National Repository of Grey Literature 31 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
PM2.5 Chemical Composition at the Rural Background Site Košetice.
Schwarz, Jaroslav ; Cusack, Michael ; Karban, Jindřich ; Chalupníčková, E. ; Havránek, Vladimír ; Smolík, Jiří ; Ždímal, Vladimír
Measurements of atmospheric aerosols at rural background areas are important because they are not influenced by the urban emissions, and are therefore better suited to investigate the influence of long-range transport and trends in concentrations of individual pollutants. Summary of the measurements of total concentration and the concentration of PM10 and PM2.5 components was carried out in the works Putaud et al. (2004, 2010). Although the later work included the measurement of more than 60 stations across Europe, the post-communist countries contained data on PM2.5 from only four locations (Prague, Debrecen, Hungary, and two rural locations). Although Košetice place where this study was made, is also discussed there, it was for only PM10 and total carbon (TC). Therefore, the aim of this study is to fill this information gap, and provide additional information regarding the PM2.5 fraction and composition at the Central European background station Košetice.
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On Usage of Size Segregated Particle Number Concentration to Guess The Origin of PM2.5 at the Rural Background Site Košetice.
Schwarz, Jaroslav ; Cusack, Michael ; Karban, Jindřich ; Chalupníčková, E. ; Havránek, Vladimír ; Smolík, Jiří ; Ždímal, Vladimír
Rural background studies serve mainly to assess the long-range transport influence and long-term trends. However, it is difficult to find a place with no influence of local sources. This is also the case of Košetice observatory having three small settlements within two km from the observatory. Therefore we attempted to analyze if the influence of these or other nearby sources can be seen in our data on PM2.5 chemical composition. Besides other possibilities like specific ratios of various gaseous compounds we concentrated on using size resolved number concentration data because of their dynamics that leads in general into particle growth until they reach accumulation mode. Several similar studies (e.g. Cusack et al. 2013) were performed during recent years.
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Fractionation of Turmerones from Turmeric rhizomes (Curcuma longa L.) by Methods Using Supercritical Carbon Dioxide
Topiař, Martin ; Sajfrtová, Marie ; Karban, Jindřich
Cílem této práce je zakoncentrování turmeronů z oddenků kurkumovníku pomocí superkritické sorpce, metody založené na dělení extrahovaných látek pomocí sorbentu, přičemž mobilní fází je zde místo organického rozpouštědla superkritický CO2, jehož rozpouštěcí vlastnosti závisí na jeho hustotě, kterou lze snadno ovlivnit změnami tlaku a teploty.
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Extraction Kinetics and Insecticidal Activity of Volatile Components Isolatedfrom rue by Supercritical CO2.
Sajfrtová, Marie ; Karban, Jindřich ; Sovová, Helena ; Pavela, R.
The aim of the work was to describe the SFE of volatile components from rue and to analyse their insecticidal effects. The objectives consisted in: (a) optimizing the SFE condition (pressure, temperature, extraction time, use of additional separator and concentration of modifier in CO2),investigating their effect on the yield, concentration volatiles in extract and the insecticidal activity, determination of the SFE kinetics of major components in the rue extracts and comparing the SFE with hydrodistillation and maceration.
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Fractionation of Volatile Compounds from Eucalyptus and Lippia Using Sorbents together with Supercritical Fluid Extraction
Topiař, Martin ; Sajfrtová, Marie ; Sovová, Helena ; Karban, Jindřich
The aim of this work was to separate and concentrate the groups of terpenes and terpenoids from eucalyptus (Eucalyptus grandis L.) and lippia (Lippia javanica L.) to several fractions using SFE in one step with adsorption. Extracts of both plants contain significant amount of biologically active compounds and therefore they can find application in medicine or as botanical insecticide in agriculture.
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Optimization and Mathematical Modelling of Hydrodistillation from Eucalyptus grandis and Lippia javanica
Topiař, Martin ; Sajfrtová, Marie ; Sovová, Helena ; Karban, Jindřich
K získání silice z rostlin Eucalyptus grandis a Lippia javanica sloužila hydrodestilace s použitím Clevengerova nástavce. Proměnnými parametry procesu byla doba varu, velikost částic a hydromodul. K vyhodnocení kinetických konstant hydrodestilace obou rostlin byl použit vhodný matematický model1, který počítá s rozdělením destilátu na dva podíly, kdy jeden je extrahován rychleji a druhý pomaleji, přičemž každému podílu přísluší vlastní kinetická konstanta. Mezi hlavní analyzované složky silice z eukalyptu patřil 1,8 cineol, alfa-pinen (8,2 hm. %), aromadenrden a spathulenol. Majoritní složky získané z výtažku lipie byly perillaldehyd, limonen a germacren. Bylo zjištěno, že optimálními parametry z hlediska maximalizace výtěžku jsou doba varu 5 h s poměrem navážka k objemu vody 1:5. Velikost částic nemá u zkoumaných rostlin zásadní vliv na velikost výtěžku. Maximální výtěžek eukalyptové silice dosahoval 26,7 mg/g, zatímco u lipie byl maximální výtěžek poloviční, a to 12,8 mg/g.
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29Si NMR Phenylsilane Polymer Analysis
Pinkas, Jiří ; Blechta, Vratislav ; Karban, Jindřich ; Sýkora, Jan
Here we focus on the analysis od dehydrocoupling polymerization reactions of phenylsilane. the molar mass distribution depends on the catalytic system and can be easily monitored by on-flow LC-NMR experiment.
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1 Karban, Jan
1 Karban, Jaroslav
1 Karban, Jiří
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