This work is part of an effort to develop an unstructured, three-dimensional, direct simulation Monte Carlo/particle-in-cell (DSMC/PIC) code for the simulation of non-ionized, fully ionized and partially-ionized flows in micropropulsion devices. Flows in microthrusters are often in the transitional to rarefied regimes, requiring numerical techniques based on the kinetic description of the gaseous or plasma propellants. The code is implemented on unstructured tetrahedral grids to allow discretization of arbitrary surface geometries and includes an adaptation capability. In this study, an existing 3D DSMC code for rarefied gasdynamics is improved with the addition of the variable hard sphere model for elastic collisions and a vibrational relaxation model based on discrete harmonic oscillators. In addition the existing unstructured grid generation module of the code is enhanced with grid-quality algorithms. The unstructured DSMC code is validated with simulation of several gaseous micronozzles and comparisons with previous experimental and numerical results. Rothe s 5-mm diameter micronozzle operating at 80 Pa is simulated and results are compared favorably with the experiments. The Gravity Probe-B micronozzle is simulated in a domain that includes the injection chamber and plume region. Stagnation conditions include a pressure of 7 Pa and mass flow rate of 0.012 mg/s. The simulation examines the role of injection conditions in micronozzle simulations and results are compared with previous Monte Carlo simulations. The code is also applied to the simulation of a parabolic planar micronozzle with a 15.4-micron throat and results are compared with previous 2D Monte Carlo simulations. Finally, the code is applied to the simulation of a 34-micron throat MEMS-fabricated micronozzle. The micronozzle is planar in profile with sidewalls binding the upper and lower surfaces. The stagnation pressure is set at 3.447 kPa and represents an order of magnitude lower pressure than used in previous experiments. The simulation demonstrates the formation of large viscous boundary layers in the sidewalls. A particle-in-cell model for the simulation of electrostatic plasmas is added to the DSMC code. Solution to Poisson's equation on unstructured grids is obtained with a finite volume implementation. The Poisson solver is validated by comparing results with analytic solutions. The integration of the ionized particle equations of motion is performed via the leapfrog method. Particle gather and scatter operations use volume weighting with linear Lagrange polynomial to obtain an acceptable level of accuracy. Several methods are investigated and implemented to calculate the electric field on unstructured meshes. Boundary conditions are discussed and include a formulation of plasma in bounded domains with external circuits. The unstructured PIC code is validated with the simulation of a high voltage sheath formation.

<p>Free2Move AB is developing products for the market within wireless communication</p><p>and identification, among those active RFID-tags. The company had an idea about</p><p>providing one of their active RFID tags with a GPS receiver and transmit positions via</p><p>an existing RFID protocol. Desire from the company was also the possibility to log</p><p>positions and measure temperature. The finished prototype should also be able to be</p><p>activated by movement. The company had proposal about components that were to be</p><p>used in the project. A large part of the work was to understand how these worked and</p><p>how to combine them to fulfill the requirements established in agreement with</p><p>supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype</p><p>and software implemented for communication with GPS, RFID tag and other</p><p>components. The result was a working prototype where an existing RFID tag was</p><p>integrated in the same printed circuit board layout as the GPS receiver and other</p><p>components that were used in the project.</p>

<p>For this project I was planning to construct a clock that could be synchronized with an external source. The clock should be able to keep the time between synchronizations as these may be sparse. It also needed to be able to store the current time in a memory and keep a register of stored times. The current time and the register must be viewable by the user and the clock must also have the ability to count down the last five seconds prior to a minute selected by the user. I have performed this work at home with my own equipments.</p><p>As an external source for the synchronization I have chosen the DCF-77 clock signal broadcasted from Germany. To receive this signal I used a cheap AM receiver built specifically for this purpose. For the actual clock I used a PIC microcontroller which I programmed in C. The chip had all I needed including an oscillator and a RAM memory. I also connected a 3x16 character LCD display to the clock as well as 4 1-pole buttons for the user interface.</p><p>The program is built upon an interrupt routine that with help of an internal timer is set to execute once every hundreds of a second. During this interrupt routine all other functions are executed. These functions include a DCF decoder, an internal clock to keep the time, an LCD driver and a user interface.</p><p>I have managed to read the clock signal from the receiver but due to interferences from the computer I used to program the PIC chip, I have not been able to get any good reception close to the computer. Apart from this setback the clock works as it should and it meets all other criteria.</p>

Interactive Institute’s Power Studio i Eskilstuna har ett projekt som heter AWARE. AWARE är ett designorienterat forskningsprojekt som syftar till att öka människors medvetenhet om hur elenergi används i vardagen, speciellt i hemmen. Målet är att uppmärksamma människor om deras elanvändning samt ge de ett medel att kunna kontrollera och göra deras elanvändning mer effektiv.Som en del i AWARE ska en intelligent bärbar armatur som är batteridriven tas fram som ska få människor att tänka på att elenergi inte är något konstant och outtömligt. Det ska finnas visuella effekter som på ett bra sätt kan väcka dessa tankar. Vid laddning av dessa armaturer kan t.ex. ett svagt pulserande ljus användas för att ge effekten av att armaturen tankas med elenergi. Detta examensarbete bygger på att producera två prototyper av dessa armaturer som kan kommunicera trådlöst med varandra.Examensarbetet resulterade i två stycken fungerande prototyper. Dessa prototyper klarar av att kommunicera och styra varandra och utgör en enkel plattform för vidare utveckling. Med lite mer arbete kommer prototyperna

For this project I was planning to construct a clock that could be synchronized with an external source. The clock should be able to keep the time between synchronizations as these may be sparse. It also needed to be able to store the current time in a memory and keep a register of stored times. The current time and the register must be viewable by the user and the clock must also have the ability to count down the last five seconds prior to a minute selected by the user. I have performed this work at home with my own equipments. As an external source for the synchronization I have chosen the DCF-77 clock signal broadcasted from Germany. To receive this signal I used a cheap AM receiver built specifically for this purpose. For the actual clock I used a PIC microcontroller which I programmed in C. The chip had all I needed including an oscillator and a RAM memory. I also connected a 3x16 character LCD display to the clock as well as 4 1-pole buttons for the user interface. The program is built upon an interrupt routine that with help of an internal timer is set to execute once every hundreds of a second. During this interrupt routine all other functions are executed. These functions include a DCF decoder, an internal clock to keep the time, an LCD driver and a user interface. I have managed to read the clock signal from the receiver but due to interferences from the computer I used to program the PIC chip, I have not been able to get any good reception close to the computer. Apart from this setback the clock works as it should and it meets all other criteria.

Free2Move AB is developing products for the market within wireless communication and identification, among those active RFID-tags. The company had an idea about providing one of their active RFID tags with a GPS receiver and transmit positions via an existing RFID protocol. Desire from the company was also the possibility to log positions and measure temperature. The finished prototype should also be able to be activated by movement. The company had proposal about components that were to be used in the project. A large part of the work was to understand how these worked and how to combine them to fulfill the requirements established in agreement with supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype and software implemented for communication with GPS, RFID tag and other components. The result was a working prototype where an existing RFID tag was integrated in the same printed circuit board layout as the GPS receiver and other components that were used in the project.

The ability to control the output for a given input is an important feature of neurons as it allows them to respond to a multitude of inputs via the production of a scalable output. Using compartmental models of morphologically accurate reconstructions of feline spinal motoneurons, we examined the ability for motoneurons of the feline spinal cord to alter their input-output properties via the variable activation of persistent inward currents (PICs) due to L-type Ca2+ channels located in hotspots on their dendrites. Traditionally, the activation of PICs is thought to be a threshold-dependent event reliant on the response of hotspots of these channels to a depolarization beyond a specific local voltage. Converse to this belief, we have found that the response of spinal motoneuron PICs is not exclusively voltage-dependent but is also reliant on time-varying fluctuations in membrane potential (noise). Moreover, we show that the activation of PICs in motoneurons is dependent on the location of these dendritic hotspots, which is correlated with cell size. Small motoneurons exhibited delayed activation in response to time-varying input and large motoneurons exhibited no change. The activity of the models was measured via discharge frequency which was due to the activation of dendritically located synapses either firing in a time-averaged (tonic) manner or a Poisson-distributed spike train (transient) with the same overall conductance and distribution as the tonic synapses. These results demonstrate a novel mechanism for the activation characteristics of PICs in motoneurons and, in turn, the ability for the neuron to intrinsically alter its input-output properties. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2009-11-30 14:10:24.905

El presente trabajo de título consistió en la elaboración de un osciloscopio digital de propósito general, sencillo de implementar y de bajo costo. El sistema está dividido en tres fases principales: la etapa de adquisición y acondicionamiento de la señal, transporte de la información por USB y transmisión de dicha información dentro de una red LAN utilizando microcontroladores PIC. En cuanto al acondicionamiento de la señal, se diseñó en base a lo visto en la revisión bibliográfica una atenuación inicial y posterior amplificación variable mediante amplificadores operacionales de ganancia variable, controlada digitalmente mediante la multiplexión de un arreglo de resistencias que definen la ganancia. La idea fundamental fue acondicionar señales de distinta amplitud al rango dinámico del conversor análogodigital utilizado (0 – 5 volts). Una vez convertido el dato mediante interrupciones que garantizan la separación constante de tiempo entre muestras, se guarda dentro de la RAM interna del PIC y mediante transacciones PC-Microcontrolador PIC18F2550 se envían paquetes de datos por USB, los cuales son procesados y posteriormente graficados. Paralelo a esto, se trasfieren los datos captados a un segundo PIC (18F452), el cual define una conexión TCP/IP mediante el controlador Ethernet ENC28J60 y envía paquetes con la información recibida dentro de una LAN. Independiente al método de adquisición utilizado (USB o Ethernet), se diseñó un software basado en capas o módulos, el cual recibe la información, y la guarda en una cadena, y dependiendo si está o no definida la opción de trigger, localiza el punto de disparo y lo centra en pantalla, lo cual da la posibilidad de implementar también un control de desplazamiento vertical.

Les contraintes mécaniques liées à la pratique physique jouent un rôle prépondérant dans l’optimisation de la masse, la géométrie et le métabolisme osseux. Pour ce travail, nous avons suivi pendant deux années une cohorte de 170 personnes âgées de 16-28 ans, pratiquant ou non un sport de haut niveau (>6heures/semaine). Nous avons décrit que lorsque la pratique sportive était débutée à l’adolescence et maintenue à l’âge adulte, le statut osseux était significativement meilleur par rapport à des individus non sportifs. D’autre part, plus les impacts mécaniques et l’intensité de pratique étaient élevés plus les valeurs osseuses biologiques de formation et densitométriques étaient importantes. Nous avons confirmé l’implication de la leptine et de l’insuline dans le métabolisme énergétique. Nous avons également validé une méthode novatrice d’analyse du tibia par la DXA et avons démontré que ce site osseux répondait fortement aux contraintes mécaniques. Afin d’étudier un modèle de masse corporelle extrême, nous avons spécifiquement étudié les rugbymen. Ils présentaient une hypoleptinémie significative avec une masse grasse similaire à celle des témoins, d’où probablement un effet direct de l’exercice physique sur le métabolisme de la leptine. Enfin, nous avons démontré que les paramètres osseux biologiques et densitométriques ne semblent plus évoluer significativement sur la période d’étude de deux ans. Les Pics de Masse et de Géométrie Osseuse semblent donc atteints, indépendamment du sexe et du statut sportif pour ce type de population d’adultes jeunes. / Mechanical strains induced by physical activity play an important role in bone mass, geometry and metabolism optimization. For this work, we have followed during 2 years, a cohort of 170 persons aged 16-30 years, who practiced or not a high level weight bearing sport (>6hours/week). We have described that when the practice was initiated during adolescence and maintained during adulthood, bone status was significantly greater compared to sedentary controls. Moreover, the more the mechanical impacts and practice intensity were, the higher bone formation rates and densitometry parameters were. We have confirmed the leptin and insulin implication in energy metabolism. We have also validated a new method to assess tibia bone parameters with DXA and we have demonstrated that this bone site strongly responded to mechanical strains. On the other hand, we have specifically studied rugby players as a model of “extreme” body composition. We have observed a significant hypoleptinaemia compared to controls whereas they had a similar fat mass: “extreme” practice would have a depressive action on leptin metabolism. Finally, we have showed that biology and densitometry bone parameters did not significantly evaluate whatever the bone site: Peak Bone Mass and Geometry appeared to be reached, independently of sex and sport status.

This thesis discusses the recent developments to the electric propulsion plume code DRACO as well as a validation and sensitivity analysis of the code using data from an AFRL experiment using a Busek 200 W Hall Thruster. DRACO is a PIC code that models particles kinematically while using finite differences schemes to solve the electric potential and field. The DRACO code has been recently modified to improve simulation results, functionality and performance. A particle source has been added that uses the Hall Thruster device code HPHall as input for a source to model Hall Thrusters. The code is now also capable of using a non-uniform mesh that uses any combination of uniform, linear and exponential stretching schemes in any of the three directions. A stretched mesh can be used to refine simulation results in certain areas, such as the exit of a thruster, or improve performance by reducing the number of cells in a mesh. Finally, DRACO now has the capability of using a DSMC collision scheme as well as performing recombination collisions. A sensitivity analysis of the newly upgraded DRACO code was performed to test the new functionalities of the code as well as validate the code using experimental data gathered at AFRL using a Busek 200 W Hall Thruster. A simulation was created that attempts to numerically recreate the AFRL experiment and the validation is performed by comparing the plasma potential, polytropic temperature, ion number density of the thruster plume as well as Faraday and ExB probe results. The study compares the newly developed HPHall source with older source models and also compares the variations of the HPHall source. The field solver and collision model used are also compared to determine how to achieve the best results using the DRACO code. Finally, both uniform and non-uniform meshes are tested to determine if a non-uniform mesh can be properly implemented to improve simulation results and performance. The results from the validation and sensitivity study show that the DRACO code can be used to recreate a vacuum chamber simulation using a Hall Thruster. The best results occur when the newly developed HPHall source is used with a MCC collision scheme using a projected background neutral density and CEX collision tracking. A stretched mesh was tested and proved results that are as accurate as a uniform mesh, if not more accurate in locations of high mesh refinement. / Master of Science