Дисертації з теми "Cascade dynamics"
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Nackley, Brittany B. "Temporal Dynamics of the Defense Cascade." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99987.
Повний текст джерелаM.S.
The more we understand about how people’s bodies and their energies act when they feel threatened, the better we can find help for folks who struggle with anxiety, trauma or other challenging conditions. This research uses a theoretical model called the defense cascade to explore how people respond mentally and physically to threatening situations. Nineteen undergraduates went through a virtual reality (VR) experience that was designed to feel threatening while their body and its energy systems were measured. A scale was introduced called the Subjective Units of Distress Scale (SUDS) and was used to help the researchers understand how distressed people felt while they were in the VR experience. Averaged SUDS reports suggested that the VR stimulus was experienced as threatening for most participants, but their body response patterns did not fit those predicted by the defense cascade. Participants whose questionnaire responses suggested they were not anxiety-prone or traumatized, tended to show bodily activation that uncoupled their two autonomic bodily systems during a baseline period before the threatening stimulus. However, their autonomic responses during the stimulus period varied. Nearly all participants showed either both autonomic systems acting together or only one system acting in a mutually exclusive way to the other system during the stimulus period. This was the case for most participants except those reporting the most trauma involving dissociative experiences. This latter group mostly showed uncoupled autonomic bodily patterns.
Monaco, Jeffrey Francis. "Supersonic flows of Bethe-Zel'dovich-Thompson fluids in cascade configurations." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06112009-063024/.
Повний текст джерелаZambonini, Gherardo. "Unsteady dynamics of corner separation in a linear compressor cascade." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEC049/document.
Повний текст джерелаThe present work focuses on the study of the corner separation phenomenon in compressors carried out by experimental investigations on a subsonic linear cascade test rig (Re=3.8x105, M=0.12, blade profile NACA 65-009). Usually, this particular three-dimensional separation takes place in the corner between the blade and the endwall of compressor rows, mostly at hub, both in stators and rotors.Its main features are high total pressure losses and blockage of the flow, with consequent impacts on the efficiency. Whereas time averaged characteristics are well known from the past, only recent advanced experimental studies and improvements of numerical simulations, such as URANS and LES, have permitted to uncover the highly unsteady behavior of corner separation in compressors. Precedent studies on the same test rig have reported an intermittent unsteady behavior of corner separation, called bimodal behavior. In the present thesis it is shown that the bimodal behavior corresponds to two specific states of the flow: a closed separation, almost suppressed, and an open separation characterized by massive blockage and losses. Clearly hub-separation bimodal switches appearing in a real machine could have a first order detrimental effect on the stability of the flow in the compressor. By using high speed PIV coupled with unsteady pressure measurements on the surface of the blade the flow in a single blade passage has been investigated for different incidences. The PIV measurements provide, for the first time, time-resolved flow visualizations of the size switch of the separation with an extended field of view covering the entire blade section. The interaction of random large structures of the incoming boundary layer with the blade is found to be a predominant element that destabilizes the separation boundary and enlarges the recirculation region. Such a massive separation persists until the blockage in the passage causes the breakdown of the largest structures in the aft part of the blade, reestablishing the closed separation state. Such dynamics coincide with the aperiodic intermittent flow regime of diffusers, called transitory stall regime, and the associated Fourier spectra show the largest energy amplitudes in the low frequency range. Conditional ensemble averages of pressure and proper orthogonal decomposition (POD) of velocity fields have been applied to show the feedback effect of the blockage of the separation on the flow angle around the blade leading edge. These results draw the picture of a self-sustained instability caused by the diffusion imposed by the inter-blade passage. To answer the question about the interaction between adjacent corner separations, time-resolved total pressure measurements have been carried out by using high frequency response sensors positioned in bimodal points of multiple passages. The coherent propagation velocity and the linearity of the phase angle found between the signals confirm that the unsteadiness of the separation can propagate in pitch-wise direction. It is interesting to underline that equivalent elements characterize rotating disturbances appearing in annular test rigs. This finally shows that, even in an isolated stator blade row, the intrinsic unsteadiness of corner separation can start the propagation of instabilities. It is the first time that such a propagation effect is observed in a linear compressor cascade
Kiss, Tibor. "Experimental and numerical investigation of transonic turbine cascade flow." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-02022007-133636/.
Повний текст джерелаZaccaria, Michael A. "Development of a transonic turbine cascade facility." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53201.
Повний текст джерелаMaster of Science
Rodger, Philippe (Philippe William) Carleton University Dissertation Engineering Aerospace. "Establishing two-dimensional flow in the large-scale planar turbine cascade." Ottawa, 1992.
Знайти повний текст джерелаCarneal, James P. "Experimental investigation of reversed flow in a compressor cascade." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42096.
Повний текст джерелаMoore, H. "Experiments in a turbine cascade for the validation of turbulence and transition models." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5356/.
Повний текст джерелаMenzel, Stefan. "Intraband Electron Dynamics in new materials and designs for quantum cascade lasers." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500220.
Повний текст джерелаFriart, Gaetan. "Semiconductor laser dynamics: two polarization feedback, quantum cascade lasers, and ring lasers." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/248835.
Повний текст джерелаLes lasers à semi-conducteur sont sensibles aux perturbations externes et celles-ci peuvent déstabiliser leur faisceau de sortie d’intensité constante. Ceci est particulièrement marquant quand le laser à semi-conducteur est sujet à un feedback optique, c’est-à-dire quand une partie de la lumière sortant du laser est réinjectée dans sa cavité après réflexion par un miroir distant. Pour certaines applications, cela représente une nuisance que l’on souhaite éviter. Mais le feedback optique peut aussi engendrer des régimes dynamiques utiles pour de nouvelles applications. Dans cette thèse, nous étudions différents problèmes où un laser à semi-conducteur est soumis à un feedback retardé ou à un signal injecté. Nos travaux sont motivés par de récentes expériences, des questions technologiques ou des phénomènes dynamiques particuliers. Nous combinons des techniques analytiques, des simulations numériques ainsi que des expériences afin d’analyser les mécanismes de bifurcation menant à une large variété de régimes oscillants.Nous étudions en premier lieu la dynamique d’un laser à semi-conducteur soumis à un feedback avec rotation de la polarisation. Nous examinons, à la fois théoriquement et expérimentalement, la séquence de bifurcations menant à des oscillations sous forme d’ondes carrées. Nous mettons en évidence une multistabilité entre différentes ondes carrées de périodes spécifiques. Nous introduisons alors un mécanisme de contrôle qui nous permet de sélectionner l’onde carrée désirée. Nous analysons ensuite les frontières de stabilité d’un laser à semi-conducteur à deux polarisations soumis à une injection optique. Nous montrons que si les gains des deux modes de polarisation sont suffisamment proches, un état stationnaire mixte stable peut exister. Nous explorons également les conditions permettant une bistabilité entre un état stationnaire pur et un état stationnaire mixte. Les lasers à cascade quantique sont de nouveaux lasers à semi-conducteur prometteurs qui possèdent une forte tolérance au feedback optique. Nous examinons de façon systématique leur stabilité dans la limite des grands retards. Nous montrons que des instabilités oscillantes sont cependant possibles pour de faibles valeurs du courant de pompe. Le dernier dispositif que nous étudions dans cette thèse est le laser à semi-conducteur en anneau soumis à un feedback optique. Nous identifions le mécanisme de bifurcation, appelé pont de bifurcation, responsable des instabilités oscillantes dans le faisceau de sortie du laser. Ces oscillations sont indésirables pour la plupart des applications impliquant de tels lasers. Nous montrons qu’elles peuvent être évitées en contrôlant la phase du feedback.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Wang, Cheng. "Modulation dynamics of InP-based quantum dot lasers and quantum cascade lasers." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0009/document.
Повний текст джерелаHigh performance semiconductor lasers are strongly demanded in the rapidly increasing optical communication networks. Low dimensional nanostructure lasers are expected to be substitutes of their quantum well (Qwell) counterparts in the next-generation of energy-saving and high-bandwidth telecommunication optical links. Many efforts have been devoted during the past years to achieve nanostructure lasers with broad modulation bandwidth, low frequency chirp, and reduced linewidth enhancement factor. Particularly, 1.55-μm InP-based quantum dash (Qdash)/dot (Qdot) lasers are preferable for long-haul transmissions in contrast to the 1.3-μm laser sources. In this dissertation, we investigate the dynamic characteristics of InPbased nanostructure semiconductor lasers operating under direct current modulation, including the amplitude (AM) and frequency (FM) modulation responses, the linewidth enhancement factor (also known as α-factor), as well as large-signal modulation responses. Using a semi-analytical analysis of the rate equation model, it is found that the modulation bandwidth of the quantum dot laser is strongly limited by the finite carrier capture and relaxation rates. In order to study the α- factor and chirp properties of the quantum dot laser, we develop an improved rate equation model, which takes into account the contribution of carrier populations in off-resonant states to the refractive index change. It is demonstrated that the α-factor of quantum dot lasers is strongly dependent on the pump current as well as the modulation frequency, in comparison to the case of Qwell lasers. The α-factor remains constant at low modulation frequencies (<0.1 GHz) and higher than the value derived at high modulation frequencies (beyond several GHz) from the FM/AM technique. These unique features are mostly attributed to the carrier populations in off-resonant states. Further simulations show that the α-factor can be reduced by enlarging the energy separation between the resonant ground state (GS) and off-resonant states. Lasing from the excited state (ES) can be a promising alternative to enhance the laser’s dynamic performance. The laser exhibits a broader modulation response and the α-factor can be reduced by as much as 40%. The optical injection technique is attractive to improve the laser’s dynamical performance, including bandwidth enhancement and chirp reduction. These are demonstrated both theoretically and experimentally. The phase-amplitude coupling property is altered as well in comparison with the free-running laser and the optical gain depends on the injection strength and the frequency detuning. This work proposes a new method derived from the Hakki-Paoli method, enabling to measure the α-factor of semiconductor lasers under optical injection both below and above threshold. In addition, it is demonstrated theoretically that the α-factor in nanostructure lasers exhibits a threshold discontinuity, which is mainly attributed to the unclamped carrier populations in the off-resonant states. It is a fundamental limitation, preventing the reduction of the α-factor towards zero. Quantum cascade (QC) lasers rely on intersubband electronic transitions in multi-quantum well heterostructures. QC lasers show flat broadband AM response (tens of GHz) without resonance, which constitutes promising features for free-space communications. Surprisingly, calculations show that the QC laser exhibits an ultrabroad FM bandwidth on the order of tens of THz, about three orders of magnitude larger than the AM bandwidth. Optically injection-locked QC lasers also exhibit specific characteristics by comparison to interband semiconductor lasers. Both positive and negative frequency detunings enhance the modulation bandwidth
Grove, Darren V. "Experimental and numerical investigation of second-generation, controlled-diffusion, compressor blades in cascade." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA333407.
Повний текст джерелаShaffer, Damon M. "Reynolds stress measurements downstream of a turbine cascade." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/45735.
Повний текст джерелаMaster of Science
Mezynski, Alexis. "Measurements of pressure and thermal wakes in a transonic turbine cascade." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06112009-063252/.
Повний текст джерелаChesnakas, Christopher J. "Experimental studies in a supersonic through-flow fan blade cascade." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39790.
Повний текст джерелаPh. D.
Eickemeyer, Felix. "Ultrafast dynamics of coherent intersubband polarizations in quantum wells and quantum cascade laser structures." Doctoral thesis, [S.l.] : [s.n.], 2002. http://dochost.rz.hu-berlin.de/dissertationen/eickemeyer-felix-2002-07-03.
Повний текст джерелаGlova, Michael A. "Experimental verification of the flow around compressor blades in cascade at stall with initial numerical simulations." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FGlova.pdf.
Повний текст джерелаThesis Advisor(s): Garth V. Hobson. "March 2006." Includes bibliographical references (p. 69-70). Also available online.
Horne, Kyle S. "Nano-scale Thermal Property Prediction by Molecular Dynamics Simulation with Experimental Validation." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3089.
Повний текст джерелаSpitz, Olivier. "Mid-infrared quantum cascade lasers for chaos secure communications." Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT054.
Повний текст джерелаThe mid-infrared domain is a promising optical domain because it holds two transparency atmospheric windows, as well as the fingerprint of many chemical compounds. Quantum cascade lasers (QCLs) are one of the available sources in this domain and have already been proven useful for spectroscopic applications and free-space communications. The purpose of that dissertation is to go one step further by implementing a secure free-space communication relying on optical chaos and consequently, to give an accurate cartography of non-linear phenomena in quantum cascade lasers. Initial efforts about free-space secure chaotic transmission have been carried out during this Ph.D. thesis with two chaos-synchronized QCLs, which is a pioneer result paving the way for mid-infrared private communications. In order to have a global picture about the non-linear dynamics in QCLs under external optical feedback, we tuned many experimental parameters and this allowed us studying new phenomena in QCLs. We thus found similarities between QCLs and laser diodes when the chaotic dropouts are synchronized with an external modulation, known as the entrainment phenomenon. A cross-polarization reinjection technique led to square-wave emission in the output of the QCL. Eventually, we studied the triggering of rogue waves in QCLs. Rogue waves are a quite common phenomenon in optics (among other domains in science) but they have never been triggered on-demand in semiconductor lasers under external optical feedback before. Further studies will try to avoid such phenomenon in the output of a QCL under external optical feedback since it can disturb the message to be transmitted in a secure communication. All these experimental results allowed a better understanding of the non-linear dynamics of QCLs and will extend the potential applications of this kind of semiconductor lasers, which have currently been restricted to molecular spectroscopy and optical countermeasure systems
Rogers, Daniel R. "Design of a Three-Passage Low Reynolds Number Turbine Cascade with Periodic Flow Conditions." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2684.pdf.
Повний текст джерелаAinslie, Walter E. "The effect of solidity on the pre- and post-stall flow in a linear compressor cascade." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43579.
Повний текст джерелаAn experimental investigation of the performance characteristics of a solid wall linear compressor cascade was conducted. The purpose of the experiments was to determine the effects of the blade row configuration parameters stagger and solidity on the pre-and post-stall behavior of the flow in the cascade. Tests were conducted at a solidity of 1.5, and for two stagger angles, 36.4 degrees and 25 degrees.
The investigation included the use of high speed motion pictures with smoke flow visualization in the cascade, measurements of the total pressure and velocity of the flow upstream and downstream of the cascade, and measurements of the blade surface pressures. The experiments were conducted for a range of angle of attack from 0 degrees to 45 degrees.
To determine the effects of solidity on the pre- and post-stall behavior of the flow in the cascade, the results obtained for the present 1.5 solidity cascade were compared to previous results from the same cascade tested at a solidity of 1.0. The flow in the two cascades was observed to be similar in nature, but the influence of the reduced blade loading in the high solidity cascade was apparent. For the higher solidity cascade, flow losses at low angle of attack were found to be larger, but stalling behavior was delayed.
Master of Science
Jumpertz, Louise. "Photonique non-linéaire dans les lasers à cascade quantique moyen infrarouges." Electronic Thesis or Diss., Paris, ENST, 2016. https://pastel.hal.science/tel-03689516.
Повний текст джерелаMid-infrared quantum cascade lasers are unipolar semiconductor lasers, which have become widely used sources for applications such as gas spectroscopy, free-space communications or optical countermeasures. Applying external per-turbations such as optical feedback or optical injection leads to a strong modification of the quantum cascade laser prop-erties. Optical feedback impacts the static properties of mid-infrared Fabry-Perot and distributed feedback quantum cas-cade lasers, inducing power increase, threshold reduction, modification of the optical spectrum, which can become either single- or multimode, and enhanced beam quality of broad-area transverse multimode lasers. It also leads to a different dynamical behavior, and a quantum cascade laser subject to optical feedback can oscillate periodically or even become chaotic: this work provides the very first analysis of optical instabilities in the mid-infrared range. A numerical study of optical injection furthermore proves that quantum cascade lasers can injection-lock over a few gigahertz, where they should experience enhanced stability and especially improved modulation bandwidth. Furthermore, some promising dynamics appear outside the locking range with periodic oscillations at a tunable frequency or high-intensity events. A quantum cascade laser under external control could therefore be a source with enhanced properties for the usual mid-infrared applications, but could also address new applications such as tunable photonic oscillators, extreme events gen-erators, chaotic LIDAR, chaos-based secured communications or unpredictable countermeasures
Walker, Richard James. "Quantum cascade laser spectroscopy : developments and applications." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:5021ac50-c69d-4a1d-8071-e59ffed9fcb8.
Повний текст джерелаMcDonald, William J. "Design and computational analysis of aerodynamics in an annular cascade." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1112.
Повний текст джерелаBachelors
Engineering and Computer Science
Aerospace Engineering
Le, Roy Pascal. "Cascade inverse et dispersion turbulente en turbulence bidimensionnelle." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1988. http://tel.archives-ouvertes.fr/tel-00529772.
Повний текст джерелаFitzgerald, Kevin D. "Examination of flow around second-generation controlled diffusion compressor blades in cascade at stall." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FFitzgerald.pdf.
Повний текст джерелаDubos, Thomas. "Cascade bidimensionnelle d'un traceur : diagnostic dans l'espace physique et modélisation." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2001. http://tel.archives-ouvertes.fr/tel-00007421.
Повний текст джерелаArisi, Allan Nyairo. "Heat Transfer and Flow Characteristics on the Rotor Tip and Endwall Platform Regions in a Transonic Turbine Cascade." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64501.
Повний текст джерелаPh. D.
Russ, Thomas William. "A surface flow visualization study of boundary layer behavior on the blades of a solid-wall compressor cascade at high angles of attack." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53161.
Повний текст джерелаMaster of Science
Nessler, Chase A. "Characterization of Internal Wake Generator at Low Reynolds Number with a Linear Cascade of Low Pressure Turbine Blades." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1270749309.
Повний текст джерелаHayward, Erin M. G. "Atomistic studies on irradiation damage in iron." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34004.
Повний текст джерелаNunes, Bonaventure R. "Numerical Loss Prediction of high Pressure Steam Turbine airfoils." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/51742.
Повний текст джерелаMaster of Science
Gompertz, Kyle Adler. "Separation Flow Control with Vortex Generator Jets Employed in an Aft-Loaded Low-Pressure Turbine Cascade with Simulated Upstream Wakes." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243990496.
Повний текст джерелаSeverin, Timm Steffen [Verfasser], Dirk [Akademischer Betreuer] Weuster-Botz, Dirk [Gutachter] Weuster-Botz, and Harald [Gutachter] Klein. "Computational Fluid Dynamics Assisted Design of Thin-Layer Cascade Photobioreactor Components / Timm Steffen Severin ; Gutachter: Dirk Weuster-Botz, Harald Klein ; Betreuer: Dirk Weuster-Botz." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1152006517/34.
Повний текст джерелаSeverin, Timm Steffen Verfasser], Dirk [Akademischer Betreuer] [Weuster-Botz, Dirk [Gutachter] Weuster-Botz, and Harald [Gutachter] Klein. "Computational Fluid Dynamics Assisted Design of Thin-Layer Cascade Photobioreactor Components / Timm Steffen Severin ; Gutachter: Dirk Weuster-Botz, Harald Klein ; Betreuer: Dirk Weuster-Botz." München : Universitätsbibliothek der TU München, 2017. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20171206-1363208-1-0.
Повний текст джерелаVallgren, Andreas. "Dynamic properties of two-dimensional and quasi-geostrophic turbulence." Doctoral thesis, KTH, Mekanik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25712.
Повний текст джерелаQC 20101029
Gorbach, Kathleen R. "Benthic Community Structure Response to Flow Dynamics in Tropical Island and Temperate Continental Streams." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1354226302.
Повний текст джерелаBlackbourn, Luke A. K. "An analytical, phenomenological and numerical study of geophysical and magnetohydrodynamic turbulence in two dimensions." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/4291.
Повний текст джерелаLjungbäck, Jacob. "Characterization of Cascade gearbox for wave energy converter." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182811.
Повний текст джерелаDetta examensarbete utfört i samarbete med CorPower Ocean, är det slutgiltiga steget i författarens utbildning på masternivå på KTH (Kungliga Tekniska Högskolan) Stockholm. Syftet med arbetet är att karakterisera en kaskadväxellåda som används för att omvandla vertikal rörelse från vågor till rotation som driver generatorer i företagets framtida vågkraftverk samt att utifrån resultat föreslå möjliga förbättringar och belysa eventuella problem. Den metod som använts för att karakterisera kaskadväxellådan var att via fysiska mätningar, på den testrigg placerad på KTH (Kungliga Tekniska Högskolan) i Stockholm, erhålla data för lastfördelningen i den geometriskt överbestämda konstruktionen. Dessa data användes sedan för att kalibrera en statisk och en dynamisk modell som också utvecklades för det här projektet. Huvudfokus för arbetet har legat i att ta reda på om den konstruktion som används för att fördela lasten mellan kugghjulen fungerar tillfredställande samt att säkerställa att inget kugghjul tar mer än de 2,5% överlast vid fullast växellådan är dimensionerad för vid något tillfälle. Examensarbetet inkluderar även feltoleransers inverkan på lastfördelningen i kaskadväxeln. Resultaten visade att den nuvarande konstruktionen presterar inom de specificerade dimensioneringsintervallen. Några oväntade karaktärsdrag upptäckdes dock vid analys av resultaten. På grund av en avsiktlig geometrisk oregelbundenhet släpade hälften av kugghjulen efter åt ena hållet vilket i sin tur resulterade i en ojämn lastfördelning och oönskade sidokrafter på kuggracken. Flexenheterna som används för att fördela lasten likvärdigt mellan kugghjulen skilde sig åt i styvhet. Den inverkan spridningen av dessa har på lastfördelningen belystes också eftersom lastfördelningen konvergerar mot värden direkt proportionella mot styvhetsförhållandet mellan dem. Slutsatsen från examensarbetet är att den nuvarande konstruktionen, även om den fungerar tillfredställande, lämnar utrymme för förbättringar som potentiellt kan förbättra både livslängd och lastfördelningsprestanda.
Raven, Hans Rafael. "Flow Control Optimization for Improvement of Fan Noise Reduction." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/30847.
Повний текст джерелаMaster of Science
Gelwick, Katrina D. "Full of Hot Air: Heat Flow at the Medicine Lake Volcano Hot Spot, Modoc County, California." Oberlin College Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1398936533.
Повний текст джерелаMukherji, Shankar 1982. "The dynamics of enzymatic switch cascades." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32747.
Повний текст джерелаIncludes bibliographical references (leaf 67).
We examine the dynamics of the mitogen-activated protein kinase (MAPK) multi-step enzymatic switching cascade, a highly conserved architecture utilised in cellular signal transduction. In treating the equations of motion, we replace the usual deterministic differential equation formalism with stochastic equations to accurately model the 'effective collisions' picture of the biochemical reactions that constitute the network. Furthermore we measure the fidelity of the signaling process through the mutual information content between the output of a given switch and the original environmental input to the system. We find that the enzymatic switches act as low-pass filters, with each switch in the cascade able to average over high frequency stochastic fluctuations in the network and throughput cleaner signals to downstream switches. We find optimal regions of mutual information transfer with respect to reaction velocity and species number parameters, and observe the dynamical memory-gain and memory-loss as well as decay in mutual information in quadruple-linked switch systems.
by Shankar Mukherji.
S.B.
Vallgren, Andreas. "Statistical characteristics of two-dimensional and quasigeostrophic turbulence." Licentiate thesis, KTH, Linné Flow Center, FLOW, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13128.
Повний текст джерелаTwo codes have been developed and implemented for use on massively parallelsuper computers to simulate two-dimensional and quasigeostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. This has allowed for the highest resolution simulations of two-dimensional and quasigeostrophic turbulence so far reported in the literature.The direct numerical simulations have focused on the statistical characteristicsof turbulent cascades of energy and enstrophy, the role of coherent vorticesand departures from universal scaling laws, theoretized more than 40 yearsago. In particular, the investigations have concerned the enstrophy and energycascade in forced and decaying two-dimensional turbulence. Furthermore, theapplicability of Charney’s hypotheses on quasigeostrophic turbulence has beentested. The results have shed light on the flow evolution at very large Reynoldsnumbers. The most important results are the robustness of the enstrophycascade in forced and decaying two-dimensional turbulence, the unexpecteddependency on an infrared Reynolds number in the spectral scaling of theenergy spectrum in the inverse energy cascade, and the validation of Charney’spredictions on the dynamics of quasigeostrophic turbulence. It has also beenshown that the scaling of the energy spectrum in the enstrophy cascade isinsensitive to intermittency in higher order statistics, but that corrections mightapply to the ”universal” Batchelor-Kraichnan constant.
Listén, Hedlin Embla. "Enzymatic cascade for dynamic kinetic resolution of amines." Thesis, KTH, Skolan för bioteknologi (BIO), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215018.
Повний текст джерелаToombes, Luke. "Experimental study of air-water flow properties on low-gradient stepped cascades /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16746.pdf.
Повний текст джерелаMcBean, Ivan William 1974. "Simulation of 3-dimensional aeroelastic effects in turbomachinery cascades." Monash University, Dept. of Mechanical Engineering, 2002. http://arrow.monash.edu.au/hdl/1959.1/7690.
Повний текст джерелаFletcher, Nathan James. "Design and Implementation of Periodic Unsteadiness Generator for Turbine Secondary Flow Studies." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1560810428267352.
Повний текст джерелаIima, Makoto. "Dynamical Aspects of Cascade Process in Fully Developed Turbulence." 京都大学 (Kyoto University), 1998. http://hdl.handle.net/2433/182439.
Повний текст джерелаLIN, PENG. "Enzyme cascade reactions on 3D DNA scaffold with dynamic shape transformation." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/265209.
Повний текст джерела新制・課程博士
博士(エネルギー科学)
甲第23437号
エネ博第424号
新制||エネ||81(附属図書館)
京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻
(主査)教授 森井 孝, 教授 佐川 尚, 教授 片平 正人
学位規則第4条第1項該当
Doctor of Energy Science
Kyoto University
DFAM
Roux, Louis. "Modélisation dynamique du départ d'une pale et de la tenue des pales suiveuses dans une turbomachine." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI056.
Повний текст джерелаDuring the certification process of a turbo engine, the engine manufacturer has to demonstrate that the loss of a rotor blade does not lead to the "knocking-off" phenomenon, in other words to the cascading failure of the successive blades. Generally, this demonstration is carried out through a costly rig test driving to the partial destruction of the engine. Thanks to the improvement of computational resources, it is now possible to simulate the transient response of the structure subjected to this complex loading. The knowledge of material behavior turns out to be the essential starting point for the simulation. However, only a few studies have been published on the dynamic behavior of nickel-based single crystal superalloys at high temperature reaching 1000°C. With a view to efficiently predicting the consequences of impacts on turbine blades, experimental and numerical works have been conducted on a single crystal frequently used by Turbomeca. High-temperature dynamic compressive tests on Split Hopkinson Pressure Bars (SHPB) have enabled to estimate the material plasticity level and hardening, depending on the crystal orientation, strain rate and temperature. The parameters of a viscoplastic anisotropic law have been identified to effectively model the MC2 macroscopic behavior under highly intense and multiaxial loading. At Safran Snecma Villaroche, ballistic tests have been undertaken on both single crystal plates and blades under high temperatures. In order to consider the fragmentation of profiles in blade-off simulations, a plastic strain criterion depending on stress triaxiality has been calibrated and validated by comparison with the impacts on blades. Post-mortem digital images correlation measurements and high-speed camera recordings have confirmed these simulations. Using LS-Dyna solver, a blade-off modeling strategy has been created and applied to an actual blade-off industrial case. Finally, a rotordynamics approach has been developed and validated with the aim of separately analyzing the primary damage, caused by direct impacts on the first following blades, and the secondary damage due to the effects of unbalance on a flexible rotor