Concerns about the use of certain chemical species within the aerospace field are growing in recent years. A European regulation, REACh, now makes the use of hydrazine uncertain in – among others- attitude control thrusters. Green monopropellants, which are alternatives for this species already exist, but they all require a catalyst to react. Catalysts constitute the limiting factor for the lifespan of satellites because of the number of thermal cycles they endure. A joint project between ONERA, the French aerospace research center and CNES, the French space agency, was born to develop a high-performance green monopropellant thruster operating without any catalyst. Sizing the thruster and particularly its combustion chamber is not an easy task because of the explosive properties and the lack of knowledge regarding the monopropellant reaction process. The thesis aims at simulating the flow in a combustion chamber using CNES05, a new promising green monopropellant. This monopropellant has a very low vapor pressure and is an energetic liquid. As such, its reaction above a certain temperature -which is called decompositionis not well understood and must be observed closely. For this matter, a test bench was created, and it paved the way for the development of a specific model of decomposition. Indeed, even if the CNES05 decomposition cannot be modeled with the classical theory of isolated droplets, the setup showed us the order of magnitude of the reaction kinetics and the presence of a break up phenomenon. Using this model, the simulations of the flow inside the combustion chamber give us the heat flux profile through its walls, a sizing parameter for the thruster. Large recirculation zones are observed and the influence of the angle of injection seems to be the major injection parameter of influence. The sensitivity of the parameters used in the model is also studied.

Modeling the effects of surface roughness is an area of concern in many practical engineering applications. Many current roughness models to this point have involved the use of empirical 'constants' and equivalent sand grain roughness. These underdeveloped concepts have little direct relationship to realistic roughness and cannot predict accurately and consistently the flow characteristics for different roughness shapes. In order to aid in the development of turbulence models, the present research is centered around the experimental investigation of seven various shaped single roughness elements and their effects on turbulence quantities in a two-dimensional turbulent boundary layer. The elements under scrutiny are as follows: cone, cone with spatial variations equal to the smallest sublayer structure length scale, cone with spatial variations equal to 2.5 times the smallest sublayer structure length scale, Gaussian-shaped element, hemisphere, cube aligned perpendicular to the flow (cube at 90°), and a cube rotated 45° relative to the flow. The roughness element heights, k+, non-dimensionalized by the friction velocity (U_tau) of the approaching turbulent boundary layer, are 145, 145, 145, 145, 80, 98, and 98 respectively. Analysis of a three-dimensional fetch of the same Gaussian-shaped elements described previously was also undertaken. In order to analyze the complex flow fields, detailed measurements were obtained using a fine-measurement-volume (50 micron diameter) three-velocity component laser-Doppler velocimetry (LDV) system. The data reveals the formation of a horseshoe vortex in front of the element, which induces the downwash of higher momentum fluid toward the wall. This 'sweep' motion not only creates high Reynolds stresses (v^2, w^2, -uv) downstream of the element, but also leads to higher skin-friction drag. Triple products were also found to be very significant near the height of the element. These parameters are important in regards to the contribution of the production and diffusion of the turbulent kinetic energy in the flow. The 'peakiness' of the roughness element was found to have a direct correlation to the production of circulation, whereas the spatial smoothing does not have an immense effect on this parameter. The peaked elements were found to have a similar trend in the decay of circulation in the streamwise direction. These elements tend to show a decay proportional to (x/d)^-1.12, whereas the cube elements and the hemisphere do not have a common trend. A model equation is proposed for a drag correlation common to all roughness elements. This equation takes into account the viscous drag and pressure drag terms in the calculation of the actual drag due to the roughness elements presence in the boundary layer. The size, shape, frontal and wetted surface areas of the roughness elements are related to one another via this model equation. Flow drawings related to each element are presented which gives rise to a deeper understanding of the physics of the flow associated with each roughness element. / Master of Science

No description available.

Isolated inverter can provide galvanic isolation which is necessary for some applications with safety regulations. Traditionally, a two-stage configuration is widely applied with isolated dc-dc stage and a sinusoidal pulse-width-modulated (SPWM) dc-ac stage. However, this two-stage configuration suffers from more components count, more complex control and tend to have lower efficiency and lower power density. Meanwhile, a large dc bus capacitor is needed to attenuate the double line frequency from SPWM for two-stage configuration. Therefore, the single-stage approach including an isolated dc-rectified sine stage and a line frequency unfolder is preferable. Since the unfolder circuit is at line frequency being almost lossless, the isolated dc-rectified sine stage becomes critical. However, the relevant research for the single-stage isolated inverter is limited. People either utilize PWM based converter as dc-rectified sine stage with duty cycle adjustment or apply SRC or LLC resonant converter for better soft switching characteristics. For PWM based converter, hard switching restricts the overall inverter efficiency, while for SRC/LLC, enough wide voltage gain range and full range ZVS are the major issues. This dissertation aims to provide solutions for a high-efficiency, high-frequency resonant converter based single-stage soft-switching isolated inverter design. The LLC and LCLCL resonant converters are applied as the isolated dc-rectified sine stage with variable frequency modulation (VFM). Therefore, the rectified sine wave generation consists of many dc-dc conversion with different switching frequencies and an efficient dc-rectified sine stage design needs each dc-dc conversion to be with high efficiency. This dissertation will first propose the optimization methods for LLC converter dc-dc conversion. ZVS models are derived to ensure fully ZVS performance for primary side GaN devices. As a large part in loss breakdown, the optimization for transformer is essential. The LLC converter can achieve above 99% efficiency with proposed optimization approach. Moreover, the channel turn-off energy model is presented for a more accurate loss analysis. With all the design and optimization considerations, a MHz LLC converter based isolated inverter is designed and a hybrid modulation method is proposed, which includes full bridge (FB) VFM for output high line region and half bridge (HB) VFM for output low line region. By changing from FB to HB, the output voltage gain is reduced to half to have a wider voltage gain range. However, the total harmonic distortion (THD) of output voltage at light load will be impacted since the voltage gain will be higher with lighter load at the maximum switching frequency. A MHz LCLCL converter based isolated inverter is proposed for a better output voltage THD at light load conditions. The paralleled LC inside the LCLCL resonant tank can naturally create a zero voltage gain point at their resonant frequency, which shows superior performance for rectified sine wave generation. Besides the better THD performance, the LCLCL converter based isolated inverter also features for easier control, better ZVS performance and narrower switching frequency range. Meanwhile, the LCLCL based inverter topology has bi-directional power flow capability as well. With variable frequency modulation for ac-dc, this topology is still a single-stage solution compared to the traditional two-stage solution including PFC + LLC configuration. / Doctor of Philosophy / Inverters can convert dc voltage to ac voltage and typically people use two-stage approach with isolated dc-dc stage and dc-ac stage. However, this two-stage configuration suffers from more components count, more complex control and tend to have lower efficiency and lower power density. Therefore, the single-stage solution with dc-rectified sine wave stage and a line frequency unfolder becomes appealing. The unfolder circuit is to unfold the rectifier sine wave to an ac sine wave at the output. Since the unfolder is at line frequency and can be considered lossless, the key design is for the dc-rectified sine stage. The resonant converter featured for soft switching seems to be a good candidate. However, the inverter needs soft switching for the whole range and an enough wide voltage gain, which makes the design difficult, especially the target is high efficiency for the overall inverter. This dissertation aims to provide solutions for a high-efficiency, high-frequency resonant converter based single-stage soft-switching isolated inverter design. The LLC and LCLCL resonant converters are applied as the isolated dc-rectified sine stage with variable frequency modulation (VFM). Therefore, the rectified sine wave generation consists of many dc-dc conversion with different switching frequencies and an efficient dc-rectified sine stage design needs each dc-dc conversion to be with high efficiency. The design considerations and optimization methods for the LLC dc-dc conversion are firstly investigated. Based on these approaches, a MHz LLC converter based isolated inverter is designed with proposed hybrid modulation method. To further improve the light load performance, a MHz LCLCL converter based isolated inverter topology is proposed. The paralleled LC inside the LCLCL resonant tank can naturally create a zero voltage gain point which shows superior characteristics for rectified sine wave generation. Moreover, the LCLCL resonant converter based topology has bi-directional capability as well so it can work well for ac voltage to dc voltage conversion.

With the development of solar energy, power conversion systems responsible for energy delivering from photovoltaic (PV) modules to ac or dc grid attract wide attentions and have significantly increased installations worldwide. Modular power conversion system has the highest efficiency of maximum power point tacking (MPPT), which can transfer more solar power to electricity. However, this system suffers the drawbacks of low power conversion efficiency and high cost due to a large number of power electronics converters. High-power density can provide potentials to reduce cost through the reduction of components and potting materials. Nowadays, the power electronics converters with the conventional silicon (Si) based power semiconductor devices are developed maturely and have limited improvements regarding in power conversion efficiency and power density. With the availability of wide bandgap devices, the power electronics converters have extended opportunities to achieve higher efficiency and higher power density due to the desirable features of wide bandgap devices, such as low on-state resistance, small junction capacitance and high switching speed. This dissertation focuses on the application of wide bandgap devices to the dc-dc power conversion for the modular PV applications in an effort to improve the power conversion efficiency and power density. Firstly, the structure of gallium-nitride (GaN) device is studied theoretically and characteristics of GaN device are evaluated under testing with both hard-switching and soft-switching conditions. The device performance during steady-state and transitions are explored under different power level conditions and compared with Si based devices. Secondly, an isolated high-efficiency GaN-based dc-dc converter with capability of wide range regulation is proposed for modular PV applications. The circuit configuration of secondary side is a proposed active-boost-rectifier, which merges a Boost circuit and a voltage-doubler rectifier. With implementation of the proposed double-pulse duty cycle modulation method, the active-boost-rectifier can not only serve for synchronous rectification but also achieve the voltage boost function. The proposed converter can achieve zero-voltage-switching (ZVS) of primary side switches and zero-current-switching (ZCS) of secondary side switches regardless of the input voltages or output power levels. Therefore, the proposed converter not only keeps the benefits of highly-efficient series resonant converter (SRC) but also achieves a higher voltage gain than SRC and a wide range regulation ability without adding additional switches while operating under the fixed-frequency condition. GaN devices are utilized in both primary and secondary sides. A 300-W hardware prototype is built to achieve a peak efficiency of 98.9% and a California Energy Commission (CEC) weighted efficiency of 98.7% under nominal input voltage condition. Finally, the proposed converter is designed and optimized at 1-MHz switching frequency to pursue the feature of high-power density. Considering the ac effects under high frequency, the magnetic components and PCB structure are optimized with finite element method (FEM) simulations. Compared with 140-kHz design, the volume of 1-MHz design can reduce more than 70%, while the CEC efficiency only drops 0.8% at nominal input voltage condition. There are also key findings on circuit design techniques to reduce parasitic effects. The parasitic inductances induced from PCB layout of primary side circuit can cause the unbalanced resonant current between positive and negative half cycles if the power loops of two half cycles have asymmetrical parasitic inductances. Moreover, these parasitic inductances reflecting to secondary side should be considered into the design of resonant inductance. The parasitic capacitances of secondary side could affect ZVS transitions and increase the required magnetizing current. Because of large parasitic capacitances, the dead-time period occupies a large percentage of entire switching period in MHz operations, which should be taken into consideration when designing the resonant frequency of resonant network. / Doctor of Philosophy / Solar energy is one of the most promising renewable energies to replace the conventional fossils. Power electronics converters are necessary to transfer power from solar panels to dc or ac grid. Since the output of solar panel is low voltage with a wide range and the grid side is high voltage, this power converter should meet the basic requirements of high step up and wide range regulation. Additionally, high power conversion efficiency is an important design purpose in order to save energy. The existing solutions have limitations of narrow regulating range, low efficiency or complicated circuit structure. Recently, the third-generation power semiconductors attract more and more attentions who can help to reduce the power loss. They are named as wide band gap devices. This dissertation proposed a wide band gap devices based power converter with ability of wide regulating range, high power conversion efficiency and simple circuit structure. Moreover, this proposed converter is further designed for high power density, which reduces more than 70% of volume. In this way, small power converter can merge into the junction box of solar panel, which can reduce cost and be convenient for installations.

With the development of information technology, the market for power management of telecom and computing equipment keeps increasing. Distributed power systems are widely adopted in the telecom and computing applications for the reason of high performance and high reliability. Recently industry brought out aggressively high efficiency requirements for a wide load range for power management in telecom and computing equipment. High efficiency over a wide load range is now a requirement. On the other hand, power density is still a big challenge for front-end AC/DC converters. For DPS systems, front-end AC/DC converters are under the pressure of continuous increasing power density requirement. Although increasing switching frequency can dramatically reduce the passive component size, its effectiveness is limited by the converter efficiency and thermal management. Technologies to further increase the power density without compromising the efficiency need to be studied. The industry today is also at the beginning of transferring their design from analog control to full digital control strategy. Although issues are still exist, reducing components count, reducing the development cycle time, increasing the reliability, enhancing the circuit noise immunity and reducing the cost, all of these benefits indicate a great potential of the digital control. This thesis is focusing on how to improve the efficiency and power density by taking the advantages of the digital control. A novel Ï /2 phase shift two Channel interleaving PFC is developed to shrink the EMI filter size while maintain a good efficiency. A sophisticated power management strategy that associates with phase shedding and adaptive phase angle control is also discussed to increase the efficient for the entire load range without compromising the EMI filter size. The method of current sampling is proposed for Ï /2 phase shift two Channel interleaving PFC and multi-channel adaptive phase angle shift PFC is proposed to accurately extract the average total current information. A noise free current sampling strategy is also proposed that adjusting the sampling edge according to duty cycle information. An isolated ZVS dual boost converter is proposed to be the DC/DC stage of the front-end converter. This PWM converter has similar performance as the LLC resonant converter. It has hold up time extension capability without compromising the normal operation efficiency. It can achieve ZVS for all the switches. The current limit and SR implementation is much easier than LLC. State plane method, which potentially can be extent to other complex topologies, is used to fully study this circuit. All the operation modes are understood through the state plane method. The best operation mode is discovered for the front end applications. Light load efficiency is improved by the proposed pulse skipping method to guarantee the ZVS operation meanwhile reduce the switching frequency. Current limit operation is also proposed to restrict a best operation mode by fully taking the advantage of digital control that precisely control the circuit under the over current condition. High efficiency high power density is achieved by new topology, innovative interleaving, and the sophisticated digital control method. / Master of Science

<p dir="ltr">Increased scrutiny from customers and regulators to design aeroengines that are more efficient and environmentally friendly has pushed the need to investigate new engine architectures, manufacturing techniques, and computational fluid dynamic methods. This has led to the development of the CSTAR Gen. 2.5 centrifugal compressor, which uses an additively manufactured diffusion system and investigates the aerodynamic performance of an axi-centrifugal aeroengine. Additionally, an isolated unsteady diffuser computational model was previously developed that seeks to significantly reduce the computational cost of unsteady CFD in the diffuser.</p><p dir="ltr">The research presented in this paper is part of an ongoing attempt to utilize the capabilities of isolated unsteady diffuser modeling and rapid prototyping enabled through additive manufacturing in CSTAR Gen. 2.5 to develop a design framework that allows for quick computational and experimental analysis of diffusion systems in centrifugal compressors. Specifically, the scope of isolated unsteady diffuser modeling, which was previously only implemented in CSTAR Gen. 1 and at a single loading condition, is expanded by analyzing computational instabilities when applying the methodology to CSTAR Gen. 2.5 and analyzing results from four loading conditions (high loading, design point, low loading, and near choke) along a speedline.</p><p dir="ltr">Computational instabilities in the CSTAR Gen. 2.5 isolated diffuser models were determined to be caused by the decreased vaneless space compared to Gen. 1, which led to less “mixed” flow at the impeller outlet and a stronger diffuser potential field affecting the inlet profile. A boundary profile correction approach was developed which slightly increased very low total pressure near the diffuser shroud and negative radial velocity regions near the shroud and pitchwise locations of the diffuser vane leading edges while minimizing the overall affected area. The correction was successfully validated using 3D flow structure and minimum, average, and maximum total pressure, absolute velocity magnitude, and pressure comparisons at the diffuser inlet between an isolated and full-stage model.</p><p dir="ltr">Prediction capabilities of 3D flow structures and 1D performance parameters by isolated unsteady diffuser models were validated with results from full-stage unsteady models at each loading condition. The analysis indicated consistent performance by the isolated unsteady diffuser model at all loading conditions. An overall agreement in 3D flow structures was found, and trends in the full-stage unsteady models along the speedline were tracked well by the isolated unsteady model. At all loading conditions, there was a consistent over-representation of the separation region along the diffuser vane pressure side in the diffuser passage, overprediction of total pressure magnitude at the core of the flow at the diffuser outlet, and over- or underprediction of total pressure loss and static pressure recovery respectively. The similarity in the results between full-stage and isolated unsteady models, tracking of trends along the speedline, and consistent differences in 3D flow structure predictions and 1D performance parameters validates the isolated unsteady diffuser methodology for use at loading conditions from surge to choke.</p>

[ES] De forma general, el trabajo realizado durante la presente tesis doctoral se ha enfocado al diseño y optimización de catalizadores heterogéneos basados en Pd y Ru soportado sobre óxidos metálicos y materiales carbonosos. A fin de optimizar los catalizadores se han relacionado los ensayos catalíticos con las propiedades físico-químicas de los materiales mediante diferentes técnicas (XPS, HAADF-STEM, Fotoluminiscencia, IR, ¿) siguiendo un proceso iterativo de ensayo-caracterización-optimización. En concreto, la presente tesis doctoral se puede dividir en dos partes en función de las reacciones estudiadas: 1. Durante la primera parte, capítulo 3, se han preparado catalizadores basados en Au, Pd y Pd(OH)2 soportado sobre diferentes óxidos metálicos con objeto de realizar el homoacoplamiento oxidativo de benzoato de metilo en ausencia de disolvente y empleando oxígeno como único agente oxidante. Se ha conseguido identificar la especie activa como clústeres de Pd mediante el empleo de espectroscopia de infrarrojo de adsorción de CO y fotoluminiscencia. Con este conocimiento se ha podido diseñar un pre-tratamiento de activación específico para maximizar la actividad catalítica con el cual se ha logrado obtener un rendimiento catalítico similar al del catalizador homogéneo de Pd(OAc)2. 2. En la segunda parte de la tesis, se ha estudiado la hidroformilación de 1-hexeno empleando catalizadores alternativos basados en Ru. En particular, durante el capítulo 4 se han desarrollado catalizadores de Ru soportados sobre una matriz orgánica-inorgánica compuesta por un biopolímero natural, quitosán, y SiO2 detectándose un efecto sinérgico entre las especies lixiviadas de Ru (TON > 3000, TOF > 550 h-1) y los grupos funcionales del quitosán que ha sido estudiado mediante espectroscopia de absorción de rayos-X. Finalmente, el objetivo del capítulo 5 ha sido estabilizar las especies de Ru mediante un tratamiento térmico de pirólisis. Empleando un biopolímero natural se ha conseguido diseñar un catalizador estable, capaz de hidroformilar selectivamente el enlace terminal de olefinas de diferente tamaño de cadena con alta regioselectividad (S > 90%) que puede ser re-usado. Gracias al uso de técnicas espectroscópicas avanzadas se ha podido relacionar la actividad intrínseca de las especies de Ru soportadas identificándose a los átomos aislados de Ru como los más activos (TOF > 12.000 h-1). / [CA] This doctoral thesis has focused on the design and optimization of heterogeneous Pd and Ru catalysts supported on metallic oxides and carbon materials. In order to optimize the catalysts a relationship has been stablished between the observed reaction kinetics and the physico-chemical properties of the materials by means of different characterization techniques (XPS, HAADF-STEM, photoluminescence, IR ¿) following an iterative kinetic test-characterization-optimization process. In particular, this thesis can be divided in two different parts depending on the reaction studied: 1. In chapter 3, different catalysts based on Au, Pd and Pd(OH)2 supported on a variety of mixed oxides have been prepared with the aim of performing the oxidative homocoupling of methyl benzoate in absence of solvent with molecular oxygen as the only oxidising agent. In this case, Pd clusters have been identified as the active species by means of photoluminescence and infrared spectroscopy using CO as probe molecule. After identifying the active species, a specific activation pre-treatment could be designed in order to maximize the catalytic activity which is on par with the homogeneous Pd(OAc)2 counterpart. 2. In the next chapter (Chapter 4), the hydroformylation of 1-hexene using alternative Ru based catalysts was studied. In particular, a series of hybrid organic-inorganic Ru catalysts composed of a natural biopolymer, chitosan, and SiO2 were developed which showed and interesting synergistic effect between the lixiviated species of Ru and the functional groups of chitosan. This effect was studied by X-ray absorption spectroscopy. The catalyst showed a high activity (TON > 3000 and TOF > 550 h-1) as well as a high regioselectivity towards formation of lineal aldehyde (S > 95%). 3. Finally, the objective of chapter 5 was to go one step further trying to stabilize the Ru species observed in previous chapter by means of a pyrolytic thermal treatment. Thus, with the aid of a natural biopolymer and a carbonaceous support the goal of designing a reusable and stable catalyst, able to selectively catalyse the hydroformylation of terminal olefins with variable chain length and high regioselectivity (S > 90%) towards the lineal aldehyde was successfully achieved. In this case, the intrinsic activity of the different Ru supported entities was studied by advanced spectroscopy techniques allowing the identification of isolated single Ru atoms as the most active catalytic centers (TOF > 12000 h-1) / [EN] En general, el treball realitzat durant la present tesi doctoral s'ha centrat en l'optimització de catalitzadors heterogenis basats en Pd i Ru suportat sobre òxids metàl·lics i materials carbonacis. Amb l'objectiu d'optimitzar els catalitzadors, s'ha establert una relació entre els resultats dels experiments catalítics i les propietats fisicoquímiques dels materials mitjançant la utilització de diferents tècniques (XPS, HAADF - STEM, fotoluminescència, IR,...) seguint un esquema iteratiu d'assaig - caracterització - optimització. En concret, la present tesi doctoral es pot dividir en dos parts, en funció de les reaccions estudiades: 1. En la primera part, capítol 3, s'han preparat catalitzadors basats en Au, Pd i Pd(OH)2 suportat sobre diferents òxids metàl·lics amb l'objectiu de realitzar la reacció d'homoacoblament oxidatiu del benzoat de metil en absència de dissolvent i utilitzant oxigen com a únic agent oxidant. S'ha aconseguit identificar els clústers de Pd com a espècies actives de la reacció gràcies a l'espectroscòpia d'infraroig d'adsorció de CO i a la fotoluminescència. D'aquesta forma, s'ha pogut dissenyar un pretractament d'activació específic per aconseguir maximitzar l'activitat catalítica. S'han aconseguit obtenir uns valors de rendiment catalític similars al presentats pel catalitzador homogeni Pd(OAc)2. 2. En la segona part de la tesi, s'ha estudiat la hidroformilació de l'1-hexè utilitzant catalitzadors alternatius basats en Ru. En concret, en el capítol 4, s'han desenvolupat catalitzadors de Ru suportats sobre una matriu orgànica - inorgànica constituïda per un biopolímer natural, quitosan, i SiO2. Així doncs, s'ha pogut detectar un efecte sinèrgic entre les espècies lixiviades de Ru (TON > 3000 and TOF > 550 h-1) i els grups funcionals del quitosan. Dit efecte s'ha estudiat per mitjà de l'espectroscòpia d'absorció de rajos X. Finalment, l'objectiu del capítol 5 ha consistit en estabilitzar les espècies de Ru per mitjà d'un tractament tèrmic de piròlisis. Utilitzant un biopolímer natural, s'ha aconseguit dissenyar un catalitzador estable, capaç d'hidroformilar selectivament i amb una elevada regioselectivitat (S> 90%) l'enllaç terminal d'olefines de diferent longitud; i poder ésser posteriorment reutilitzat. A partir de tècniques d'espectroscòpia avançades, s'ha pogut relacionar l'activitat intrínseca de les espècies de Ru suportades, i s'han identificat els àtoms aïllats de Ru com aquelles espècies més actives (TOF > 12.000 h-1). / Escobar Bedia, FJ. (2021). Catalizadores metálicos subnanométricos altamente eficientes en reacciones de formación de enlaces C-C [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172628

BACKGROUND: Clinical evidence shows that diabetes may provoke uncontrolled blood pressure (BP) in hypertensive patients. However, racial differences in the associations of diabetes with uncontrolled BP outcomes among diagnosed hypertensive patients have not been evaluated. METHODS: A total of 6,134 diagnosed hypertensive subjects aged ≥ 20 years were collected from the National Health and Nutrition Examination Survey 1999-2008 with a stratified multistage design. Odds ratios (ORs) and relative ORs of uncontrolled BP and effect differences in continuous BP for diabetes over race/ethnicity were derived using weighted logistic regression and linear regression models. RESULTS: Compared with participants who did not have diabetes, non-Hispanic black participants with diabetes had a 138% higher chance of having uncontrolled BP, Mexican participants with diabetes had a 60% higher chance of having uncontrolled BP, and non-Hispanic white participants with diabetes had a 161% higher chances of having uncontrolled BP. The association of diabetes with uncontrolled BP was lower in Mexican Americans than in non-Hispanic blacks and whites (Mexican Americans vs. non-Hispanic blacks: relative OR = 0.55, 95% confidence interval (CI) = 0.37-0.82; Mexican Americans vs. non-Hispanic whites: relative OR = 0.53, 95% CI = 0.35-0.80) and the association of diabetes with isolated uncontrolled systolic BP was lower in Mexican Americans than in non-Hispanic whites (Mexican Americans vs. non-Hispanic whites: relative OR = 0.62, 95% CI = 0.40-0.96). Mexican Americans have a stronger association of diabetes with decreased systolic BP and diastolic BP than non-Hispanic whites, and a stronger association of diabetes with decreased diastolic BP than non-Hispanic blacks. CONCLUSIONS: The association of diabetes with uncontrolled BP outcomes is lower despite higher prevalence of diabetes in Mexican Americans than in non-Hispanic whites. The stronger association of diabetes with BP outcomes in whites should be of clinical concern, considering they account for the majority of the hypertensive population in the United States.

The axiomatic theory of ` Zelazko defines a variety of general spectra where specified axioms are satisfied. However, there arise a number of spectra, usually defined for a single element of a Banach algebra, that are not covered by the axiomatic theory of ` Zelazko. V. Kordula and V. M¨uller addressed this issue and created the theory of regularities. Their unique idea was to describe the underlying set of elements on which the spectrum is defined. The axioms of a regularity provide important consequences. We prove that the set of Koliha-Drazin invertible elements, which includes the Drazin invertible elements, forms a regularity. The properties of the spectrum corresponding to a regularity are also investigated. / Mathematical Sciences / M. Sc. (Mathematics)