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  • 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.
121

Analýza sexuálního feromonu ovocných mušek rodu Ceratitis fasciventris, Ceratitis anonae a Ceratitis rosa / Analýza sexuálního feromonu ovocných mušek rodu Ceratitis fasciventris, Ceratitis anonae a Ceratitis rosa

Faťarová, Mária January 2013 (has links)
Ceratitis fasciventris, Ceratitis anonae and Ceratitis rosa are polyphagous agricultural pests originating from African continent. Their behaviour is heavily altered by pheromones. Insect chemical communication channels are species-specific, represents taxonomic and reproduction barriers. Taxonomy of this group (so-called Ceratitis FAR complex) is unclear. Therefore new chemical approaches along with genetic tests for identification of entities within the cryptic species FAR complex are being developed. To study multi-component mixtures of male volatiles originating from the three mentioned fruit fly species, comprehensive two-dimensional gas chromatography with time- of-flight mass spectrometer (GC×GC-TOFMS) was used. A number of compounds were identified, out of which 23 were found to be distributed and shared among the studied species, 11 out of these were present in all three species. Analyses of male pheromone volatiles, using gas chromatography combined with electroantennographic detector (GC-EAD) revealed 4 common compounds with antennal activity shared among three studied species: methyl (E)-hex-3-enoate, 6-methylhept-5-en-2- one, linalool, and methyl (2E,6E)-farnesoate. The species-specific EAD active compounds in C. fasciventris were esters of isomers of hexenoic acid, whereas isomers of...
122

Komplexní analýza výstražných a obranných látek ploštic vysokoúčinnými separačními metodami / Comprehensive analysis of warning and defense compounds of true bugs by high-performance separation methods

Krajíček, Jan January 2016 (has links)
Insects have developed many strategies of defence against predators in the course of evolution. The evolutionarily oldest and most widely used type of defence is chemical defence, followed by acoustic or optical defence. However, many species of insects use simultaneously multiple types of warning signals, which affect different sensory receptors of the given predator. Such a complex method of warning signals is called multimodal method. It may consist of a combination of simultaneous chemical and optical signals, or a combination of acoustic and optical signalling. The combination of chemical and optical signalling used against a predator is probably the most common form of multimodal signalling. The presented work deals with the analysis of biologically active substances, which participate in the defence mechanisms of a widespread species of insects - true bugs (Heteroptera). Pterin derivatives represent a large group of natural compounds derived from pteridin, bicyclic heterocycle, and they are found in virtually all living organisms from bacteria to vertebrates. In insects, they primarily serve as pigments, resulting for example in striking coloration of cuticles of Heteroptera. The first part of the dissertation was focused on identification and quantification of pterin derivatives in cuticles...
123

Stanovení netěkavých N-nitrosaminů ve sladu / Determination of non-volatile N-nitrosamines in malt

Vavrová, Dominika January 2016 (has links)
The aim of diploma thesis has been development and optimization of method determination of N- nitrososarcosine and N-nitrosoproline in malt by gas chromatography with chemiluminiscence detector. Optimization of extraction method has been performed by response surface method. Quantification has been performed by internal standard method (N-nitrosopipecolic acid, in which matrix effects has been studied. These has been verified in münchen and pilsen malt, therefore matrix-matched calibration has been constructed. The developed method has been aplicated on wheat, münchen and pilsen malt. N- nitrosoproline was detected only in münchen malt and in other cases has been under limit of detection (LOD=4,0 µg/kg). N-nitrososarcosine was in all cases under limit of detection (LOD=3,7 µg/kg). The matrix-matched calibration has been constructed for experimental münchen malt with N-nitrosoproline concentration at 13,2 ± 2,9 µg/kg. Powered by TCPDF (www.tcpdf.org)
124

Analýza těkavých látek lidského tělesného pachu pomocí komprehenzivní dvoudimenzionální plynové chromatografie / Analysis of a human body odour using comprehensive two-dimensional gas chromatography

Bušovská, Radka January 2021 (has links)
Body odour perception plays an important role in human mate choice, especially in women. It was previously proposed that women select partners whose body odour resembles that of woman's fathers. Yet, this phenomenon has only been confirmed using ethological studies based on subjective perception of body odour similarities. Therefore, the aim of my diploma thesis was to test this hypothesis instrumentally using comprehensive GC×GC-TOFMS and subsequent multidimensional analyses of body odour chemical profiles of male partners and fathers of adult women. Body odour sampling from left and right axilla of fathers and partners of 41 women (altogether 164 samples) was performed using cotton swabs, which were then frozen and extracted into hexane. Typical human volatile substances, such as hydrocarbons, carboxylic acids, esters, alcohols, aldehydes, ketones, sterols and terpenes were detected in all examined samples. Using a newly available "tile-based" chromatographic alignment algorithm, we obtained a set of 341 compounds systematically occurring in male axillary odour. The principal component analysis was used to calculate Euclidean distances for all pairs of the studied male subjects. These estimates of "chemical distances" revealed to be significantly smaller for father-partner pairs of individual...
125

Rusko-běloruské sjednocování. Vybrané problémy a perspektivy Svazového státu (1999-2008) / Russia-Belarus Unification. Chosen Problems and perspectives of Union State (1999-2008)

Osipova, Kristina January 2011 (has links)
Russo-Belarus Unification. Chosen Problems and perspectives of Union State (1999-2008). The main subject of the diploma thesis is cooperation between Russia and Belarus within the Union State of Russia and Belarus, which was established in 1999. After the break up of the USSR, cooperation between the newly independent states was largely defined by their membership in CIS. However, during the first five years an integration core emerged, consisting of Russia, Belarus, Kazakhstan, Kyrgyzstan and Tajikistan. These states were mainly cooperating in economic sphere, which finally emerged into international organization (Eurasian Economic Community). Belarus is one of the former Soviet republics, which kept and is still keeping very close relations with Russian Federation. Their bilateral integration begins after the breakup of USSR and culminates in 1999, when treaty of establishing Union State of Russia and Belarus is signed. During the almost 10 year period between 1999 and 2008, however, the cooperation did not move forward as was originally planned. In my opinion, the main topics which delay effective Russo-Belarus integration are as follows: prices for energetic commodities (oil and gas) for Belarus; implementation of common currency - Russian ruble; and ratification of Constitutional Act of Union State....
126

Česká republika a její připojení na nové LNG terminály - posílení plynové bezpečnosti / Czech Republic and its connection to new LNG terminals - strengthening of the gas security

Prouza, Petr January 2012 (has links)
Master thesis "Czech Republic and its connection to new LNG terminals - strengthening of the gas security" examines the level of gas security in the Czech Republic. Dependency of the Czech Republic on gas supplies from foreign countries is almost 100 %. Russian federation is dominant supplier with roughly 75 % of the supplies. High dependency on one exporter is considered hazardous from energy security perspective. The Czech government should strive to change and improve this situation. The diversification is considered as a useful tool to improve the gas security. Currently there are new gas projects built in neighboring countries, which may influence energy security of the Czech Republic. The study researches the impact of these new projects on the Czech Republic. Namely we focused on gas pipeline Nord Stream and its Czech connection Gazelle, which will connect North Germany and Bavaria through the Czech Republic. Second project is gas network called "the North - South Corridor" connecting Baltic and Adriatic Sea. The North - South corridor may be potentially linked up to the new LNG terminals Świnoujście in Poland or Adria in Croatia. Furthermore, there are long-lasting plans to open new "South" gas route from Caspian region to Europe. The main goal of this thesis is to explore real...
127

Severojižní plynový koridor jakožto východisko pro zajištění energetické bezpečnosti EU v souladu s její dlouhodobou politikou / North-South gas corridor - the way how to provide an energy security of EU in accordance with a long-term policy of EU

Stráník, Tomáš January 2013 (has links)
This work will try to analyse, if a project of Nort-South gas corridor is a really effective solution for EU and if this project really supports an effort to achieve a common energy security of EU. Work is based on hypothesis that natural gas and significant difference between member states of EU in dependence on Russian gas are the main problems which complicate efforts to achieve a common energy security of EU. Project, which could support efforts to achieve a common energy security of EU must be a project which could assure a diversification of gas routes and diversification of gas sources without weakening of energy security of any of EU member states. This work will try to analyse if existing gas projects (North Stream, South Stream, Nabucco and North- South gas corridor are really realistic projects which meet energy needs of member states of EU and long-term policy of EU. This work will try to prove, that North- South gas corridor is f the project, which really brings diversification of gas sources and gas routes and existence of this project will have also positive influence on efforts to achieve a common energy security of EU.
128

Vývoj analytických metod pro stanovení fosforylovaných složek bakteriálních buněčných membrán / Development of analytical methods for determination of phosphorylated components of bacterial cell membranes

Mikulecká, Jana January 2013 (has links)
Phospholipids are dominant components of bacterial cell membranes, where they create double layers. Bacteria differ in their phospholipid composition determination of which can help in identification of important groups of microorganisms. Phospholipid composition of bacteria is influenced by many environmental factors, therefore its variation can be observed within one bacterial stem also. Because of its simplicity, thin layer chromatography is usually applied to identification and determination of bacterial phospholipids. Disadvantage of this method are the high demands of time, carefulness and skills of the analytical personnel. The increasing interest in the phospholipid double-layer promotes the detailed investigation of their fatty acid composition because the more detailed analyses allows for more information yield about bacteria. Gas chromatography hyphenated with mass spectrometry seems to be the best choice for these purposes. Fatty acid identity and total fatty acid content in phospholipid molecules could be determined by this method. Additionally, number, position and isomerism of double bonds and presence of other functional groups on hydrocarbon chain could be determined. Whereas a suitable and...
129

Teplonosné látky tepelných soustav / Of heat transfer fluid of heat systems

Ženožička, Filip January 2018 (has links)
The subject of this diploma thesis is the design of heating and hot water in the administrative building in Zlin on Jižní Svahy. The building has five floors above ground and one underground floor. There are designed two variants of heat source for heating and hot water (transfer sta-tions and gas boiler). Part A solves water quality in heating systems. Part B deals with design of the heating system, hot water heating, insurance and facility expansion, technical report and drawings heating in the building. The last part C is the experimental measurement of the quality of heating water in the CZT systems.
130

Vytápění základní školy / Heating of elementary school

Holiš, Martin Unknown Date (has links)
The goal of this thesis is to design a heating system for a building of an elementary school in Polešovice. The thesis is divided into three parts. The first, theoretical, part discusses heat pumps with the main focus on gas absorption heat pumps. The se-cond part addresses the design of the school heating as well as the design of an ecological heat source. The part consisting calculations introduces the calculation of heat losses, the optimal choice of temperature gradient, the design of heating surfaces, the design of heat sources including the design of the bivalent source, the way of hot water preparation, dimensioning, the security equipment and other calculations. The last part deals with the drawing documentation, the technical report and also some economical questions such as return on investment based on measured efficiency of the heat source.

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