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[pt] O crescimento microbiológico em águas de sistemas de resfriamento pode resultar na formação de biofilme, o qual pode causar problemas de biocorrosão, perdas de carga em tubulações, redução de taxa de transferência de calor e obstrução de fluxo. Os principais e tradicionais biocidas utilizados no controle microbiológico de águas de resfriamento são os compostos à base de cloro. Entretanto, nos últimos anos o ácido peracético tornou-se uma alternava aos compostos clorados, uma vez que este biocida deixa como resíduo apenas o acetato o qual é biodegradável e não forma subprodutos organoclorados. Este trabalho analisou a aplicação do ácido peracético comparando-o com o hipoclorito de sódio no controle microbiológico e na corrosividade de materiais, empregando uma árvore de teste em escala de laboratório. Foi investigada a taxa de corrosão dos materiais metálicos de aço carbono, cobre e aço inoxidável, além da efetividade na redução da contagem bacteriana. Os experimentos foram realizados em condições de fluxo turbulento, pH 8 e temperatura de 32 C empregando uma água de estudo real, carregada de matéria orgânica (DQO = 350 mg/L). As concentrações usadas de ácido peracético foram 0,75; 1,0 e 3,0 mg/L e de hipoclorito de sódio foram 1,0 e 3,0 mg/L. O ácido peracético na concentração de 3,0 mg/L reduziu a carga bacteriana de 1,5x10 (elevado a 5) UFC/mL para 5,24x10 (elevado a 3) UFC/mL. Comparado ao hipoclorito de sódio, o ácido peracético foi menos corrosivo para o aço carbono em todas as concentrações. Na concentração de 1,0 mg/L a taxa de corrosão do cobre em ácido peracético foi menor do que na solução de hipoclorito de sódio. Já na concentração de 3,0 mg/L ocorreu o inverso. Não foi observada corrosão significativa no aço inoxidável para os biocidas estudados. / [en] Microbiological growth in cooling systems water may result in biofilm formation, which can cause problems of bio-corrosion, pressure drop in the pipes, reduction of heat transfer rate and flow obstruction. The main and traditional biocides applied in microbiological control of cooling waters are the chlorine based compounds. However, in recent years, peracetic acid has become an alternative to chlorinated compounds, since this biocide leaves as residue only the acetate, which is biodegradable and does not form chlorinated organic byproducts. This work analyzed the application of peracetic acid comparing to sodium hypochlorite in the microbiological control and material corrosivity using a laboratory scale test tree. The corrosion rate of carbon steel, copper and stainless steel alloys in addition to the effectiveness in reducing the bacterial count. The experiments were carried out under conditions of turbulent flow, pH 8 and temperature of 32 C using a real industrial test water loaded with organics (COD = 350 mg/L). Peracetic acid concentrations used were 0.75, 1.0 and 3.0 mg/L and sodium hypochlorite were 1.0 and 3.0 mg/L. Peracetic acid at the concentration of 3.0 mg/L decreased the bacterial load from 1.5x10 (raised to 5) UFC/mL to 5.24x10 (raised to 3) UFC/mL. Peracetic acid compared to sodium hypochlorite was less corrosive to carbon steel at all concentrations. At the concentration of 1.0 mg/L the corrosion rate of copper in peracetic acid was lower than in sodium hypochlorite solution. At the concentration of 3.0 mg/L, the reverse occurred. No significant corrosion was observed in stainless steel for the biocides studied.

Solar-induced chlorophyll fluorescence (SIF) has been widely cited in carbon cycling studies as a proxy for photosynthesis, and SIF data are commonly incorporated into terrestrial primary productivity models. Though satellite-based SIF products show close relationships with gross primary productivity (GPP), this is not universally true at intermediate scales. A meta-analysis of the tower-based and airborne SIF literature revealed that mean SIF retrievals from unstressed vegetation span three orders of magnitude. While reporting on spectrometer calibration procedures, hardware characterizations, and associated corrections is inconsistent, laboratory and field experiments show that these factors may contribute to significant uncertainty in SIF retrievals. Additionally, there remain ongoing questions regarding the interpretation of SIF data made across spatial scales and the link between satellite SIF retrievals and primary productivity on the ground. Chlorophyll fluorescence originates from dynamic energy partitioning at the leaf level and does not exhibit a uniformly linear relationship with photosynthesis at finer scales. As a standalone metric, SIF measured at the tower scale was not found to track changes in carbon assimilation following stomatal closure induced in deciduous woody tree branches. This lack of relationship may be explained by alternative energy partitioning pathways, such as thermal energy dissipation mediated by xanthophyll cycle pigments; the activity of these pigments can be tracked using the photochemical reflectance index (PRI). Gradual, phenological changes in energy partitioning are observed as changes in the slope of the SIF-PRI relationship over the course of a season. Along with high frequency effects such as wind-mediated changes in leaf orientation and reflectance, and rapid changes in sky condition due to clouds, PRI offers crucial insights needed to link SIF to leaf physiology. While SIF offers tremendous promise for improving the characterization of terrestrial carbon exchange, and a fuller understanding of the boundaries on its utility and interpretation as a biophysical phenomenon will help to create more reliable models of global productivity.

Increasing energy demand and carbon emissions have driven the development of alternative energy solutions. One promising technology is wind energy. Wind energy technology developments has advanced substantially since the 1980s. Offshore wind turbines have become a major research focus, due to the promising offshore wind resource. However, challenges in offshore wind energy have arisen due to the additional wave loading and strong wind loads. Structural control systems have been implemented and researched in order to decrease dynamic response of these systems. The previous studies were successful at decreasing fatigue loads in the tower and support structure of offshore wind turbines. Giving these results, it is still unknown if the reduced loading enabled by structural control systems can allow for reduced material costs in the major structural components. This research examines on an offshore wind turbine's tower-monopile structure by adding several configurations of passive tuned mass dampers, while simultaneously reducing the thickness of the structure in order to reduce costs. A range of candidate tower-monopile systems are created, and simulated in FAST-SC with and without passive tuned mass dampers. Fatigue and ultimate loads are calculated and analyzed. A variety of design criteria are considered including fatigue and ultimate loads, as well as local and global buckling. The results demonstrate that the tower-monopile thickness may be reduced up to 6.2% and still satisfy all design criteria.

Syftet med detta arbete har varit att genomföra en konceptstudie av en teknisk lösning för öppning och stängning av en testcells avgastorn. Detta som en del av det projekt som omfattar ombyggnation av testcellens utlopp. Frågeställningen som studien skall svara på är om det lönar sig att ha en lucka på tornet med hänsyn till det skydd den kan erbjuda och den ekonomiska kostnaden. De mål som sattes upp var att framställa en lämplig kravspecifikation, framställa minst ett fullständigt koncept, framställa en jämförelsematris, föreslå en lösning att ta till förstudie och ge förslag på fortsatt arbete till förstudien. Konceptmetodiken har hämtats från den metod som SAAB använder sig av i utvecklingsprojekt men har modifierats aningen av författarna. Intressenterna till testcellen står i fokus för att framställa en kravspecifikation utifrån deras behov. Intervjuer genomfördes med intressenter och sakkunniga för att erhålla uttalanden. Dessa uttalanden skulle sammanställas och användas som en del av underlaget till en rekommendation. Ett iterativt arbetssätt användes i konceptgenereringen där koncept framställdes och dess funktion utvärderades. De koncept som togs vidare utvärderades mot de identifierade behoven och mot varandra i ett antal jämförelsematriser. Den ekonomiska prognosen byggdes på uppskattade värden och historisk data för kostnader. En övervägande del av intressenterna och sakkunniga som intervjuats har varit positivt inställda till att ha en lucka på avgastornet. Framförallt för det utökade skydd det bidrar med och den potentiellt förlängda livslängden. Kravspecifikationen utformades på ett sådant sätt att det skulle fungera som ett styrdokument för studien, men också innehålla tillräckligt med information för att ge en översiktlig bild av problemet vid överlämning. Tre slutgiltiga koncept presenterades varav ett rekommenderas att ta vidare till förstudie, med motiveringen att den uppfyllde kravet på funktionalitet bäst. Det var även en känd lösning så livscykelanalysen hade en högre grad av säkerhet. / The purpose of this work has been to carry out a concept study of a technical solution for opening and closing a test cell's exhaust tower. This is a part of the project that includes rebuilding the test cell outlet. The question that the study will answer is whether it pays to have a hatch on the tower with regard to the protection it can offer and the financial cost. The goals that were set were to produce an appropriate requirements specification, produce at least one complete concept, produce a comparison matrix, propose a solution to use for a prestudy and provide suggestions for further work for the prestudy. The concept methodology has been taken from the method that SAAB uses in development projects but has been slightly modified by the authors. The stakeholders in the test cell are the prime focus as the requirements specification is based on their needs. Interviews were conducted with stakeholders and experts to obtain statements. These statements would be compiled and used as part of the basis for are commendation. An iterative approach was used in the concept generation where concepts were produced and its function was evaluated. Suitable concepts were evaluated against the identified needs and against each other in a number of comparison matrices. The economic forecast was based on estimated values and historical data for costs. A predominant part of the interviewed stakeholders and experts were positive about having a hatch on the exhaust tower. Mainly because of the increased protection it would contribute and the potential extension of the towers lifespan. The requirements specification was designed to function as a control document but also contain enough information to provide an overview of the problem for the handover to the prestudy. Three final concepts were presented, one of which is recommended for further study, with the justification that it best met the requirement for functionality. It was also a known solution so the life cycle analysis had a higher degree of certainty.

An entry for the World Trade Center Memorial Competition was expanded upon as a study into the nature of design. The project influenced its own evolution and revealed exciting outcomes. The memorial is a reinforced concrete tower with an acrylic water tank at the top. The water tank acts as a prism casting colorful light displays both in the tower and around the site. The tank is also the source for continually falling droplets of water. The drops fall 450 feet through an open chamber to land in a shallow overflowing pool and then wash over a stone sepulcher containing the unidentified remains of victims. / Master of Architecture

Computational fluid dynamics was used to simulate solar chimney power plants and investigate modeling techniques and expected energy output from the system. The solar chimney consists of three primary parts: a collector made of a transparent material such as glass, a tower made of concrete located at the center of the collector, and a turbine that is typically placed at the bottom of the tower. The collector absorbs solar radiation and heats the air below, whereby air flows inward towards the tower. As air exits at the top of the tower, more air is drawn below the collector repeating the process. The turbine converts pressure within the flow into power. The study investigated three validation cases to numerically model the system properly. Modeling the turbine as a pressure drop allows for the turbine power output to be calculated while not physically modeling the turbine. The numerical model was used to investigate air properties, such as velocity, temperature, and pressure. The results supported the claim that increasing the energy into the system increased both the velocities and temperatures. Also, increasing the turbine pressure drop decreases the velocities and increases the temperatures within the system. In addition to the numerical model, analytical models representing the vertical velocity without the turbine and the maximum power output from a specific chimney were used to investigate the effects on the flow when varying the geometry. Increasing the height of the tower increased the vertical velocity and power output, and increasing the diameter increased the power output. Dimensionless variables were used in a regression analysis to develop a predictive equation for power output. The predictive equation was tested with new simulations and was shown to be in very good agreement. / Master of Science

Through this thesis I explore how a train station can serve as the platform for an experience that is more profound than simply coming and going, and instead can provide a moment that allows travelers to appreciate the location that they are traveling to or from. A train station is almost uniquely positioned to serve as the first or last building any train traveler encounters in a city, serving as the gateway to the modern city. This presents an opportunity where the station itself will have a direct influence on a traveler's initial or final experience of the city. And so, I propose a station that, through its architecture and relationship to the site, provides the traveler a space where they can stop, look, and take in the view of the city from which they are about to depart or at which they are just now arriving. It allows those new to the city to get an understanding of the basic urban layout and its relationship to its surroundings. It becomes a destination in itself, that allows the local population to regain knowledge of their city and to reinterpret what they already know about their home. / Master of Architecture

The mental space in which the architect formulates, tests, and cultivates an idea is deformed by memory, so that nothing projected into this space is bereft of association. However, neither is this space constrained by physical reality, allowing the architect a certain freedom to visualize the totality of an object and the world in which it is projected, simultaneously and in suspension: a space between memory and imagination. Memories and experiences layer richness upon this inner world and form the context for its manifestation; its realization. The deliberate and conscientious curation of this inner world-- the architect as archivist of memory and experience-- is an essential practice for the development of the architect and the worlds in which they operate. / Master of Architecture