The effects of using an insert Heat Flux Microsensor (HFM) versus an HFM deposited directly on a turbine blade to measure heat flux in a transonic cascade are investigated. The HFM is a thin-film sensor, 6.35 mm (0.250") in diameter (for an insert gage, including the housing) which measures heat flux and surface temperature. The thermal time response of both gages was modeled using a 1-D, finite difference technique and a 2-D, finite element solver. The transient response of the directly deposited gage was also tested against insert gages using an unsteady shock wave in a bench test setup and using a laser of known output. The effects of physical gage offset from the blade surface were also investigated. The physical offset of an insert HFM near the stagnation point on the suction side of a turbine blade was intentionally varied and the average heat transfer coefficient measured. Turbulence grids were used to study how offset affects the heat transfer coefficient with freestream turbulence added to the flow. The time constant of the directly deposited gage was measured to be 856 ms compared to less than 30 ms for the insert gages. Model results predict less than 20 ms for both gages and rule out the anodization layer (used for electrical isolation of the directly deposited gage from the blade) as the cause for the directly deposited gage's much slower time response. Offsets of ± 0.254 mm (0.010") at the gage location with an estimated boundary layer thickness of 0.10 mm (0.004") produced a higher average heat transfer coefficient than the 0.000" offset case. Using an insert HFM resulted in a higher average heat transfer coefficient than using the directly deposited gage and reduced the effects of freestream turbulence. To accurately measure heat transfer coefficients and the effects of freestream turbulence, the disruption of the flow caused by a gage must be minimized. Depositing a gage directly on the blade minimizes the effects of offset, but the cause of the slow time response must first be resolved if high speed data is to be taken. / Master of Science

The effects of grid generated freestream turbulence on surface heat transfer to turbine blades were measured experimentally. Time-resolved and unsteady heat flux measurements were made with Heat Flux Microsensors at two positions on the suction side of turbine blades. The experiments were conducted on a stationary cascade of aluminum turbine blades for heated runs at transonic conditions. Non-dimensional flow parameters were matched to actual engine conditions including the design exit Mach number of 1.26 and the gas-to-wall temperature ratio of 1.4. Methods for determining the adiabatic wall temperature and heat transfer coefficient are presented and the results are compared to computer predictions for these blades. Heat transfer measurements were taken with a new, directly deposited HFM gage near the trailing edge shock on nitrogen cooled blades. The average heat transfer coefficient for Mach 1.26 was 765 W/(m² °C) and matched well with a predicted value of 738 W/(m² °C). Freestream turbulence effects were studied at a second gage location 1.0 cm from the stagnation point on uncooled blades. Results at this location show an increase in freestream turbulence from 1 % to 8% led to a 15% increase of the average heat transfer coefficient and also matched well with predictions. The fast response time of the HFM illustrated graphically the increase in energy spectra due to freestream turbulence at the 0 - 10kHz range. The heat flux turbulence intensity (Tu_q) was defined as another physical quantity important to turbine blade heat transfer. / Master of Science

Mono-energetic neutrons have been produced with the low-voltage Cockroft-Walton accelerator at North Texas State College using two different reactions. It is the purpose of this paper to report the angular distribution and total flux of the neutrons obtained from the T(D,n) reaction.

À ce jour, quelques biocapteurs ont été proposés pour mesurer rapidement et facilement les caractéristiques et les propriétés des microrganismes individuels membres d'une population hétérogène, mais aucune de ces approches ne s'est avérée être adéquate pour effectuer des mesures directement sur le terrain. Les biocapteurs pour les organismes microscopiques nécessitent généralement une sensibilité ou une spécificité extrême, qui sont difficiles à combiner avec un dispositif général portatif. Cette étude propose un dispositif portatif basé sur la cytométrie de flux d'impédance qui peut détecter et quantifier le diamètre de microbilles de tailles supérieure à 50 µm directement sur le terrain, tout en présentant un faible coût, une taille réduite, une basse consommation de puissance, et une simplicité de conception et d'opération qui maximise le potentiel de l'impression 3D et de la fabrication industrielle de circuits imprimés. Un exemple est offert afin de démontrer les capacités du capteurs pour de larges échantillons, avec un jeu de données contenant 2380 microbilles détectées de tailles entre 50 µm et 90 µm. / To this day, a couple of biosensors have been proposed to quickly and easily measure the features and properties of individual microorganisms member of an heterogeneous population, but none of these approaches were adequate candidates to perform measurements directly in the field. Biosensors for micron-scale organisms generally require extreme sensitivity or specificity, which are difficult to combine with a portable general device. This study proposes a portable device based on Impedance Flow-Cytometry that can detect and quantify directly in the fields the size and velocity of microbeads of size bigger than 50 µm, while boasting a low cost, low size, low power, and simplicity of design and operation utilizing the potential of 3D-printing and industrial PCB fabrication. An example is provided for a Big Data application from a sampled dataset containing 2380 successfully detected microbeads of sizes between 50 µm and 90 µm.

Pour les limnologistes étudiant les écosystèmes nordiques, les premiers indicateurs des changements climatiques apparaissent au bas de la chaine trophique : notamment dans les populations phytoplanctoniques. Une des techniques fréquemment utilisées pour caractériser cette frange du microbiome aquatique est la cytométrie en flux, une approche qui permet de caractériser individuellement la réponse optique, en fluorescence ou en diffusion, des cellules dans un échantillon. Malheureusement, ces instruments sont généralement très mal adaptés aux conditions que l'on peut retrouver en régions éloignées, notamment en raison de leur volume, leur poids et la sensibilité de leur alignement optique. De ce fait, les échantillons doivent généralement être préservés à −80°C puis être analysés au retour dans les laboratoires dans le sud. Ainsi, nous avons proposé de développer un cytomètre en flux portable optimisé pour la mesure optique de la fluorescence des pigments photosynthétiques des phytoplanctons et des cyanobactéries dans la gamme de taille de 0,2 à 2,0 µm (pico). Pour ce faire, un dispositif miniaturisé incorporant les structures microfluidiques nécessaires à la focalisation hydrodynamique des cellules ainsi que des fibres optiques permettant d'acheminer la lumière d'excitation et d'extraire la fluorescence avec un alignement robuste a été développé. Avec ce dispositif, un coefficient de variation de 9,5 % a été obtenu pour des particules de 2,0 µm de diamètre. Ensuite, un système intégrant ce dispositif dans un format portable a été développé. Ce système permet pour l'instant la mesure en laboratoire sur trois canaux, soit en diffusion à 633 nm et en fluorescence de la phycocyanine et de la chlorophylle-a, respectivement à 648±5 et 685±10 nm. Finalement, le dispositif microfluidique et le système ont été utilisés conjointement pour caractériser des échantillons de cultures de picophytoplanctons. Il a été possible de distinguer deux souches, une culture de picoeucaryotes (prasinophyceae RCC2335 ) et de picocyanobactéries CASES 2002 ) avec une efficacité de 91,3 %.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper will present techniques for accurately measuring the power flux density (PFD) of interfering signals at telemetry receiving stations. The solar power flux density is measured daily by radio astronomers and will be used as a calibration signal. The electromagnetic spectrum is being used more intensely as time marches on so being familiar with interference measurement techniques is becoming more important because more interfering signals are present.

While it is not the most abundant greenhouse gas, a significant portion of the greenhouse effect is caused by methane. The amount of methane in the atmosphere is increasing, indicating that there is a continuous source of methane to the atmosphere. One significant source of methane is freshwater lakes, even though they cover only a small portion of the Earth’s surface. Because of this, it is important to monitor methane fluxes from lakes in order to understand the processes which affect the magnitude of these fluxes. Methane is produced in the sediment at the bottom of the lake, and transported through the water by ebullition, diffusive flux, storage flux, or plant mediated emission. This study looked to examine the amount of methane transmitted to the atmosphere by these processes on Lake Erken in eastern Sweden. Using the eddy covariance method, we can study the methane flux with good spatial and temporal resolution. Regular sampling of lake water, both from the surface and depths of 5 and 10 meters, also helps us to understand the amount of methane dissolved in the lake. These measurements can help us to better understand the transfer velocity, or the efficiency of the exchange between water and air, as well as the amount of methane transported from lakes to the atmosphere. Water sampling showed that there is very little variation in methane concentration between different parts of the lake. Concentrations at four surface locations are nearly identical. These surface measurements are also similar to concentrations at different depths. Over time, the concentrations generally stayed the same, with isolated high and low concentration events. The amount of methane emitted by the lake was studied with the lake divided into a shallow water area, and a deep water area. The magnitude of fluxes from both areas was very similar, but the area of shallow water had a higher total flux. The fluxes were well correlated with wind speed; higher fluxes coming during times with higher wind speed. This relates well to the transfer velocity theory, and the bulk flux approximation. However, there was no clear diurnal cycle in methane fluxes. The fluxes during the night were similar to daytime fluxes. Atmospheric pressure also had an impact on fluxes, with greater fluxes coming at times of lower pressure. A large seasonal variation was clear. More methane escaped the water in autumn and winter than in spring or summer. This is due in part to the fluxes from when the lake freezes over/thaws and the water in the lake turns over, bringing methane rich water from the lake’s bottom to the surface. As expected, the waterside concentration of methane also had a strong correlation with the fluxes. The main conclusions of this study are: 1) Methane fluxes are variable with wind speed, waterside concentrations, and the seasons 2) Water depth and diurnal cycles do not affect methane fluxes as strongly. Keywords: methane, transfer velocity, flux, waterside concentration, eddy covariance

Flux is continually emerging on the Sun, making its way from the solar interior up into the atmosphere. Emergence occurs on small-scales in the quiet Sun where magnetic fragments emerge, interact and cancel and on large-scales in active regions where magnetic fields emerge and concentrate to form sunspots. This thesis has been concerned with the large-scale emergence process and in particular the results from previous solar flux emergence modelling endeavours. Modelling uses numerical methods to evolve a domain representing simplified layers of the Sun’s atmosphere, within which the subsurface layer contains magnetic flux. The flux is initialised such that it will rises towards the surface at the start of the simulation. Once the flux reaches the solar surface, it can only emerge into the atmosphere if a magnetic buoyancy instability occurs, after which it expands rapidly both vertically and horizontally. The aim of this thesis is to test the robustness of these general findings from simulations to date upon the seed magnetic field. More explicitly, we have used three-dimensional numerical simulations to investigate how variations in the subsurface magnetic field modify the emergence process and the resulting atmospheric field. We initially consider a simple constant twist flux tube for the seed field and vary the tube’s magnetic field strength and degree of twist. Additionally, we have examined the effects of using non-constant twist flux tubes as the seed field by choosing two different profiles for the twist that are functions of the tube’s radius. Finally, we have investigated the effects of increasing the complexity of the seed field by positioning two flux tubes below the solar surface and testing two different configurations for the tubes. In both cases, the magnetic fields of the two tubes are such that, once the tubes come into contact with each other, reconnection occurs and a combined flux system is formed. From our investigations, we conclude that the general emergence results given by previous simulations are robust. However, for constant twist tubes with low field strength and twist, the buoyancy instability fails to be launched when the tubes reach the photosphere and they remain trapped in the low atmosphere. Similarly, when the non-constant twist profile results in a low tension force throughout the tube, we find that the buoyancy instability is not initialised.

La synchronisation des flux physiques a reçu une importante attention dans la littérature. Si le non flux physique a reçu une attention toute particulière dans des domaines tels que le SCM, le pendant financier a longtemps était délaissé. Plus inquiétant, les délais de paiement ont longtemps été perçus comme un moyen de réduction du besoin en fonds de roulement des grandes entreprises. La crise des Subprimes a eu de lourdes conséquences sur le financement des entreprises les plus modestes, mettant en danger l’existence même de ces dernières. Notre travail initial de synchronisation des flux physiques et financiers instruits dans la cadre d’un partenariat CIFRE visait à trouver des solutions à ces problématiques en proposant des modèles d’optimisation sous contraintes. Néanmoins, notre volonté de mettre en œuvre nos travaux fut vaine et notre sujet a progressivement drifté vers la découverte de l’échec du déploiement d’un système ERP. Notre enracinement au sein d’une grande entreprise du secteur de la défense française nous a permis de mettre en œuvre une recherche action canonique en trois phases distinctes et a débouché sur la production d’un modèle de diffusion de l’innovation appliqué à l’ERP. Ce modèle en 6 phases, décrits les étapes successives du déploiement, en mettant en exergue l’impact des forces politiques au sein de l’organisation. / Synchronization of physical flows received significant attention in the literature. If the non-physical flows received special attention in areas such as SCM, financial for a long time was helpless. More worryingly, payment delays have long been seen as a means of reducing the need for working capital for large firms. The subprime crisis has had a serious impact on the financing of the smaller companies, endangering the very existence of the latter. Our initial synchronization job physical and financial flows educated in the context of a CIFRE partnership aimed at finding solutions to these problems by proposing models of optimization under constraints. However, our commitment to implement our work was in vain and our subject has gradually drifted to the discovery of the failure of the deployment of an ERP system. Our roots in a large enterprise sector French defense allowed us to implement an action research canonical three distinct phases and resulted in the production of a model of diffusion of innovation applied to the ERP. This model into 6 phases, described the successive stages of deployment, highlighting the impact of political forces within the organization

Le nettoyage en place des membranes en industrie agro-alimentaire est une opération cruciale qui, outre les exigences de sécurité sanitaire des installations et des produits traités doit permettre de restaurer les performances de la filtration (sélectivité, flux) en éliminant le colmatage formé pendant l'étape de production. Malheureusement cette étape repose encore sur des bases empiriques et non optimisées. A cause d'un manque de notions fondamentales, elle est encore pressentie comme un frein à l'utilisation massive des procédés membranaires. Une démarche originale a été menée dans le cadre de cette thèse incluant la réflexion sur l'incidence des paramètres hydrodynamiques des conditions de production sur la cohésion du dépôt colmatant et plus particulièrement de sa fraction irréversible, dont la nettoyabilité est étudiée. Pour fonder cette démarche, une étude comparée du colmatage et du nettoyage au flux limite et au flux critique a été réalisée en intégrant le rôle de la physico-chimie et de l'hydrodynamique pendant la phase de production. cette étude s'inscrit dans un cadre d'éco-conception de procédé, avec une analyse de cycle de vie réalisée afin d'estimer l'impact environnemental de l'étape de nettoyage via divers scénarii simplifiés. / The cleaning in place of membranes in food-processing industry is crucial operation which, besides the requirements of sanitary safety of the installations and the treated products allows to restore the performances of the filtration (flux, selectivity) by removing the fouling formed during the production step. Unfortunately, this cleaning step still rests on empirical and not optimized bases. Because of a lack of fundamental notions, it is still anticipated as a brake in the massive use of the membrane processes. An original approach is led within the framework of this thesis including the reflexion on the incidence of the hydrodynamics parameters of the conditions of production on the cohesion of the fouling deposit and more particularly its irreversible fraction which this cleanability is studied. To establish this approach, a study compared by the fouling and by the cleaning with the limiting flux and with the critical flux is realized by integrating the role of the physic-chemistry and the hydrodynamics during the production step. This study joins in a frame of eco-design of process, with an analysis of life cycle realized to estimate the environmental impact of the cleaning step by diverse scenarios.