|
| |
|
| |
|
|
Bedload transport in Polar gravel-bed rivers
Ondráčková, Lenka
The thesis deals with the transport of sediments in gravel streams in Polar regions. The study of bedload sediments, the transport and changes in their grain size and shape characteristics has a long history, but only recently have they been studied in proglacial rivers of high latitudes. The assigned work aims to study and compare the behaviour of braided gravel-bed rivers and to develop appropriate methods of study and data collection in the Polar regions. Three catchments of proglacial braided gravel-bed streams were selected for the research. Two river catchments are located on the Svalbard archipelago in northern Billefjorden and one river catchment is located on James Ross Island in Antarctica. These catchments of gravel-bed streams are located in the forefield of glaciers, which has been studied since 2016 during the research expeditions. The Munin River catchment on Svalbard was selected due to the morphology of the whole river catchment, the presence of active sediment sources and the well-developed river bed. The second catchment of the Keller River on James Ross Island was selected as a suitable example for assessing the impact of connectivity in the catchment area on sediment transport. The third catchment of the Hørbye River on Svalbard is characterized by gravel sediments in front of...
|
|
| |
|
|
Cleaning library documents with a two-phase spray.
Mašková, Ludmila ; Smolík, Jiří ; Vávrová, P. ; Neoralová, J. ; Součková, M. ; Novotná, D. ; Jandová, Věra ; Ondráček, Jakub ; Ondráčková, Lucie ; Křížová, T. ; Kocová, K.
The cleaning of particles from library materials (paper, textile, and collagen materials) using a high-speed CO2 snow jet was investigated. The measurements included\ndetermination of the cleaning efficiency, and evaluation of possible adverse effects. The method was compared with nitrogen jet cleaning. The results showed that the CO2 snow\njet is able to effectively remove particles from the surfaces. Any adverse effects were not observed at paper and textile. However, application on collagen materials caused\ndegradation of the surface.
Plný tet:  PDF
|
|
|
Personal exposure measurement during dental nanocomposite grinding
Ždímal, Vladimír ; Ondráčková, Lucie ; Ondráček, Jakub ; Schwarz, Jaroslav ; Bradna, P. ; Roubíčková, A. ; Pelclová, D. ; Rössnerová, Andrea
The purpose of this study was to measure the personal exposure of each participant of the study and to compare the results with those of static monitoring. Personal nanoparticle sam-plers (PENS), which can simultaneously detect both nanoparticles (PM0.1) and respirable parti-cles (PMA), were used to determine personal exposure (Tsai et al., 2012). Area monitoring in-cluded measurement of mass concentrations using the Berner Low Pressure Impactor (BLPI 25/0.018 /2, Hauke GmbH, Gmunden, Austria) and the Low Volume Sampler (LV5, Sven Leckel Ingenieurbüro GmbH, Germany). The number concentrations and their size distributions were measured with the Scanning Mobility Particle Sizer (5MP5 3936, T5I Inc., USA) and the Aerody-namic Particle Sizer (APS 3321, TSI Inc., USA). Measurements with all of the above- mentioned instruments were performed in four shifts with six participants per shift. Each participant milled for 10 minutes and then remained in the room until the group finished the session, so the total exposure lasted about 70 minutes. Due to the high content of filler nanoparticles, the nanocom-posite Filtek Ultimate (body A2, 3M ESPE, USA) was selected for these measurements.
Plný tet: PDF
|
|
|
Methodology for cleaning paper, textiles and collagen materials using the two-phase spray of CO2 snow particles in the carrier gas stream.
Mašková, Ludmila ; Smolík, Jiří ; Vávrová, P. ; Součková, M. ; Neoralová, J. ; Novotná, D. ; Jandová, Věra ; Ondráček, Jakub ; Ondráčková, Lucie ; Křížová, T. ; Kocová, K.
The aim of this methodology was to create a set of procedures and recommendations for library and archive staff or restorers, using which it is possible to remove dust particles from the surface of paper, textiles and collagen materials using the two-phase spray of CO2 snow particles in the carrier gas. The result is an effective and safe alternative to existing cleaning methods. Furthermore, the research aimed to compare the results of this type of treatment with commonly used mechanical cleaning procedures for library collections and archival documents and to analyse in detail the potential use of the new method.
|
|
| |
|
|
Methodology of cleaning paper, textiles and collagen materials using thr two-phase spray of CO2 snow particles in the carrier gas stream
Mašková, Ludmila ; Smolík, Jiří ; Vávrová, Petra ; Součková, Magda ; Neoralová, Jitka ; Novotná, Dana ; Jandová, Věra ; Ondráček, Jakub ; Ondráčková, Lucie ; Křížová, Tereza ; Kocová, Kateřina
Cílem této metodiky bylo vytvořit soubor postupů a doporučení pro pracovníky knihoven a archivů či pro restaurátory, s jejichž využitím je možné pomocí dvoufázového spreje sněhových částic CO2 v nosném plynu odstraňovat prachové částice z povrchu papíru, textilu a kolagenních materiálů. Výsledkem je efektivní a bezpečná alternativa ke stávajícím metodám čištění.
Fulltext: PDF
|
|
|
Možnosti využití druhu Physalis philadelphica Lam.
Ondráčková, Lenka
Physalis philadelphica Lam. is an interesting vegetable. Its comes from Central America. Mexico is an important grower and producer of fresh and preserved forms of fruit. A typical feature for Physalis philadelphica Lam. is the calyx that surrounds the fruit. This calyx bursts in the ripening of the fruit, which also has an aestethic effect. In Czech Republic, it is not grown in large number. It’s for many people unknown vegetables. Claims for cultivation are not high. It needs sun, warmth, good watering and space. Fresh seeds are also important. In our environment is a one-year plant. It has no proven therapeutic effect. Its advantage is the variety in the kitchen. A fruit, rarely a calyx, is used. It was done in three locations. It was attended by 30 respondents. Five samples were available. The specimens were fresh fruit pulp and food made from them. On the basis of the tasting, the numerical figure revealed interest in jam and salsa verde. The unconventional taste and variety of fruit processing has been recognized.
|
guest ::
RSS feed.