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Monitoring the influence of concrete composition on abrasion resistance
Černá, Hana ; Novosad, Petr (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis focuses on the resistance of concrete to abrasion with regard to the raw materials used for their production. In the theoretical part of the thesis are described admixtures, different types of aggregate and aggregate composition which influence the resistance of concrete to abrasion. In the experimental part, 15 different C30 / 37, S4 concrete formulations were proposed. Different types of aggregates - fecal gravel (Žabčice), biotic granodiorite (Olbramovice) and amphibolite (Želešice) have always been used in the recipes. Fine ground limestone, micro-silica, high-temperature fly ash and finely ground slag were ingredients that were added to the proposed recipes. Consistency was determined by the method of cone seating and the density of fresh concrete. In the hardened state, concrete density, compressive strength, bending tensile strength, tensile strength, watertightness, concrete absorption, and abrasion resistance were determined using the Böhm method and wide wheel method. The test specimens were tested after 7, 28, and 90 days of maturation.
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The Appliances Immunity to Short Voltage Dips and Interruptions
Bok, Jaromír ; Beláň, Anton (referee) ; Santarius, Pavel (referee) ; Drápela, Jiří (advisor)
This Ph.D. thesis deals with problems about voltage dips and short voltage interruptions, generally named as voltage events, which origin in power supply networks and have a negative influence for all connected electric appliances. In this thesis single phase appliances are considered. These problems closely relate with area of electromagnetic compatibility which solve all questions about correct operation of different types of electric appliances during electromagnetic disturbances impact. Voltage events are ones of the many types of electromagnetic disturbances. The connection between disturbance sources and sensitive electric appliances is created by power supply lines. The immunity of electric appliances to voltage dips and short interruptions is currently tested via voltage dips with strictly defined parameters which are intended by class of electromagnetic environment in which the usage of electric appliance is recommended. During immunity tests the rectangular shape of voltage dips is preferred. The main descriptive parameters of testing voltage events are the residual voltage and the event time duration. But voltage dips and short interruptions defined by this way do not closely relate with parameters of real voltage dips and interruptions occurred in public supply system where parameters of voltage dips are variable. Moreover in the power supply system there are many of others voltage parameters which can have a significant influence to immunity level of connected electric appliances. This Ph.D. thesis also deals with finding more voltage event parameters. Although the voltage events occurrence in the power supply system is not limited and voltage events are considered only as informative voltage parameter it is important to monitor voltage events occurrence. The monitoring device has to be able to operate for ling time period and it has to detect parameters of voltage events with adequate accuracy. The accuracy of detected event parameters and the detection delay depends on the detection algorithm characteristics. That is why the part of this thesis relates with a comparison of several detection algorithms and their abilities to correct detection of voltage event parameters. The main purpose of this thesis is the proposal of connection between classification of voltage dips and short interruptions occurred in power supply system with the classification of electric appliances immunity to these voltage events. On the base of many of provided electric appliances immunity tests and also on the base of long time period voltage events monitoring the special compatibility levels are proposed in this thesis. The observation of proposed compatibility levels will bring the increasing level of reliable operation of all connected electric appliances.
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Study of influence of secondary raw materials on mechanical resistence of the industrial floors
Figala, Petr ; Bydžovský, Jiří (referee) ; Drochytka, Rostislav (advisor)
Secondary raw materials are nowadays increasingly used as materials in many sectors of the construction industry. This thesis evaluates current state of industrial floor systems and their final adjustments to increase its mechanical and chemical resistance. At the same timethis thesis focuses on the possibilities of using secondary raw materials in the development of new industrial floors. The goal is to partly replace the silicate binder in the raw material mix of cement screed with a secondary raw material to achieve the same or better physical and mechanical characteristics. This part is also verified experimentally, and its conclusion is to design an optimal recipe of screed by using secondary raw materials.
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Study of the properties of fillers to the composites requiring high temperature resistance
Vovesný, Václav ; Gross,, Tomáš (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis is focused on the behaviour of natural and synthetic aggregates and their behaviour in polymer – cement composites, while being exposed to high temperature. The processes, happening in aggregates and mortar under the thermal load, were described in the theoretical part of the thesis same as the testing of heat effects on the aggregates and mortar. Further, the influence of high temperature on each component of concrete was described, followed by the suggestion of the appropriate components for concrete exposed to high temperature. Various aggregates were tested in the experimental part of the thesis. The basic physical and mechanical properties of aggregates were examined same as their mineralogical composition with using XRD, DTA and SEM methods. At the mortar, the influence of high temperature on the concrete density, compressive strength and tensile strength was defined. The gained knowledge was evaluated in the final part of the thesis
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Architectural lighting and desing particularity
Haluza, Miroslav ; Maixner, Tomáš (referee) ; Baxant, Petr (advisor)
The goal of this thesis is make a list of theoretic routes outside (architectural) lighting and draw up accessible light fitting. Further are in those work included principle for handy suggestion architectural lighting after technical norms and practical recommendationthat the is necessary at projection hereof lighting adhere. Last but not least is here mentioned problems installation and upkeep architectural lighting and safeness and immunity electric arrangement.
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Eudaimonia: Happy city
Hermanová, Ada ; Holubová, Martina (referee) ; Mléčka, Jan (advisor)
The aim of the project is to create eudaimonic environment in the framework of existing city blocks of Husovice in Brno. Simple interventions and minimal means are used to create environment which allows it´s inhabitants to live complex and fulfilled lives.
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Resistance to freezing and thawing of hydraulically bound mixtures to roads
Švantner, Lukáš ; Mondschein,, Petr (referee) ; Stehlík, Dušan (advisor)
The theoretical part of this master’s thesis contain comparing the methods of endurance hydraulic bound mixtures of concrete recycles against influence of water and freeze in Czech republic and some other states of The European Union. The practical part is dedicated about laboratory testing concrete recycles with mixtures of binders and its endurance against the water and freeze cycles in Czech republic. In made rollers is compared the strength in pure compression with the strength in pure compression after freezing cycles. From the results of the exams is considered about suitability of using these hydraulic bound mixtures to road construction depending on the kind of use binder, amount of the binder and water. Results of this thesis will be used to revision of national postscript of technological norm ČSN 73 6124-1.
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Mortar with alkali-activated matrix
Černá, Hana ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
The thesis addresses the issue of alkali-activated materials and their manufacturing components. In the theoretical part the description of such materials is provided and the requirements for source materials are defined. The theoretical part further addresses the resistance of alkali-activated materials and their lifespan - namely sulphate resistance, chloride resistance, acid resistance, frost resistance, porosity, carbonation, resistance, abrasion resistance and heat resistance. The experimental part of the thesis focuses on compounding four different mixtures of alkali-activated materials. In the loosened stage, the weight was measured. In the hardened stage the weight was measured as well as the tensile strength when bending, the strength under pressure applied, heat resistance, water and defrosting chemicals resistance and formation of cracks.
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Srovnání přístupu k adaptačním opatřením na změnu klimatu v lesích ve vybraných státech na úrovni národních plánů a politik
Papalová, Alexandra
The topic of the bachelor's thesis is Comparison of the approach to climate change adaptation measures in forests in selected countries at the level of national plans and policies. In this context, the bachelor thesis deals with adaptation measures that are applied in order to mitigate the effects of climate change on forests and forestry. The bachelor thesis is written in the form of research. The thesis first deals with basic concepts such as climate change and its effects in general, the effects of climate change on forests and forestry, and adaptation to climate change. Subsequently, it deals with the characteristics of natural and socio-economic conditions and their vulnerability, the distribution of forest ownership and change in forest cover in Finland, Spain and Kenya. The last part is devoted to applied adaptation policies and national plans to climate change in the mentioned countries.
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The influence of resilience social support and religiosity on the wellbeing of victims of domestic violence in Accra Ghana
Ahmed, Osman Abdul
ABSTRACT Domestic violence and abuse continue to be an issue of alarming concern for governments and nations across the globe because of the threats that it poses to victims psychologically and physically as well as the family, communities and the nation at large. Although many studies have been done on the subject, these studies focus mainly on the antecedents to abuse and its impact on the victims. Few studies have also focused on the punitive measures and the legal framework around which perpetrators of domestic violence are dealt with less focus on psychological, social and spiritual factors that can improve the wellbeing of victims. It is against this background that this study was conducted to examine the influence of resilience, social support and religiosity on the wellbeing of victims of domestic violence in Accra, Ghana. Using the biopsychosocial and spiritual theory of illness and wellbeing, a cross sectional survey was conducted by purposively sampling 100 victims of domestic violence and abuse (M= 28.57; SD= 5.55) within the period of September and October, 2021. The respondents filled questionnaires that examined resilience, social support, religiosity and psychological wellbeing. Results indicated that resilience (r = -.52, p < .001) has a significant negative relationship with wellbeing while social support (r =.48, p > .001) and religiosity (r = .53, p < .001) has a significant positive relationship with wellbeing. Both social support and religiosity predicted wellbeing in the victims of domestic violence accounting for forty-five percent of the variance in wellbeing scores of the victims (p<0.001, Adj. R2=0.45). It is discussed that psychological support be provided for victims and this support should focus on resiliency training, family and community support and spiritual and religious mindfulness. Limitations of this study are also discussed with recommendations to chart the path for future studies.
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