National Repository of Grey Literature 204 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The effect of constant temperature and moisture to house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae
Gajdová, Tereza ; Hubert, Jan (advisor) ; Žůrek, Luděk (referee)
House dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae inhabit house dust worldwide. These commensals are for humans harmful especially as producers of many allergens. According to Klimov-OConnor's hypothesis, these mites had a parasitic ancestor who had evolved into a free-living form during the evolution. This thesis focuses on another possible aspect of this transition: it compares optimal hygrothermal conditions for development, reproduction, and population growth of Dermatophagoides dust mites with those which are preferred by the house dust mite's related - parasitic genera Sarcoptes and Psoroptes. Since all these three genera are closely related, it was analyzed whether their hygrothermal preferences would be similar in any respect. However, the results of this literature review suggest that dust mites - compared to their parasitic relatives - prefer combinations of lower temperatures and humidity. Like the representatives of the convergent group of storage mites - e. g. Tyrophagus putrescentiae and Acarus siro. Apart from the comparison of the preferred conditions of previously mentioned genera, this thesis also presents a summary of the effect of different combinations of temperatures and humidity on the duration of development, fecundity, and the population growth of...
Study of properties of bent FRP reinforcement
Lipoldová, Marie ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
The diploma thesis deals with the study of bent FRP reinforcements with the main focus on the methods of production of bent FRP reinforcement, examples of their application in structures. The work also mentions the effects of aggressive environments on the durability of FRP. In the practical part, a search of the possibilities of testing the properties of bent FRP reinforcement. Subsequently, an experiment is designed and performed to monitor changes in the properties of straight and bent FRP reinforcement exposed to the alkaline environment and water at 20 °C and 40 °C. Finally, the evaluation of changes in mechanical properties and observation of reinforcements using optical and scanning electron microscopy is performed.
Optimization of air conditioning of the ice stadium
Zach, Daniel ; Rubinová, Olga (referee) ; Blasinski, Petr (advisor)
This diploma thesis is divided into three parts: theoretical, calculation and experimental measurement. The issue of humid air and air-conditioning in winter stadiums is elaborately analysed in the theoretical part. In the calculation part, the dessertation focuses on the optimization of current draft of hockey hall air conditioning system. The hall is now in operation during the season, which means from September to March. In the dissertation are discussed two variants of the draft. The first variant is draft upgrade to year-round operation with condensing dehumidification. The second option is solved as a combination of air handler unit system and absorption dehumidification. This variant is also designed for seasonal and year-round operation of the ice rink. At the end of the dissertation are all of them compared in terms of annual costs. The experimental measurement is carried out on dehumidification of air from areas with high water gains, in this case swimming pool hall model. This problematics is solved by changing the speed of ventilator and using Peltier generator.
Analýza metod posouzení pevnosti lepených materiálů z masivního dřeva
Pipíška, Tomáš
This study aims to compare the strength of bonding joint and bonding quality depending on the proportion of violations. The first part contains a research of various types of adhesives. Based on the research, two types of adhesive were chosen - the PVAC and UF adhesives. These adhesives are used directly in manufacturing of solid wood panels. Our test samples were made of beech wood and oak wood using both types of adhesive, four groups of samples altogether. The thesis contains an analysis of the requirements for bonding strength as well as production of samples from solid wood panel. According to current standards, the tests were performed to determine the density, moisture content, strength of bonding joint, the bonding quality and proportion of violations.
Hustotní profil a jeho vliv na vlastnosti třískových desek
Matyáš, Michal
The goal of this thesis is to determine properties of manufactured particleboards with different percent content of recycled wood. The objective was to determine density values, thickness swelling, moisture content, internal bonding, bending properties and vertical density profile of particleboards. The research question was to report the effect of different percent content of recycled wood on final properties of particleboard. The own method was established and various particleboards produced. The properties of materials were tested according to EN standards and by descriptive statistics, analysis of variance (ANOVA) and linear regression evaluated. In summary in research it was observed that percent content of recycled wood has little impact on final properties of particleboard, although there were several factors which may have affected these results. These factors are described in this thesis.
Srovnání lineárního a nelineárního výpočtu teplotního pole v obvodovém plášti dřevostavby
Dziamidau, Dzianis
The bachelor thesis deals with the comparison of the linear and nonlinear principle of calculation of the temperature field in the circumferential shell of wooden structures using 1D and 2D simulation in software based on the finite element method. The essence of this work is to determine the difference between these two ways and to find out if this difference in methods is at all relevant to real life. After the results were processed, it was found that the difference between these methods was not, but taking into account the presence of moisture the difference appeared and I would say the essence. The results show that wood moisture influences not only the values of the heat transfer coefficient but also the final result, such as the interior temperature or heat loss during heating.
Monitoring mikroklimatu pšenice seté pro fytopatologické a fenologické účely
Konečná, Petra
In 2016, a microclimatic monitoring was established in the Žabčice area on the grounds of the School Farm Enterprise, located in winter wheat. Several aspects have been observed, especially relative humidity and air temperature in this stand. The measurements were made at three heights (ground floor, effective height and 2 meters above ground). Measured values of temperature and relative air humidity in winter wheat were recorded during phenological development and their course was then graphically evaluated. It has been confirmed that the structure of the crop affects its microclimate. Furthermore, the occurrence of leaf pathogens was monitored according to the methods of the UKZUZ, depending on changes in microclimate in the stand. Based on these observations, it is possible to predict pathogen attack.
Využití odkorňovací hlavice harvestoru v podmínkách kůrovcové kalamity
Mergl, Václav
The aim of this thesis was to describe the use of debarking head of one grip harvester in the salvage logging. For this purpose, a time study was chosen in which debarking heads with usual tools were compared with debarking heads with debarking sets on five research plots with two machines. The manufacturing process was divided into several operations, which were evaluated separately. Specifically, it was divided into operations: searching, felling, fall of the tree, manipulation, delimbing, and ascertainment. In the next step the quality of debarking was observed, depending on the moisture and on the diameter of logs. Debarking heads were measured during the growing season. It was discovered that the debarking head with debarking set needed twice as much time to process the whole tree as a head with usual tools. Delimbing contributes more than half to this difference. Furthermore, it was discovered that debarking quality does not dependent on the log's moisture at the time of harvest but on the hydraulic pressure of knives and feed rollers. Considering dimensions, the central parts of logs were debarked the best. Following these evaluations, recommendations were made for the practice of using machinery with debarking heads and improving debarking quality.
Vliv klimatických podmínek na pevnost lepených spojů MDF
Boštík, Vít
This bachelor thesis deals with the influence of the climatic conditions on bonding strength of MDF. Three types of bonded joints were used for testing – MDF-MDF, MDF-oak and MDF-artificial stone. The specimens were glued together with two component polyvinyl acetate adhesive. One half of testing joints was exposed to higher temperature and humidity, the second half of testing joints was exposed to normal conditions. After conditioning the specimens were subjected shear tension test. Then it was compared strength of bonded joints between normal conditions and higher temperature and humidity conditions.
Posouzení vlivu podmínek skladováni loupané dýhy na její vlhkost v závodě ALFA Solnice
Borek, Ondřej
The purpose of this bachelor thesis is to assess the influence of the conditions of veneer storage in technological processes which are mainly dependent on the humidity of the peeled veneer. These are in particular the technological parts behind the peeling machine and the drying room from which the peeled veneer is transported to the warehouse. Determination of the moisture of the peeled veneer was carried out by the weighting method. Thanks to the moisture results it was judged how moisture was variable before the drying process which is then reflected on the dried veneers that are transported to the warehouse. Conclusion is how to modify the sorting and storage of peeled veneers in the production process so that the moisture content of peeled veneers is as balanced as possible during storage.

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