L'objectif de ce travail est de modéliser les sources et la propagation atmosphérique du bruit généré par les éoliennes afin de mieux comprendre les caractéristiques de ce bruit à grande distance et d'aider les fabricants d'éoliennes et les développeurs de parc à respecter la réglementation. En couplant des modèles physiques de source aéroacoustique et de propagation, nous sommes capables de prédire les spectres de bruit, ainsi que la directivité et les modulations d'amplitude associées, pour différentes conditions atmosphériques. Le bruit aérodynamique large bande, à savoir le bruit d'impact de turbulence,le bruit de bord de fuite et le bruit de décrochage, est généralement dominant pour les éoliennes modernes. Le modèle analytique d'Amiet est choisi pour prédire le bruit d'impact de turbulence et le bruit de bord de fuite, en considérant plusieurs améliorations par rapport à la théorie initial : 1, une correction empirique pour l'épaisseur du bord d'attaque est introduite dans le calcul du bruit d'impact de turbulence ; 2, un modèle spectral des fluctuations de pression pariétale proposé récemment pour un écoulement avec gradient de pression défavorable est utilisé dans le calcul du bruit de bord de fuite. Ces modèles sont validés par comparaison avec des mesures de la littérature en soufflerie avec des profils fixes.Le modèle d'Amiet est ensuite appliqué à une éolienne complète pour prédire le bruit émis en champ proche. L'effet de la rotation des pales et l'effet Doppler sont pris en compte. On utilise d'abord des profils de vent constant sans turbulence, puis l'effet du cisaillement du vent et de la turbulence atmosphérique sont inclus à l'aide de la théorie de la similitude de Monin-Obukhov. De bons accords sont obtenus avec des mesures sur site éolien lorsque l'on considère à la fois les bruits de bord de fuite et d'impact de turbulence. On retrouve à l'aide du modèle les caractéristiques classiques du bruit des éoliennes, comme la directivité et les modulations d'amplitude. Des comparaisons avec un modèle semi-empirique montrent que le bruit de décrochage peut être significatif dans certains conditions.L'étape suivante consiste à coupler la théorie d'Amiet avec des modèles de propagation pour estimer le bruit à un récepteur en champ lointain. On étudie dans un premier temps un modèle analytique de propagation en conditions homogènes au-dessus d'un sol d'impédance finie. On montre que l'effet de sol modifie la forme des spectres de bruit, et augmente les modulations d'amplitude dans certains tiers d'octave. Dans un second temps, une méthode pour coupler le modèle de source à un code d'équation parabolique est proposée et validée pour prendre en compte les effets de réfraction atmosphérique. En fonction de la direction de propagation, les niveaux de bruit varient car l'effet de sol est influencé par les gradients de vent et car une zone d'ombre est présente dans la direction opposée au vent. On discute pour finir l'approximation de source ponctuelle à l'aide des modèles de propagation analytique et numérique. / The purpose of this work is to model wind turbine noise sources and propagation in the atmosphere in order to better understand the characteristics of wind turbine noise at long range and to help wind turbine manufacturers and wind farm developers meet the noise regulations. By coupling physically-based aeroacoustic source and propagation models, we are able to predict wind turbine noise spectra, directivity and amplitude modulation in various atmospheric conditions.Broadband noise generated aerodynamically, namely turbulent inflow noise, trailing edge noise and separation/stall noise, is generally dominant for a modern wind turbine. Amiet's analytical model is chosen to predict turbulent inflow noise and trailing edge noise, considering several improvements to the original theory: 1, an empirical leading edge thickness correction is introduced in the turbulent inflow noise calculation; 2, a wall pressure fluctuation spectrum model proposed recently for adverse pressure gradient flow is used in the trailing edge noise predictions. The two models are validated against several wind tunnel experiments from the literature using fixed airfoils.Amiet's model is then applied on a full-size wind turbine to predict the noise emission level in the near field. Doppler effect and blade rotation are taken into account. Cases with constant wind profiles and no turbulence are used first, then wind shear and atmospheric turbulence effects obtained from Monin-Obukhov similarity theory are included. Good agreements against field measurements are found when both turbulent inflow noise and trailing edge noise are considered. Classical features of wind turbine noise, such as directivity and amplitude modulation, are recovered by the calculations. Comparisons with a semi-empirical model show that separation noise might be significant in some circumstances.Next, Amiet's theory is coupled with propagation models to estimate noise immission level in the far-field. An analytical model for the propagation over an impedance ground in homogeneous conditions is studied first. The ground effect is shown to modify the shape of the noise spectra, and to enhance the amplitude modulation in some third octave bands. A method to couple the source model to a parabolic equation code is also proposed and validated to take into account atmospheric refraction effects. Depending on the propagation direction, noise levels vary because the ground effect is influenced by wind shear and a shadow zone is present upwind. Finally, the point source assumption is reviewed considering both the analytical and numerical propagation models.

Groundwater inflow is a challenge in construction of tunnels in fractured bedrocks since it affects the safety function of tunnels and leads to potential problems in the surrounding environment, such as subsidence, dropdown of the groundwater table. Quantification of groundwater inflow into the tunnel is also important for design of grouting in the construction of the tunnel. Modelling groundwater flow in fractured bedrocks currently remains a challenge. Commonly used groundwater models are based on continuum assumptions and they do not consider realistic structures of discrete fractures, which leads to high potential uncertainty in prediction of tunnel groundwater inflow. This thesis focuses on prediction of tunnel groundwater inflow, using a discreet fracture-matrix (DFM) model. The DFM model is evaluated and compared with the conventional continuum model based on Darcy’s law. This DFM model considers, in particular, multi-scale heterogeneity, e.g. fracture networks and variable fracture aperture structures. Applying this DFM model, the impact of variable fracture aperture structures on tunnel inflow is investigated through stochastic analysis. The results show that under the same boundary conditions, the traditional continuum model overestimates the inflow compared to the DFM model. The difference in equivalent permeability is 2 to 3 orders of magnitude. The sensitivity analysis shows that the discreet fracture model is sensitive to the variability of fracture aperture. The estimated equivalent permeability values by discreet fracture modelling is in the order of 5×10-6 to 1×10-7 m/s for a fracture density of 1.2 fractures per square meter. This study demonstrates that the DFM represents the more realistic features of fractured rock structures, which is useful and can be used to predict groundwater inflow in fractured rock tunnels. / Grundvatteninflöde är en utmaning vid byggnation av tunnlar i sprucken berggrund eftersom det påverkar tunnlarnas säkerhetsfunktion och leder till potentiella problem i den omgivande miljön, såsom sättningar och Grundvattennivåsänkning. Kvantifiering av grundvatteninflöde till tunneln är också viktig för utformning av injektering i tätning? byggandet av tunneln. Att modellera grundvattenflödet i sprucken berggrund är för närvarande en utmaning. Grundvattenmodeller man normalt använder är baserade på kontinuumantaganden, och de tar inte hänsyn till realistiska strukturer av diskreta sprickor, vilket leder till hög potentiell osäkerhet i uppskattning av tunnelgrundvatteninflöde. Denna avhandling fokuserar på förutsägelse av tunnelinläckage, med hjälp av en diskret sprickmatris (DFM) modell. DFM-modellen utvärderas och jämförs med den konventionella kontinuummodell vilken är baserad på Darcys lag. Denna DFM-modell tar särskilt hänsyn till multi-skala heterogenitet, till exempel spricknätverk och variabla dubbelkolla. Genom att tillämpa denna DFM-modell undersöks effekten av strukturer med variabel spricköppning på grundvatteninflödet genom stokastisk analys. Resultaten visar att under samma randvillkor överskattar den traditionella kontinuummodellen inflödet jämfört med DFM-modellen. Skillnaden i ekvivalent permeabilitet är 2 till 3 storleksordningar. Känslighetsanalysen visar att den diskreta sprickmodellen är känslig möt variationen i spricköppningen. De uppskattade ekvivalenta permeabilitetsvärdena med diskret sprickmodellering är i storleksordningen 5x10-6 till 1x10-7 m/s för en spricktäthet på 1,2 sprickor per kvadratmeter. Denna studie visar att DFM representerar de mer realistiska egenskaperna hos sprickiga bergstrukturer, vilket är användbart och kan användas för att uppskatta grundvatteninflöde i sprickiga bergtunnlar.

[pt] Estudos recentes estimam que a elegibilidade ao programa de seguro desemprego aumenta a probabilidade de demissão em 12 por cento no Brasil. Esse artigo desenvolve um modelo de equilíbrio parcial onde trabalhadores buscam por emprego e podem se demitir para coletar benefícios do seguro desemprego. Calibramo-lo usando dados do Brasil e o utilizamos para medir as consequências desse comportamento sobre o acúmulo de capital humano específico à firma e sobre a produtividade do trabalho na economia. Por meio de exercícios contrafactuais, descobrimos que tornar a elegibilidade ao seguro desemprego mais estrita aumentaria o salário médio, a estabilidade no emprego, mas também a taxa de rotatividade. Discutimos esse último resultado e concluímos que isso depende de como a política modifica a fração de trabalhadores empregados que voluntariamente se separam de seus empregos. Em outro exercício, encontramos uma relação negativa entre a mudança na taxa de reposição do programa de seguro desemprego e a duração média do emprego. / [en] Recent studies estimate that eligibility for unemployment insurance program raises layoff probability by 12 per cent in Brazil. This paper develops a partial equilibrium model where workers search for jobs and might quit them in order to collect UI benefits. We calibrate it using data from Brazil and use it to assess the consequences of this behavior on firmspecific human capital accumulation and labor productivity in the economy. Through counterfactual exercises, we find that a stricter job tenure eligibility threshold would raise the average wage, the job tenure, but also the turnover rate. We discuss this last result and conclude that it depends on how the policy modifies the fraction of employed workers who voluntarily separate from their jobs. In another exercise, we find a negative relationship between the change in the UI replacement rate and the average employment duration.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / This study attempts to determine the water quality changes in stock tanks and what factors are instrumental in the changes, and to assess the effects of the changes. Algal growth was the most prominent change taking place in the tanks with time. Little change in the water chemistry was noted until just before the tanks dried up. As algae died, ions tied up by the algae were released to the water, causing an increase in concentration of many of the nutrients. In order to determine the impact of various factors on algal growth, the data from eight stock tanks were analyzed by stepwise linear regression. Although 20 variables were used in the complete analysis, six variables were associated with 56.3 percent of the variance: time (since first sampling), total n, potassium, pH, inflow (recharge to the tanks), and hco3 concentration. Time and total n explained 51.3 percent of the variance, and potassium increased the variance to 52.8 percent. The pH reversed the relative positions of time and total n, with total n becoming dominant. The last two factors, inflow and hco3 were negative (resulting in a decrease in algal population) and increased the coefficient of variance to 56.3 percent.

Coastal transition zones form important interlinking regions where marine ecosystems, rivers and estuarine environments significantly influence each other. Coastal rocky shores are key habitats that sustain a variety of primary producers and invertebrates and due to the dynamic nature of coastal ecosystems, suspension-feeders on rocky shores can be influenced by an array of autochthonous and allochthonous food sources. Fatty acid and stable isotope trophic markers were employed to distinguish between regional and temporal changes in the potential food sources to rocky shore suspension-feeders in the Eastern Cape Province of South Africa. The primary aim was to assess the spatial and temporal influences of contrasting river flows on the available food sources to three indigenous coastal suspensionfeeders, namely the volcano barnacle Tetraclita serrata, brown mussel Perna perna and tubebuilding polychaete Gunnarea capensis. This was done by examining the intra- and interspecific changes in the fatty acid and stable isotope signatures of the barnacles, mussels and polychaetes in the adjacent marine environment of a freshwater-restricted (Kariega) and freshwater-dominated (Great Fish) estuary during austral summer and winter. Multivariate and Kruskal-Wallis analyses of variance on the fatty acid and isotopic signatures, respectively, identified significant regional changes in the barnacles and mussels, while only stable isotopes distinguished between the Kariega and Great Fish polychaetes (P < 0.05). In addition, significant temporal changes were observed in consumer fatty acids and isotope values in both regions (P < 0.05). Bacterial sources, detritus and phytoplankton assemblages, which are influenced by hydrology and vegetation, differed between regions and were mainly responsible for the regional and temporal separations. Principal component analyses on the consumer fatty acid signatures distinguished between animals situated upstream (i.e. north) and downstream (i.e. south) of the Kariega Estuary mouth in summer. The north/south separation was mainly due to greater contributions of diatoms to northernlocated animals and dinoflagellates and detritus to southern-located consumers. In addition, the south-flowing Agulhas Current on the eastern shores of southern Africa appeared to influence the north/south separation in the Kariega region, as water leaving the estuary was probably entrained into the south-easterly flowing currents, thereby depositing estuarinederived detritus to southern populations. In general, diatoms and detritus were essential food sources to the filter-feeders in summer, and flagellates, diatoms, zooplankton and detritus were important in winter. Coastal macroalgae was a key food source in the Kariega and Great Fish regions during both seasons. Consistently large levels of diatom markers (16:1n-7 and 20:5n-3) and dinoflagellate markers (22:6n-3) in consumer tissues in the Kariega and Great Fish regions identified that phytoplankton was their dominant food source. The barnacles, mussels and polychaetes had similar fatty acid markers and a fairly narrow δ¹³C range (-16.5 to -14.4 ‰), suggesting that they probably consumed similar food. Carbon isotope analyses, however, separated the suspension-feeders into slightly depleted (barnacles; -16.5 to -16.1 ‰), intermediate (mussels; -15.8 to -15.0 ‰) and enriched (polychaetes; -15.0 to -14.4 ‰) consumers, but did not provide conclusive evidence of their preferences for specific phytoplankton. Conversely, fatty acid analyses highlighted that barnacles and mussels had greater proportions of dinoflagellate markers (22:6n-3; 7.0-15.3 % TFA), while polychaetes had larger diatom levels (20:5n-3; 15.1-22.2 % TFA). In addition, all three species had consistently large contributions from bacterial fatty acids (15:0, i-16:0, 17:0 and i-18:0; 4.2-13.6 % TFA) in summer and winter, and large proportions of saturated fatty acids (33.3-53.1 % TFA) including those with 14 to 18 carbons, indicating that bacterial and detritus food sources played an important role in their diets. Barnacles had small levels of terrestrial markers (18:2n-6 and 18:3n-3; <2.5 % TFA) and demonstrated increased omnivorous feeding compared with the other suspension-feeders [increased levels of 20:1n-11 and 20:1n-9, higher 18:1n-9/18:1n-7 ratios at ~2.1, enriched δ¹⁵N values at ~10.6 ‰; zooplankton (potentially including microzooplankton, larvae and protists) contribution of up to 61 % of the diet]. Mussels contained significant proportions of the terrestrial markers (18:2n-6 and 18:3n-3; >2.5 % TFA) and exhibited intermediate omnivory (intermediate levels of 20:1n-11 and 20:1n-9, intermediate 18:1n-9/18:1n-7 ratios at ~1.3, less enriched δ¹⁵N values at ~7.9 ‰; zooplankton contribution of 10-15 % of the diet). The more depleted nitrogen signatures in the mussels relative to the barnacles and polychaetes possibly illustrated a stronger preference for autotrophic food. Polychaetes mainly consumed plant food sources (i.e. microalgae, macroalgae and detritus; high levels of i-18:0, 18:1n-9, 18:4n-3 and 20:5n-3) and displayed little omnivory (low levels of 20:1n-11 and 20:1n-9, low 18:1n-9/18:1n-7 ratios at ~0.4, intermediate δ¹⁵N values at ~9.1 ‰; zooplankton contribution of <10 % of the diet). The barnacles, mussels and polychaetes are all suspension-feeders, originally presumed to consume the same food sources. The variations observed among the species, therefore, may result from differences in the proportional contributions of the various food sources to their diets as well as distinctions in metabolism. The distinct changes in the fatty acid and stable isotope signatures in all three filter-feeders in the Kariega and Great Fish regions are likely influenced by the diversity in regional vegetation and hydrology in the different systems, combined with interspecific differences in resource partitioning among the species.

Diploma thesis is aimed on description of wastewater treatment plant with gravitational inflow. Focus is on WWTP in the Czech Republic, particularly in the South Moravia region - in this aspect the thesis presents relevant statistics like the number of WWTP per region and the total, capacity of WWTP per region and their substance load on inflow /outflow. The recherche is also limited according to the core subject of theoretical part, which is technology of small WWTP in the category up to 2000 equivalent habitants. The experimental part presents comparsion of particular wastewater treatment plant of this category in the South Moravia region: one with gravitational inflow and one with inflow pump station. The examined wastewater treatment plant are compared according to substance load, hydraulic load and technology. Thesis is concluded with a review of the different operation parameters of the both types of WWTP.

Philosophiae Doctor - PhD / Tuberculosis is a bacterial infection which is a major cause of death worldwide. TB is a curable disease, however the bacterium can become resistant to the first line treatment against the disease. This leads to a disease called drug resistant TB that is difficult and expensive to treat. It is well-known that TB disease thrives in communities in overcrowded environments with poor ventilation, weak nutrition, inadequate or inaccessible medical care, etc, such as in some prisons or some refugee camps. In particular, the World Health Organization discovered that a number of prisoners come from socio-economic disadvantaged population where the burden of TB disease may be already high and access to medical care may be limited. In this dissertation we propose compartmental models of systems of differential equations to describe the population dynamics of TB disease under conditions of crowding. Such models can be used to make quantitative projections of TB prevalence and to measure the effect of interventions. Indeed we apply these models to specific regions and for specific purposes. The models are more widely applicable, however in this dissertation we calibrate and apply the models to prison populations.

This study investigates how the mandatory adoption of the international reporting standards IFRS (International Financial Reporting Standards) for publicly listed companies affect countries’ levels of in- and outflow of cross-border capital. The continued harmonization of financial reporting standards on an international level is bringing up questions regarding supposed benefits of their implementation. These benefits cover areas such as increased accessibility of external financing, lower costs of capital, greater opportunities to receive a loan with longer terms, and the perceived improvements to the quality and transparency of annual reports. These factors, along with others, are driving forces as to why countries should experience changes in cross-border flows of capital when they officially adopt IFRS. It is this study’s goal to establish differences and relationships between different components of the international flow of capital and the aforementioned adoption. In this study the components are represented by the dependent variables; foreign direct investment inflow, foreign direct investment outflow, foreign portfolio investment, foreign loans as well as loans that are given to other countries. To analyse differences caused in these values by the adoption, paired t-tests are performed on data consisting of 2 360 observations from 59 countries during the period of 2001-2019. In addition, 42 countries from the continent of Asia are investigated during the period of 2013-2019 with several multiple regression analyses to determine relationships, in this case the data consisted of 4 410 observations. The paired t-tests exhibited statistically significant increases in all variables as of the adoption while the multiple regressions analyses resulted in only one out of five variables having a significant relationship with the event, that variable being foreign direct investment outflow. The results put to question previous studies successful attempts to show significant positive relationships between adoption and countries’ levels of foreign direct investment inflow, foreign portfolio investment, foreign loans and loans given to other countries. The result also has implications for further research in regard to choice of controlling variables as well as method of data collection. / Denna studie undersöker hur den obligatoriska implementeringen av de internationella redovisningsstandarderna IFRS (International Financial Reporting Standards) för börsnoterade företag påverkar länders in- och utgående flöden av gränsöverskridande kapital. Den fortsatta harmoniseringen av redovisningsstandarder på internationell nivå tar upp frågor gällande implementeringens påstådda fördelar. Fördelar som implementering av IFRS leder till täcker områden såsom ökad tillgänglighet av extern finansiering, lägre kapitalkostnader, större möjligheter att ta ut lån med längre löptider, och att årsredovisningar upplevs få bättre kvalitet och bli mer transparenta. Ovanstående faktorer m.fl. utgör grunden till varför länder borde uppleva förändringar i gränsöverskridande kapitalflöden i och med implementering av redovisningsstandarderna. Det är denna studies mål att etablera skillnader och samband mellan olika beståndsdelar av det internationella kapitalflödet och denna implementering. De beståndsdelarna representeras i denna studie av de fem olika beroende variablerna; ingående utländsk investering, utgående utländsk investering, utländsk portföljinvestering, utländska lån samt lån som delas ut till andra länder. För att undersöka ifall skillnader uppstår i dessa värden i och med implementering utförs parade t-test på ett dataunderlag av 2 360 antal observationer tagna från 59 länder under perioden 2001–2019. Dessutom undersöks 42 länder i kontinenten Asien under perioden 2013–2019 med multipla regressionsanalyser för att påvisa samband, datan i detta fall uppgick till 4 410 stycken observationer. T-testen visade på statistiskt signifikanta ökningar i alla variabler i och med implementeringen av IFRS medan de multipla regressionsanalyserna resulterade i att endast en av de fem olika variablerna, nämligen utgående utländsk investering, hade ett signifikant positivt samband med händelsen. Resultaten problematiserar tidigare studier som föreslår att det existerar signifikanta positiva samband mellan implementering och länders nivåer av ingående utländsk investering, utländsk portföljinvestering, utländska lån och lån som delas ut till andra länder. Undersökningen har även implikationer för framtida undersökningars val av kontrollvariabler och datainsamlingsmetod.

Many numeric models simulate the transport of sediment within rivers and streams. Engineers use such models to monitor the overall condition of a river or stream and to analyze the impact that the aggradation and degradation of sediment has on the stability of bridge piers and other features within a stretch of a river or stream. A model developed by the Federal Highway Administration, FST2DH, was recently modified to include the simulation of sediment movement within a channel. The tools for modeling sediment movement with FST2DH remain unproven. This thesis examines the sediment capabilities of FST2DH. It evaluates the sediment results for reasonableness and compares the results to those obtained from a sediment transport model developed by the Army Corps of Engineers, SED2D WES. Resulting concentrations from another program created by the Army Corps of Engineers, SAMwin, provide additional data comparison for FST2DH sediment solutions. Several test cases for laboratory flumes give additional insight into the model's functionality. Finally, this thesis suggests further enhancements for the sediment capabilities of the FST2DH model and provides direction for future research of the sediment transport capabilities of FST2DH. Results show that FST2DH appropriately models sediment movement in channels with clear-water and equilibrium transport rate inflow conditions. Transport formulas found to be functional include the Engelund—Hansen, Yang sand and gravel, and Meyer-Peter—Mueller equations. FST2DH has difficulty modeling channels with user-specified inflow concentrations or transport rates, models with very small particles, models containing hydraulic jumps, and models with small elements. The test cases that successfully run to completion provide appropriate patterns of scour and deposition. Other trends in the results further verify the functionality of many of the sediment transport options in FST2DH.