Syftet med den här studien är att studera vindprofiler och klassificera Low Level Jets (LLJ) och även analysera den termiska vinden över Östergarnsholm. Östergarnsholm är en liten ö som ligger 4 kilometer öster om Gotland. Viseringar och sonderingar från åren 1995 till 2001 samt år 2003 har använts. Det kriteriet som har använts för att klassificera LLJs är att det ska finnas ett vindhastighetsmaximum under 500 meters höjd. De undersökta orsakerna till uppkomsten av en LLJ är sjöbris, tröghetssvängning och termisk vind. För att kunna ta ut LLJs orsakade av sjöbris har vindprofiler över hela dygn använts. Vindens vridning vid marken, under dagen, jämfört med den överlagrade vindens riktning vid 2000 meters höjd har undersökts. LLJs som uppkommit på grund av tröghetssvängning har analyserats. Metoden för tröghetssvängning bygger på att analysera den geostrofiska vindens hastighet och vindriktning för att sedan kunna räkna ut hur vinden har blåst och var en eventuell LLJ skulle kunna bildas. Här har vindriktningar mellan 20º – 220º använts eftersom det medför att vinden då blåser från havet. Resterande vindriktningar medför att vinden har blåst över Gotland vilket resulterar i att en eventuell tröghetssvängning skulle störas och en LLJ skulle försvinna innan den når Östergarnsholm. Vindhastigeter och vindriktningar har jämförts med teoretiskt uträknade värden från tryckmätningar. Från alla 245 viseringar fanns 103 vindprofiler med LLJs. Utav dessa var 27 stycken, under 12 dygn, orsakade av sjöbris. Hur många LLJs som bildats av tröghetssvängning är oklart. Detta eftersom olika resultat erhålles beroende på om vindhastigheter och vindriktningar tas från viseringarna eller är beräknade från tryckmätningar, samt om beräkningarna av transporttiden sker med raka eller krökta trajektorier. Totalt hittades 9 LLJs som orsakats av tröghetssvängning. Metoden som använts för att analysera tröghetssvängning ger förmodligen bättre resultat över land än över hav. Detta eftersom det är svårt att mäta de exakta vindförhållandena längs luftens transport över hav. Den geostrofiska vindens ändring med höjden över ön, det vill säga den termiska vinden, har analyserats genom att undersöka alla vindprofiler, även de utan LLJs. Dessa har jämförts med den geostrofiska vinden beräknad från tryckmätningar, som representerar vinden vid marken, för att se om det uppkommer termiska vindar över Östergarnsholm. En LLJ som orsakats av termisk vind uppkommer när den geostrofiska vinden avtar med höjden, det vill säga vid negativ termisk vind. Antalet fall där den geostrofiska vinden avtar med höjden och där vinden är konstant med höjden var ungefär lika många. Däremot fanns något fler fall där den geostrofiska vinden ökade med höjden, dessa uppgick även till högre hastigheter än när vinden avtog med höjden. Det finns inget samband för vindvridningen med höjden då det förekommer LLJs på grund av termisk vind. Däremot finns ett tydligt samband mellan den negativa termiska vindens u- och v-komponent och den geostrofiska vindens u- respektive v-komponent. I båda fallen så tenderar vinden att gå mot noll med höjden. Totalt hittades 41 LLJs som var orsakade av termisk vind. Vid ungefär 50% av alla vindprofiler, både när den geostrofiska vinden avtog och ökade med höjden, var den termiska vindens nord-sydliga komposant positiv och den ost-västliga komposanten negativ. Detta ger att den varmare luften finns i nordost. / The aim of this study is to classify Low Level Jets (LLJ) and analyze the thermal wind over Östergarnsholm. Östergarnsholm is a small island that is situated 4 kilometres east of Gotland in the Baltic Sea. Pibal trackings and soundings from 1995 to 2001 and 2003 have been used in the study. The criteria that have been used to classify the LLJs is that there must be a maximum of the wind speed below 500 meters. Wind profiles from a specific day have been used to determine if the LLJs is caused by sea breeze. The shift of wind direction at ground level, during the day, compared to the geostrophic wind at 2000 meters has been analyzed. LLJs caused by internal oscillation have been analyzed. In the used method the geostrophic wind speed and wind direction have been analyzed to determine how the wind has blown and where a LLJ possibly could be formed. Only wind directions between 20º and 220º have been used to avoid that the wind should have passed Gotland. If the winds have passed Gotland the internal oscillation has been disturbed and no LLJ can appear. Measured wind speeds and directions have been compared to theoretical values from pressure measurements. 103 wind profiles with LLJs were found from all pibal trackings. In 27 of these pibal trackings, from 12 days, were LLJs caused by sea breeze. It is difficult to say how many LLJs that are caused by an internal oscillation. This due to the different results obtained when using wind speeds and wind directions from pibal trackings or pressure measurements. Also using straight line trajectories or trajectories following the isobars gives different results. Totally 9 LLJs were found, caused by an internal oscillation. Probably this way of analyze the internal oscillations is a better method for measurements over land than over sea. This due to the difficulties in measuring the exact wind speed and wind direction over the whole traveling distance over sea. The thermal wind over the island has been analyzed by studying all pibal trackings, even those without LLJs. The pibal trackings have been compared to the geostrophic wind calculated from pressure measurements to determine if thermal winds occur over Östergarnsholm. A LLJ caused by thermal wind occur when the geostrophic wind decreese with height, i.e. negative thermal wind. There was no difference in the amount of negative thermal winds and cases with no thermal wind. There were a few more positive thermal winds and they had higher wind speeds than the negative ones. There is no connection in the shift of wind direction when there is a LLJ caused by thermal wind. But there is a significant connection between the u- and v-component of the negative thermal winds and the u- and v-component of the geostrophic wind. In both cases the geostrophic wind tends to decreese towards zero with height. 41 of all LLJs were caused by thermal winds. About 50% of both negative and positive thermal winds have a positive v-component and a negative u-component. This means that the warmer region is in the north east.

No description available.

L’amélioration des performances aérodynamiques et environnementales est un enjeu majeur dans le domaine des transports terrestres et aériens. Pour pouvoir répondre à ses exigences, une des solutions est de contrôler les écoulements. Pour cela, des actionneurs performants sont nécessaires. Une technique innovante, le jet synthétique par plasma (JSP), consiste à appliquer une décharge haute tension dans une micro cavité. Un plasma est ainsi créé dans la chambre augmentant en quelques microsecondes la température et la pression du gaz générant un micro-jet par l’orifice de l’actionneur. Le but de la thèse est de développer cet actionneur, d’en comprendre son fonctionnement et de le mettre en oeuvre pour contrôler le bruit d’un jet subsonique à grand nombre de Mach.La première partie de l’étude s’applique à définir les besoins pour le contrôle d’écoulement et de réaliser un prototype d’actionneur. Il est ensuite caractérisé expérimentalement par des mesures de la décharge électrique et de l’aérodynamique du micro-jet. En s’inspirant du modèle de Braginskii, un modèle simple de la décharge électrique est réalisé et appliqué au JSP. Le rendement de l’actionneur en est déduit. Le modèle de Braginskii modifié est ensuite couplé à une modélisation URANS ce qui permet de simuler le fonctionnement en fréquence de l’actionneur. Ces résultats sont ensuite comparés avec les mesures de l’aérodynamique du micro-jet et montrent un excellent accord.L’actionneur est ensuite mis en application pour contrôler le bruit de jet. En premier lieu, des visualisations par strioscopie de l’interaction des micro-jets avec le jet principal sont effectuées. Des mesures acoustiques sont ensuite réalisées etmettent en évidence que les JSP sont de bons candidats pour contrôler le bruit de jet. / Improvement of aerodynamics and environmental performances is a major issue for terrestrial and aeronautical industry.For fulfilling increasing demand, one of the answers is flow control. To achieve flow control, high performance actuators are needed. An innovative technique called Plasma Synthetic Jet actuator consists on applying an electrical discharge in asmall cavity. Plasma is created and increases gas temperature and pressure which results on the creation of a micro-jet through cavity opening.The PhD objectives are to develop the PSJ actuator, to describe actuator mechanisms and to apply it for controlling noise of a high subsonic jet. The first part of the study consists on defining flow control needs and on developing a PSJ actuator prototype. Then,actuator performances are characterised using electrical measurements of the discharge and using aerodynamic measurements. These measurements show that an electrical model of the discharge is needed. Based on the Braginskii model, a simple model is carried out and is applied to the actuator. Efficiency of the PSJ is deduced.The modified Braginskii model is then coupled with an URANS model to achieve frequency modelling of the actuator. Results match aerodynamics measurements .PSJ actuators are applied for controlling jet noise in a second part of the study. Schlieren visualisations are used to show micro-jet interaction with the main jet. Acoustic measurements are then performed and show that the PSJ is a goodactuator to control high subsonic jet noise.

In the first part of the thesis, theoretical uncertainties of jet cross-section have been calculated for proton-proton collision at the center of mass energy of 8 TeV. For jet identification the anti-kT algorithm with scale parameter R = 0.6 was used. As the calculations showed, the major contribution to the total theoretical uncertainty comes from the uncertainty of parton distribution function parameters. In the second part of the thesis, the angular distribution of dijet events produced in proton-proton collisions at the center of mass energy 8 TeV were simulated using Pythia 8 Monte Carlo event generator. New physics model of quark compositeness that should manifest itself by quark contact interaction was studied using angular distribution of dijet events. Three angular variables were discussed and these variables were used to calculate 95% CL lower limit on contact interaction scale. The results were compared and it emerged that the sensitivity to contact interaction signals varies for these variables.

Dans le cadre de cette thèse, il s’agit de voir l’influence de la composition du fluide sur le flux extrait. En effet l’eau utilisée pour le refroidissement des bandes d’acier en sortie de laminoir est recyclée et est potentiellement polluée par des résidus d’huile provenant de la lubrification des cylindres de laminoir. Nous avons conçu un dispositif expérimental original qui consiste à chauffer sur sa face supérieure un disque en Nickel à des températures de l’ordre de 600°C grâce à un dispositif d’induction électromagnétique et ensuite à le refroidir par un jet impactant. La face non refroidie est accessible à une mesure par thermographie infrarouge. Ces conditions de mesures nous ont permis d’estimer le flux extrait sur la face supérieure (lieu du refroidissement) à partir des mesures de température par thermographie infrarouge sur la face inférieure à l’aide d’un modèle de conduction inverse spécifiquement développé. Les résultats ont permis de montrer que la présence d’huile, si elle dégrade le flux maximal extrait dans certaines zones, conduit à une cinétique globale du refroidissement supérieure à celle de l’eau pure. / In this work, we are interested in the influence of the fluid’s composition on the cooling flux. In fact water used for cooling is recycled and can be potentially polluted by residues oil from the lubrication of rolling cylinder. We have designed an original experimental device which consists of heating a Nickel disk on its upper face at temperatures of 600°C through electromagnetic induction and then cooling it by jet impingement. The reverse face is available by infrared thermography measurements. These conditions allowed us to estimate the heat flux on the upper face (the cooling area) by infrared thermography measurements with a specific inverse heat conduction model. The results showed that the presence of oil, if it degrades the maximum cooling flux in some areas, led to a better overall cooling than that obtained with pure water.

Title: Partonic showers and jets Author: Ondřej Hladík Department: Institute of Theoretical Physics MFF UK Supervisor: Mgr. Alexander Kupčo, Ph.D., Institute of Physics ASCR, v. v. i. Abstract: In the present thesis we compare experimentally measured differential and integrated jets shapes with predictions of quantum chromodynamics (QCD) at the second order (NLO) of perturbative expansion. The measured jet sha- pes were taken from ATLAS experiment at LHC in proton-proton collisions at a center-of-mass energy √ s = 7 TeV and were compared with these predictions. The jets were reconstructed by means of anti-kT jet algorithm with R = 0.6. The predictions at NLO QCD agree with data in wider kinematics region than predictions at leading order (LO). The agreement, however, is still in some kine- matical regions not satisfactory. Keywords: QCD, jets, jet shapes, LHC

Vid luftens passage från en typ av yta till en annan byggs ett internt gränsskikt upp där luftens egenskaper förändras successivt. Detta är grunden för bl.a. bildandet av advekterade low-level jets orsakade av en tröghetssvängning, vilken har sitt ursprung i att under vissa förhållanden erhålls obalans mellan de krafter som påverkar vinden. Målet med arbetet var att kartlägga inflytandet av low-level jets på vindprofilen på Näsudden, Gotland, ovan 100 m höjd. För detta syfte användes mätningar under perioden maj 2000 till juli 2001 gjorda i tre mätmaster i området. En mätmast var placerad på land 1.5 km från Näsuddens kust-linje, en andra mast precis vid kustlinjen och en tredje mast ute i Östersjön 4.6 km från kusten. Eftersom masten ute i havet var placerad mitt i Bockstigens vindpark, omgiven av fem vindturbiner, påverkades vindmätningarna av turbinvakar i vissa riktningssektorer. Genom jämförelser mellan vindmätningar i masten och på turbinerna i för masten ostörda sektorer, togs en korrektion fram så att vind-mätningarna gjorda på turbinerna kunde användas i de sektorer mastmätningarna stördes av turbinvakar. För att kunna studera påverkan av low-level jets på vindprofilen användes data från Bockstigens vindpark tillsammans med en vindmodell, byggd på rörelseekvationerna, Monin-Obukhovs similaritetsteori och K-teori. Modellen, som ej kan generera low-level jets, användes för att beräkna vindprofilerna över havet och hur dessa vind-profiler modifierades vid passagen av kusten. Resultatet från modellen jämfördes sedan med observationer från den 145 m höga masten på Näsudden, 1.5 km från kusten. Det visade sig att de observerade vindhastigheterna på 145 m höjd i medeltal var ca 0.8 m/s högre än vad som beräknats med modellen vid vindriktningar från havet in över Näsudden, vilket kan antas bero på inflytandet från low-level jets. Under månaderna mars till maj är vattnet i Ösersjön klimatologiskt sett mycket kallare än luften, ett förhållande som är fördelaktigt för bildandet av low-level jets. Det visade sig att under dessa månader var vindhastigheten mätt på 145 m höjd inom vind-riktningssektorn 220°-250° hela 1.7 m/s högre än vad som beräknades med vind-modellen, vilket understryker betydelsen av low-level jets under denna del av året. Under resten av året befanns skillnaden mellan observerad och modellberäknad vindhastighet på 145 m höjd vara ca 0.8 m/s för samma vindriktningar. / When air is flowing from one type of surface to another, an internal boundary layer is built up where the properties of the air gradually change. This is the basic condition for the development of for example advected low-level jets caused by inertial oscillations, whose origin is that under certain conditions an imbalance will occur between the forces driving the wind. The purpose with the present work was to map the influence from low-level jets on the wind profile at Näsudden, Gotland, above 100 m height. For this purpose, measurements taken on three towers in the area during the period May 2000 to July 2001 were used. One tower was located inland 1.5 km from the coastline of Näsudden, a second tower was located just at the coastline, and a third one was located offshore 4.6 km from the coast. Since the offshore tower was located in the middle of the Bockstigen wind farm, surrounded by five wind turbines, the wind measurements were affected by turbine wakes in certain wind direction sectors. By comparing the wind measurements taken on the tower with measurements taken on the turbines for directions where the tower was not in the wake, corrections were determined where by the wind measurements taken on the turbines could be used for sectors where the tower was located in wakes. To investigate the influence from low-level jets on the wind profile, data from Bockstigen were used together with a wind model based on the equations of motion, Monin-Obukhov’s similarity theory, and K-theory. The model, which is unable to generate low-level jets, was used to calculate the wind profiles over the sea and how these profiles were modified after passage of the coastline. The results from the model were compared to observations made on the 145 m high tower at Näsudden, 1.5 km from the coast. The comparison showed that the observed wind speed at 145 m height on the average was ca 0.8 m/s higher than the wind speed calculated with the model for wind directions from the sea at Näsudden, which could be assumed to be the effect of the presence of low-level jets. During the months March to May the water in the Baltic Sea is climatologically colder than the air temperature, which is favorable for the development of low-level jets. The results from these months showed that the measured wind speed at 145 m height in the wind direction sector 220°-250° was as much as 1.7 m/s higher than what was calculated with the model, which points at the importance of low-level jets during this part of the year. During the rest of the year the average difference between observed and modeled wind speed at the 145 m level was about 0.8 m/s for the same wind direction.

Ce travail de doctorat a permis de développer un biocapteur dédié à l’analyse de l'activité hydrolytique d'une enzyme sur un composant de la paroi végétale, l'arabinoxylane, dans un contexte où le nombre d'enzymes à tester augmente.Ce biocapteur permet non seulement de détecter une enzyme active mais également de classer son activité hydrolytique au sein d’un ensemble d’enzyme. L’identification est réalisée simplement à l'œil nu mais le classement nécessite une observation instrumentée. Des techniques de micro-fabrication sont utilisées pour dispenser de manière précise l’arabinoxylane sur un support. La composition de la solution à base d'arabinoxylane a été optimisée afin d’assurer sa stabilité ainsi que l’uniformité de l’épaisseur du dépôt solide. L’influence de la mouillabilité du support est également étudiée. Notre suivi permet de détecter l’hydrolyse enzymatique et de quantifier le taux d’hydrolyse. La fonctionnalité du biocapteur est validée avec une xylanase commerciale par comparaison avec une technique standard en enzymologie utilisant un substrat colorimétrique. Ce nouvel outil a également été évalué sur des enzymes issues de clonage métagénomique. Son seuil de sensibilité est de 3 nkat/ml, comparable aux autres techniques mais permet de diviser par deux le temps d’analyse. / This thesis focused on the development of a biosensor able to detect the hydrolysis capabilities of enzymes. In a context in which an increasing number of enzymes must be tested for their ability to decompose biomass, we choose to use arabinoxylan as our sensor's active layer as it is a major component of plant cell walls. This biosensor doesn’t only make it possible to detect an enzymatic activity but also to rank several enzymes according to their respective activities. While the precise ranking of enzymes requires an instrument, detecting a hydrolytic activity can be done without it. We rely on microfabrication techniques to precisely deposit arabinoxylan on a solid support. We have developed an arabinoxylan based and tuned its composition to maximize its stability and ensure deposits’ homogeneity. The influence of the wetting properties of the support itself was also thoroughly investigated. We are able to quantify the progressive degradation of the arabinoxylan deposits and thus extract the hydrolysis rate. We have benchmarked our approach with the standard techniques (colorimetry) used in enzymology on a commercial Xylanase. Our approach was further evaluated in a metagenomic enzyme screening context. We have demonstrated that while twice faster than the existing techniques, we maintain a limit of detection at the state of the art (3nkat/mL).

No description available.

The work reflected in this thesis includes a detailed study of co-flow jet (CFJ) technologies as they are applied to a typical thin airfoil, NACA 6415, at take-off and landing speeds. Numerical analysis and experimental testing were conducted on baseline and co-flow jet airfoils of the same plan form. The CFJ mechanism employs high pressure air injected along the span at the leading edge while a low pressure source removes the same amount of air along the span at the trailing edge. Hence, the net mass flux of the system is zero energy loss is minimized. The jet produced along the upper surface of the airfoil mixes with and excites the free stream flow resulting in increased lift, augmented stall margin, and decreased drag. At certain angles of attack the decreased drag is negative and thrust is produced. The research was comprised of four phases including computational fluid dynamics (CFD) simulations, design and manufacturing of a transformable baseline and adjustable slot size CFJ airfoil, implementation of a CFJ Wind Tunnel Laboratory, and wind tunnel testing. A computational fluid dynamics code, developed at the University of Miami, was used to study flow fields and to obtain analytical results of aerodynamic properties for the baseline and CFJ airfoils. Modeling of both wing shapes utilized the baseline ordinates of a cambered NACA 6415 airfoil. The free stream steady state flow was set to Mach=0.1 to simulate take-off and landing speeds where the co-flow jet mechanism would demonstrate its largest increase in performance. CFD simulations of both models provided aerodynamic coefficients as well as mass flow and jet effect data specifically useful to the CFJ airfoil. The NACA 6415 model used for wind tunnel testing was designed and produced to provide both baseline and CFJ results with adjustable injection and suction slot sizes. Connections for a side-mounted force balance and an air delivery system for the co-flow jet were included in the airfoil model. The design and manufacturing of a wind tunnel test section extension was necessary to provide support for the additional aerodynamic loads induced by the CFJ airfoil and to house various air connections and test sensors. A CFJ Wind Tunnel Laboratory was designed and constructed during the course of the research and included selection of proper air delivery apparatus for the injection and suction air for the CFJ jet. All testing controls and sensor equipment were acquired and installed to obtain various data needed for experimental analysis. Finally, a data acquisition system was designed to consolidate all testing information for ease of use. Wind tunnel testing of the baseline and CFJ airfoils provided the aerodynamic loads and coefficients needed to demonstrate the performance enhancements of the co-flow jet flow control method. Experimental and numerical results were examined to understand the benefits of the co-flow jet as it compares to a similar baseline airfoil. The CFD simulations and experimental measurements agree fairly well. All results indicate that the CFJ flow control method is very effective for a typical thin airfoil with 15% maximum thickness.