Das maximale Laktat-steady-state (MLSS) gilt als ein physiologischer Parameter der Ausdauerleistungsfähigkeit. Bereits in den 1980er Jahren entwickelte Mader (1984) auf Basis der Michaelis-Menten-Kinetik eine Berechnungsmethode zur Bestimmung der Leistung im MLSS. Diese Methode setzt die Kenntnis der maximalen Reaktionsgeschwindigkeiten von Glykolyse und Atmung voraus. Die Goldstandard-Methode zur Ermittlung der Leistung im MLSS sind mehrere 30-minütige konstante Dauerbelastungen. Das hauptsächliche Ziel der vorliegenden Arbeit bestand in dem Vergleich der berechneten mit der empirisch ermittelten Leistung im MLSS. 57 männliche Probanden unterzogen sich zunächst in randomisierter Reihenfolge einem Test zur Bestimmung der maximalen Laktatbildungsrate sowie der maximalen Sauerstoffaufnahme. Im Anschluss absolvierten die Testpersonen mehrere 30 minütige Dauertests zur empirischen Ermittlung der Leistung im MLSS. Die ermittelten Ergebnisse zeigen, dass zwischen beiden Testmethoden eine hochsignifikante Korrelation (r = 0,89; p< 0,001) sowie eine mittlere Differenz von -13 Watt vorliegt. Ausgehend von den ermittelten Ergebnissen kann der Schluss gezogen werden, dass die Leistung im MLSS, ermittelt unter Verwendung der Methode nach Mader (1984) im Mittel mit der empirisch ermittelten Leistung im MLSS sehr gut übereinstimmt. Neben der angeführten Hauptstudie, wurde in der vorliegenden Arbeit weiterhin die Reliabilität und Tag-zu-Tag-Variabilität der Leistung im MLSS, der Einfluss der Testdauer auf die Laktatbildungsrate sowie die Praktikabilität der berechneten Leistung im MLSS in einem Einzelzeitfahren näher untersucht.

Doctor of Philosophy / Department of Horticulture, Forestry, and Recreation Resources / Dale J. Bremer / Turfgrass covers 1.9% of the nation’s surface area and is the largest irrigated crop in the USA. Developed urbanized land is projected to double by 2025, which will increase turf’s environmental impact. Studies were conducted to evaluate environmental impacts by characterizing nitrogen, carbon, and water fluxes in turfgrass ecosystems. Emissions of nitrous oxide (N[subscript]2O), a major greenhouse gas and ozone depleter were measured from bermudagrass (Cynodon dactylon L. Pers. x C. transvaalensis Burtt-Davy) (bermuda), perennial ryegrass, (Lolium perenne L.) (rye), and zoysiagrass, (Zoysia japonica Steud.) (zoysia) under regional N management. In a separate study, N2O fluxes were measured from bermuda fertilized with controlled-release N fertilizers including polymer-coated and organic-N, and quick release urea. Emissions of N2O were measured using static surface chambers and gas chromatography. Zoysia, with less N requirements, had lower emissions than bermuda. Cumulative N[subscript]2O emissions were similar among N types. To measure water and carbon fluxes, a portable non-steady state chamber was designed and tested. The chamber had minimal affects to the canopy during field measurements: leak values averaged <1.5 micromol CO[subscript]2 m[superscript]-2 s[superscript]-1; average chamber pressure was 0.09 Pa ±0.01 Pa; temperature rise inside the chamber averaged 0.74C; and the chamber had 90% photosynthetically active radiation transmittance. Using the chamber, differences were detected in net photosynthesis (Pnet), gross photosynthesis (Pg), evapotranspiration (ET), canopy stomatal conductance (gc), and water use efficiency (WUE) in well-watered tall fescue (Festuca arundinacea Schreb.), Kentucky bluegrass (Poa pratensis L.) (KBG), zoysia, and bermuda. Irrigation requirements, visual quality ratings, and genetic rooting potential of 28 KBG cultivars and 2 Texas bluegrass hybrids (P. pratensis x P. arachnifera Torr.) were quantified in greenhouse and rainout facility studies. Average water applied ranged from 23.4 to 40.0 cm among cultivars. Bedazzled, Preakness, and Bartitia required less water and had higher average quality than other cultivars. Compact America and Mid-Atlantic phenotypes exhibited greatest potential for success in integrating reduced water inputs with maintenance of acceptable visual quality. Results indicated that turfgrass management could mitigate N[subscript]2O emissions and conserve water while maintaining healthy turfgrass, and the new chamber will enhance turfgrass studies by providing rapid measurements of photosynthesis.

This thesis describes the generic modeling of a Doubly-Fed Induction Generator (DFIG) based wind turbine. The model can also represent a wind plant with a group of similar wind turbines lumped together. The model is represented as a controlled current source which injects the current needed by the grid to supply the demanded real and reactive power. The DFIG theory is explained in detail as is the rationale for representing it by a regulated current source. The complete model is then developed in the time-domain and phasor domain by the interconnection of various sub-systems, the functions of which have been described in detail. The performance of the model is then tested for steady-state and dynamic operation. The model developed can be used for bulk power system studies and transient stability analysis of the transmission system. This thesis uses as its basis a report written for NREL [1]. / text

The main objective of this study is to explore the complex fluid flow phenomena that result in the generation of a high frequency noise in counterbalance valves through an experimental and numerical investigation of the flow. Once the influence of the different components involved in noise generation is established, a secondary objective is the introduction of design modifications that eliminate the undesired effect without altering the operation envelope or the performance of the valve. A hydraulic test bench was used to carry out an experimental investigation of the noise generation process. A computer based data acquisition system was used to record pressure fluctuations, flowrates and hydraulic oil temperatures in a production valve under a variety of operational conditions. Extensive experimental measurements and numerical modeling lead to the hypothesis that noise generation is the result of an acoustic resonance triggered by shear layer instability at the valve inlet. The pressure gradients developed when the shear layer entrains the stagnant fluid in the valve main cavity cause the layer to become unstable and oscillate. The oscillation frequency will depend on a great number of factors such as valve geometry, pressure and velocity gradients and the density and viscosity of the fluid. It is postulated that the observed noise is generated when this frequency matches one of the resonant frequencies of the valve cavity. The proposed mechanism is theoretically poorly understood and well beyond simplified analysis, its accurate numerical simulation is computational very intensive requiring sophisticated CFD codes. The numerical investigation was carried out using STAR–CCM+, a commercially available CFD code featuring 3-D capabilities and sophisticated turbulence modeling. Streamline, pressure, velocity-vector and velocity-scalar plots were obtained for several valve configurations using steady and unsteady state flow simulations. An experimental and numerical analysis of an alternative valve geometry was carried out. Experimental results demonstrated a greatly reduced instability range. The numerical analysis of the unsteady behavior of the shear-layer streamlines for both valves yielded results that were compatible with the experimental work. The results of this investigation promise a great positive impact on the design of this type of hydraulic valves.

The waste heat recovery technologies have become very relevant since many industrial plants continuously reject large amounts of thermal energy during normal operation which contributes to the increase of the production costs and also impacts the environment. The simulation programs used in industrial engineering enable development and optimization of the operational processes in a cost-effective way. The company Chematur Engineering AB, which supplies chemical plants in many different fields of use on a worldwide basis, was interested in the investigation of the possibilities for effective waste heat recovery from the hydrogenation of dinitrotoluene, which is a sub-process in the toluene diisocyanate manufacture plant. The project objective was to implement waste heat recovery by application of the Organic Rankine Cycle and the Absorption Refrigeration Cycle technologies. Modeling and design of the Organic Rankine Cycle and the Absorption Refrigeration Cycle systems was performed by using Aspen Plus® simulation software where the waste heat carrier was represented by hot water, coming from the internal cooling system in the hydrogenation process. Among the working fluids investigated were ammonia, butane, isobutane, propane, R-123, R-134a, R-227ea, R-245fa, and ammonia-water and LiBr-water working pairs. The simulations have been performed for different plant capacities with different temperatures of the hydrogenation process. The results show that the application of the Organic Rankine Cycle technology is the most feasible solution where the use of ammonia, R-123, R-245fa and butane as the working fluids is beneficial with regards to power production and pay-off time, while R-245fa and butane are the most sustainable choices considering the environment.

It is specifically important to focus on voltage stability analysis of the power system to avoid worst case scenarios such as voltage collapse. The purpose of this thesis is to identify methods for enhancing the steady-state voltage stability using FACTS devices and determining their impact on real and reactive power losses, improvement of bus voltage magnitude, and transmission line loadability. To achieve this, FACTS devices such as Static VAR Compensator (SVC), Static Synchronous Compensator (STATCOM), and Thyristor Controlled Series Capacitor (TCSC) are used in the test system as three separate test cases. The results obtained assist in drawing conclusions on the effectiveness of each FACTS devices at generator, load and swing buses, on lines between two load buses, and between a load bus and a generator bus, in terms of metrics such as voltage magnitude profile, PV curves, and active and reactive power losses.

Orientador: João Candido Fernandes / Banca: Edson Antonio Capello Sousa / Banca: Andrea Cintra Lopes / Resumo: O objetivo desta pesquisa foi determinar os níveis de atenuação de Dispositivos de Proteção Auditivos (DPAs), usando um teste chamado Resposta Auditiva de Estado Estável (RAEE). O teste RAEE é um exame eletrofisiológico que usa elétrodos para captar a atividade elétrica do tronco encefálico, sem depender da resposta do indivíduo, eliminando a subjetividade, assim como aspectos ligados à atenção, tempo de resposta, níveis de audição, etc. Neste método foram avaliados dez indivíduos, por meio da RAEE, estimulando-se o sistema de audição, primeiro sem protetor e, subsequentemente, com dois tipos de protetores auditivos, a saber um de inserção intra-auricular outro circunauricular de uso comum no mercado. Os resultados evidenciaram valores inferiores àqueles expressos no Certificado de Aprovação: para o plug, uma diferença de 10,3 dB, e para a concha, 4,3 dB. Na repetição dos testes, encontrou-se uma boa repetitividade, com diferença entre zero e 5 dB para 75% das frequências testadas. / Abstract: The purpose of this research was to determine the levels of attenuation of Hearing Protection Devices (HPDs) using a test called Auditory Steady-State Response (ASSR). The ASSR test is an electrophysiological examination that uses electrodes to capture the electrical activity of the auditory nerve and the brainstem without depending on the individual's response, thus eliminating the subjectivity of personal factors such as attention, response time, hearing ability, etc. This paper presents the results of a ten test which evaluated the hearing threshold of individuals, by first stimulating the hearing system without a protector and subsequently with a hearing protector. The results of this study were lower than those expressed in the Certificate of Approval: to plug a gap of 10.3 dB and dB the ear mufflers. The repetition of tests found a good repeatability with a difference between zero and 5 dB for 75% of the frequencies tested. / Mestre

A máxima fase estável do lactato (MFEL) é considerada uma intensidade critica em exercício dinâmico e sua intensidade é específica do grupo etário. No entanto, apesar da relação existente entre a intensidade de esforço e os ajustes cardiovasculares, metabólicos e ventilatórios durante o exercício resistido, a MFEL foi muito pouco estudada neste tipo de exercício. O objetivo do estudo foi verificar e comparar a existência de MFEL nos exercícios leg press (LP) e supino reto (SR) em dois grupos: jovens e idosos. Além disso, analisar o comportamento das variáveis ergoespirométricas (VE, VO2 e VCO2), lactacidemia, freqüência cardíaca (FC), pressão arterial (PA) e percepção subjetiva de esforço (PSE) na intensidade da MFEL. Foram avaliados 13 homens jovens (26,1 +/- 2,9 anos) e 11 idosos (68,9 +/- 4,0 anos) saudáveis e com experiência mínima de 6 meses em treinamento resistido, que passaram por teste de 1 repetição máxima (1RM), teste crescente para determinação do limiar anaeróbio (LAn) e mais três sessões para a determinação da MFEL. Todas as sessões foram realizadas no mesmo horário do dia, separadas por 48 a 72 horas de intervalo. O LAn, expresso em %1RM, foi significativamente superior no LP em relação ao SR para os dois grupos estudados (LP: 27,8 +/- 3,6 %1RM nos jovens e 27,9 +/- 5,0% 1RM nos idosos; SR: 24,0 +/- 3,0% 1RM nos jovens e 21,5 +/- 3,1% 1RM nos idosos). Não foram observadas diferenças estatisticamente significativas na intensidade do LAn entre os grupos em cada aparelho. A lactacidemia na intensidade do LAn foi significativamente inferior no LP (1,86 +/- 0,63 mmol/L nos jovens e 1,23 +/- 0,34 mmol/L nos idosos) em relação ao SR (2,08 +/- 0,41 mmol/L nos jovens e 1,91 +/- 0,40 mmol/L nos idosos). A intensidade da MFEL no grupo de jovens foi 29,2 +/- 6,7% 1RM no LP e 21,7 +/- 4,4% 1RM no SR. No grupo e idosos, a MFEL ocorreu a 30,9 +/- 4,9% 1RM no LP e 23,3 +/- 6,6% 1RM no SR. A MFEL ocorre em intensidade significativamente menor no aparelho SR para os dois grupos (p < ou = 0,05), sem diferenças estatisticamente significativas entre os grupos. Não houve diferença significativa entre as intensidades do LAn e da MFEL para os dois grupos nos dois aparelhos. Durante a realização do exercício na MFEL, ocorreu a estabilização dos parâmetros ergoespirométricos, FC, PA e PSE entre a série 9 e série 15. Estes resultados demonstram que é possível determinar MFEL nos exercícios LP e SR para as duas populações estudadas. A MFEL ocorre em intensidades superiores no exercício LP. A intensidade da MFEL, expressa em percentual de 1RM, é semelhante à intensidade do LAn. / The maximal lactate steady state (MLSS) is considered a critical intensity of dynamic exercise and its intensity is specific to the age group. However, despite the relationship between exercise intensity and cardiovascular, metabolic and ventilatory adjustments during resistance exercise, the MLSS was unknown in this type of exercise. The purpose of the study was to verify and to compare if there is a maximal lactate steady state (MLSS) for leg press (LP) and bench press (BP) exercises in two different groups: young and older people. Furthermore, to evaluate the ventilatory responses (VE, VO2 e VCO2, blood lactate concentration (BLC), heart rate (HR), blood pressure and rate of perceived exertion (RPE) to those exercises performed on MLSS intensity. 13 young men (26,1 +/- 2,9 years) and 11 elderly healthy men (68,9 +/- 4,0 years) with a minimal experience of 6 months of resistance training volunteered for the study. Volunteers underwent a 1 repetition maximum test (1RM), an incremental test to determine anaerobic threshold (AT) and three more sessions to determine MLSS. Session were performed on the same time of day and separated by a 48-72 h interval. AT intensity (%1RM) was significantly higher for LP than BP for the two groups studied (LP: 27,8 +/- 3,6% 1RM for young group and 27,9 +/- 5,0% 1RM for elderly; BP: 24,0 +/- 3,0%1RM for young group and 21,5 +/- 3,1%1RM for elderly). There was no significant difference between groups in the AT intensity. BLC on AT was significantly lower for LP (1,86 +/- 0,63 mmol/L for young group and 1,23 +/- 0,34 mmol/L for elderly) than BP (2,08 +/- 0,41 mmol/L for young and 1,91 +/- 0,40 mmol/L for elderly). MLSS intensity for young group was 29,2 +/- 6,7% 1RM in LP and 21,7 +/- 4,4% 1RM in BP. For elderly, MLSS was 30,9 +/- 4,9% 1RM in LP and 23,3 +/- 6,6% 1RM in BP. MLSS intensity was significantly lower in BP for both groups (p < or = 0,05), with no statistical differences between groups. There was no significant difference between AT and MLSS intensities on both groups. During exercise on MLSS, ventilatory parameters, HR, blood pressure and RPE stabilized between set 9 and set 15. These results show that it is possible to identify MLSS on the LP and BP exercises for both populations. MLSS intensity is higher in LP exercise, when compared to BP. MLSS intensity is similar to the AT intensity.

Neste trabalho, descrevemos vários protocolos para a geração de estados estacionários não clássicos, suportados principalmente pela engenharia de hamiltonianos seletivos Jaynes-Cummings, e de reservatórios atômicos. Começamos apresentando um protocolo para engenhar interações seletivas lineares e não lineares do tipo Jaynes-Cummings como também simulações numéricas para comprovar a eficácia de nosso esquema. Analisamos também como aplicar essas interações seletivas à preparação e proteção de estados de Fock estacionários via reservatório atômico. Esta estratégia combina a ação dos mecanismo de amortecimento da cavidade com os de um reservatório atômico engenhado para conduzir uma distribuição térmica inicial a um estado de Fock estacionário. A mesma técnica pode ser utilizada para fatiar as distribuições de probabilidade no espaço de Fock, permitindo assim a preparação de uma variedade de estados de equilíbrio não clássicos. Também apresentamos um protocolo para a engenharia de interações upper-bound e sliced Jaynes-Cummings e anti-Jaynes-Cummings na eletrodinâmica quântica de cavidade. No Hamiltoniano upper-bound, a interação átomo-campo está confinada a um subespaço de Fock com estados que vão desde &Iota;0&gt; até &Iota;4&gt; enquanto que no Hamiltoniano sliced vão desde &Iota;M&gt; até &Iota;M + 4&gt;. Mostramos como construir Liouvillianos upper-bound independentemente da engenharia do Hamiltoniano upper-bound. Os Hamiltonianos e Liouvillianos upper-bound e sliced podem ser usados, entre outras aplicações, para gerar estados de Fock estacionários no modo da cavidade e para a implementação de um dispositivo de tesoura quântica para truncagem de estado óptico. Finalmente, propomos um esquema para a preparação de estados emaranhados estacionários em redes bosônicas dissipativas. Descrevemos a sua aplicação em um sistema de cavidades acopladas interagindo com um reservatório construído por átomos de três níveis. Os emblemáticos estados Bell e NOON, e estados multipartites (tipo W) podem ser produzidos com alta fidelidade e pureza. / In this work, we describe various protocols for the generation of nonclassical steady-state, supported mainly by the engineering selective Hamiltonian Jaynes-Cummings-type, and atomics reservoirs. We started presenting a framework to engineer nonlinear selective JaynesCummings-type interactions with numerical simulations to prove the effectiveness of our scheme. We further analyses how to apply these selective interactions to the preparation and protection of steady Fock states via atomic reservoir. This strategy combines the action of cavity damping mechanisms with that of an engineered atomic reservoir to drive an initial thermal distribution to a Fock equilibrium state. The same technique can be used to slice probability distributions in the Fock space, thus allowing the preparation of a variety of non-classical equilibrium states. Also we present a protocol to engineer upper-bound and sliced Jaynes-Cummings-type and anti-Jaynes-Cummings-type Hamiltonians in cavity quantum electrodynamics. In the upper-bounded Hamiltonians, the atom-field interaction is confined to a subspace of Fock states ranging from &Iota;0&gt; up to &Iota;4&gt;, while in the sliced interaction the Fock subspace ranges from &Iota;M&gt; up to &Iota;M + 4&gt;. We also show how to build upper-bounded and sliced Liouvillians irrespective of engineering Hamiltonians. The upper-bounded and sliced Hamiltonians and Liouvillians can be used, among other applications, to generate steady Fock states of a cavity mode and for the implementation of a quantum-scissors device for optical state truncation. Finally we propose a scheme for the preparation of steady entanglements in bosonic dissipative networks. We describe its implementation in a system of coupled cavities interacting with an engineered reservoir built up of three-level atoms. Emblematic bipartite (Bell and NOON) and multipartite (W -class) states can be produced with high fidelity and purity.

Neste trabalho realizou-se uma analise detalhada das vantagens e desvantagens da sequencia de Precessao Livre no Estado Estacionario (Steady State Free Precession - SSFP) para aquisicao rapida de espectros de Ressonancia Magnetica Nuclear (RMN) de 13C. O regime de SSFP e obtido atraves da aplicacao de um trem de pulsos de mesma fase, duracao e intensidade, separados por um intervalo de tempo (Tp) menor que os tempos de relaxacao longitudinal (T1) e transversal (T2) da amostra. Nestas condicoes e possivel acumular dezenas de espectros por unidade de T1, proporcionando um incremento significativo na razao sinal/ruido (s/r) do espectro. Ao comparar os resultados obtidos com as sequencias de SSFP e convencional (pulsos de 90 graus e T 5T1 p >= ), verificou-se que a SSFP apresentou um ganho medio de 30 vezes no tempo de analise para uma mesma s/r. No entanto, os espectros obtidos com a SSFP apresentam anomalias de fase e amplitude do sinal, decorrente da refocalizacao da magnetizacao na forma de um eco de spin. Comparou-se tambem a SSFP com a sequencia padrao usada para obtencao de espectros de 13C, que utiliza pulsos de 30 graus e Tp = 1.38s. Neste caso os ganhos da SSFP foram menores (5,5 vezes no tempo de analise para uma mesma s/r) verificando que a sequencia padrao utiliza a vantagem da SSFP (Tp < T1, T2). A formacao do eco e, consequente das anomalias de fase nao sao observadas na sequencia padrao, pois a aquisicao do sinal e truncada em 0,9s, e a ciclagem de fase dos pulsos reduz a formacao do eco, por levar a uma perda de coerencia do sinal SSFP. Neste trabalho tambem analisou-se os metodos propostos por Rudakov, Freeman e Hill e Schwenk para supressao destas anomalias nos espectros de RMN 13C quando adquiridos no regime de SSFP. Os resultados demonstraram que a aplicacao destas metodologias proporciona uma melhora significativa na qualidade do espectro. No entanto, verificou-se que nenhum metodo foi capaz de suprimir totalmente as anomalias de fase e amplitude do sinal. / It was performed a detailed analysis of the advantages and disadvantages of Steady State Free Precession (SSFP) sequence for a rapid acquisition of 13C Nuclear Magnetic Resonance (NMR) spectra. The SSFP regime is obtained by the application of a pulse train with the same phase, duration and intensity, separated by a time interval (Tp) shorter than the transverse (T2) and longitudinal (T1) relaxation times. In these conditions it is possible to accumulate tens of spectra per units of T1, providing a significant increase in the spectrum signal-to-noise ratio (s/n). By comparing the spectra obtained by SSFP and conventional pulse sequence (90 degree pulse and T 5T1 p >= ) it was noted that SSFP shows an average gain of 30 times in analysis time for the same s/n. However, the SSFP spectra show phase and intensity anomalies due to the refocusing of the magnetization, generating a spin echo. We also compared the SSFP with the standard 13C pulse sequence, that uses a 30 degree pulses and Tp = 1.38 s. In this comparison the SSFP gain were small (5,5 times in analysis time for the same s/n), because the standard sequence also uses the advantage of SSFP (Tp < T1, T2). The echo signal and the phase anomalies are not observed in the standard sequence because the signal acquisition is truncated at 0.9s and the cycling of the pulse phase, that partially destroy the SSFP coherence. We also analyzed the methods proposed by Rudakov, Freeman and Hill and Schwenk to suppress those anomalies in the 13C NMR spectrum when acquired in SSFP regime. The results showed that the application of these methodologies provides a significant improvement in the spectrum quality. However, it was verified that none of the methods were able to completely eliminate the phase and intensity anomalies.