood protections.
|
|
|
Analysis of changes in land use in the selected area
KUČERA, Jaroslav
This thesis deals with the analysis of changes in the selected area, specifically in the cadastral Vodňany. The aim of this study was to evaluate changes in the period between 1842 - 2011. As a bases were used maps of the 2nd military mappings, the state map derived of 1: 5000 and the current orthophoto updated in 2011. The maps of the 2nd military mappings were obtained using a WMS service of the National INSPIRE Geoportal, the state map derived orthophoto and the current drawn from the order of the portal CUZK. All work involving the preparation of maps, map outputs and associated data acquisition were made in the ArcMap 10 program. The obtained data were further processed, there were created tables and graphs that serves as an overview of land use changes in the area and they were all created in Microsoft Excel. This work tries to answer on why these changes occurred and what was the reason for the change of land use in the area.
|
|
|
Mass culture
Kučera, Jakub ; SLÁMA, Bohdan (advisor) ; MAREK, Petr (referee)
Mass cultrure is like mirror of society which determines estetic and politic view on global world. Work has an incentive to present historic context of existence mass culture and massmédia. Benefits and disadventeges releted with levels of comunication, critic, and levels of sociaty.
|
|
| |
|
|
Nondestructive determination of nitrogen in biological and other materials by photon activation analysis
Krausová, Ivana ; Mizera, Jiří ; Chvátil, David ; Krist, Pavel ; Řanda, Zdeněk ; Kučera, Jan ; Štursa, Jan
A procedure has been developed for assaying nitrogen in biological materials by means of instrumental photon activation analysis (IPAA). The determination has been based on counting of the non-specific 511 keV annihilation gamma rays of 13N, product of the photonuclear reaction 14N(γ, n)13N and a pure positron emitter. IPAA allowed determination of nitrogen down to 1 wt.%. in selected biological reference standards - NIST RM 8433 Corn Bran, 1547 Peach Leaves, 8414 Bovine Muscle, and 1577b Bovine Liver. The optimized procedure was applied also to assaying nitrogen in pulverized nanodiamond intended for medical purposes.
|
|
| |
|
|
Comparison of eddy covariance and bowen ratio energy balance method. Energy balance cloruse versus bowen ratio similarity assumption
Fischer, Milan ; Trnka, Miroslav ; Pozníková, Gabriela ; Sedlák, Pavel ; Orság, Matěj ; Kučera, J. ; Žalud, Z.
The Bowen ratio and the Monin-Obukhov similarity principles are based on the assumption that the eddy diff usivities for temperature and humidity are equal to each other under all atmospheric stratifi cations within turbulent surface boundary layer. However, several authors reported that this equality was violated under advective inversion or during the non-stationary conditions due to clouds passing by and sudden change of wind speed and direction. Th e inequality of the eddy diff usivity can lead to errors in the energy partitioning estimates by gradient techniques like the Bowen ratio energy balance (BREB) and the aerodynamical method, or methods based on residual energy balance such as the Penman-Monteith or Priestley-Taylor models. Th is study investigates two seasons of simultaneous measurement by eddy covariance (EC) and BREB above a high density poplar plantation at the Domanínek locality. Th e direct measurement of eddy diff usivities by EC is reinvestigating the validity of the long term measurement (since 2008) by BREB. Results showed unequal exchange coeffi cients with their mean 0.31 to 0.35 m2 s-1 for 2011 and 2012, respectively, favouring the transport of latent heat. Th is might be explained by the diff erent footprints of the BREB and EC methods, an undeveloped internal boundary layer or instrumental errors.
|
|
|
Non-destructive determination of nitrogen in biological and other materials by the photon activation analysis
Krausová, Ivana ; Mizera, Jiří ; Chvátil, David ; Krist, Pavel ; Řanda, Zdeněk ; Kučera, Jan ; Štursa, Jan
The study presents a procedure for assaying nitrogen in biologocial materials by means of instrumental photon activation analysis (IPAA). The determination has been based on counting of the non-specific 511 keV annihilation gamma rays of 13N, product of the photonuclear reaction 14N(γ, n)13N, which is a pure positron emitter. IPAA allowed determination of nitrogen down to 1 wt.%. in selected biological reference materials - NIST RM 8433 Corn Bran, 1547 Peach Leaves, 8414 Bovine Muscle, and 1577b Bovine Liver. The optimized procedure was applied also to assaying nitrogen in pulverized nanodiamond intended for medical purposes.
|
guest ::
RSS feed.