My thesis is divided into three separate parts. The first part is devoted to the theoretical part of the ventilation systems. The second part deals with the determination of the conditions for a number of air exchange, a comparison of three variants of the location of air outlets in dwelling units and the application image airflow from experimental measurements on the common room. The third part is focused on the description of the experimental tasks in the laboratory at the Institute building services.

The thesis is aimed at the problem of the air distribution in buildings. The object of research is the concert hall. The thesis contains three different technical proposals and technical views of the microclimate concert hall. The microclimate’s solutions are focused on the air distribution in the hall. The part of the thesis is an experiment. The experiment continues on the one of the technical proposals. Its purpose is to determine the characteristics of air flowing from distribution element.

My diploma thesis focuses on design of air-conditioning system for chicken breeding spaces. In the background are considered general issues of air-conditioning, hatchery layout and microclimate for eggs incubation and chicken breeding. The research part is divided into two parts – Calculations and Design. The Calculations address the amount of incoming fresh air, heat loss, heat load and psychrometric calculations for summer and winter periods. The Design focuses on defining suitable diffusers and air-ducts, optimal air-conditioning unit with fans corresponding to hatchery requirements and pressure loss in ducts. The technical drawings and a list of used material are included.

Zur Validierung des Verfahrens der akustischen Tomographie, das als Fernerkundungssverfahren trägheits- und berührungslos arbeitet, werden Vergleichsmessungen mit herkömmlichen Sensoren für die Lufttemperatur und Luftfeuchte durchgeführt. Dabei zeigen sich die Grenzen der Erfassung dieser Größen in Bezug auf Strahlungseinfluss und Trägheit der Messgeräte. Hier werden einige Probleme bei der Verwendung konventioneller Hütten und Lösungsvorschläge aufgezeigt. / In order to validate measurements with the acoustic tomography, which operates as an remote sensing system lagless and contactless, comparison measurements were performed with conventional sensors for the air temperature and humidity. The accuracy of these quantities is limited by the radiation influence and the lag of the instruments. Here some difficulties are pointed out by using conventional shelters and solutions are demonstrated.

in english Introduction: Composite restorations in the oral cavity are exposed to an aggressive environment and mechanical challenge that gradually impairs their physical and mechanical properties. This may result in an enhanced wear rate, loss of esthetic properties and an increased risk of a restoration fracture or its marginal failure with a negative impact on the restoration's durability. Worn or failed restorations are usually completely replaced, which increases the irreversible loss of dental hard tissues. Repair of composite restorations by their partial replacement is therefore a minimally invasive, preventive and less time-consuming alternative to their complete replacement and increases their longevity. In the oral cavity, the adhesive bond between the existing composite restoration and the repair composite resin is exposed to various chemical substances and mechanical stress, e.g. surfactants in toothpastes, which can initiate its degradation. By decreasing the surface tension, the penetration of water into the adhesive joint can be enhanced, accelerating the hydrolysis of the adhesive and reducing the composite repair strength. The major and not yet fully resolved issue of composite repairs is how to achieve a strong and durable bond between the existing and repair composite materials....

Due to the high-speed flow in a chute spillway, cavitation damages often occur. This undesired phenomenon threatens the safety of the structure. For the purpose of eliminating the damages, an aerator is often installed in the spillway. To understand its characteristics, physical model tests are a popular method. To complement the model tests, computation fluid dynamics (CFD) simulations are used to study aerator flows. To represent the two-phase flows, multiphase models should be employed. This thesis examines two of them, namely, the Volume-Of-Fluid model (VOF) and Two-Fluid model. Based on the background of the Bergeforsen dam, the aerator flow is modelled by means of the VOF model. The simulated spillway discharge capacity is in accordance with the experimental data. Compared with the results, empirical formulas fail to evaluate the air supply capacity of aerator as it is wider than the conventional width. A hypothetical vent modification is proposed. For the original and proposed layouts, the study illustrates the difference in the air-flow conditions. The results show that a larger vent area is, for a large-width aerator, preferable in the middle of the chute. To study the flip bucket-shaped aerators in the Gallejaur dam, physical model tests and prototype observations are conducted. The results lead to contradicting conclusions in terms of jet breakup and air entrainment. A CFD model is, as an option, employed to explain the reason of the discrepancy. The numerical results coincide with the prototype observations. The jet breakup and air entrainment are evaluated from air cavity profiles; the air-pressure drops are small in the cavity. The discrepancy is due to overestimation of the surface-tension effect in the physical model tests. Based on the experimental data of an aerator rig at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, the Two-Fluid model is used to predict air concentration distributions in the aerated flow. The model includes relevant forces governing the motion of bubbles and considers the effects of air bubble size. The numerical results are conformable to the experiments in the air cavity zone. Downstream of the cavity, the air concentration near the chute bottom is higher, which is presumably caused by the fact that the interfacial forces in the Two-Fluid model are underestimated. / <p>QC 20170224</p>

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This thesis examines how artists working for the War Artists' Advisory Committee (WAAC) represented aerial warfare. In contrast to the scholarly attention lavished on wartime films and posters, official war art remains a much neglected aspect of the propaganda war. The few studies that do exist, most notably by Brian Foss, survey the collection as a whole and consider it from an art history perspective. By focusing on the single theme of aviation, a central and defining experience of the Second World War, I embed the WAAC within the economic, social, military and cultural histories of the period and locate it within a longer time frame. Through bringing these usually disparate fields of study into dialogue, I am able to use the art to enrich broader understandings of the period, in particular, the ways in which aerial warfare was represented, how this image evolved during the war and how these cultural products related to economic, military and social factors. This thesis highlights the different roles the WAAC was expected to fulfil. Housed within the Ministry of Information, the WAAC was expected to perform a propagandist function. The committee distanced itself from propaganda and insisted that its primary function was to record for posterity the experience of living through the war. I assess exactly what kind of record the WAAC bequeathed by looking thematically at the key aspects of aerial warfare: aircraft production; the Battle of Britain; the Blitz and the bombing of Germany. I argue that whilst there was broad correlation between war art and propaganda, these images registered aspects of experience that were incongruent with and therefore absent from wartime propaganda, such as the fear of aerial bombardment and the true nature of the bombing of Germany. Moreover, propagandist constructions were not entirely separate to lived experience, rather they both reflected experience and shaped the way that individuals understood and made sense of the world around them. Therefore, in producing images that accorded with propagandist portrayals, the WAAC artists were recording a fundamental part of the experience of living through the war.

Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.

Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.