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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.
11

Real time detectionof airborne fungal spores and investigations into their dynamics in indoor air

Kanaani, Hussein January 2009 (has links)
Concern regarding the health effects of indoor air quality has grown in recent years, due to the increased prevalence of many diseases, as well as the fact that many people now spend most of their time indoors. While numerous studies have reported on the dynamics of aerosols indoors, the dynamics of bioaerosols in indoor environments are still poorly understood and very few studies have focused on fungal spore dynamics in indoor environments. Consequently, this work investigated the dynamics of fungal spores in indoor air, including fungal spore release and deposition, as well as investigating the mechanisms involved in the fungal spore fragmentation process. In relation to the investigation of fungal spore dynamics, it was found that the deposition rates of the bioaerosols (fungal propagules) were in the same range as the deposition rates of nonbiological particles and that they were a function of their aerodynamic diameters. It was also found that fungal particle deposition rates increased with increasing ventilation rates. These results (which are reported for the first time) are important for developing an understanding of the dynamics of fungal spores in the air. In relation to the process of fungal spore fragmentation, important information was generated concerning the airborne dynamics of the spores, as well as the part/s of the fungi which undergo fragmentation. The results obtained from these investigations into the dynamics of fungal propagules in indoor air significantly advance knowledge about the fate of fungal propagules in indoor air, as well as their deposition in the respiratory tract. The need to develop an advanced, real-time method for monitoring bioaerosols has become increasingly important in recent years, particularly as a result of the increased threat from biological weapons and bioterrorism. However, to date, the Ultraviolet Aerodynamic Particle Sizer (UVAPS, Model 3312, TSI, St Paul, MN) is the only commercially available instrument capable of monitoring and measuring viable airborne micro-organisms in real-time. Therefore (for the first time), this work also investigated the ability of the UVAPS to measure and characterise fungal spores in indoor air. The UVAPS was found to be sufficiently sensitive for detecting and measuring fungal propagules. Based on fungal spore size distributions, together with fluorescent percentages and intensities, it was also found to be capable of discriminating between two fungal spore species, under controlled laboratory conditions. In the field, however, it would not be possible to use the UVAPS to differentiate between different fungal spore species because the different micro-organisms present in the air may not only vary in age, but may have also been subjected to different environmental conditions. In addition, while the real-time UVAPS was found to be a good tool for the investigation of fungal particles under controlled conditions, it was not found to be selective for bioaerosols only (as per design specifications). In conclusion, the UVAPS is not recommended for use in the direct measurement of airborne viable bioaerosols in the field, including fungal particles, and further investigations into the nature of the micro-organisms, the UVAPS itself and/or its use in conjunction with other conventional biosamplers, are necessary in order to obtain more realistic results. Overall, the results obtained from this work on airborne fungal particle dynamics will contribute towards improving the detection capabilities of the UVAPS, so that it is capable of selectively monitoring and measuring bioaerosols, for which it was originally designed. This work will assist in finding and/or improving other technologies capable of the real-time monitoring of bioaerosols. The knowledge obtained from this work will also be of benefit in various other bioaerosol applications, such as understanding the transport of bioaerosols indoors.
12

Optimalizace větrání divadelní haly / Optimizing theater hall ventilation

Lenhart, Marek January 2018 (has links)
This master’s thesis is focuses on flow theory and optimizing current state of air distribution in theater hall by CFD simulations. A part of this thesis is project solution of one variant.
13

Modelování obrazů proudění / Airflow modeling

Vičan, Martin January 2014 (has links)
The master thesis explores modelling fluid dynamics images in simulation software Star-CCM+ Version 8.04.007. Three proposed variants are modelled. The first variant describes modelling swirl diffusers, the second and third variant describe modelling wall diffusers. The results of modelling are processed in the form of scalar and vector arrays, which depict the velocity of flowing air, temperature and the age of air.
14

Návrh zařízení pro měření a hodnocení tepelného stavu prostředí / Device Proposal for Measurement and Evaluation of Environmental Thermal State

Janečka, Jan January 2012 (has links)
The thesis deals with evaluation of the environmental thermal state in closed rooms with people inside the room. The achievement of thermal comfort is related to thermal balance of human body. People are producing heat during their work, which has to be carried away from the body to surrounding area by radiation, convection, conduction, respiration and evaporation. The intensity of heat removal is influenced by environmental parameters, especially by air temperature, mean radiant temperature, air velocity and humidity. Personal factors as energy expenditure of human body and clothing resistance are influencing the intensity of heat removal as well. People are able to influence the thermal comfort by their behaviour in given environment, appropriate clothing and regulation of basic environmental parameters. CSN EN ISO 7730 standard states that environmental parameters should be estimated or measured. The operative temperature is than evaluated from collected data. This operative temperature is defined as the temperature of black enclosed area where the human body will be by convection and radiation sharing the same amount of heat as in real inconsistent environment. Nowadays on the market there is no cheap solution for sensor which is able to evaluate the operating temperature and could be used in buildings. There are a lot of professional sensors which have very high accuracy, but are very expensive. Therefore are mainly used only for research or for single and exceptional measurement of environmental thermal state in rooms. The thesis is therefore focused on proposal of suitable (compact) operative temperature sensor assembled according to valid regulations and standards. Emphasis is placed mainly on the sensor price together with guarantee of sufficient accuracy. The proposed sensor is providing information to control system which is than able to adjust the parameters of environment using appropriate way based on relevant requirements. Here is some space for energy savings due to possible continuous measurement and evaluation of environmental thermal state in different rooms. Therefore, during continuous measurement no unnecessary rooms overheating in winter as well as unreasonable cooling in summer should occur. This research and solution is than reflected in reduction of energy consumption used for building operation and subsequently reduction of the pollutants production. This issue is being watched with increasing interest. Another advantage is that whole system is able to work autonomously without human intervention. People no longer have to continuously adjust air temperature because the control system is able to evaluate the most appropriate adjustments based on objective data obtained from the sensor. The thesis includes subsequent verification of proposed sensor as well as the definition of sensor technical parameters including analysis of measurement uncertainties.
15

Blown Away: The Shedding and Oscillation of Sessile Drops by Cross Flowing Air

Milne, Andrew J. B. Unknown Date
No description available.
16

Analýza konstrukce části elektrického stroje / Structural analysis of part of electrical machine

Fodor, Viktor January 2013 (has links)
This thesis discusses the optical diagnostics of electrical motor parts using a 3D scanner. It describes the construction of electrical induction motors, their heat losses, cooling and refrigeration systems that may be used by such motors. It approaches the possibilities of heat recording and briefly explains the 3D scanner’s principal. It also introduces the simulation program ANSYS which uses the finite element method. This thesis shows the post processing of the digitalized object and the simulations and compares the simulation and measurement results. The final part is devoted to the analysis of the obtained results.
17

Studium možnosti optimalizace vlastností alternativních tepelně izolačních materiálů na bázi přírodních vláken / Study of possibilities of optimalization of properties of alternative thermal insulating materials on natural base

Břicháček, Pavel January 2014 (has links)
The presented work investigates the mechanisms of propagation of heat and moisture in the structure of heat-insulating materials based on natural fibers. The main aim of this work is the experimental verification of theoretical patterns, which are involved in the transport of heat and moisture in fibrous materials, especially the influence of fibers thickness and density of the fibrous materials. To widen outputs of the work were selected different kinds of natural fiber materials of vegetable and animal origin. The results of the work should help to optimize the production processes of natural insulation materials considering their optimal thermal properties. From the data collected are deduced general conclusions to better understanding the behavior of these materials.

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