The diploma thesis deals with the analysis of temperature and humidity in the construction of flat roofs with influence even without influence of solar radiation. It was necessary to study and verify the properties of building materials, the physical nature of the influence of solar radiation on building structures and the transport mechanisms of moisture. The theoretical part describes the basic physical theory on solved problems, the essence and division of solar radiation, the description of thermal moisture properties of building materials and the calculation method of determination of moisture in structures according to valid standards. Practical part deals with description of work in software DEKSOFT - Thermal technology 1D and WUFI 2D software, description of individual models and analysis of achieved results. At the end of the practical part the achieved theoretical knowledge is validated by analyzing the obtained data from the practical model.

Entering of thesis focuses on large-scale solar systems. Large solar-scale system will be used for heating water in public swimming pool. The pool is located in Brno - country. The pool is operated year-round. Great emphasis of the thesis is on the surface heat loss. Evaporation of water from the water surface is also applied in the experimental part of the thesis. In the calculations is used software for modeling the thermal microclimate of buildings and air conditioning design Teruna.

PhD (Physics) / Department of Physics / Dye sensitized solar cells (DSSCs) have attracted rapid interest over the recent years with prospect of emerging as a viable alternative to conventional silicon based solar cells. The photoanode of DSSCs comprises of dye molecules anchored to the surface of semiconductors such as TiO2. However, the major drawback of Titanium dioxide (TiO2) is its wide band gap (3.0 eV to 3.2 eV) which limits its photocatalytic activities to the ultraviolet region of the electromagnetic spectrum. Understanding the interaction of dye molecules with the surfaces of TiO2 is crucial for optimizing light-harvesting, photoconversion function and photocurrent densities in DSSCs. The three polymorphs of TiO2 are anatase, brookite and rutile. The optical properties of brookite semiconductor have not been much studied although brookite has been reported to have good photocatalytic properties. In this work, Density functional theory (DFT) computational approach was used through various computational softwares which are CASTEP, GAUSSIAN, GAUSSUM, GPAW, ASE, and AVOGADRO with B3LYP, LANL2DZ, PBE, and GGA functional to explore the photocatalytic properties of the typical ruthenium N3 complex, polyenediphenyl-aniline dye moiety, croconate dye molecules and three modelled surfaces of brookite which are (TiO2)5, (TiO2)8 and (TiO2) 68 for application in DSSCs. We also studied the absorption of the corresponding dye molecules on the three surfaces of brookite TiO2. Our findings showed strong binding ability, good electronic coupling, efficient charge separation, spontaneous electron injection and good spectral properties upon adsorption of the dye molecules to brookite TiO2 semiconductor clusters. Our findings on the optical absorption spectra of ruthenium N3 dye, croconate dye and polyenediphenyl-aniline dye molecule absorbed on (TiO2)5 and (TiO2)8 brookite cluster shows bathocromatic shift of the absorption maxima to higher wavelength and improve optical response of TiO2 brookite cluster. A red spectra shift and absorption over a wide range of the solar spectrum in the visible and near infra-red region of the solar spectrum was achieved upon absorption of the ruthenium N3 complex and polyenediphenyl-aniline dye molecules on (TiO2)5 and (TiO2)8 brookite cluster. The results generally suggest that the absorption of dye molecules on TiO2 brookite cluster improves its spectra responsivity in the UV region and makes it possible to absorb over the whole spectrum range, that is, the UV, visible and near infra – red region of the solar spectrum. Our findings also showed good electron injection kinetics from the dye to TiO2 brookite clusters, which suggests higher photocurrents density and open circuit voltage in DSSCs. / NRF

Das thermische Raummodell THERAKLES berechnet das dynamische Verhalten eines Raumes und seiner Umschließungsflächen in Abhängigkeit von realistischen Klimarandbedingungen, sowie Nutzer- und Anlagenverhalten. Neben Energieverbrauchswerten werden die operative Temperatur sowie weitere Kriterien zur Beurteilung der Behaglichkeit berechnet. Schwerpunkt der Anwendung liegt auf Optimierung der thermischen Behaglichkeit im Sommerfall, sowie energetischer Optimierung der Regelung von Heizungsanlagen unter Ausnutzung der Dynamik schwerer Baukonstruktionen und Massivbauwände. Das Modell beschreibt das dynamische Verhalten der Umfassungskonstruktionen durch instationäre, räumlich aufgelöste Simulation der Wand-, Fußboden-, und Decken- bzw. Dachflächen. Dadurch werden in der Konstruktion enthaltene Phasenwechselmaterialien (PCM) berücksichtigt und die zeitliche Verfügbarkeit der zusätzlichen Wärmespeicherfähigkeit abgebildet.

The purpose of the study was to provide further knowledge about if the total amount of solar radiation during the marsh fritillary’s (Euphydryas aurinia) period for larvae development (April 15th – May 15th) and/or flying period (June 1st – June 30th) influenced the average of larvae colonies in the autumn at 12 sites in Dalarna County. Among increased temperatures, global climate models also predict an increased amount of solar radiation and a decrease in cloudiness in northern Europe, as a result of the climate changes. The marsh fritillary has declined rapidly, especially in the Northern of Europe and are in Sweden red-listed as vulnerable (VU). The marsh fritillary is a univoltine species who are dependent on open, sunny, and moist semi-natural grasslands with the hostplant devil’s bit (Succisa pratensis). The data over solar radiation was received from SMHI and had been measured in Borlänge over the last 14 years. The data over the number of larvae colonies was received from Länsstyrelsen Dalarna and had been measured over the last 15 years. The linear regression analysis for both the period of larvae development (p=0,58) and the whole period (p=0,07) indicates that during those periods the solar radiation did not influence the average of larvae colonies. However, the total amount of solar radiation during the flying period (p=0,02) influence the average of larvae colonies during the autumn.

In this study eddy covariance was used to measure sensible heat, latent heat, and carbon dioxide fluxes for the months of August, September, and October of 2009 within the roughness sublayer (RSL) of the urban center of Portland, OR. Vehicle traffic and solar radiation were also measured for the month of October. Flux measurements were compared with measurements from other urban areas as a test of reasonableness. CO₂ fluxes were nearly always positive and were strongly correlated with the weekday diurnal traffic cycle. CO₂ fluxes averaged 6.6 μmol/m^²s, which is less than other published measurements in urban areas. Sensible and latent heat fluxes followed the expected diurnal profile associated with solar radiation. Average sensible heat flux decreased as the season changed from summer to fall, moving from an average of 39 W/m^² in August to 12 W/m^² in October. A corresponding increase in latent heat flux was observed during this period, changing from an average of 10 W/m^² in August to 17 W/m^² in October. Heat flux behavior and amplitude was consistent with other urban measurements, though amplitude varies considerably from city to city. Stationarity was shown to positively influence measured CO₂ fluxes, but to have little effect on measured heat fluxes. Preliminary comparisons of October sensible heat and CO₂ fluxes to an inventory-based estimate of vehicle emissions indicate that eddy covariance measurements underestimate the true fluxes by 50%.

The signaling mechanisms involved in UVB-induced skin cancer are complex and although the scope of this work is inherently limited in focus, the findings may provide insight into how estrogen receptor signaling impacts cell growth, senescence, and apoptosis to protect keratinocytes. Additional signaling due to E2-activation of the estrogen receptor may provide back-up or redundant pathways in response to UVB.

The study relates international knowledge of climatically responsive and energy-efficient design to work done in South Africa. It also explores the relevance of design devices from international regions to the climates of this country. The research approach explores existing analyses of the main climate regions and the effects of climate factors on human comfort in each, in order to derive appropriate design solutions for the climate of South Africa. In South Africa obstacles exist in the face of energy efficiency. The cheapness of electricity to the consumer and the virtual non-existence of appropriate legislation appear to be two of the most significant obstacles. Design and subsequent construction of suburban residences is carried out with little regard for climatic context. Water is shown to be a particularly scarce and unevenly distributed commodity, which the affluent have greater access to and consume in greater quantities. However, it is demonstrated that the South African climate is virtually ideal for several climate-responsive energy-efficiency techniques. Especially due to the high solar radiation levels there is potential for various active and passive solar design techniques and technologies. The impact of atmospheric temperature and humidity, wind, radiation and precipitation on human comfort is investigated. Humidity and wind are demonstrated to be very influential on human comfort, whereas radiation and wind are the most easily manipulated through design. Furthermore, the specific topography and location of a site can influence the microclimate and solar access of an area to a significant degree. The South African climate is predominantly either hot semi-arid or temperate. Most of the western interior is hot arid whereas the eastern interior and highveld is predominantly temperate, with temperatures increasing to the north and decreasing to the south. The only cool region of the country is found in the highlands of the Drakensberg, with a significant portion of the eastern coast being hot humid. Methodologies and guidelines for both layout, or macro design, and detailed design of residential suburbs are explored. The manipulation of solar radiation, sunlight and wind, as well as the management of rainwater and used household water is explored. It is shown that designing suburbs to create access to solar radiation forms the basis of solar design, with solar access control, material and surface treatment largely determining the success of individual designs. Wind manipulation is achieved mainly through planting design, influencing mostly heat loss and gain ratios into buildings. Effective household water management can substantially reduce its consumption. Further research is needed in all aspects of climate-responsive design, especially classification of the South African climate and development of design techniques adapted to this context. / Dissertation (M (Landscape Architecture))--University of Pretoria, 2004. / Architecture / unrestricted

Prestressed concrete is a popular construction material for highway bridges. A variety of girder span values, cross-sectional shapes, and prestressing strand layouts has been used in bridges across the United States. A major concern for such bridges is the possibility of corrosion damage in the prestressing strands or reinforcing bars, which is commonly caused by the use of deicing salts on the deck or saltwater spray in coastal regions. The present study aims at establishing analytical tools for the accurate simulation of chloride ingress, corrosion and mechanical damage (cracking) in the concrete, and for the evaluation of the impact of corrosion on the flexural and shear strength of bridge girders. First, an efficient and accurate analytical scheme is formulated to enable the calculation of the load-carrying capacity of corrosion-damaged girders. The analyses rely on two types of models, namely, beam models and nonlinear truss models. The latter are deemed necessary to obtain reliable estimates of the shear capacity, as beam models are not well-tailored for capturing shear failures. A procedure to account for the reduction in area and deformability of corroded strands, based on visually observed corrosion damage, is proposed and implemented. The models are calibrated and validated with the results of experimental tests on prestressed girders which exhibited varying levels of corrosion damage. Further analyses allow the comparison of the capacity of corrosion-damaged girders to that of their undamaged counterparts. The accuracy of a simplified procedure, using equations in the AASHTO code to determine the flexural and shear capacity of the damaged girders, is also determined. Subsequently, a computation scheme was proposed to describe the intrusion of chloride ions in prestressed bridge girder sections. The approach accounts for multiple, coupled processes, i.e., heat transfer, moisture transport, and chloride advective and diffusive transport. The constitutive models for moisture and chloride transport rely on previous pertinent work, with several necessary enhancements. The modeling scheme is calibrated with data from previous experimental tests on concrete cylindrical and prismatic specimens. The calibrated models are then validated using data from chloride titration tests conducted on girders removed from two bridges in Virginia after 34 and 49 years of service. The results indicate that the proposed framework can accurately reproduce the experimentally measured chloride content. The modeling approach also allows the evaluation of the accuracy of simplified, design-oriented tools for estimating the evolution of chloride content with time. The multi-physics simulation scheme is further refined to account for the corrosion-induced mechanical damage (cracking), by incorporating a phenomenological description of the electrochemical reaction kinetics, generation of expansive corrosion products, and subsequent development of tensile stresses and cracking in the surrounding concrete. The impact of cracking on the chloride and moisture transport mechanisms is also taken into account. The last part of this dissertation pursues the quantification of the uncertainty governing the chloride ingress in bridge girders, through the use of a stochastic collocation approach. The focus is on understanding how the inherent uncertainty in the value of input parameters (e.g., material transport parameters, ambient conditions etc.) is propagated, leading to uncertainty in the evolution of chloride content and the expected corrosion initiation time for a given bridge. / Doctor of Philosophy / Prestressed concrete is widely utilized in the construction of highway bridges in the United States. A significant concern arises regarding potential corrosion damage in the prestressing strands or reinforcing bars, which is commonly attributed to the application of deicing salts on the deck or exposure to saltwater spray in coastal regions. This study aims to develop analytical tools that can accurately simulate the intrusion of corrosive agents (namely chloride ions), and subsequent damage (cracking) in concrete. Furthermore, the research seeks to assess the impact of corrosion on the bearing capacity of bridge girders. Two different classes of analytical approaches are pursued. The first class employs purely mechanical (stress/deformation) models for capturing the strength, deformability and failure modes of girders with visual corrosion damage. These models rely on two approaches to capture the flexural and shear capacity of specimens, namely, beam-based models and truss-based models. The impact of corrosion is established through appropriate modification of the model parameters, based on the extent of visually observed corrosion damage. The analytical approaches are validated through a series of experimental tests previously conducted on corrosion-damaged girders. The second class of analytical approaches employs multi-physics models, to describe the mechanisms leading to corrosion-induced damage. The models account for heat transfer, moisture transport, and chloride transport in prestressed beam sections. Model parameters are calibrated with experimental tests in literature. The computational scheme is used to quantitatively describe the chloride ingress on bridge girders decommissioned from two different bridges in Virginia, after 34 and 49 years of service. The analysis results are found capable of capturing the actual chloride content at various depths from the exposure surface, as determined by chloride titration tests. The temporal evolution of chloride on the surface of prestressing strands indicates that corrosion has been taking place over a period of time for the two bridges. The multi-physics simulation approach is further enhanced to account for the corrosion-induced mechanical damage (cracking), by explicitly incorporating a description of the reaction kinetics, generation of expansive corrosion products and subsequent development of cracking in the surrounding concrete. The last part of this dissertation pursues the quantification of the uncertainty in the expected service life of prestressed concrete bridge structures. Given the inherent uncertainty to key values of model parameters, a parametric study is employed to investigate the propagation of uncertainty to the time history of chloride content at particular locations of the section and the probability of corrosion initiation at specific age values.

[pt] Com a necessidade de uma maior diversificação da matriz energética mundial e a inevitabilidade de investimento em fontes de energia limpa, a energia solar fotovoltaica tem se mostrado uma fonte energética promissora. Seu crescimento hoje é exponencial e se revela cada vez mais presente na matriz energética da maioria dos países. No Brasil, já se vê um mercado fotovoltaico sólido com geração de milhares de empregos e investimentos de bilhões de reais. Sua intermitência e imprevisibilidade é razão de grande pesquisa, no intuito de obter dados confiáveis que estimam a geração de um sistema solar fotovoltaico ao longo de seu ciclo de vida. Sendo assim, este trabalho conduz uma extensa revisão bibliográfica, passando pelos fundamentos básicos, até o desenvolvimento de um algorítmico robusto, integrando modelos matemáticos presentes na literatura. Os dados de radiação solar global, velocidade do vento e temperatura, são obtidos de mapas gerados por 39 estações solarimétricas dentro e próximas das fronteiras do estado do Rio de Janeiro. O simulador, também conta com uma extensa base de dados atual de módulos solares e inversores. Após uma série de validações e análises de sensibilidade, apresentou resultados satisfatórios quanto a sua capacidade de previsão. Dessa forma, é possível simular e dimensionar sistemas solares fotovoltaicos, calculando indicadores e fluxo de caixa detalhado que refletem a viabilidade de um determinado projeto. Além disso, o simulador tem a capacidade de gerar mapas georreferencidos que contribuem para uma avaliação técnica, economia e ambiental, de uma região a ser analisada. Com isso, se torna uma ferramenta fundamental para investidores do setor. / [en] With the need for greater diversification of the world energy matrix and the inevitability of investment in clean energy sources, photovoltaic solar energy has proved to be a promising energy source. Its growth today is exponential and is increasingly present in the energy matrix of most countries. In Brazil, there is already a solid photovoltaic market with the generation of thousands of jobs and investments of billions of reais. Its intermittency and unpredictability is the reason for great research, in order to obtain reliable data that estimate the generation of a photovoltaic solar system throughout its life cycle. Therefore, this work conducts an extensive bibliographic review, going through the basic foundations, until the development of a robust algorithm, integrating mathematical models present in the literature. Global solar radiation, wind speed and temperature data are obtained from maps generated by 39 solarimetric stations within and near the borders of the state of Rio de Janeiro. The simulation tool also has an extensive current database of solar modules and inverters. After a series of validations and sensitivity analyzes, it presented satisfactory results in terms of its forecasting capacity. In this way, it is possible to simulate and size solar photovoltaic systems, calculating indicators and detailed cash flow that reflect the viability of a given project. In addition, the simulation tool has the ability to generate georeferenced maps that contribute to a technical, economic and environmental assessment of a region to be analyzed. As a result, it becomes a fundamental tool for investors in the sector.