Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents the development, experimentation and validation of a reliable and robust system to monitor the injector pulse generated by an Engine Control Module (ECM) and send the corresponding fueling quantity to the real-time computer in a closed loop Hardware In the Loop (HIL) bench. The system can be easily calibrated for different engine platforms as well. The fueling quantity that is being injected by the injectors is a crucial variable to run closed loop HIL simulation to carry out the performance testing of engine, aftertreatment and other components of the vehicle. This research utilized Field Programmable Gate Arrays (FPGA) and Direct Memory Access (DMA) transfer capability offered by National Instruments (NI) Compact Reconfigurable Input-Output (cRIO) to achieve high speed data acquisition and delivery. The research was conducted in three stages. The first stage was to develop the HIL bench for the research. The second stage was to determine the performance of the system with different threshold methods and different sampling speeds necessary to satisfy the required accuracy of the fueling quantity being monitored. The third stage was to study the error and its variability involved in the injected fueling quantity from pulse to pulse, from injector to injector, between real injector stators and cheaper inductor load cells emulating the injectors, over different operating conditions with full factorial design of experimentation and mixed model Analysis Of Variance (ANOVA). Different thresholds were experimented to find out the best thresholds, the Start of Injection (SOI) threshold and the End of Injection (EOI) threshold that captured the injector “ontime” with best reliability and accuracy. Experimentation has been carried out at various data acquisition rates to find out the optimum speed of data sampling rate, trading off the accuracy of fueling quantity. The experimentation found out the expected error with a system with cheaper solution as well, so that, if a test application is not sensitive to error in fueling quantity, a cheaper solution with lower sampling rate and inductors as load cells can be used. The statistical analysis was carried out at highest available sampling rate on both injectors and inductors with the best threshold method found in previous studies. The result clearly shows the factors that affect the error and the variability in the standard deviations in error; it also shows the relation with the fixed and random factors. The real-time application developed for the HIL bench is capable of monitoring the injector waveform, using any fueling ontime table corresponding to the platform being tested, and delivering the fueling quantity in real-time. The test bench made for this research is also capable of studying injectors of different types with the automated test sequence, without occupying the resource of fully capable closed loop test benches for testing the ECM unctionality.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis focuses on optimization of wind power tracking control systems in order to capture maximum wind power for the generation system. In this work, a mathematical simulation model is developed for a variable speed wind turbine power generation system. The system consists a wind turbine with necessary transmission system, and a permanent magnet synchronous generator and its vector control system. A new fuzzy based hill climbing method for power tracking control is proposed and implemented to optimize the wind power for the system under various conditions. Two existing power tracking control methods, the tip speed ratio (TSR) control method and the speed sensorless control method are also implemented with the wind power system. The computer simulations with a 5 KW wind power generation system are performed. The results from the proposed control method are compared with those obtained using the two existing methods. It is illustrated that the proposed method generally outperforms the two existing methods, especially when the operating point is far away from the maximum point. The proposed control method also has similar stable characteristic when the operating point is close to the peak point in comparison with the existing methods. The proposed fuzzy control method is computationally efficient and can be easily implemented in real-time.

Thèse de doctorat présentée en vue de l'obtention du doctorat en psychologie - recherche intervention, option neuropsychologie clinique (Ph.D) / Les oscillations endogènes cérébrales sont associées à des fonctions cognitives spécifiques et jouent un rôle important dans la communication entre les différentes régions corticales et sous-corticales. Les rythmes alpha (8-12 Hz) et bêta (13-30 Hz) ont été observés de façon dominante dans les aires sensorimotrices, avec des moyennes de fréquence autour de 10 et 20 Hz, et jouent un rôle dans les fonctions motrices. Ces oscillations cérébrales peuvent être entrainées par une stimulation externe, notamment par la stimulation électrique transcrânienne par courant alternatif (SEtCA). Ainsi, la SEtCA de 10 et 20 Hz a un effet sur certaines mesures physiologiques comme l’excitabilité corticospinale et la puissance des oscillations via la stimulation magnétique transcrânienne (SMT) et l’électroencéphalogramme (EEG), respectivement. Toutefois, les effets post-stimulation sont variables et parfois incohérents. De plus, à ce jour, aucune étude n’a mesuré les effets physiologiques d’une stimulation bilatérale sensorimotrice tant sur l’activité locale que sur l’interaction entre les deux aires sensorimotrices. Les articles composant le présent ouvrage visent à explorer les effets post-stimulation de deux fréquences de stimulation, soit 10 Hz et 20 Hz, sur les régions sensorimotrices à l’aide d’un montage SEtCA bilatéral. Ce travail de recherche s’est effectué à travers une revue de la littérature ainsi que deux études avec des paramètres méthodologiques relativement similaires, mais avec des mesures différentes et complémentaires de SMT et d’EEG. L’article 1 sert d’assise à la pertinence de l’évaluation de la connectivité entre le cortex moteur et les différentes aires du cerveau. Cet excursus recense et décrit les différents protocoles de stimulation magnétique pairée qui ont été développés au cours des dernières années afin d’évaluer la connectivité effective entre les aires sensorimotrices du cerveau. L’article 2 montre que la SEtCA bilatérale à 10 Hz a permis de réduire l’excitabilité corticospinale via la SMT après la stimulation. La fréquence bêta de 20 Hz n’a cependant mené à aucun changement. De plus, la SEtCA n’a pas modulé de façon significative les mesures d’interaction entre les régions sensorimotrices, telles l’inhibition interhémisphérique et les mouvements miroirs physiologiques. Dans l’article 3, les résultats démontrent que la SEtCA bilatérale à 10 et 20 Hz appliquée sur les aires sensorimotrices peut modifier la puissance des oscillations alpha et bêta après la stimulation. Notons que les résultats étaient associés à une variabilité interindividuelle qui est également rapportée dans la littérature. Ces résultats peuvent avoir des implications dans la conception de protocoles visant à induire des changements persistants dans l'activité cérébrale. / Endogenous brain oscillations are associated with specific cognitive functions and are known to have an important role in regimenting communication between cortical and subcortical areas. Alpha (8-12 Hz) and beta (13-30 Hz) rhythms have been observed predominantly in sensorimotor areas, with averages around 10 and 20 Hz, and are believed to play a role in motor functions. These cerebral oscillations can be entrained by external stimulation, in particular by transcranial alternating current stimulation (tACS). Thus, tACS has shown an impact on certain physiological measures such as corticospinal excitability and the power of oscillations via transcranial magnetic stimulation (TMS) and electroencephalogram (EEG), respectively. However, the after-effects are variable and incoherent. In addition, to date no study has measured the physiological effects of a bilateral sensorimotor stimulation montage on both local activity and the interaction between the two sensorimotor areas. Thus, the studies included in the present thesis aim to explore the after-effects of two stimulation frequencies, 10 Hz and 20 Hz, on sensorimotor regions using a bilateral montage. This research was carried out through a review of the literature as well as two methodological studies with relatively similar parameters, but using different and complementary measures of TMS and EEG. Article 1 provides a basis for the relevance of assessing the connectivity between the motor cortex and different areas of the brain. This excursus identifies and describes the different paired magnetic stimulation protocols that have been developed in recent years to assess the effective connectivity between sensorimotor areas of the brain. Study 2 shows that bilateral 10 Hz tACS significantly reduced corticospinal excitability via TMS after stimulation. However, the 20 Hz frequency did not lead to any change. In addition, tACS did not significantly modulate measures of interaction between sensorimotor regions, such as interhemispheric inhibition and physiological mirror movements. In study 3, the results failed to demonstrate reliably that bilateral tACS at 10 and 20 Hz administered over sensorimotor areas could modulate offline alpha and beta oscillations power at the stimulation site. Note that the results were associated with inter-individual variability, which is also reported in the literature. These findings may have implications for the design and implementation of future protocols aiming to induce sustained changes in brain activity.

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L'objectif de cette thèse est de fournir une meilleure compréhension des différents phénomènes physiques liés aux microplasmas/microdécharges. Pour cela, des matrices de microréacteurs sur silicium ont été étudiées. De nombreuses configurations ont été construites de manière à analyser l’influence de chaque paramètre physique sur le fonctionnement de ces dispositifs. Le présent travail porte sur l'élaboration et la caractérisation de dispositifs micro-décharge à base de silicium. Dans ce travail de thèse, les régimes de courant continu (DC) et de courant alternatif (AC) sont étudiés en utilisant des configurations de décharges différentes. Pour la fabrication de ces réacteurs, nous sommes partis de wafers de Silicium que nous avons structurés et traités en salle blanche. La technologie de fabrication utilisée est compatible avec les méthodes de fabrication de dispositifs CMOS. Les microréacteurs sont constitués d’électrodes de nickel et de silicium séparés par une couche diélectrique de SiO2 de 6 μm d’épaisseur. L’épaisseur du diélectrique est ici beaucoup plus faible que celle des microréacteurs étudiés jusqu’à présent. Les dispositifs sont constitués de cavités de 25 à 150 microns de diamètre. Les essais de microdécharge ont été effectués dans des gaz inertes à une pression comprise entre 100 et 1000 Torrs. Nous avons d’abord étudié les phénomènes d’allumage et d’extinction à partir de microdispositifs monocavité en alumine. Puis, nous avons étudié le fonctionnement en DC/AC de microréacteurs en silicium comportant un nombre de cavité compris entre 1 et1024. Les caractéristiques des microdécharges ont été étudiées grâce à des mesures électriques, des mesures de spectroscopie d'émission optique (OES), de spectroscopie d’absorption à diode laser (DLAS) et de spectroscopie d'émission optique résolue en temps (PROES). Ces différents diagnostics nous ont permis de mettre en évidence les phénomènes d’allumage, d’extinction, d’instabilité et les mécanismes de défaillance de nos microdispositifs. Ce travail de thèse a permis de tester les performances et les limites technologiques des matrices de microdécharges sur silicium. Une attention particulière a été portée sur leur durée de vie. / The objective of this thesis is to provide a better understanding of various physical phenomena related to microplasmas/microdischarges. For this purpose, arrays of microreactors on silicon were studied. Different array configurations were fabricated to analyse the influence of each parameter on the physical operation of these devices. The present work focuses on the development and characterisation of micro-discharge devices based on silicon. In this thesis, direct current (DC) and alternating current (AC) regimes are studied using different discharge configurations. For the fabrication of these reactors, Silicon wafers are structured and processed in a cleanroom. Fabrication technology used is compatible with the CMOS technology. The microreactors are fabricated with nickel and silicon electrodes, separated by a dielectric layer of SiO2 with a thickness of 6 μm. The thickness of the dielectric is much lower here than the microreactors studied so far. The devices consist of cavities with 25 to 150 μm in diameter. Experiments of the microdischarges are performed in inert gases at a pressure between 100 and 1000 Torr. We first studied the phenomena of ignition and extinction for the microdevices based on alumina. Then, we studied the microreactors based on silicon containing 1 to 1024 cavities under DC and AC regimes. Characteristics of microdischarges were studied by electrical measurements, measurements of optical emission spectroscopy (OES), laser diode absorption spectroscopy (DLAS) and phase resolved optical emission spectroscopy (PROES). These diagnostics allowed us to investigate the phenomena of ignition, extinction, instability and failure mechanisms of the microplasma devices. This thesis work allowed testing the performance and technological limitations of the silicon based microdischarge arrays. Particular attention was paid to their life time.

The objective of this thesis is to provide a better understanding of various physical phenomena related to microplasmas/microdischarges. For this purpose, arrays of microreactors on silicon were studied. Different array configurations were fabricated to analyse the influence of each parameter on the physical operation of these devices. The present work focuses on the development and characterisation of micro-discharge devices based on silicon. In this thesis, direct current (DC) and alternating current (AC) regimes are studied using different discharge configurations. For the fabrication of these reactors, Silicon wafers are structured and processed in a cleanroom. Fabrication technology used is compatible with the CMOS technology. The microreactors are fabricated with nickel and silicon electrodes, separated by a dielectric layer of SiO2 with a thickness of 6 μm. The thickness of the dielectric is much lower here than the microreactors studied so far. The devices consist of cavities with 25 to 150 μm in diameter. Experiments of the microdischarges are performed in inert gases at a pressure between 100 and 1000 Torr. We first studied the phenomena of ignition and extinction for the microdevices based on alumina. Then, we studied the microreactors based on silicon containing 1 to 1024 cavities under DC and AC regimes. Characteristics of microdischarges were studied by electrical measurements, measurements of optical emission spectroscopy (OES), laser diode absorption spectroscopy (DLAS) and phase resolved optical emission spectroscopy (PROES). These diagnostics allowed us to investigate the phenomena of ignition, extinction, instability and failure mechanisms of the microplasma devices. This thesis work allowed testing the performance and technological limitations of the silicon based microdischarge arrays. Particular attention was paid to their life time.

Numerical cognition has been shown to share many aspects of spatial cognition, both behavioural and neurological. However, it is unclear whether a particular type of spatial cognition, visuospatial mental imagery (VSMI), may play a role in symbolic numerical representation. In this thesis, I first show that mental rotation, a form of VSMI, is related to two measures of basic numerical representation. I then show that number-space synaesthesia (NSS), a rare type of VSMI involving visualised spatial layouts for numbers, does not show an advantage in mental rotation, but shows interference in number line mapping. I next present a study investigating links between NSS and the ability to learn novel numerical symbols. I demonstrate that NSS shows an advantage at learning novel numerals, and that transcranial random noise stimulation, which increases cortical excitability, confers broadly similar advantages that nonetheless differ in subtle ways. I present a study of transcranial alternating current stimulation on the same symbol learning paradigm, which fails to demonstrate effects. Lastly, I present data showing that strength of numerical representation in these newly-learnt symbols is correlated with a measure of mental rotation, and also with visual recognition ability for the symbols after, but not before, training. All together, these findings suggest that VSMI does indeed play a role in numerical cognition, and that it may do so from an early stage of learning symbolic numbers.

This thesis deals with a power flow control in the electric power system. An overview of FACTS devices is introduced; their basic characteristics as well as examples of their application are discussed. A significant part of this thesis investigates phase shifting transformers (PST´s), which seem to be suitable for implementation in the transmission system of the Czech Republic. The PST´s are useful devices that control active power flows on cross-border lines and regulate unwanted and unexpected power flows. Basic types and characteristics of the PST´s are discussed. In chapter 7 is designed laboratory task that should validate the regulatory capabilities of the transformer PST. Designs of models of individual parts of this laboratory task are presented. In the last part of this thesis the regulation effect of the PST is validated in the GLF/AES program.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis proposes a family of non-isolated bidirectional converter in order to interface dc and ac variables. Such power electronics solutions guarantee: (i) bidirectional power flow between dc and ac converter sides, (ii) independent control in both converter sides, (iii) high level of integration with a reduction of one power switch and its drive circuits, (iv) implementation of two functions by using a unique power conversion stage and (v) reduction of the capacitor losses. Despite proposing new power converter solutions, this thesis presents an analysis of the converters in terms of pulse-width-modulation (PWM) strategy, dc-link capacitor variables, and suitable a control approach. Solutions for single-phase, three-phase and three-phase four-wire systems are proposed by employing a converter leg with three switches. A possible application of this converter is in Vehicle-to-Grid (V2G) systems and interfacing dc microgrid with a utility grid. In addition to the new power electronics converters proposed in this thesis, an experimental setup has been developed for validation of the simulated outcomes. The proof-of-concept experimental setup is constituted by: DSP, Drivers & Integrating Board, Power Supply and, Power Converter & Heat-Sink .

The main goal of this thesis is to get an insight into a field of non-destructive testing using potential drop techniques that have nowadays become the standard not only in the fatigue and loading tests but also in the industry. These methods can serve to non-destructively and continuously measure material specimens, thickness, corrosion losses, deformations, spectroscopy and detection and analysis of crack geometry. They can help to identify materials and measure material changes over time. The second part of this thesis deals with designing the aperture for detection of cracks in steam and product piping using potential drop technique modified by Ing. Ladislav Korec, CSc. Last part deals with extensive testing, experimenting and evaluation of the aperture.