• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 135
  • 6
  • 2
  • Tagged with
  • 143
  • 117
  • 110
  • 90
  • 47
  • 47
  • 45
  • 35
  • 22
  • 20
  • 20
  • 18
  • 18
  • 18
  • 17
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Rychlé metody analýzy migrantů z materiálů ve styku s potravinami / Fast methods for analysis of migrants from food-contact materials

Vavrouš, Adam January 2020 (has links)
(AJ) Food contact materials pose a risk to human health due to a variety of contaminants which they can release into food. These compounds, migrants, include aromatic hydrocarbons, dialkyl phthalates, bisphenols, printing ink photoinitiators, and perfluoroalkyl compounds. The determination of all these substances can be expensive and time-consuming since universally applicable analytical approaches are not available nowadays. This work attempted to develop methods for the simultaneous determination of migrants from all of the mentioned groups in paper-based food contact materials and fatty food. A total of 68 contaminants were studied in paper products using liquid chromatography and gas chromatography coupled with tandem mass spectrometry detection. All analytes were isolated simultaneously using the modified "QuEChERS" method. This method demonstrated acceptable recovery and repeatability for most analytes in the validation study; LOQs ranged from 1.3 to 220 µg/kg. Analysis of 132 real paper products confirmed the occurrence of almost all studied analytes, which were often present in complex mixtures and at concentrations up to 628 mg/kg. A total of 41 potential contaminants were monitored in fatty foods by liquid chromatography with tandem mass detection. Contamination of the mobile phase by...
142

Chirální analýza syntetických vonných látek ve vodním ekosystému / Chiral analysis of musk compounds in water ecosystem

Švarcová, Lucie January 2014 (has links)
Diploma thesis summarizes available information about chiral analysis of synthetic musk compounds in the aquatic environment. In the theoretical part of the thesis chirality and importance of chiral analysis by means of examples of different environmental pollutants is documented. Further consideration is aimed on musk compounds, their classification, characteristics and their fate in the environment, especially in the aquatic environment. After that methods for chiral analysis of synthetic musk compounds are reviewed. The aim of the experimental part of this diploma thesis was to carry out the determination of thirteen representatives of musk compounds (2-cyclohexylethanol, allylcyklohexylpropionate, Arocet, Aroflorone, Citronellol, Fresco Menthe, Galaxolide, hexyl cinnamic aldehyde, HSA, isoamylsalicylate, isobornylacetate, Lilial and Linalool), out of which some compounds are chiral and some are achiral. For the analysis samples of wastewater from the wastewater treatment plant Brno - Modřice were taken. Target compounds were isolated by solid phase microextraction (SPME) and were subsequently analyzed by gas chromatography with flame ionization and mass spectrometric detection. On the basis of data evaluation the removal efficiency forgiven musk compounds in the wastewater treatment plant was assessed.
143

Úspory ve vytápění budov / The savings in heating buildings

Rokůsek, Petr January 2012 (has links)
This thesis theoretically in Part A deals with the solution in savings heating building and heating hot water. It examines the impact of austerity measures on the overall need for and consumption of heat energy and its economic impact and compared with each other in order to achieve maximum efficiency. Part B is their subsequent application to a given object - a residental building, various design alternatives and the resulting energy savings improvements. Experimental Part C deals with indirect measurement of the thermal conductivity of building materials.

Page generated in 0.3075 seconds