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Journal articles on the topic "Adiabatic production of single photons":
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Fernandez, E., W. T. Ford, N. Qi, A. L. Read, J. G. Smith, T. Camporesi, R. De Sangro, et al. "Search for Single Photons from Supersymmetric Particle Production." Physical Review Letters 54, no. 11 (March 18, 1985): 1118–21. http://dx.doi.org/10.1103/physrevlett.54.1118.
Brange, Fredrik, Adrian Schmidt, Johannes C. Bayer, Timo Wagner, Christian Flindt, and Rolf J. Haug. "Controlled emission time statistics of a dynamic single-electron transistor." Science Advances 7, no. 2 (January 2021): eabe0793. http://dx.doi.org/10.1126/sciadv.abe0793.
Quantum technologies involving qubit measurements based on electronic interferometers rely critically on accurate single-particle emission. However, achieving precisely timed operations requires exquisite control of the single-particle sources in the time domain. Here, we demonstrate accurate control of the emission time statistics of a dynamic single-electron transistor by measuring the waiting times between emitted electrons. By ramping up the modulation frequency, we controllably drive the system through a crossover from adiabatic to nonadiabatic dynamics, which we visualize by measuring the temporal fluctuations at the single-electron level and explain using detailed theory. Our work paves the way for future technologies based on the ability to control, transmit, and detect single quanta of charge or heat in the form of electrons, photons, or phonons.
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GOGYAN, ANAHIT, STÉPHANE GUÉRIN, HANS-RUDOLF JAUSLIN, and YURI MALAKYAN. "DETERMINISTIC GENERATION OF INDISTINGUISHABLE SINGLE-PHOTON PULSES IN THE SINGLE-ATOM-CAVITY QED SYSTEM." International Journal of Quantum Information 09, supp01 (January 2011): 239–49. http://dx.doi.org/10.1142/s0219749911007253.
We present a mechanism to produce indistinguishable single-photon pulses on demand from a single atom-optical cavity system. We use sequences of two laser pulses of alternate circular polarizations at the two Raman transitions of a four-level atom. They allow the production of the same cavity-mode photons without repumping of the atom between photon generations. Photons that are emitted from the cavity with near-unity efficiency in well-defined temporal modes, feature the same polarization, frequency and identical shapes, controlled by the laser fields. The second order correlation function reveals the single-photon nature of the proposed source. A realistic setup for the experimental implementation is presented.
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Wei, Yu-Jia, Yu-Ming He, Ming-Cheng Chen, Yi-Nan Hu, Yu He, Dian Wu, Christian Schneider, et al. "Deterministic and Robust Generation of Single Photons from a Single Quantum Dot with 99.5% Indistinguishability Using Adiabatic Rapid Passage." Nano Letters 14, no. 11 (October 30, 2014): 6515–19. http://dx.doi.org/10.1021/nl503081n.
MARIOTTO, C. BRENNER, and V. P. GONÇALVES. "NONLINEAR GLUON EVOLUTION AND PHOTON PRODUCTION IN HADRONIC COLLISIONS." International Journal of Modern Physics E 16, no. 09 (October 2007): 2984–88. http://dx.doi.org/10.1142/s0218301307008872.
In this contribution we consider the influence of nonlinear gluon evolution in the production of prompt photons at the LHC pp collider. We consider the EHKQS parton distributions, which are based on the GLR-MQ evolution equations, and imply in an enhanced small-x gluon distribution at Q2 ≤ 10 GeV 2 relative to the LO DGLAP gluon distribution. We find an enhancement of low-pT photons for both single and double photon production. Consequences of this effect for the Quark-Gluon Plasma searches and for the QCD background to Higgs are also discussed.
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BIANCHI, NICOLA. "EXCLUSIVE MESON AND PHOTON PRODUCTION AT HERMES." International Journal of Modern Physics A 18, no. 08 (March 30, 2003): 1311–18. http://dx.doi.org/10.1142/s0217751x03014654.
First promising results for exclusive electroproduction of vector mesons, pseudoscalar mesons and real photons from HERMES are presented. Different observables like cross sections and single spin azimuthal asymmetries have been investigated. Results have been discussed within the recent formalism of the Generalized Parton Distributions.
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Ford, W. T., N. Qi, A. L. Read, J. G. Smith, T. Camporesi, I. Peruzzi, M. Piccolo, et al. "search for single photons from radiative neutrino or supersymmetric-particle production." Physical Review D 33, no. 11 (June 1, 1986): 3472–75. http://dx.doi.org/10.1103/physrevd.33.3472.
Adam, W., T. Adye, E. Agasi, I. Ajinenko, R. Aleksan, G. D. Alekseev, R. Alemany, et al. "Search for anomalous production of single photons at and 136 GeV." Physics Letters B 380, no. 3-4 (July 1996): 471–79. http://dx.doi.org/10.1016/0370-2693(96)00671-5.
Sawyer, R. F. "Production of single plasmons and photons by neutrinos in a medium." Physical Review D 46, no. 3 (August 1, 1992): 1180–85. http://dx.doi.org/10.1103/physrevd.46.1180.
Astraatmadja, Tri L. "Detecting TeV γ-rays from GRBs with km3 neutrino telescopes." Proceedings of the International Astronomical Union 7, S279 (April 2011): 321–22. http://dx.doi.org/10.1017/s1743921312013154.
AbstractObserving TeV photons from GRBs can greatly enhance our understanding of their emission mechanisms. Under-sea/ice neutrino telescopes—such as ANTARES in the Mediterranean Sea or IceCube at the South Pole—can also operate as a γ-ray observatory by detecting downgoing muons from the electromagnetic cascade induced by the interaction of the photons with the Earth's atmosphere. Theoretical calculations of the number of detectable muons from single GRB events, located at different redshifts and zenith distances, have been performed. The attenuation by pair production of TeV photons with cosmic infrared background photons has also been included.
Dissertations / Theses on the topic "Adiabatic production of single photons":
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Federico, Maxime. "Spatio-temporal description of single photons : from cavity production to local detection." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCK013.
Ce travail fournit une analyse des propriétés spatio-temporelles d'états à un photon. En commençant par une quantification directement réalisée en espace position, nous démontrons que deux formulations différentes de la théorie sont équivalentes : elles prédisent les mêmes résultats. L'équivalence est formulée sous forme d'un isomorphisme de leurs espaces de Hilbert respectifs. On utilise par la suite cette construction en espace position pour étudier la propagation des photons décrit par des impulsions. Nous démontrons que la dynamique de n'importe quel état du champ électromagnétique quantique est alors donnée par l'évolution temporelle de la représentation de l'état, telle que décrite par les équations de Maxwell classiques. Nous construisons également un modèle de détection locale de photons en utilisant l'opérateur densité d'énergie. Ce modèle nous permet de démontrer la non localité de tout état à un photon grâce à la propriété d'antilocalité de l'opérateur fréquence Ω=c(-Δ)^{1/2}. Nous caractérisons ensuite cette non localité pour un état à un photon produit par l'émission spontanée d'un atome d'Hydrogène et montrons que la décroissance de sa densité d'énergie se comporte asymptotiquement comme pour des distances r loin de l'atome. Enfin, nous nous interessons à la production de photons en cavités pour laquelle nous démontrons au travers d'un argument topologique que, dans la limite adiabatique, l'approximation de l'onde tournante (rotating wave approximation) est justifiée et permet donc la production de photons très proches de photons uniques parfaits. Nous construisons aussi, comme résultat préliminaire, un modèle heuristique utilisant des modes quasinormaux pour décrire la procution de photons dans des cavités ouvertes This work provides an analysis of spatio-temporal properties of single-photon states. Starting with a direct quantization in position space representation, we show that two different formulations are equivalent, i.e., they give the same quantum theory. The equivalence is formulated in terms of isomorphisms of their respective Hilbert space of states. We then use this construction in position space to study the propagation of photons in terms of pulses and we show that the dynamics of any state of the quantum electromagnetic field is given by the classical Maxwell equations for the classical pulse onto which the photons are defined. We also construct a model for local detection of photons using the energy density operator. This model allows us to show the nonlocality of all single-photon states using the anti-local property of the frequency operator Ω=c(-Δ)^{1/2}. We then characterize this nonlocal property for a single-photon state spontaneously emitted by a Hydrogen atom and we show a radial decay of its energy density of 1/r^6 in the asymptotic limit of large distances r from the atom. Finally, we consider the production of photons in cavities where we show through topological arguments that in the adiabatic limit, the rotating wave approximation is justified and thus the photons produced with these techniques can be very close to perfect single photons. We also construct as a preliminary result a heuristic model using quasinormal modes to describe the production of photons inside leaky cavities
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Holleczek, Annemarie. "Linear optics quantum computing with single photons from an atom-cavity system." Thesis, University of Oxford, 2016. http://ora.ox.ac.uk/objects/uuid:d655fa1c-3405-413d-8af8-eecf6212ab74.
One of today’s challenges to realise computing based on quantum mechanics is to reliably and scalably encode information in quantum systems. Here, we present a photon source to on-demand deliver photonic quantum bits of information based on a strongly coupled atom-cavity system. The source operates intermittently for periods of up to 100 μs, with a single-photon repetition rate of 1 MHz, and an intra-cavity production efficiency of up to 85%. Our ability to arbitrarily control the photons’ wavepackets and phase profiles, together with long coherence times of 500 ns, allows to store time-bin encoded quantum information within a single photon. To do so, the spatio-temporal envelope of a single photon is sub-divided in d time bins which allows for the delivery of arbitrary qu-d-its. This is done with a fidelity of > 95% for qubits, and 94% for qutrits verified using a newly developed time-resolved quantum-homodyne measurement technique. Additionally, we combine two separate fields of quantum physics by using our deterministic single-photon source to seed linear optics quantum computing (LOQC) circuits. As a step towards quantum networking, it is shown that this photon source can be combined with quantum gates, namely a chip-integrated beam splitter, a controlled-NOT (CNOT) gate as well as a CNOT4 gate. We use this CNOT4 gate to entangle photons deterministically emitted from our source and observe non-classical correlations between events separated by periods exceeding the travel time across the chip by three orders of magnitude. Additionally, we use time-bin encoded qubits to systematically study the de- and re-phasing of quantum states as well as the the effects of time-varying internal phases in photonic quantum circuits.
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Bimbard, Erwan. "Production and interaction of photons using atomic polaritons and Rydberg interactions." Thesis, Palaiseau, Institut d'optique théorique et appliquée, 2014. http://www.theses.fr/2014IOTA0015/document.
Produire et faire interagir entre eux des photons optiques de façon contrôlée sont deux conditions nécessaires au développement de communications quantiques à longue distance, et plus généralement au traitement quantique d’information codée sur des photons. Cette thèse présente une étude expérimentale de solutions possibles a ces deux problèmes, en utilisant la conversion des photons en excitations collectives (polaritons) dans un nuage d’atomes froids, placé dans le mode d’une cavité optique de faible finesse (~100). Dans un premier temps, des polaritons entre états atomiques fondamentaux sont utilisés pour « mettre en mémoire » une excitation unique dans le nuage. Celle-ci est ensuite convertie efficacement en un photon unique, dont le champ est analysé par tomographie homodyne. La fonction de Wigner de l’état à un photon est reconstruite a partir des données expérimentales, et présente des valeurs négatives, démontrant que les degrés de liberté de ce photon (mode spatio-temporel et état quantique) sont complètement contrôlés. Dans un second temps, les photons sont couplés à des polaritons impliquant des états de Rydberg. Les fortes interactions dipolaires entre ces derniers se traduisent par des non-linéarités optiques dispersives très importantes, qui sont caractérisées dans un régime d’excitation classique. Ces non-linéarités peuvent être amplifiées jusqu’à ce qu’un seul photon suffise à modifier totalement la réponse du système, permettant en principe de générer des interactions effectives entre photons Controllably producing optical photons and making them interact are two key requirements for the development of long-distance quantum communications, and more generally for photonic quantum information processing. This thesis presents experimental studies on possible solutions to these two problems, using the conversion of the photons into collective excitations (polaritons) in a cold atomic cloud, inside the mode of a low-finesse optical cavity (~100). Firstly, ground-state polaritons are used to store a single excitation in the cloud memory. This polariton is then efficiently converted into a single photon, whose field is characterized via homodyne tomography. The single photon state’s Wigner function is reconstructed from the experimental data and exhibits negative values, demonstrating that the photon’s degrees of freedom (spatio-temporal mode and quantum state) are well controlled. Secondly, photons can be coupled to polaritons involving Rydberg states. The strong dipolar interactions between these give rise to very strong optical dispersive nonlinearities, that are characterized in a classical excitation regime. These nonlinearities can be amplified until a single photon is enough to modify the entire system’s response, allowing in principle for the generation of effective photon-photon interactions
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Marchiori, Giovanni. "Prompt photons at the LHC : selection, measurements of single- and di-photon production cross sections, and Higgs boson searches with the ATLAS detector." Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00919608.
This document, prepared to obtain the "Habilitation à Diriger des Recherches", is a compendium of the photon-related analysis activities I carried on within ATLAS in the past four years and a half. The activities I will describe can be broadly classified into three categories: optimization and/or in situ measurement of photon-related performance, measurements of the cross sections of Standard Model processes producing prompt photons, and searches (leading to discovery!) of a Standard Model Higgs boson decaying to final states containing photons.
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Lavine, Theodore Leigh. "Search for single-photons from radiative production of supersymmetric particles or neutrinos." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15577665.html.
Thesis (Ph. D.)--University of Wisconsin--Madison, 1986. Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 122-128).
Book chapters on the topic "Adiabatic production of single photons":
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Tanyag, Rico Mayro P., Bruno Langbehn, Thomas Möller, and Daniela Rupp. "X-Ray and XUV Imaging of Helium Nanodroplets." In Topics in Applied Physics, 281–341. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94896-2_7.
AbstractX-ray and extreme ultraviolet (XUV) coherent diffractive imaging (CDI) have the advantage of producing high resolution images with current spatial resolution of tens of nanometers and temporal resolution of tens of femtoseconds. Modern developments in the production of coherent, ultra-bright, and ultra-short X-ray and XUV pulses have even enabled lensless, single-shot imaging of individual, transient, non-periodic objects. The data collected in this technique are diffraction images, which are intensity distributions of the scattered photons from the object. Superfluid helium droplets are ideal systems to study with CDI, since each droplet is unique on its own. It is also not immediately apparent what shapes the droplets would take or what structures are formed by dopant particles inside the droplet. In this chapter, we review the current state of research on helium droplets using CDI, particularly, the study of droplet shape deformation, the in-situ configurations of dopant nanostructures, and their dynamics after being excited by an intense laser pulse. Since CDI is a rather new technique for helium nanodroplet research, we also give a short introduction on this method and on the different light sources available for X-ray and XUV experiments.
Conference papers on the topic "Adiabatic production of single photons":
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Schaller, Richard D. "Efficient production of multiexcitons from single photons in semiconductor nanocrystals for low-cost, high efficiency photovoltaics." In LEOS 2008 - 21st Annual Meeting of the IEEE Lasers and Electro-Optics Society (LEOS 2008). IEEE, 2008. http://dx.doi.org/10.1109/leos.2008.4688470.
Bazilevsky, A. "Measurement of Single Transverse-spin Asymmetry in Forward Production of Photons and Neutrons in pp Collisions at s = 200 GeV." In SPIN 2002: 15th International Spin Physics Symposium and Workshop on Polarized Electron Sources and Polarimeters. AIP, 2003. http://dx.doi.org/10.1063/1.1607202.
Nanophotonic devices are becoming increasingly important for enabling the controlled and efficient production of photons in well defined modes of optical resonators and waveguides. A particular class of such devices which has seen extensive application in recent years is that of evanescently coupled waveguides which can be used to create fiber-coupled single photon sources or to couple light to other nanophotonic systems. However, evanescent coupling typically results in equal intensities coupled to either port of the waveguide, leading to a 50% if it is desired to send photons to a particular receiver.
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Deutsch, Ivan H., Raymond Y. Chiao, and John C. Garrison. "Two-photon bound states and self-trapped solitons in a nonlinear Fabry-Perot resonator." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.ff7.
Propagation of light beams in a Fabry-Perot resonator filled with a self-focusing Kerr material is described by the nonlinear Schrodinger equation. If the degrees of freedom are restricted to one transverse dimension through the use of a line focus at the input face, the system possesses classical soliton solutions analogous to those for travelling-wave self-trapped beams. When the classical field theory is quantized, one obtains an effective nonrelativistic many-body field theory in which pairs of photons interact through attractive delta function potentials. The existence of bound states between photons is the microscopic phenomenon that prevents beams from spreading by diffraction. The fundamental bound state consists of two photons, which we call the "diphoton." We consider production of these quasi-particles in a single longitudinal mode Fabry-Perot resonator filled with an alkali vapor. The injected light is strongly attenuated to excite few photons in the cavity and is detuned slightly above the atomic resonance, giving rise to the self-focusing nonlinearity. Detection of the diphoton can be achieved by rejecting the unbound component by using a spatial filter and detecting the remaining signal in coincidence counting. The diphoton signature is a characteristic Lorentzian-squared two-point correlation profile.1
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Rickmers, Peter, Christian Eigenbrod, and Konstantin Klinkov. "N-Heptane: Comparison of Spray Autoignition Experiments and Single Droplet Simulations." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22348.
To achieve high process efficiency, modern combustion machines, inject liquid hydrocarbon fuels into compressed air at high temperatures and high pressure, resulting in a limited residence time of the fuel in the combustion chamber or a premixing duct before autoignition. The residence time however, is the only available time to provide a well stirred mixture with a lean overall equivalence ratio, near the adiabatic flammability limit, reducing the combustion temperature and in turn the production of thermal nitric oxides (NOx) produced via the Zeldovich mechanism [1]. This paper details new results of experiments conducted in a Ludwieg–tube type wind tunnel, providing high temperature (≤1000K) and pressure (≤ 1.5MPa) flows with moderate flow rates (≤ 100m/s). N-heptane was injected into the flow in a simple unobstructed jet in cross flow (JICF) configuration in the middle of the test section. Single droplet numerical simulations were then conducted with an in-house code, the closed–vessel–simulation (CVS), which allows the simulation of the autoignition of a single droplet in a closed environment with fixed overall mixture ratio, using a reduced n-heptane kinetic with 67 species and 437 reactions [2]. The simulations were compared to the spray experiments, by assuming a Rosin-Rammler distribution for the spray and mapping the CVS results onto this distribution. The results show a promising similarity of the simulations and the experiments with a spray ignition likelihood distribution that has a maximum near the MMD (Mass Median Diameter).
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Onur, Mustafa, and Kiymet Gizem Gul. "Temperature Transient Modeling and Analysis for Hydraulically Fractured Wells." In SPE EuropEC - Europe Energy Conference featured at the 83rd EAGE Annual Conference & Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209653-ms.
Abstract In this work, new analytical sandface temperature solutions are developed for linear flow towards an infinite-conductivity hydraulically fractured well producing under specified constant-rate or constant- bottomhole pressure (BHP) production. The solutions apply for slightly compressible, single-phase undersaturated oil reservoirs with irreducible water saturation or liquid-dominated geothermal reservoirs. They include the effects of conduction, convection, the Joule-Thomson expansion of fluids and adiabatic expansion of the total rock and fluid system, and fluid loss fracture damage. They neglect the variation of rock and fluid properties with pressure and temperature so that pressure diffusivity and thermal energy balance equations are decoupled to obtain the analytical linear-flow temperature solutions using Laplace (for constant-rate) and Boltzmann (for constant-BHP) transformations. To validate the analytical solutions, a numerical solution is developed to solve the mass and thermal energy balance equations simultaneously and account for the variation of rock and fluid properties with pressure and temperature. We proposed a correction to fluid viscosity variation as input for the analytic solutions. The numerical and analytical solutions have been compared and verified with a commercial thermal reservoir simulator. Results indicate that the fracture surface temperature is decreasing with a square of time for constant-rate production but is constant for constant BHP production. The temperature responses for both modes of production are controlled by the adiabatic expansion of the rock and fluid properties and the thermal diffusivity of the rock. The effect of thermal conductivity plays a significant role for both production modes as the matrix permeability decreases. The fracture damage has different signatures on temperature transients at early and late times for both modes of production. The approximate analytical solutions show the information content of temperature transient data acquired from an infinitely conductive hydraulically fractured well under matrix linear flow. They are simple and can be used to perform matrix linear flow analysis jointly with pressure and rate transient data to estimate the thermal and mechanical properties of the rock and fluids. The numerical solution can be used for a more general analysis procedure based on automated history matching for constant as well as variable rate and pressure production test sequences.
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Ely, Marc J., and B. A. Jubran. "A Numerical Study on Increasing Film Cooling Effectiveness Through the Use of Sister Holes." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50366.
Film cooling has been the primary focus of turbine blade cooling research for the past half century. However, as engines become more powerful, more effective non-traditional means of cooling become necessary. The current study branches out into a new scheme for film cooling; sister holes. The geometry of the current work makes use of three cylindrical holes inclined at 35° to the horizontal: one primary injectant hole bound by two sister holes. Numerical simulations were run with blowing ratios varying from M = 0.2 to M = 1.5, using the realizable k-ε turbulence model with near-wall modeling. The results were analyzed for both adiabatic thermal effectiveness as well as vortex production due to flow mixing. In general, sister holes offer significant advantages in thermal protection over their single hole counterparts both laterally and along the centre-line, particularly in regions close to the hole. Simulations showed that the laterally averaged adiabatic thermal effectiveness increased by a factor of 1.35 for M = 0.2 up to a factor of 1.62 for M = 1.5. Similarly, the centre-line effectiveness increased by a factor of 1.22 at M = 0.2 up to a factor of 1.68 at M = 1.5. These benefits are heavily weighted by the near-hole region; however, increases are evident throughout the computational domain. This sister hole technique offers significant advantages with minimal penalties, making it a valuable candidate for future blade cooling applications.
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Lellek, Stephan, and Thomas Sattelmayer. "NOx-Formation and CO-Burnout in Water Injected, Premixed Natural Gas Flames at Typical Gas Turbine Combustor Residence Times." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63128.
With the transition of the power production markets towards renewable energy sources an increased demand for flexible, fossil based power production systems arises. Steep load gradients and a high range of flexibility make gas turbines a core technology in this ongoing change. In order to further increase this flexibility research on power augmentation of premixed gas turbine combustors is conducted at the Lehrstuhl für Thermodynamik, TU München. Water injection in gas turbine combustors allows for the simultaneous control of NOx emissions as well as the increase of the power output of the engine and has therefore been transferred to a premixed combustor at lab scale. So far stable operation of the system has been obtained for water-to-fuel ratios up to 2.25 at constant adiabatic flame temperatures. This paper focuses on the effects of water injection on pollutant formation in premixed gas turbine flames. In order to guarantee for high practical relevance experimental measurements are conducted at typical preheating temperatures and common gas turbine combustor residence times of about 20 ms. Spatially resolved and global species measurements are performed in an atmospheric single burner test rig for typical adiabatic flame temperatures between 1740 and 2086 K. Global measurements of NOx and CO emissions are shown for a wide range of equivalence ratios and variable water-to-fuel ratios. Cantera calculations are used to identify non-equilibrium processes in the measured data. To get a close insight into the emission formation processes in water injected flames local concentration measurements are used to calculate distributions of the reaction progress variable. Finally, to clarify the influence of spray quality on the composition of the exhaust gas a variation of the water droplet diameters is done. For rising water content at constant adiabatic flame temperature the NOx emissions can be held constant, whereas CO concentrations increase. On the contrary, both values decrease for measurements at constant equivalence ratio and reduced flame temperatures. Further analysis of the data shows the close dependency of CO concentration on the equivalence ratio, however, due to the water addition a shift of the CO curves can be detected. In the local measurements changes in the distribution of the reaction progress variable and an increase of the flame length were detected for water injected flames along with changes of the maximum as well as the averaged CO values. Finally, a strong influence of water droplet size on NOx and CO formation is shown for constant operating conditions.
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Montonen, Jori, Erno Keskinen, Michel Cotsaftis, Juha Miettinen, and Wolfgang Seeman. "Dynamics of Single-Hit Pneumatic Test Drill for Pulse-Shaping Analysis of Impacting Waves." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64835.
Rock drilling is one of the elementary processes in mining industry. As larger diameter holes are drilled by hitting with units attached to the crone adapter down in the hole, the smaller blast holes are hit with units impacting the rod neck at rock surface. Key question in the performance and energy efficiency of the blast-hole drilling process is then, how completely the impact energy can be transmitted to the crone over the relatively long wave guide. There have been discussions about the effect of wave length and shape on to the penetration dynamics of rock drills. As the drilling process is a continuous set of hits following each other at relatively high constant period and the response is a random overlapped mixture of coming waves and returning reflected waves from multiple delayed hits, a detailed analysis of penetration dynamics is rather a complex problem. To overcome this difficulty, a full-scale half-manual test-drill has been designed and built to produce single hits for a systematic production and analysis of optimally shaped stress waves. The test-drill is an air-powered pneumatic gun, whose impact energy can be adjusted by setting the initial pressure level to correspond the desired end velocity of the piston. The design parameters, by which the pulse shape can be modified, are the length and the geometric profile of the piston body. The first problem to be faced is then to determine the optimal pulse shape for maximized penetration depth and the second one is to produce such desired shape by an optimal choice of the design parameters. The rig has been modelled using finite elements for the rod system and adiabatic state equations for the compressed and expanding air volumes. By modifying the design parameters, different penetration responses can be produced. In the first step, the model has been updated by means of experimental response measurements. The second step has been to modify the geometrical profiles of the piston body by starting from piece-vice linear and parabolic cross-sectional distributions. The output of the numerical analysis is to evaluate the penetration depth pro hit for different geometrical profiles. The most promising geometry has then been selected for the fabrication of the prototype piston. An experimental hitting test then completes the analysis, whose repeatability showed to be limited due to the random variation of the rock properties in the test bed. Test results obtained by using more regular concrete specimens exhibited reduced deviations in the responses, but the weakness in the test is the different damaging mechanism during the penetration. Another option is the use of an artificial load-sensing endsupport in order to produce a known boundary condition to replace the tool-rock resistance in the model-updating phase.
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Ditmire, T., J. W. G. Tisch, E. Springate, M. B. Mason, N. Hay, R. A. Smith, J. P. Marangos, and M. H. R. Hutchinson. "High Energy Explosion of Super-Heated Atomic Clusters." In Applications of High Field and Short Wavelength Sources. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/hfsw.1997.thb2.
Though the nature of intense, short pulse laser interactions with single atoms and solid targets has been the subject of extensive experimental and theoretical investigation over the last 15 years, only recently has the nature of intense laser interactions with van der Waals bonded atomic clusters of 20 -100 Å been addressed in experiments. These experiments have suggested that the laser-cluster interaction is much more energetic than that of isolated atoms, producing bright x-ray emission (100 - 5000 eV photons) when a low density gas containing clusters is illuminated [1,2]. While experiments have indicated indirect evidence for keV electron production in the cluster through time resolved x-ray spectroscopic data [2], until recently no direct data on the exact nature of the kinetic energies produced by the intense irradiation of clusters existed. In this paper we present the first energy distribution measurements of both electrons and ions resulting from the interaction of a femtosecond laser pulse with van der Waals bonded clusters. We find that the cluster is rapidly heated by collisional inverse bremsstrahlung. This heats a sizable fraction of the electrons in the cluster to a temperature above 1 keV. The super-heated cluster then explodes, ejecting ions with substantial kinetic energy. In fact, ions with energy up to 1 MeV are produced in Xe clusters.
