This is a genetic study of flowering time in cultivated barley with the aim to identify the alleles contributing to rapid flowering and frost resistance. We have genotyped a collection of 23 historic barley varieties for the crucial genes [VRN-1, VRN-2, VRN-3 (HvFT), Ppd-H1, CO, and Vrs1]. We have amplified the polymorphic mutations by PCR-based methods, and sequenced them to identify possible haplotype groups. The row type was not determined of all accessions, but all the Scandinavian varieties were found to carry mutant alleles of Vrs1, that indicates them to be six-row barleys. The deletion of the crucial segment of VRN-1 vernalization contributes dominant spring growth habit. We found haplotype groups 2 and 4 to be dominant in Northern barleys whereas haplotype groups 1 and 5 dominated in south. The presence of dominant allele VRN-2 gene is addressed to floral repression until plants get vernalized. Most of the 23 varieties were found to have deleted allele of VRN-2, which is connected with a spring growth habit. The only four of the accessions that have the dominant allele of Ppd-H1 that contribute flowering are generally from the south of Europe. HvFT and CO genes CO-interact to influence flowering time. CO haplotype grouping suggest a geographical distribution of different alleles but needs more disseminations. Certain HvFT alleles cause extremely early flowering during apex development in the varieties that have deletion of VRN-2 alleles under long days. VRN-3 alleles of 14 varieties were identified.

The master´s thesis discusses the life of building structures in terms of selected causes of failures are listed and discussed in ISO 16204 - "Durability - Service life design of concrete structures". The selected causes of failures will be carbonation and frost resistance of concrete. These causes will be performed computational analyzes for few types of concrete, based on these anayzes will be possible to compare and analyze the requirements specified in standards ČSN EN 1990, ČSN EN 1992 and ČSN EN 206.

The diploma thesis deals with the possibilities of evaluating the degradation of mechanical resistance of non-air-entrained concrete in the structure by frost cycles. The first part is focused on concrete, its resistance and test methods. This is followed by the definition of frost resistance, the effects of freeze-thaw on concrete at all stages of its service life and the possibilities of determining freeze-thaw resistance according to current standards. It describes in more detail selected test methods for determining frost resistance. In the practical part, it focuses on the determination of degradation resistance of test specimens made in molds and taken from the structure using reference and non-reference methods. In conclusion, it compares the different test methods and their suitability for the determination of freeze-thaw resistance.

Dans un objectif de réduction des consommations énergétiques et des impacts environnementaux, la pompe à chaleur (PAC) s'est imposée comme une alternative aux systèmes à combustion fossile pour le chauffage et la production d'eau chaude sanitaire dans les secteurs résidentiel et tertiaire. Les industriels ne cessent de chercher à accroitre la performance énergétique des pompes à chaleur. Toutefois, un phénomène encore mal maitrisé limite les progrès : le givrage. En effet, dans certaines conditions de température et d'humidité de l'air extérieur, du givre peut se former sur la surface de l'évaporateur de la PAC, provoquant ainsi une chute de performance. En France, près de 98 % des PAC du marché utilisent l'air extérieur comme source de chaleur et sont donc exposées à ce phénomène. Malgré des logiques de dégivrage de plus en plus sophistiquées mises en œuvre par les industriels, le fonctionnement cyclique givrage/dégivrage réduit fortement les performances des PAC. Pour optimiser les méthodes de dégivrage, il est nécessaire de comprendre en amont, les mécanismes d'apparition et de croissance du givre. Ce travail de thèse propose ainsi d'étudier la formation et le développement du givre sur une plaque plane refroidie. Une étude approfondie de la bibliographie a permis d'établir des bases de données regroupant des points expérimentaux de l'épaisseur et de la masse volumique du givre. Des modèles et corrélations de formation du givre disponibles dans la littérature ont été reproduits et appliqués à ces bases de données afin d'évaluer la capacité de prédiction de chacun de ces modèles. Les plus performants ont ainsi pu être identifiés. En parallèle, un banc d'essais a été conçu pour observer la formation et la croissance du givre sur une plaque plane. L'étude de sensibilité menée sur la température de l'air, la température de la plaque froide, la vitesse de l'air et l'humidité relative a permis d'évaluer l'impact de ces paramètres sur la formation du givre, et plus particulièrement sur trois de ses propriétés : l'épaisseur, la masse volumique et la conductivité thermique. L'humidité relative et la température de la plaque froide ont été identifiées comme les paramètres prépondérants. Un des résultats importants de ce travail a été de mettre en évidence le rôle de la structure du givre sur ses propriétés (masse volumique et conductivité). Les points expérimentaux obtenus sur le banc d'essais ont été comparés aux résultats issus des modèles de la littérature. Les méthodes de prédiction identifiées comme satisfaisantes dans la partie bibliographique de cette thèse ont fourni des résultats similaires d'un point de vue statistique. Des perspectives de travail ont également été proposées. / In the energy consumption and environmental impact reduction goal, heat pumps emerged as an alternative to fossil fuel systems for space heating and hot water production in residential and tertiary sectors. Manufacturers still try to improve energy performance of heat pumps. However, a non-controlled phenomenon is limiting progress: frosting. Indeed, in some outdoor air temperature and relative humidity conditions, frost can form on the heat pump evaporator surface, leading to performance reduction. On the French market, almost 98 % of the heat pumps are using outdoor air as heat source and are thus affected. Despite more and more sophisticated defrosting strategies, the frosting/defrosting cyclic operation strongly reduces heat pump performance. For optimizing defrosting strategies, there is a need understanding frost appearance and growth mechanisms. This PhD work thus proposes to study frost formation and development on a cold plane plate. An in-depth bibliography study helped establishing databases gathering experimental points on frost thickness and frost density. Models and correlations of frost formation available in the literature have been reproduced and applied to the databases in order to evaluate their prediction capacity. The most performing models have been identified. Meanwhile, an experimental bench allowing visualization of frost formation and development on a cold plane plate has been set up. The sensitivity analysis on air temperature, cold plate temperature, air velocity and relative humidity allowed an evaluation of these parameters impact on frost formation, and more particularly on three of its properties thickness, density and thermal conductivity. Relative humidity and cold plate temperature have been identified as the leading parameters. One of the main results of this work was to highlight the frost crystal structure role on properties (i.e. density and thermal conductivity). Experimental data points obtained with the test bench have been compared to the results provided by literature models. Predictive methods identified as satisfying in the bibliography study gave similar results (from a statistical point of view). Perspectives for future work have also been proposed.

This diploma thesis is focused on methodology for sorting of solid fired bricks for reconstruction of historical buildings. The theorethical part of this thesis includes description of production technology of solid fired bricks and diagnostic methods. In practical part there are these methods aplied on the solid fired bricks, which are intended for reconstruction of the bridge in Sedlec. There are monitored changes in structure of solid fired bricks caused by repeated freezing and defrosting. This changes are monitored by resonant frequency method and ultasonic pulse method.

The thesis is focused on the analysis of the theoretical part of the unbound mixtures, their implementation and compliance. Further deals with determining the extent frost susceptibility direct and indirect method in the Czech Republic and the Member States of the European Union. The practical part is focused on the performance of tests on selected samples of unbound mixtures for which was gradually increased the content of fine particles and that direct and indirect method of determining the rate of frost susceptibility and also the evaluation of direct methods of particular customized way, which does not impose the appropriate standard. At the conclusion of the work is carried out an evaluation of the samples and comparison of the different methods with each other.

This diploma thesis deals with the issue of the determination of the frost susceptibility of soils in the subgrades of road structures. The theoretical part compares the ways of testing the frost susceptibility in the Czech Republic and other selected countries of the European Union. Furthermore, it also deals with the development of the frost susceptibility index in the Czech Republic. The empirical part focuses on the laboratory testing of the frost susceptibility of the given sample of soil by the direct frost heave method. Moreover, it also deals with the simulation of penetration of frost by the subgrade and the possibility of shortening the length of the freezing during the direct testing the frost susceptibility.