Thèses sur le sujet « Implosion »
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Gish, Lynn Andrew. « Analytic and numerical study of underwater implosion ». Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81699.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (p. 203-205).
Underwater implosion, the rapid collapse of a structure caused by external pressure, generates a pressure pulse in the surrounding water that is potentially damaging to adjacent structures or personnel. Understanding the mechanics of implosion, specifically the energy transmitted in the pressure pulse, is critical to the safe and efficient design of underwater structures. Hydrostatically-induced implosion of unstiffened metallic cylinders was studied both analytically and numerically. An energy balance approach was used, based on the principle of virtual velocities. Semi-analytic solutions were developed for plastic energy dissipation of a symmetric mode 2 collapse; results agree with numerical simulations within 10%. A novel pseudo-coupled fluid-structure interaction method was developed to predict the energy transmitted in the implosion pulse; results agree with fully-coupled numerical simulations within 6%. The method provides a practical alternative to computationally-expensive simulations when a minimal reduction in accuracy is acceptable. Three design recommendations to reduce the severity of implosion are presented: (1) increase the structure's internal energy dissipation by triggering higher collapse modes, (2) initially pressurize the internals of the structure, and (3) line the cylinder with a flexible or energy absorbing material to cushion the impact between the structure's imploding walls. These recommendations may be used singly or in combination to reduce or completely eliminate the implosion pulse. However, any design efforts to reduce implosion severity must be part of the overall system design, since they may have detrimental effects on other performance areas like strength or survivability.
by Lynn Andrew Gish.
Ph.D.
Scardigli, Corinne. « Implosion : gestion des stocks par la replanification amont ». Grenoble INPG, 1994. http://www.theses.fr/1994INPG0057.
Texte intégralKrueger, Seth R. « Simulation of cylinder implosion initiated by an underwater explosion ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FKrueger.pdf.
Texte intégralThesis Advisor(s): Young S. Shin. "June 2006." Includes bibliographical references (p. 99-100). Also available in print.
Szirti, Daniel. « Development of a single-stage implosion-driven hypervelocity launcher ». Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112585.
Texte intégralSigley, Thomas E. « Evangelism implosion getting to the heart of the issue / ». Theological Research Exchange Network (TREN), 1997. http://www.tren.com.
Texte intégralKinnear, Timothy Michael. « Investigation into triggered star formation by radiative driven implosion ». Thesis, University of Kent, 2016. https://kar.kent.ac.uk/52436/.
Texte intégralSmith, Joel Aaron. « Implosion of steel fibre reinforced concrete cylinders under hydrostatic pressure ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ45939.pdf.
Texte intégralCardoso, Pedro Daniel Martins Lucas. « The future of old-age pensions its explosion and implosion / ». [Amsterdam : Amsterdam : Thela Thesis] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/76523.
Texte intégralLoiseau, Jason. « Phase velocity techniques for the implosion of pressurized linear drivers ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=94919.
Texte intégralL'étude présente porte sur l'évaluation de plusieurs techniques pour générer une vitesse de phase dans un explosif afin de produire de très hautes vitesses de détonation sur des cibles linéaires ou cylindriques. En particulier, il a été démontré que le jumelage de deux composantes explosives ayant des vitesses de détonation différentes pour faire glisser une onde de détonation structurée est une méthode pouvant précisément générer des vitesses de phase désirées. La méthode de la division d'une onde de détonation dans plusieurs canaux individuels fut évaluée et il fut démontré qu'elle est aussi précise. Des modèles analytiques pour la conception des composantes explosives nécessaires à la production des vitesses de phase désirées en utilisant ces techniques sont présentés en détail. Une nouvelle méthode pour générer une vitesse de phase axisymétrique, implosive et linéaire a été également mise au point en faisant varier l'épaisseur de la paroi d'un tube métallique cylindrique. Il fut démontré que cet appareil est capable de produire des vitesses de phase, mais avec des écarts importants avec les prévisions analytiques. La technique qui utilise les deux composantes a également été appliquée à un tube à chocs explosif linéaire. Le tube à chocs a été construit à partir d'un tube métallique à parois mince et entouré par un anneau mince d'explosifs puis un tube de métal à parois épaisse. L'onde de détonation a été progressivement injectée par une mince fente dans le haut du tube à parois épaisse. Une onde de choc a été entraînée à des vitesses allant jusqu'à 11~km/s avec cet appareil.
Rallu, Arthur Seiji Daniel. « A multiphase fluid-structure computational framework for underwater implosion problems / ». May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Texte intégralKamram, Kazem. « A compressible Lagrangian framework for the simulation of underwater implosion problems ». Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/128876.
Texte intégralEl desarrollo de métodos eficientes para modelar la dinámica de implosión presenta varios desafíos. El primero es una representación eficaz de la dinámica del sistema acoplado de aire-agua. El segundo es que el método tiene que permitir una detección exacta o un seguimiento adecuado de la interfase entre ambas fases. Por último el método tiene que ser capaz de resolver cualquier choque que podría generar en el aire o en el agua, sobre todo en la última fase del colapso. Nosotros presentamos un método numérico compresible y totalmente Lagrangiano para simular la implosión bajo el agua. Tanto el aire como el agua se consideran compresibles y las ecuaciones Lagrangianos para la hidrodinámica del choque se estabilizan mediante un método multiescala que es variacionalmente consistente [109]. Se utiliza una definición de interfase que coincide perfectamente con los nodos [57, 25]. Ésta, nos facilita duplicar eficazmente las variables cinéticas como la presión y la densidad en los nodos de la interfase. Con el fin de obtener suficiente resolución alrededor de la interfase, la malla se genera de forma adaptativa y respetando la posición de la interfase. A continuación el método desarrollado se utiliza para simular la implosión bajo el agua de una burbuja cilíndrica del tamaño de un centímetro. Varios fenómenos se han capturado durante el colapso: un ciclo inmediato de colapso-crecimiento de la burbuja que ocurre en un espacio (0.3mm) y tiempo (0.1ms) bastante limitado, aparición de inestabilidades de tipo Rayleigh-Taylor en la interfase y formaron de varias ondas de choque que viajan tanto en el agua como en el aire. Después, seguimos el desarrollo del método para modelar la implosión bajo el agua de un contenedor metálico considerando una interacción monolítica de fluido y estructura. El cilindro de aluminio, que a su vez contiene aire a presión atmosférica y está rodeada de agua en alta presión, se modelando con elementos de lámina de tres nodos y sin grados de libertad de rotación. El cilindro se somete a deformaciones transitorias suficientemente rápidos y enormes hasta llegar a colapsar. Un nuevo modelo elástico de contacto sin considerar la fricción se ha desarrollado para detectar el contacto y calcular las fuerzas en el dominio discretizado entre las superficies medianas de las laminas. Dos esquemas temporales están considerados, uno es implícito utilizando el método de Bossak y otro es explícito utilizando Forward Euler. Al final los resultados de ambos casos se comparan con los resultados experimentales.
Haboub, Abdelmoula. « Study of ablation and implosion phases in cylindrical and star wire arrays ». abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3387809.
Texte intégralHuneault, Justin. « Development of an implosion-driven hypervelocity launcher for orbital debris impact simulation ». Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117206.
Texte intégralLa capacité d'accéléré des projectiles à des vitesses au-delà de 10 km/s est d'intérêt pour de nombreuses applications, incluant la protection contre les débris spatiaux. La performance des lanceurs hyper-vitesse de pointe n'est pas capable de rejoindre ces vitesses. Le lanceur à implosion utilise des explosifs pour comprimer un gaz léger de façon dynamique, afin d'atteindre des pressions et des températures beaucoup plus élevés que des lanceurs hyper-vitesse typiques. Pour cette raison, le lanceur à implosion à le potentiel de surpasser la performance de tout autre lanceur. Ce travail mettra l'accent sur l'établissement d'une compréhension des paramètres de conception critiques du lanceur à implosion dans le but d'améliorer la performance du lanceur. A cet effet, un code capable de simuler la balistique interne du lanceur a été développé. La pression et la température élevées dans le gaz causent plusieurs pertes durant le cycle de lancement, y compris l'expansion des parois du lanceur, le transfert de chaleur par convection, et les fuites de gaz. Ces pertes ont un effet important sur la performance du lanceur. Les modèles utilisés pour simuler ces pertes sont aussi présentés. Le code complet sera utilisé en conjonction avec la théorie classique de la balistique interne ainsi que des résultats expérimentaux afin d'amélioré le lanceur. Cette analyse a conduit à l'élaboration d'un lanceur à implosion capable d'accéléré un projectile de 0,1 g à 9,1 km/s.
Oudkerk, Richard. « The parabolic implosion for f0(z) = z + zv+1 + O(zv+2) ». Thesis, University of Warwick, 1999. http://wrap.warwick.ac.uk/56137/.
Texte intégralDemeter, Jason M. « Melancholy and the Implosion of the Family in Early- and Post-Modern Tragedy ». University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1208264666.
Texte intégralHall, Gareth. « The relationship between implosion dynamics and stagnation structure in aluminium wire-array Z-pinches ». Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444403.
Texte intégralKhoory, Essa. « Experimental study of plasma implosion dynamics in a two-stage wire array Z-pinch configuration ». Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14271.
Texte intégralBianchi, Fabrizio. « Motions of Julia sets and dynamical stability in several complex variables ». Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30099/document.
Texte intégralIn this thesis we study holomorphic dynamical systems depending on parameters. Our main goal is to contribute to the establishment of a theory of stability and bifurcation in several complex variables, generalizing the one for rational maps based on the seminal works of Mané, Sad, Sullivan and Lyubich. For a family of polynomial like maps, we prove the equivalence of several notions of stability, among the others an asymptotic version of the holomorphic motion of the repelling cycles and of a full-measure subset of the Julia set. This can be seen as a measurable several variables generalization of the celebrated lambda-lemma and allows us to give a coherent definition of stability in this setting. Once holomorphic bifurcations are understood, we turn our attention to the Hausdorff continuity of Julia sets. We relate this property to the existence of Siegel discs in the Julia set, and give an example of such phenomenon. Finally, we approach the continuity from the point of view of parabolic implosion and we prove a two-dimensional Lavaurs Theorem, which allows us to study discontinuities for perturbations of maps tangent to the identity
Chéritat, Arnaud. « Sur l'implosion parabolique, la taille des disques de Siegel et une conjecture de Marmi, Moussa et Yoccoz ». Habilitation à diriger des recherches, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00291673.
Texte intégralPour theta nombre de Brjuno, soit r(theta) le rayon conforme du disque de Siegel de P_theta(z)=exp(i.2.pi.theta)z+z^2 et Phi(theta) la variante due à Yoccoz de la somme de Brjuno. Soit Upsilon(theta) = log r(theta) + Phi(theta).
Nous avons démontré précédemment que Upsilon possède un prolongement continu à R, et donné une formule explicite pour sa valeur aux rationnels.
La conjecture de Marmi-Moussa-Yoccoz, toujours ouverte, est que la fonction Upsilon est 1/2-Höldérienne.
Nous démontrons ici que l'exposant ne peut être amélioré : quel que soit l'intervalle I non vide, Upsilon n'est delta-Höldérienne sur I pour aucun delta>1/2. Sa variation sur I est également non bornée.
La preuve est basée sur un développement asymptotique en tout p/q de Upsilon(x_n) pour certaines suites de rationnels x_n tendant vers p/q.
L'étude d'un point parabolique et de ses perturbations se fait parfois par l'introduction d'un champ de vecteurs auquel la dynamique est comparée.
Nous introduisons un champ de vecteurs particulier qui permet d'une part de donner des estimations suffisamment fines pour effectuer le développement asymptotique de Upsilon(x_n) ; d'autre part de proposer une normalisation intéressante des coordonnées de Fatou d'un point parabolique, dont nous donnons quelques propriétés de base.
J'ai apporté un soin particulier à la rédaction de l'implosion parabolique, qu'il a fallu raffiner légèrement et adapter à notre champs de vecteurs.
Ferris, Emma Grace. « A computational and experimental study of the underwater implosion of single and multiple metallic spherical shells ». Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/111762.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (pages 103-104).
Analysis of the implosion of pressure vessels in a deep-water environment is an important research area for the ocean engineering community. The majority of previous implosion research focused on the implosion of metallic cylinders, while the implosion behavior of volumes of different geometries and materials is less well researched. The behavior of pressure pulses resulting from the implosion of multiple pressure vessels is also less well researched. This thesis addresses these questions by investigating the implosion behavior of single and multiple spherical shells. Over the course of this research, I designed and predicted the collapse depth of metallic spherical volumes using shell buckling theory, then used a computational tool to model several implosion scenarios of both single and multiple sphere configurations. I then conducted implosion tests of single and multiple spherical shell configurations. The results from the initial computational models were compared with results of experimental tests and used to develop updated computational models that more accurately represented the true geometry of the test articles. Based on the analysis of the results of initial computational models and the experimental results, and the correlation between the updated computational models and experimental results, I identified ways to more accurately model scenarios involving implosions of spherical shells. In addition, I analyzed the behavior of a sympathetic implosion event involving two spherical shells and compared the result of the sympathetic implosion event to that of a single equivalent volume. This thesis concludes with guidance for future modeling and experimental testing efforts.
by Emma Grace Ferris.
S.M.
Ferris, Emma Grace. « A computational and experimental study of the underwater implosion of single and multiple metallic spherical shells ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111762.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (pages 103-104).
Analysis of the implosion of pressure vessels in a deep-water environment is an important research area for the ocean engineering community. The majority of previous implosion research focused on the implosion of metallic cylinders, while the implosion behavior of volumes of different geometries and materials is less well researched. The behavior of pressure pulses resulting from the implosion of multiple pressure vessels is also less well researched. This thesis addresses these questions by investigating the implosion behavior of single and multiple spherical shells. Over the course of this research, I designed and predicted the collapse depth of metallic spherical volumes using shell buckling theory, then used a computational tool to model several implosion scenarios of both single and multiple sphere configurations. I then conducted implosion tests of single and multiple spherical shell configurations. The results from the initial computational models were compared with results of experimental tests and used to develop updated computational models that more accurately represented the true geometry of the test articles. Based on the analysis of the results of initial computational models and the experimental results, and the correlation between the updated computational models and experimental results, I identified ways to more accurately model scenarios involving implosions of spherical shells. In addition, I analyzed the behavior of a sympathetic implosion event involving two spherical shells and compared the result of the sympathetic implosion event to that of a single equivalent volume. This thesis concludes with guidance for future modeling and experimental testing efforts.
by Emma Grace Ferris.
S.M.
Čepukas, Andrius. « Medijų visuomenės kritika J. Baudrillardo filosofijoje ». Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080924_181309-83071.
Texte intégralIn the study we analyse Baudrillard's philosophy, Problematics of the study lies on media analysis and transformation of the society.
Astorg, Matthieu. « Théorie de Teichmüller dynamique infinitésimale et domaines errants ». Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30042/document.
Texte intégralLet f be a rational map of degree d at last 2. McMullen and Sullivan introduced the dynamical Teichmüller space Teich(f), which is a complex manifold of dimension at most 2d-2. It paramtrizes the quasiconformal conjugacy class of f in the moduli space ratdvia a holomorphic map F from Teich(f) to ratd. We give a new and elementary construction of Teich(f), and we prove that the parametrization F is an immersion, answering a question of McMullen and Sullivan. This last result enables us to give simplified proofs of rigidity results of Makienko and Levin under the assumption of expansion along the critical orbit. In a second part, we construct a family of examples of polynomial endomorphisms of¨P^2(C) with a wandering domain. Our examples are skew-products, of the form (z,w) -> (f(z)+aw, g(w)). Moreover, we will construct examples with real coefficients where the wandering domain intersects R^2
Leckie, Barbara. « That ancient darkness : madness and implosion in Michael Ondaatje's The collected works of Billy the Kid and Coming through slaughter ». Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65982.
Texte intégralSpens, Ellen. « Diffrakterande praktiker med implosiva konsekvenser : Perspektiv på estetiska lärprocesser ». Thesis, Malmö högskola, Fakulteten för lärande och samhälle (LS), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-34773.
Texte intégralChéritat, Arnaud. « Recherche d'ensembles de Julia de mesure de Lebesgue positive ». Paris 11, 2001. http://www.theses.fr/2001PA112313.
Texte intégralWe define the asymptotic size of a parabolic fixed point, that enables to prove a conjecture of Douady and to give a new proof of a theorem of Yoccoz. We give a geometric construction of a holomorphic map, that extends to horn maps some results that the Blaschke fraction z squared times z minus three over one minus three z gave for quadratic polynomials with an indifferent fixed point of bounded type rotation number. We state two conjectures and two hypotheses, and prove that they imply the existence of an irrational theta such that the polynomial P of z equals rho times z plus z squared, with rho equals exponential of i times two times pi times theta has a Julia set J of positive Lebesgue measure
Samulski, Camille Clement. « Deceleration Stage Rayleigh-Taylor Instability Growth in Inertial Confinement Fusion Relevant Configurations ». Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103703.
Texte intégralMaster of Science
The direction for the future of renewable energy is uncertain at this time; however, it is known that the future of human energy consumption must be green in order to be sustainable. Fusion energy presents an opportunity for an unlimited clean renewable energy source that has yet to be realized. Fusion is achieved only by overcoming the earthly limitations presented by trying to replicate conditions at the interior of stellar structures. The pressures, temperature, and densities seen in the interior of stars are not easily reproduced, and thus human technology must be developed to reach these difficult stellar conditions in order to harvest fusion energy. There are two main branches of developmental technology geared towards achieving the difficult conditions controlled nuclear fusion presents, magnetic confinement fusion (MCF) and inertial confinement fusion (ICF)[17]. Yet in both approaches barriers exist which have thwarted the efforts toward reaching fusion ignition which must be addressed through scientific discovery. Successfully reaching ignition is only the first step in the ultimate pursuit of a self sustaining fusion reactor. This work will focus on the experimental ICF configuration, and on one such inhibitor toward achieving ignition, the Rayleigh-Taylor (RT) instability. The RT instability develops on the surfaces of the fusion fuel capsules, targets, and causes nonuniform compression of the target. This nonuniform compression of the target leads to lower pressures and densities through the material mixing of fusion fuel and the capsule shell, which ultimately leads to challenges with reaching fusion ignition. The work presented here was performed utilizing the University of Chicago's FLASH code, which is a state-of-the-art open source radiation magneto-hydrodynamic (MHD) code used for plasma and astrophysics computational modeling [11]. Simulations of the RT instability are performed using FLASH in planar and cylindrical geometries to explore fundamental Rayleigh-Taylor instability evolution for these two different geometries. These geometries provide easier access for experimental diagnostics to probe RT dynamics. Additionally, the impact of externally applied magnetic fields are explored in an effort to examine if and how the detrimental instability can be controlled.
Skrudupis, Patrikas. « Tikrovės problema Jean'o Baudrillard'o filosofijoje ». Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050602_221029-28883.
Texte intégralDaou, Maya Mounir. « Investigation of the plate-impact method as a precursor of physical phenomena and chemical processes ». Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066245/document.
Texte intégralThis manuscript aims at characterizing a new device based on a plate impact on a liquid surface to generate cavitation and evaluate its potential to induce chemical reactions. The device is composed of a reactor containing a liquid that a piston hits due to pressure difference. This impact generates a strong and uniform pressure increase in the medium followed by a depressurization. We show that the gas/vapor layer trapped between the piston and the liquid free surface influences the pressure peaks and frequencies generated in the medium. High-speed camera visualization shows that depressurization activates nucleation sites leading to bubble appearance in the solution. Bubbles expand and collapse intensively generating high velocity jets under some conditions. We also investigate the response of pre-existing bubbles. We identify a critical bubble radius that depends on the impact height, external pressure and piston’s characteristics. Bubbles with an initial radius larger than the critical one collapse at the moment of impact while smaller bubbles are only activated after it (under tension). Significant differences are observed in the pressure recordings after the impact depending on the presence/absence of large bubbles. We finally study the oxidation of phenol. We show that impacting on pure water is incapable of generating radical species responsible of the degradation. By adding hydrogen peroxide as an oxidant we show that the molecule is decomposed under certain conditions. In general, the amount of hydrogen peroxide required to initiate a significant oxidation decreases when increasing the intensity of the impact on which the degradation rate mainly depends
Kamolnick, Paul. « Abu Muhammad Al-Adnani’s May 21, 2016 Speech : More Evidence for Extreme Marginalization, Implosion, and the Islamic State Organization’s Certain Future as a Hunted Underground Ultra-Takfiri Terrorist Criminal Entity ». Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/646.
Texte intégralKamolnick, Paul. « Abu Muhammad al-Adnani’s May 21, 2016 Speech : More Evidence for Extreme Marginalization, Implosion, and the Islamic State Organization’s Certain Future as a Hunted Underground Ultra-Takfiri Terrorist Criminal Entity ». Digital Commons @ East Tennessee State University, 2018. https://amzn.com/1543478824.
Texte intégralHaworth, Thomas James. « Radiation hydrodynamic models and simulated observations of radiative feedback in star forming regions ». Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14465.
Texte intégralArtrip, Ryan Edward. « Virulence and Digital Culture ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/80512.
Texte intégralPh. D.
Capuano, Marion. « Simulations numériques d'écoulements diphasiques compressibles, visqueux et conductifs à l'aide de schémas aux différences finies d'ordre élevé ». Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC016/document.
Texte intégralThis PhD work concerns the simulation of compressible, viscous and conductive two-phase flows, using high-order centered finite-difference schemes. The equations governing two-phase flows are the Navier-Stokes equations in conjunction with two advection equations governing the interface and one equation allowing to estimate the temperature within a liquid and a gas. These are solved using conservative numerical methods which are validated from the resolution of various 1D test cases taken from the literature. The results obtained are in good agreement with the analytical or reference solutions. Then, two 2-D flows composed of two gases are considered. The first case concerns the Richtmyer-Meshkov instability developping at the interface between air and SF6. The second case deals with a cylindrical bubble filled with helium or R22 which is hit by a plane shock wave travelling through air. For these two flows, a grid convergence study is conducted and the numerical solutions compare well with the experimental data of the literature. The effect of the Reynolds number on the deformation of the bubble interface is also shown. Finally, the collpase of an air bubble in water is studied. Firstly, the spherical collapse of the bubble due to its interaction with a spherical converging shock wave is simulated. The results are in good agreement with the solutions predicted by the Rayleigh-Plesset model. The effect of the initial interface thickness and the thermal conductivity on the collapse is investigated. Secondly, the non-spherical collapse of a bubble near a wall impacted by a plane shock wave is considered. The pressure imposed on the wall and the temperature within the flow are quantified. Finally, the influence of the initial stand-off distance between the wall and the bubble is examined
Wang, Juntao. « Coronal implosions in solar eruptions and flares ». Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/31010/.
Texte intégralKemp, Andreas J. « Magnetized cylindrical implosions driven by heavy ion beams ». [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962128287.
Texte intégralTown, Richard Paul John. « Three dimensional hydrodynamical simulations of laser driven implosions ». Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46585.
Texte intégralKrispinsson, Charlotta. « Ung, samtida och postmodern : En studie av det svenska konstfältet under 1980-talet utifrån Lars Nilssons konstnärskap ». Thesis, Södertörn University College, School of Culture and Communication, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-3311.
Texte intégralThe aim of this thesis is to study the Swedish art field during the 1980s, from the perspective of the artistic production of Lars Nilsson. During this decade he became one of the most well known young artists associated with postmodernism.
The thesis is divided into three parts, where the first part examines different influences and aspects of the art of Lars Nilsson, as well as the contexts he was a part of. This is performed through a chronological as well as a categorizing presentation, based upon different exhibitions where Nilsson participated during the 1980s.
In the second part the subject is the Swedish art field, and how Lars Nilsson came to be part of a a new established category of a young generation of artists, mostly born in the 1950s, who were associated with youth, postmodernism and contemporaneousness. This part also puts attention to the importance of Lars Nittve, then art critic and curator, in introducing postmodernism, as well as establishing this new categorization of artists in Sweden.
The last part of the thesis studies four different group exhibitions, and how they all exemplify how "a younger generation of artists" were to be connected with notions of postmodernism and contemporaneousness through curatorial practice. Lars Nilsson participated at the thirst three of these exhibitions. This is followed with a last group exhibition, where the idea of younger artists as the most contemporary were to be questioned. The thesis ends with a summary and a discussion.
Arias, Beatriz. « Grupos consonánticos cultos en el siglo XVI y XVII : ¿representación fonémica o norma gráfica ? » Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/100139.
Texte intégralThis paper examines the graphic representation of some consonant groups considered educated in the colonial Mexican Spanish in documents, charts and orthographies from XVI and XVII centuries. As of this work, it has been possible the registration of some different types of graphic representations for the consonants in implosive position, they are similar to the ones registered in the popular language of this zone. This research offers two striking points. On one side, it demonstrates that the graphic study of novo-Hispanic documents provides clues about the “realization” of the educated groups from the period under scrutiny. On the other hand, I conclude that many of these phenomena occur in the outlines of the syllable, specifically in the coda, and that they are very similar to those found in the popular speech of Mexicans from the XXI.
Bland, Simon Nicholas. « Plasma dynamics in aluminium wire array Z-pinch implosions ». Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342345.
Texte intégralSavage, Maura Christine. « Studies of laser compression of high aspect ratio DT filled shells ». Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317484.
Texte intégralEl, Rafei Moustassem. « Three-Dimensional Numerical Simulations of Shock-Induced Turbulent Mixing in Spherical Implosions ». Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/28607.
Texte intégralWeinwurm, Marcus. « Cylindrically convergent implosions of metal liners for quasi-isentropic compression of deuterium ». Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/23296.
Texte intégralJohns, Heather M. « Constrained analysis of Ti line absorption spectra in OMEGA direct-drive implosions ». abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1456409.
Texte intégralXavier, Christine Fernandes. « Modelos de implosão de bolhas esféricas para sonoluminescência ». [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277081.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin"
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Resumo: Os processos de relaxação associados aos graus de liberdade vibracional, de dissociação e ionização em bolhas de gás diatômicos e monoatômicos em SBSL (sonoluminescência de uma única bolha) são analisados através da elaboração de modelos hidrodinâmicos apropriados onde o efeito da condução térmica na interface bolha-líquido é incluído de maneira auto-consistente. Simulações numéricas dos diversos processos de relaxação permitiram caracterizar a dinâmica de tais bolhas, além de permitir a obtenção dos valores associados às frações dissociadas e ionizadas dos gases no interior da cavidade. Em conexão com a análise do processo de ionização, um modelo para a emissão de radiação em SBSL é construído, suas conseqüências sendo analisadas e discutidas. O efeito da condução térmica na interface bolha líquido é também considerado
Abstract: We analyze, under appropriate hydrodynamical models, the processes of relaxation associated to vibrational degrees of freedom, dissociation and ionization of diatomic and monoatomic gas bubbles in the sonoluminescence phenomena. Numerical simulations allowed to characterize the dynamics of such bubbles and to infer values for dissociated and ionized fractions of gases that are present inside the cavity. In connection to an analysis of ionization process, we have constructed a model for the emission of SBSL (single bubble sonoluminescence) radiation whose main features are discussed. The effect of thermal conduction at the bubble-liquid interface is also considered.
Doutorado
Física
Doutor em Ciências
Casey, Daniel Thomas. « Diagnosing inertial confinement fusion implosions at OMEGA and the NIF Using novel neutron spectrometry ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76813.
Texte intégralThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 139-148).
A novel neutron spectrometer, called the Magnetic Recoil Spectrometer (MRS), was designed, built, and implemented on the OMEGA laser facility and the National Ignition Facility (NIF) to measure the neutron spectra from inertial confinement fusion (ICF) implosions. Using the MRS, the down-scattered neutron (DSn) spectrum has been used to infer the areal density ([rho]R) of ICF implosions for the first time. The DSn technique is essential for diagnosing high [rho]R (>180mg/cm²) cryogenic deuterium-tritium (DT) implosions, where most other methods fail. The MRS has helped to guide the cryogenic campaign toward the highest [rho]Rs ever achieved at OMEGA. In addition, the MRS is currently being used to diagnose the DSn spectrum from cryogenic implosions at the NIF during the beginning phases of the National Ignition Campaign (NIC). MRS data have already been essential for tuning these implosions to the highest [rho]Rs ever achieved in an ICF implosion (>1 g/cm²), and thus for guiding the NIC toward the realization of thermonuclear ignition. The first measurements of the T(t,2n)⁴He (TT) neutron spectrum in DT implosions at OMEGA have also been conducted using the MRS. The TT-neutron (TTn) spectrum was measured at low reactant central-mass energies of ~23 keV. The results from these measurements indicate that the TT reaction proceeds primarily through the direct three-body reaction channel, which is in contrast to the results obtained in higher energy accelerator experiments. Measurements of the TTn and DD proton yields were also conducted and compared to the DT neutron yield in DT implosions. From these measurements, it is concluded that the DD yield is anomalously low and the TTn yield is anomalously high, relative to the DT yield. These results have been explained by a stratification of the fuel in the core of an ICF implosion.
by Daniel Thomas Casey.
Ph.D.
Rinderknecht, Hans G. « Studies of non-hydrodynamic processes in ICF implosions on OMEGA and the National Ignition Facility ». Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99291.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references.
Ion kinetic effects are expected to modify plasma dynamics when ion mean-free-paths and collision times become comparable to the scale sizes of the plasma. Such conditions arise during the shock convergence phase of inertial confinement fusion (ICF) implosions, when they may modify the compression and ignition of the fuel from the evolution predicted by main-line hydrodynamic simulations. Kinetic plasma dynamics relevant to ICF implosions have been studied experimentally using strongly-shocked ICF implosions containing multiple ion species, and diagnosed using both new and established nuclear diagnostics and techniques. Implosions of deuterated plastic shells filled with equivalent-mass-density mixtures of deuterium and 3He gas have demonstrated for the first time ion diffusive mixing of the fuel and shell material through observations of the D3He-proton and DD-neutron yields. Implosions with initially separated populations of D in the shell and 3He in the gas produced D3He-fusion from the mixed region on par with implosions filled with equimolar D3 He fuel and an order of magnitude larger than is produced by hydrodynamic models of fuel/shell mix. An extensive survey of kinetic mix- and yield-generation mechanisms and their signatures in nuclear diagnostics establishes ion diffusion as the best candidate to explain these observations. A series of shock-driven implosions of D3He-gas filled glass shells has demonstrated two signatures of significant ion kinetic plasma effects for the first time: ion thermal decoupling and ion species separation. In low-initial gas density implosions, for which the thermal equilibration times were much longer than the burn duration, the burn-averaged ion temperatures were observed to be anomalously invariant with ion species fraction. This behavior has been shown to signify thermal decoupling of the D and 3He ion species between the shock- and fusion-phases. Comprehensive nuclear diagnostic information has been used to infer the burn-averaged deuterium fraction, which was reduced from the expectations of hydrodynamic simulations, the first direct measurement of species separation in an ICF implosion. When corrected for these effects, simulations agreed better with the observed anomalously low nuclear yields. These results have demonstrated the significant modification of ICF-relevant shocked plasmas by kinetic plasma dynamics, motivating further experimental and theoretical investigation of these highly dynamic and poorly understood regimes.
by Hans G. Rinderknecht.
Ph. D.
Schwartz, Brook-Eden 1979. « Imaging the burn region of laser driven implosions on OMEGA using the proton core imaging spectroscope ». Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29443.
Texte intégralIncludes bibliographical references (p. 143).
The first measurements of the nuclear burn region of OMEGA implosions have been made with the Proton Core Imaging Spectroscope (PCIS). Using CR-39 nuclear track detectors, PCIS applies the technique of penumbral imaging to measure the radial profile of D-D and D-3He protons produced by implosions of D2-3He-filled capsules. For capsules with 20 [mu]m-CH shells, images of D-3He protons resulted in Gaussian profiles with an average l/e radius of [approx.]35 [mu]m. Gaussian profiles inferred from the D-3He protons and D-D protons produced by implosions of 2 [mu]tm SiO2-shell capsules had average l/e radii of 60 [mu]m and 94 [mu]m, respectively. [mu]m and 94 [mu]m, respectively.
by Brook-Eden Schwartz.
S.M.
Sinenian, Nareg. « Fast-ion spectrometry of ICF implosions and laser-foil experiments at the omega and MTW laser facilities ». Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/80661.
Texte intégralCataloged from PDF version of thesis. Page 224 blank.
Includes bibliographical references.
Fast ions generated from laser-plasma interactions (LPI) have been used to study inertial confinement fusion (ICF) implosions and laser-foil interactions. LPI, which vary in nature depending on the wavelength and intensity of the driver, generate hot electrons with temperatures ranging from tens to thousands of kilo-electron-volts. These electrons, which accelerate the ions measured in this work, can be either detrimental or essential to implosion performance depending on the ICF scheme employed. In direct-drive hot-spot ignition, hot electrons can preheat the fuel and raise the adiabat, potentially degrading compression in the implosion. The amount of preheat depends on the hot-electron source characteristics and the time duration over which electrons can deposit energy into the fuel. This time duration is prescribed by the evolution of a sheath that surrounds the implosion and traps electrons. Fast-ion measurements have been used to develop a circuit model that describes the time decay of the sheath voltage for typical OMEGA implosions. In the context of electron fast ignition, the produced fast ions are considered a loss channel that has been characterized for the first time. These ions have also been used as a diagnostic tool to infer the temperature of the hot electrons in fast-ignition experiments. It has also been shown that the hot-electron temperature scales with laser intensity as expected, but is enhanced by a factor of 2-3. This enhancement is possibly due to relativistic effects and leads to poor implosion performance. Finally, fast-ion generation by ultra-intense lasers has also been studied using planar targets. The mean and maximum energies of protons and heavy ions has been measured, and it has been shown that a two-temperature hot-electron distribution affects the energies of heavy ions and protons. This work is important for advanced fusion concepts that utilize ion beams and also has applications in medicine.
by Nareg Sinenian.
Ph.D.
Kurebayashi, Shinya 1976. « Using Nuclear data and Monte-Carlo techniques to study areal density and mix in D² inertial confinement fusion implosions ». Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29369.
Texte intégralIncludes bibliographical references.
Measurements from three classes of direct-drive implosions at the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] were combined with Monte-Carlo simulations to investigate models for determining hot-fuel areal density ([rho]Rhot) in compressed, D2-filled capsules, and to assess the impact of mix and other factors on the determination of pRhot. The results of the Monte-Carlo calculations were compared to predictions of commonly used models that use ratios of either secondary D3He proton yields or secondary DT neutron yields to primary DD neutron yields to provide estimates [rho]Rhot or [rho]Rhot,n, respectively, for pRhot. For the first class of implosions, where [rho]Rhot is low (=/< 3 mg/cm2), [rho]Rhot,p and [rho]Rhot,n often agree with each other and are often good estimates of the actual [rho]Rhot. For the second class of implosions, where [rho]Rhot is of order 10 mg/cm2, pRhot,p often underestimates the actual value due to secondary proton yield saturation. In addition, fuel-shell mix causes pRhot,p to further underestimate, and [Rho]Rhot,n to overestimate, [rho]Rhot. As a result, values of [Rho]Rhot,p and [Rho]Rhot,n can be interpreted as lower and upper limits, respectively. For the third class of implosions, involving cryogenic capsules, secondary protons and neutrons are produced mainly in the hot and cold fuel regions, respectively, and the effects of the mixing of hot and cold fuel must be taken into account when interpreting the values of [rho]Rhot,p and pRhot,n. From these data sets, we conclude that accurate inference of [rho]Rhot requires comprehensive measurements in combination with detailed modeling.
by Shinya Kurebayashi.
S.M.