Dissertationen zum Thema „Experimental Jetset“
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Hofmans, Marlous. „Experimental characterization of helium plasma jets“. Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX062.
Der volle Inhalt der QuelleThis thesis studies an atmospheric pressure helium plasma jet that is powered by positive, unipolar pulses at a kHz frequency. Experiments are performed that focus on the propagation dynamics, flow structure and temperature in a freely expanding jet, as well as the influence of a metallic target on the plasma.Stark polarization spectroscopy yields an axial electric field of around 10 kV/cm in the capillary of the jet and an increase up to 20 kV/cm in the plume, which is constant for different amplitudes and durations of the applied voltage pulse. Thomson and rotational Raman scattering are used to determine the electron density and electron temperature, at different axial and radial positions, as well as the gas temperature and the density of N2 and O2 that are mixed into the helium from the surrounding air.Quantitative comparison of these experimental results with results from a 2D fluid model show a good agreement and allow for a better understanding of the obtained results, namely that the electric field in the ionization front depends linearly on the flow composition at that location. Schlieren imaging shows the onset of turbulent structures at high applied flow rates and at the application of the voltage pulses. The gas temperature, as measured by a temperature probe, is found to increase by around 12 C when the plasma is ignited and by around 25 C when a metallic target is placed in front of the jet
Kumar, Deepak Gould Roy Walter. „Experimental investigations of magnetohydrodynamic plasma jets /“. Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-04092009-163047.
Der volle Inhalt der QuelleCain, Terrence M. „An experimental study of under-expanded jets“. Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306018.
Der volle Inhalt der QuelleMeireles, Pedro M. S. „Experimental study of twin air impinging jets“. Master's thesis, Universidade da Beira Interior, 2009. http://hdl.handle.net/10400.6/2046.
Der volle Inhalt der QuelleEste trabalho baseia-se na visualização e caracterização do escoamento desenvolvido por dois jactos paralelos e verticalmente disposto em relação a uma superfície sólida. Estes fenómenos estão associados com aeronaves de descolagem e aterragem vertical ou curta (V/STOL – vertical/short take-of and landing). Particularmente, interessa a caracterização da região conhecida como “fountain upwash”, que é uma forma característica do escoamento que se forma na região da colisão. Os parâmetros analisados neste trabalho foram a distância horizontal entre os jactos e a altura destes à superfície de impacto. Foram observados diferenças significativas no padrão e propriedades do escoamento na região de “fountain upwash” devido à variação dos parâmetros em estudo. Para a realização deste estudo foi construída uma instalação experimental. A instalação é ajustável mecanicamente, contendo dois tubos de aço, com diâmetro variável. O sistema mecânico permite o ajustamento, independentemente, a distância horizontal entre os jactos e a altura dos mesmos. Como neste trabalho se vai trabalhar com ar, para ser possível visualizar o escoamento é necessário marcar o escoamento. Nesse sentido foi desenvolvido um gerador de “seeding”. Para uma melhor e mais precisa visualização do escoamento foi desenvolvido um algoritmo no “Matlab” usando “Image Processing toolbox”, onde as imagens captadas foram pós processadas.
Diebold, Benoît. „Etude experimentale des jets turbulents intracardiaques“. Paris 6, 1993. http://www.theses.fr/1993PA066353.
Der volle Inhalt der QuelleSvensson, Klas. „Experimental and Numerical Investigations of Confluent Round Jets“. Doctoral thesis, Linköpings universitet, Energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-117066.
Der volle Inhalt der QuelleAydemir, Erdoğan. „Experimental investigations into vortex rings in pulsed jets“. Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610792.
Der volle Inhalt der QuelleSoulopoulos, Nikolaos. „Experimental investigation of scalar mixing in unsteady turbulent jets“. Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508326.
Der volle Inhalt der QuelleSuzuki, Vidal Francisco Andres. „Experimental study of radiatively cooled magnetically driven plasma jets“. Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/54712.
Der volle Inhalt der QuelleKikkert, Gustaaf Adriaan. „Buoyant jets with two and three-dimensional trajectories“. Thesis, University of Canterbury. Civil Engineering, 2006. http://hdl.handle.net/10092/1126.
Der volle Inhalt der QuelleGómez, Ledesma Ramón. „An experimental investigation on the air entrainment by plunging jets“. College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1953.
Der volle Inhalt der QuelleThesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Findlay, Matthew J. „Experimental and computational investigation of inclined jets in a crossflow“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq27141.pdf.
Der volle Inhalt der QuelleGounder, James Dakshina. „An experimental investigation of non-reacting and reacting spray jets“. Phd thesis, School of Aerospace, Mechanical and Mechatronic Engineering, 2009. http://hdl.handle.net/2123/14424.
Der volle Inhalt der QuelleSegalini, Antonio <1983>. „Experimental analysis of coaxial jets: instability, flow and mixing characterization“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2474/1/segalini_antonio_tesi.pdf.
Der volle Inhalt der QuelleSegalini, Antonio <1983>. „Experimental analysis of coaxial jets: instability, flow and mixing characterization“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2474/.
Der volle Inhalt der QuelleKonduri, Indu Mohan. „Flow characteristics of jet fans in mines : experimental and numerical modeling /“. Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-152159/.
Der volle Inhalt der QuelleDogruoz, Mehmet Baris. „Experimental and Numerical Investigation of Turbulent Heat Transfer due to Rectangular Impinging Jets“. Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1370%5F1%5Fm.pdf&type=application/pdf.
Der volle Inhalt der QuelleFunk, Denise Reneé Martin. „Application of laser techniques to experimental studies of jets and plumes“. Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/21487.
Der volle Inhalt der QuelleMeares, Anthony John. „An experimental study of gas leak jets relevant to offshore structures“. Thesis, University of Hertfordshire, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245461.
Der volle Inhalt der QuelleELSHAMY, OMAR M. „EXPERIMENTAL INVESTIGATIONS OF STEADY AND DYNAMIC BEHAVIOR OF TRANSVERSE LIQUID JETS“. University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1179052529.
Der volle Inhalt der QuelleMane, Poorna. „Experimental Design and Analysis of Piezoelectric Synthetic Jets in Quiescent Air“. VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/768.
Der volle Inhalt der QuellePickworth, Louisa Alyce. „Experimental investigation of supersonic plasma jets colliding with thin metallic foils“. Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/15670.
Der volle Inhalt der QuelleRajakuperan, E. „Experimental And Computational Investigations Of Underexpanded Jets From Elliptical Sonic Nozzles“. Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/158.
Der volle Inhalt der QuelleRajakuperan, E. „Experimental And Computational Investigations Of Underexpanded Jets From Elliptical Sonic Nozzles“. Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/158.
Der volle Inhalt der QuelleSaltó, Bauzà Oriol. „Measurement of Inclusive Jet Cross Sections in Z/γ ∗( → e+e−) + jets Production in pp Collisions at √s = 1.96 TeV with the CDF Detector“. Doctoral thesis, Universitat Autònoma de Barcelona, 2008. http://hdl.handle.net/10803/3406.
Der volle Inhalt der QuelleAquesta tesi doctoral presenta la mesura de seccions eficaces inclusives de jets en esdeveniments amb Z/gamma*->ee utilitzant 1.7 fb-1 de dades obtingudes amb el detector CDF durant el Run II del Tevatron. L'algoritme de con Midpoint s'ha utilitzat per a buscar jets en els esdeveniments després d'haver identificat la presència d'un bosó Z/gamma* a través de la reconstrucció dels productes de la seva desintegració. Les mesures s'han comparat amb les prediccions del següent nivell (NLO) en pQCD per esdeveniments amb un o dos jets en l'estat final. Les prediccions pertorbatives s'han corregit per les contribucions de processos no-pertorbatius, com l'underlying event i la fragmentació dels partons en jets d'hadrons. Aquests processos no són descrits per la teoria de pertorbacions i s'han d'estimar amb models fenomenològics. En aquesta tesi, s'han realitzat un conjunt de mesures per a testejar diferents models d'underlying event i hadronització implementats en programes de Monte Carlo de LO més parton shower.
Quantum Chromodynamics (QCD) is the field theory that describes the strong interactions between quarks and gluons. The most prominent signature of QCD at hadron colliders is the production of collimated jets of hadrons. The measurement of the production of such jets in association with a vector boson, W or Z/gamma*, provides an stringent test of perturbative QCD (pQCD) calculations. Furthermore, some of new physics processes at hadron colliders, such as the production of Higgs bosons and supersymmetric particles, can be mimicked by the production of vector bosons in association with jets that constitute irreducible backgrounds to these searches. Therefore, the study and understanding of Z/gamma*+jets processes is a crucial part of the physics program of the Tevatron collider. At the Run I of the Tevatron, protons and antiprotons collided with an energy in the center-of-mass ps of 1.8 TeV. Z/gamma*+ jets production was studied during Run I with the CDF detector using 106 pb-1 of data. The measurements were compared to the predictions from leading order (LO) plus parton shower Monte Carlo generator programs. The comparisons were mainly dominated by the large scale uncertainties in the LO predictions. In Run II, the Tevatron and the CDF detector were upgraded and, among other important improvements, sqrt(s) was increased to 1.96 TeV. The good performance of the accelerator and the detector made available a larger amount of data, making possible precise differential measurements.
This Ph.D. thesis presents the measurement of inclusive jet cross sections in Z/gamma*(->ee) events using 1.7 fb-1 of data collected by the upgraded CDF detector during the Run II of the Tevatron. The Midpoint cone algorithm is used to search for jets in the events after identifying the presence of a Z/gamma* boson through the reconstruction of its decay products. The measurements are compared to next-to-LO (NLO) pQCD predictions for events with one and two jets in the final state. The perturbative predictions are corrected for the contributions of non-perturbative processes, like the underlying event and the fragmentation of the partons into jets of hadrons. These processes are not described by perturbation theory and must be estimated from phenomenological models. In this thesis, a number of measurements are performed to test different models of underlying event and hadronization implemented in LO plus parton shower Monte Carlo generator programs.
Sarkar, Arnab. „Numerical modeling and experimental studies on air impingement freezing under slot jets /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Der volle Inhalt der QuelleAmpleford, David John. „Experimental study of plasma jets produced by conical wire array z-pinches“. Thesis, Imperial College London, 2005. http://hdl.handle.net/10044/1/8511.
Der volle Inhalt der QuelleMoawad, Ahmed Kamal. „An experimental study of dilution and mixing with turbulent jets in crossflows“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq29082.pdf.
Der volle Inhalt der QuelleJanbakhsh, Setareh. „A Ventilation Strategy Based on Confluent Jets : An Experimental and Numerical Study“. Doctoral thesis, Linköpings universitet, Energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-117442.
Der volle Inhalt der QuelleGan, X. P. „Experimental and analytical studies of jets in quiescent or rotating flow fields“. Thesis, University of Bath, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278526.
Der volle Inhalt der QuelleNyantekyi-Kwakye, Baafour. „Experimental investigation on the flow characteristics of three-dimensional turbulent offset jets“. Taylor and Francis Group, 2015. http://hdl.handle.net/1993/31626.
Der volle Inhalt der QuelleOctober 2016
Andersson, Harald. „Numerical and experimental study of confluent jets supply device with variable airflow“. Licentiate thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29271.
Der volle Inhalt der QuelleUnder senare tid har applikation av Confluent jets för design av tilluftsdon studerats. Många studier har även utförts över potentialen av att applicera variabelt luftflöde (VAV) för att minska energianvändningen i ventilationssystem. Denna studie undersöker möjligheten att kombinera Confluent jets-don med VAV, både med avseende på den lokala flödesbilden och dess påverkan på termisk komfort, luftkvalitet och energieffektivitet i en klassrumsmiljö där luftflödes varieras. Denna studie baseras dels på en experimentell fältstudie där tilluftsdon baserade på Confluents jets jämfördes med befintliga deplacerande tilluftsdon. Fältstudien utvärderade energieffektiviteten, den termiska komforten och luftkvaliteten för båda typerna av tillluftsdon. Confluent jets-donen testades under varierat luftflöde för att se påverkan av flödesvariationen på ventilationens prestation under de olika flödena. Utöver fältstudien testades Confluent jets-donen experimentellt och numeriskt i ett välisolerat test-rum för få den detaljerade flödeskarakteristiken för den här typen tilluftsdon vid varierat luftflöde. Resultaten från fältstudien visar på en jämn fördelning av den lokala luftsmedelåldern i vistelsezonen, även för fallen med relativt låga luftflöden. Luftflöden har ingen signifikant effekt på omblandningen. Den termiska komforten i klassrummet ökade när luftflödet anpassades efter värmelasten jämfört med de deplacerande donen. Slutsatsen från fältstudien är att kombinationen av VAV och Confluent jets-don kan användas för att minska energianvändningen på skolan och bevara luftkvaliteten och den termiska komforten i vistelsezonen. Resultaten från den experimental och numeriska studien visar luftflödet och lufthastigheten i varje enskild dysa är direkt beroende på det totala luftflödet genom donet. Dock är flödesfördelningen mellan dysorna oberoende av de tre olika luftflödena. Den numeriska undersökningen visar att flödesprofilen för varje dysa är konstant trots att flödet varieras, men amplituden för varje profil ökar med en höjning av luftflödet. Det betyder att tilluftsdon av den här typen kan användas med VAV för att producera Confluent jets för olika luftflöden. Resultaten från båda studierna visar att luftflöde inte påverkar fördelningen av luften vare sig längs luftdonen eller på rumsnivå. Fördelningen av luften är nästan helt jämn längs donen och på rumsnivå är omblandningen och luftkvalitet den samma för varje luftflöde. Det betyder att det finns potential för att kombinera det här två teknikerna för att designa luftdistribueringssystem med hög energieffektivitet och hög termisk komfort med god luftkvalitet.
IBRAHIM, IRENE. „AN EXPERIMENTAL STUDY OF SINGLE AND TWIN TRANSVERSE JETS IN SUBSONIC CROSSFLOW“. University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141421705.
Der volle Inhalt der QuelleReeder, Mark Franklin. „An experimental study of mixing enhancement in jets with vortex generating tabs /“. The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859879941129.
Der volle Inhalt der QuelleAhmed, Zahir Uddin. „An experimental and numerical study of surface interactions in turbulent swirling jets“. Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1790.
Der volle Inhalt der QuelleCoss, Jérôme. „Etalonnage de l'énergie des jets dans l'expérience D0“. Phd thesis, Université Claude Bernard - Lyon I, 2003. http://tel.archives-ouvertes.fr/tel-00008636.
Der volle Inhalt der QuellePortell, i. Bueso Xavier. „Search for Gluino and Squark Production in Multi-jets plus Missing Transverse Energy Final States at the Tevatron using the CDF Detector“. Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3388.
Der volle Inhalt der QuellePrecisament l'escala energètica dels TeV és el rang d'energies accessible per al col·lisionador protó-antiprotó Tevatron (Fermilab). Tevatron i els seus dos experiments, els detectors CDF i D0 van ser preparats per l'anomenat "Run II" en el que les col·lisions se succeeixen cada 396 ns amb un centre de masses d'1.96 TeV. Degut a què les noves partícules són molt massives, es desintegren en cascades amb múltiples raigs de partícules (jets) d'alt moment transversal. Quan la paritat R es conserva, dos LSP són produïts que escapen del detector deixant un important desequilibri en el balanç energètic del succés.
Aquesta tesi tracta de la recerca de les super-parelles dels quarks (squarks) i gluons (gluinos) en múltiples jets i energia transversa mancant, amb les dades recollides amb el detector CDF durant gran part del Run II (371 pb-1 de lluminositat). Per aquest motiu, s'ha dut a terme un estudi curós de les condicions del feix i dels diferents processos del ME que tenen estats finals similars al senyal. Diferents talls per reduir la seva presència tot potenciant el possible senyal s'han estudiat i optimitzat. També s'han considerat les diferents fonts d'errors experimentals i teòrics per tal de fer una bona caracterització de les dades.
Observant les dades, no s'ha trobat cap desviació significativa de les prediccions del ME. Degut a aquests resultats, s'han posat límits inferiors a la massa squarks i gluinos (menor de 387 GeV/c2) en un determinat escenari del model teòric anomenat mSUGRA.
Aquest estudi és pioner al Run II de CDF i els resultats presenten millores significatives respecte a anteriors límits. En aquest sentit, el present treball constitueix la base i serà la referència per a futures extensions amb més dades.
Caminal, Armadans Roger. „Search for new phenomena in jets plus missing transverse energy final states at the LHC“. Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/287884.
Der volle Inhalt der QuelleThis thesis presents results on the search for new phenomena using 20.3 fb-1 of proton-proton collision data at √s = 8 TeV, recorded with the ATLAS experiment at the LHC. Events with a very energetic jet, large missing transverse energy, a maximum of three reconstructed jets, and no reconstructed leptons are selected, leading to a monojet-like final state. Six signal regions with thresholds on the leading jet pT and ET miss ranging between 280 GeV and 600 GeV have been defined, in order to have sensitivity to a number of models. The Standard Model processes entering in the signal regions are dominated by the irreducible Z(νν)+jets, that accounts for more than 50% of the total background. The second most important background is the W(τν)+jets, which passes the signal region selection requirements when the τ-leptons decay hadronically. Contributions from W(ℓν)+jets and Z(ℓℓ)+jets processes are also important, when the leptons are not reconstructed or are misreconstructed as jets. Other minor backgrounds like the top and diboson contributions add up to about 6% and are estimated directly from MC simulations. The multijet and non-collision background contributions, negligible in most of the signal regions, are estimated with dedicated data-driven methods. The use of control regions, allows to extract the normalizations of the different W/Z+jets processes, and to significantly reduce the total systematic uncertainty, from 20% to 30%, to values between 3% and 10%, for the different signal regions. Good agreement is found between the data and the Standard Model background estimations. The results are interpreted in terms of model independent 95% confidence level (CL) upper limits on the visible cross section. Values in the range between 96 fb and 5.2 fb are excluded. Exclusion limits at 95% CL are set, for models involving the direct pair production of third generation squarks in very compressed scenarios. In particular, stop and sbottom masses below 260 GeV are excluded. Limits on the direct production of first and second generation squarks, or the direct production of gluinos, are also computed. Masses for squarks and gluinos below 440 GeV and 600 GeV are excluded for compressed scenarios, respectively. These limits extend the previous results from other dedicated searches. The results of this analysis are also interpreted in terms of models in which Dark Matter (DM) candidates are directly produced. Models involving Weakly Interacting Massive Particles (WIMPs), light gravitinos in Gauge Mediated Supersymmetric (GMSB) scenarios, or the direct production of electroweakinos, are studied. Finally, the monojet results are interpreted in terms of the ADD model of large extra dimensions
Vieira, Marcelo Mendes. „Estudo experimental de jatos evaporativos“. Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-11042002-132126/.
Der volle Inhalt der QuelleAn experimental apparatus has been built to study the behaviour of flashing jets. An injector was designed to control and maintain the jet pressure and temperature at constant values during the injection process. A conical convergent nozzle whose main dimensions are 0,30 mm of exit diameter, 8 mm long, and a convergence half-angle of 10º is the central component of the injection system. The jet is discharged into a low-pressure chamber large enough to keep the reservoir pressure constant during the short test period of about 1 s. As the testing liquid expands in the nozzle it undergoes a sudden pressure drop causing its evaporation. The fluids are usual fuels, such as kerosene and diesel oil, and the substance ndodecane, which are distinguishable by the possibility of a complete evaporation in an isoentropic expansion process. The photographic method \"schlieren\" is used for flow visualisation. A qualitative analysis is made of the photographic documentation of the images obtained using a CCD camera. The images can be grouped into three categories of jets: (1) continuous, (2) shattering, and (3) with surface evaporation. The first regime has an undisturbed a liquid column, which remains more or less intact during the injection process. In the second type, the existing liquid jet is shattered by vapour nucleation and, in some cases, shock waves are clearly visible. It happens at higher temperature than the preceding evaporation mode. Finally, in special situations, the jet undergoes an evaporation at its surface and the two-phase mixture expands at a high speed followed by a shock wave before the mixture attains the pressure reservoir.
Xia, Liping. „An experimental and numerical investigation of a turbulent round jet issuing into an unsteady crossflow /“. Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19605377.
Der volle Inhalt der QuelleGilbertson, Mark. „Mixing in multiphase jet flow : experimental comparison with a computational model“. Thesis, University of Oxford, 1993. http://ora.ox.ac.uk/objects/uuid:98fae523-d738-4392-8b63-ab9cfbeaf37b.
Der volle Inhalt der QuelleScibilia-Cocheril, Marie-Françoise. „Contribution a l'etude des jets parietaux“. Paris 6, 1986. http://www.theses.fr/1986PA066539.
Der volle Inhalt der QuelleSegura, i. Solé Ester. „Simulation of the Measurement of the Inclusive Jet Cross Sections in Z(→e+e−/→µ+µ−)+jets Events in pp Collisions at 14 TeV witht he ATLAS experiment“. Doctoral thesis, Universitat Autònoma de Barcelona, 2009. http://hdl.handle.net/10803/3421.
Der volle Inhalt der QuelleATLAS és un dels experiments del LHC. A més a més del descobriment de nova Física en el seu programa, també està inclosa la investigació de la Física ja coneguda. Un millor coneixement de la teoria pertorbativa de Quantum Chromodynamics és un dels objectius d'ATLAS. QCD és la teoria que descriu les interaccions fortes entre quarks i gluons. Aquesta teoria encara roman sense resoldre, ja que no exiteix un mètode d'aproximació vàlid per qualsevol escala d'energies. La teoria pertorbativa de QCD pot descriure un gran nombre d'interaccions a altes energies. El seu formalisme ha donat una eina molt valuosa dins l'estudi de les interaccions fortes.
La signatura més notable dels processos QCD en col.lisionadors d'hadrons és la producció de jets de partícules col.limats. La mesura d'aquests jets en associació amb un bosó vector, W o Z, proporciona un test estricte dels càlculs de la teoria pertorbativa de QCD. A més, alguns dels processos de la nova Física, com la producció del bosó Higgs o de partícules supersimètriques, poden ser imitats per la producció dels bosons vectros en associació amb jets, que constitueixen un background irreduïble a l'investigació d'aquests nous processos.
Aquesta tesi presenta la mesura de la "inclusive jet cross section" en events amb un bosó Z(e,e,) o Z(mu,mu), comparant les prediccions teòriques amb les dades "real", i.e. events Monte Carlo "fully-reconstructed", pel primer 1fb-1 de dades obtingudes amb el detector ATLAS. Les dades reconstruïdes i corregides es comparen amb les prediccions de la teoria pertorbativa de QCD a nivell NLO i LO. Aquestes prediccions pertorbatives es corregeixen amb les contribucions de processos no pertorbatius, com l'underlying event o la fragmentació dels partons dins dels jets d'hadrons. Aquests processos no poden ser descrits per la teoria pertorbativa, i s'estimen amb models fenomenològics. S'han utilitzat dos tipus diferents de dades reconstruides Monte Carlo, ALPGEN i PYHTIA. S'han estudiat les comparacions entre les prediccions d'ambdós generadors. Els processos background han estat estimats utilitzant diferents mètodes "data-driven". Per la recerca dels jets, s'ha utilitzat l'algoritme ATLAS Cone 0.4, després d'identificar la presència d'un bosó Z mitjançant la reconstrucció del seu decaiment (electrons o muons). Les dades reconstruides han estat corregides pels efectes del detector, utilitzant factors independents.
Aquest anàlisi ha estat realitzat abans que ATLAS recollís les primeres dades reals, abans de l'inici del LHC, per aquest motiu aquesta tesi es basa en dades simulades amb generadors Monte Carlo. Mentres dura la preparació d'un experiment de Física d'altes energies com ATLAS, aquestes simulacions són molt importants pel desenvolupament d'estratègies eficaces d'anàlisi de dades i reconstrucció d'objectes físics mesurats pel detector.
Después de 20 años de preparación, el LHC va a encenderse a finales del 2009, colisionando protones a una energia de 14 TeV, para recrear los primeros momentos después del Big Bang. Las partículas serán aceleradas a lo largo del tunel circular de 27 km de circumferencia hasta velocidades próximas a la de la luz. El túnel, situado cerca de Ginebra, y sus experimentos forman uno de los más grandes esfuerzos de la história para estudiar la estructura fundamental de la materia. Se espera que a estas elevadas energías de colisión, nuevos fenómenos físicos puedan ocurrir y sean descubiertos. Entre los resultantes escombros de las colisiones entre protones, evidencias de dimensiones extras, de la misteriosa materia oscura que inunda nuestro universo o de la partícula de Higgs que da masa a las partículas elementales serán observadas.
ATLAS es uno de los experimentos del LHC. Además del descubrimiento de nueva Fisica en su programa, también está la investigación de la Fisica ya descubierta. Un mejor conocimiento de la teoría perturbativa de Quantum Chromodynamics es uno de los objetivos de ATLAS. Quantum Chromodynamics es la teoria de campos que describe las interacciones fuertes entre quarks y gluones. Esta teoría todavia permanece sin resolver, ya que no existe un método de aproximación válido para cualquier escalada de energía. La teoría perturbativa de QCD puede describir un gran numero de interacciones a altas energías. Su formulismo ha dado una herramienta muy valiosa en el estudio de las interacciones fuertes.
La signatura más notable de procesos QCD en collisionadores de hadrones es la producción de jets colimados de hadrones. La medición de estos jets en asociación con un bosón vector, W o Z, proporciona un test severo de los cálculos de la teoría perturbativa de QCD. Además, algunos de los procesos de nueva Física en los colisionadores de hadrones, como la production del boson de Higgs o de partículas supersimétricas, pueden ser imitados por la producción de bosones vectores en asociación con jets, que constituyen un background irreducible a la investigación de estos nuevos procesos.
Esta tesis presenta la medida de la "inclusive jet cross section" en sucesos con un boson Z (ee) o Z(mu,mu), comparando las prediciones teoricas con los datos "reales", i.e. sucesos Monte Carlo "fully-reconstructed", para el primer 1fb-1 de datos obtenidos con el detector ATLAS. Los datos reconstruidos y corregidos son comparados a las predicciones de la teoria perturbativa de QCD a nivel NLO y LO. Estas predicciones perturbativas se corrigen con las contribuciones de procesos no perturbativos, como el underlying event o la fragmentación de los partones en jets de hadrones. Estos procesos no pueden ser descritos por la teoria perturbativa, y son estimados con modelos fenomenologicos. Se han ultilizado dos tipos distintos de datos reconstruidos Monte Carlo, ALPGEN y PYTHIA. Comparaciones entre las predicciones de ambos generadores Monte Carlo han sido estudiadas. Los procesos background han sido estimados usando distintos métodos "data-driven". Para la búsqueda de jets se ha usado el algoritmo ATLAS Cone 0.4 jet, después de identificar la presencia de un bosón Z a través de la reconstrucción de su decaimiento (electrones o muones). Los datos reconstruidos son corregidos por los efectors del detector, usando factores independientes.
Este analisis ha sido realizado antes que ATLAS recogiera los primeros datos reales, antes del inicio del LHC, por este motivo esta tesis esta basada en datos simulados con generadores Monte Carlo. Mientras dura la preparación de un experimento de fisica de altas energías como ATLAS, estas simulaciones son de vital importancia para el desarrollo de estrategias eficaces de analisis de datos y reconstrucción de objetos físicos medidos por el detector.
After 20 years of preparation, the Large Hadron Collider is going to be switched on in late 2009, smashing protons at an energy of 14 (10) TeV, to recreate the first moments after the Big Bang. Particles will whizz around a circular tunnel of 27 km in circumference at near light speed. The tunnel, built near Geneva, and its experiments constitute one of the largest coordinated efforts ever made to study the fundamental structure of nature. It is expected that at the energies reached in the proton-proton collisions at the LHC, unknown physical phenomena will have to occur and will be observable. Among the particle debris may lie evidence for extra dimensions, mysterious dark matter that pervades the universe or the Higgs boson, which gives mass to elementary particles.
ATLAS is one of the LHC experiments. Besides the new phenomena goals in its physics program, there is the understanding of the already known physics. The better understanding of perturbative Quantum Chromodynamics theory is one of the aims of ATLAS. Quantum Chromodynamics is the field theory which describes the strong interaction between quarks and gluons. It remains an "unsolved" theory, since no single approximation method can be used to all length scales. Perturbative QCD naturally describes a large set of high-energy, large-momentum-transfer cross sections and its formalism has provided an invaluable tool in the study of the strong interactions. The most prominent signature of QCD at hadron colliders is the production of collimated jets of hadrons. The measurement of the production of such jets in association with a vector boson, W or Z, provides a stringent test of perturbative QCD (pQCD) calculations. Furthermore, some of new physics processes at hadron colliders, such as the production of Higgs bosons and supersymmetric particles, can be mimicked by the production of vector bosons in association with jets that constitute irreducible backgrounds to these searches.
This PhD. thesis presents the measurement of the inclusive jet cross section in Z → e+e− and in Z → μ+μ− events, comparing theory predictions with "real data", i.e. Monte Carlo fully-reconstructed events, for the first 1fb−1 of data at the ATLAS detector. Reconstructed corrected data is compared to next-to-LO (NLO) and LO pQCD predictions. Perturbative predictions are corrected for the contributions of the non-perturbative processes, like the underlying event and the fragmentation of the partons into jets of hadrons. These processes are not described by perturbation theory and must be estimated using phenomenological models. Two different reconstructed data are used, PYTHIA and ALPGEN Monte Carlo data. Comparisons of both Monte Carlo predictions are studied. Background processes are estimated proposing different data-driven methods to be applied to real data. ATLAS Cone 0.4 algorithm is used to look for jets in the events after identifying the presence of a Z boson through the reconstruction of its decay (electrons or muons). Reconstructed data is corrected for detector effects, using independent factors.
As this work was carried out before the "physics-data" start of the LHC, the presented studies are based on Monte Carlo simulations. During the preparation of a high-energy collider experiment, such simulations are important to develop efficient strategies for data analysis and for the reconstruction of the physics objects observed with the detectors.
Karimipanah, Taghi. „Turbulent jets in confined spaces : application in mixing ventilation: experimental and numerical studies“. Doctoral thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17832.
Der volle Inhalt der QuelleHarby, Mohamed Abd Alaal Khaled. „Experimental and Theoretical Study of the Characteristics of Submerged Horizontal Gas Jets and Vertical Plunging Water Jets in Water Ambient“. Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/18065.
Der volle Inhalt der QuelleHarby Mohamed Abd Alaal, K. (2012). Experimental and Theoretical Study of the Characteristics of Submerged Horizontal Gas Jets and Vertical Plunging Water Jets in Water Ambient [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18065
Palancia
Lima, de Assunção Thiago. „Experimental study of underexpanded round jets : nozzle lip thickness effects and screech closure mechanisms investigation“. Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2327/document.
Der volle Inhalt der QuelleThis work provides an experimental contribution to the study of the Screech phenomenon. Various experimental techniques such as microphones array, Schlieren and Particle Image Velocimetry (PIV) together with advanced post-processing techniques like azimuthal Fourier decomposition and Proper Orthogonal Decomposition (POD) are employed. These techniques enable the evaluation of the lip thickness effects on the jets generated by two different round nozzles. The differences on the flow aerodynamics and acoustics are discussed. Then, we carry out experiments to analyse the effects of the different dominant Screech modes (B and C) on the flow characteristics. No noticeable differences are found in the mean fields. However, the fluctuation fields shows the contrary: B mode has larger fluctuation. In the last part, we investigate the Screech closure mechanism. The signature of upstream jet waves is revealed in the axisymmetric (A2) and helical (C) mode. However, the mode B does not present evidence of this instability in the flow, indicating that its closure mechanism may be bonded to another kind of waves. The conclusion from the results is that the Screech phenomenon seems be driven by different closure mechanisms
Hipp, Kyle D. „Control of a Post-Stall Airfoil Using Pulsed Jets“. The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1458565037.
Der volle Inhalt der QuelleWoyciekoski, Marcos Leandro. „Estudo experimental de jatos sintéticos para resfriamento“. Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4769.
Der volle Inhalt der QuelleMade available in DSpace on 2015-08-27T23:08:49Z (GMT). No. of bitstreams: 1 MarcosWOYCIEKOSKI.pdf: 2220255 bytes, checksum: 001c865faf4b29be82c72c3341fa51a4 (MD5) Previous issue date: 2012-03
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Com a rápida evolução da tecnologia, os dispositivos eletrônicos tornaram-se compactos e com o alto poder de processamento, aumentando a geração de calor. Mas devido à baixa eficiência de ventiladores e dissipadores utilizados atualmente, há a necessidade de desenvolver novas formas de resfriamento. O uso de jatos sintéticos no resfriamento de dispositivos eletrônicos ainda é incipiente. Estudos monstram que este método pode ser uma alternativa eficaz. Assim, neste trabalho foi desenvolvido um estudo experimental com jatos sintéticos onde foram analisadas diferentes configurações de jatos com orifício retangular. Um alto-falante foi utilizado como diafragma e excitado através de um gerador de sinais senoidais para produzir o jato. A frequência de ressonância era desconhecida e foi necessário analisá-la antes de iniciar o experimento. O sistema foi montado em um suporte móvel para que fosse possível variar a posição vertical do gerador de jatos. Foram analisadas as dimensões do orifício para diferentes diâmetros hidráulicos (4 – 8 mm) e razões de aspecto (2 – 4), como também a profundidade da cavidade (2 – 8 mm). Também se analisou a transferência de calor através do impacto de jatos sobre uma placa aquecida. Dentre os estudos, verificaram-se outros parâmetros como o número de Reynolds e o número de Strouhal a fim de calcular a frequência mais adequada para a produção de vórtices. Os resultados demonstraram que para orifícios retangulares, as configurações com diâmetro hidráulico maior e razão de aspecto menor, são as melhores opções para resfriamento dos dispositivos eletrônicos.
With the rapid evolution of technology, electronics have become more compact and with higher processing power, increasing heat generation. Thus, there is a need to develop new forms of cooling, due to the low efficiency of cooling fans and heatsinks used currently. Using synthetic jets for cooling electronic device is still incipient but studies show that this method is an effective alternative. Thus, this work was developed an experimental study with synthetic jets where different configurations were tested with rectangular orifice. A loudspeaker was used as diaphragm and it was excited by a sinusoidal signal generator to produce the jet. The previously unknown ressonant frequency was determined experimentaly as part of this study. The system was mounted on a vertical traverse to allow changes in the vertical position of the synthetic jet generator. Orifice dimensions were analyzed covering variations in hydraulic diameter (4-8 mm) and aspect ratio (2-4), as well as the depth of the cavity (2-8 mm). Also the heat transfer was examined through the jet impingement on a hot plate. Other parameters such as Reynolds and Strouhal number were also examined in order to calculate the best frequency for jet performance. Results show that for rectangular orifice, geometries with larger hydraulic diameter and aspect ratio smaller are the best options for electronic cooling devices.
Brown, Gareth John Ashley. „Precision measurement of jets at the ATLAS experiment“. Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/precision-measurement-of-jets-at-the-atlas-experiment(bfc667ea-6c99-445d-8a22-6c673f50751a).html.
Der volle Inhalt der QuelleMontejo, Berlingen Javier. „Search for new physics in tt nal states with additional heavy-flavor jets with the ATLAS detector“. Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/295972.
Der volle Inhalt der QuelleThis dissertation presents searches in tt final states with additional heavy-flavor jets using 20.3 fb-1 of pp collision data at √s = 8 TeV, recorded with the ATLAS experiment at the LHC. Exploiting this final state, three analyses are presented that address the instability of the Higgs boson mass from different perspectives. The main challenge for the presented analyses lies in the precise modeling of the background, in particular tt+bb. Since no measurements have been performed yet on the tt production with additional heavy-flavor jets, the analyses have to rely on Monte Carlo (MC) simulation for the background. Recent developments in MC simulation have improved the description of the background, and a great effort is invested in porting the state-of-the-art predictions into the analyses. The systematic uncertainties on the modeling of the tt+bb background constitute the main source of sensitivity degradation. In order to reduce the impact of the systematic uncertainties, the analyses use a profile likelihood fit to reduce in-situ the leading uncertainties. A detailed statistical analysis is performed in order to test for the presence of a signal in the observed data. The first of the analyses aims to study the ttH process and to measure its production rate, from which the top Yukawa coupling can be extracted. Neural networks are used to discriminate the ttH signal from the background, where the most discriminant variable stems from the matrix element method. No evidence for the ttH process is found, and a 95% confidence level (CL) upper limit is set, excluding a signal 3.6 times larger than predicted by the SM. Performing a signal-plus-background fit the best fitted value for the signal strength is found to be: μ = 1.2±1.3. A search for vector-like top partners and four-top-quark production is presented, addressing several models that predict such signatures. The analysis of events with high jet and b-tag multiplicity, as well as multiple high-pT objects allows increasing the sensitivity of the search. No excess over the background expectation is found and 95% CL upper limits are set in different models. The same search is also used to establish limits on models predicting four-top-quark final states. Exclusion limits are set on SM tttt production, tttt production via an effective field theory model with a four-top contact interaction, sgluon pair production and Kaluza-Klein modes production. As last, a search for bosonic top partners, or stops, is presented, addressing supersymmetric models where traditional searches have little sensitivity. A search for the heavier stop, t2, is performed targeting models where the t1 is light and the mass difference to the neutralino is close to the top mass. No excess over the background expectation is found and 95 % CL upper limits are set for different masses in the mt2−mχ. For representative values of the masses exclusion limits are set as a function of the t2 branching ratios. The analyses presented constitute the most sensitive searches to date in their respective channels.