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Ftaláty v potištěných a nepotištěných obalech masných výrobků
Lavingrová, Veronika
The diploma thesis is focused on the determination of the content of phthalates (PAE) in printed and non-printed plastic packaging materials for meat products. There were analyzed 30 package samples. The sample area was 1 dm2. Concentrations of dibutyl phthalate (DBP) ranged from undetectable values (< 0.1) to 72.6 ug.dm-2 of the sample surface in printed packaging materials. In non-printed wraps it was from undetectable values (< 0.1) to 67.7 ug.dm-2 of the sample surface. Concentrations of di-2-ethylhexyl phthalate (DEHP) ranged from undetectable values (< 0.1) to 98.7 ug.dm-2 of the sample surface in printed packaging materials. In non-printed wraps it was from undetectable values (< 0.1) to 60.3 ug.dm-2 of the sample surface.
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Ftaláty v jogurtech po dobu skladování
Stará, Markéta
The thesis Phthalates in yoghurts during storage focuses on monitoring of phthalic acid esters in yogurt samples in relation to their storage period. The analyzed phthalates are di-2-(ethylhexyl)-phthalate (DEHP) and di-n-butyl-phthalate (DBP), which are among the most commonly used polymeric plasticizers, especially polyvinyl chloride. I analyzed samples of yoghurt with 1 % and 5 % chia and bamboo fiber and then subsequently compared them with natural yogurts. In total, I analyzed 120 samples of yoghurt, for which I measured DBP concentrations ranging from 0.2 mg.kg-1 to 7.7 mg.kg-1 of the original raw material and concentration of undetected values of DEHP in range up to 2.6 mg.kg-1 of the original raw material. While analyzing the yoghurt packaging, I measured average DBP values of 174.1 μg.dm-2 (68.0 μg.g-1 plastic) and DEHP values of 26.2 μg.dm-2 (10.2 μg.g-1 plastic). After prior preparation of samples, I used high performance liquid chromatography to do the phthalates analysis.
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Optimizing Bias Point Of High Efficiency Class-B Gan Power Amplifier For The Best Efficiency
Fiser, Ondrej
High performance amplifiers are always a demanding component in the world of wireless communication. The amplifier is the heart that drives each radio system. We have designed and developed a high performance one-stage class-B GaN power amplifier for drone applications in the S-band (at 1,6 GHz) with maximum output power 6 W. This paper compare fixed settings of the bias point option and optimized bias point for the best efficiency within the entire output power range. Applying the proposed method, that is particularly advantageous for low power performance to improve efficiency by more than 15 %.
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Historical biogeography of cichlid fishes in Usumacinta province (Mexico, Guatemala, Belize)
DRAGOVÁ, Klára
Historical biogeography of cichlid fishes within the Usumacinta province (Mexico, Guatemala, and Belize) is reviewed based on newly collected material specifically for this study. Five areas of endemism within the province were recognized using Parsimony analysis of endemicity. Dispersal-Vicariance analysis implemented in S-DIVA suggests only one of them (the Grijalva-Usumacinta) as the ancestral area for the whole fauna. Other areas of endemism within the Usumacinta province were colonized from this area by dispersals. This biogeographic interpretation suggests a long evolution of the richest cichlid fauna in Middle America in the Grijalva-Usumacinta area of endemism in a sympatric context.
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