<p> Oscillating single neutron stars are considered to be important quasi-continuous sources for gravitational wave emission and detection at the Laser Interferometer Gravitational-Wave Observatory (LIGO). In order to detect these oscillations above the noise level in the detector, LIGO data must be compared to theoretical templates of the signal, which means predicting the signal amplitude and frequency range. In this thesis, we compute the two most important eigenfrequencies of superfluid neutron stars where the signal might be peaked. To calculate this spectrum, we first construct the background structure of the neutron star using realistic microscopic models of dense and interacting nuclear matter. For this purpose, we use the CompOSE database which provides an array of such models with thermodynamically consistent interpolation. The fluid pertubation equations of the equilibrium configuration, including superfluidity in a two-fluid model, are solved numerically in the non-relativistic limit, yielding the eigenfrequencies upon imposing suitable boundary conditions. We find that the modes of the superfluid star support modes that are very close to the corresponding normal fluid star, but there also appear one or two purely superfluid modes, the lower one of which is intermediate between the two lowest order modes of the normal fluid. Thus, in the event that these oscillation modes can be observed, we can confirm the theoretical prediction of neutron superfluidity in neutron stars. A part of the results presented in this thesis have been published as a proceedings article in Jaikumar, Monroy and Klaehn, <i> Universe</i> 4, 58 (2018).</p><p>

Nuclear deformation and rotation can be described by collective, macroscopic models such as the liquid drop model, or by microscopic theories like the shell model, using one-body operators acting on single particle wavefunctions Algebraic mean field theory (AMFT) constructs coadjoint orbits in the dual space of a Lie algebra made up of one-body operators. The coadjoint orbits are made up of densities corresponding to the quantum mechanical expectations of the one-body operators on the single particle wavefunctions. It reduces an infinite-dimensional problem in the shell model to a problem on a finite-dimensional manifold involving simple matrix multiplication. The critical points of a realistic energy functional on the coadjoint orbit produce equilibrium solutions for a rotating ellipsoid In this paper, AMFT has been applied to the symplectic algebra sp(3,reals), which encompasses both the su(3) algebra of the shell model, and the gcm(3) algebra that is the dynamical symmetry algebra of Riemann ellipsoid theory / acase@tulane.edu

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The g2 nucleon spin-dependent structure function measured in electron deep inelastic scattering contains information beyond the simple parton model description of the nucleon. It provides insight into quark-gluon correlations and a path to access the confining local color force a struck quark experiences just as it is hit by the virtual photon due to the remnant di-quark. The quantity d2, a measure of this local color force, has its information encoded in an x2 weighted integral of a linear combination of spin structure functions g1 and g2 and thus is dominated by the valence-quark region at large momentum fraction x. To date, theoretical calculations and experimental measurements of the neutron d2 differ by about two standard deviations. Therefore, JLab experiment E06-014, performed in Hall A, made a precision measurement of this quantity. Double spin asymmetries and absolute cross-sections were measured in both DIS and resonance regions by scattering longitudinally polarized electrons at beam energies of 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target. Results for the absolute cross-sections and spin structure functions on 3He will be presented in the dissertation, as well as results for the neutron d2 and extracted color forces. / Physics

Depuis quelques années, le protactinium suscite un regain d'intérêt en raison de l'implication de cet élément dans les réacteurs à combustible thorium, qui font partie des scénarios envisagés pour répondre aux besoins énergétiques du futur. Dans ce travail, le comportement du protactinium(V) en solution aqueuse acide a été étudié en présence de deux ligands organiques : l'acide oxalique et le DTPA. L'étude a été conduite selon une double approche : structurale, à l'aide des techniques de Spectroscopie d'Absorption des rayons X (SAX) et d'Electrophorèse Capillaire (EC-ICP-MS), complétée par des calculs de type DFT, et thermodynamique par la technique d'extraction par solvant. Le protactinium forme avec l'acide oxalique un complexe limite d'ordre 3 dans lequel la présence de la liaison courte mono-oxo a été mise en évidence grâce à l'analyse des spectres XANES et EXAFS. La charge (–3) de ce complexe a pu être déduite de mesures d'électrophorèse capillaire couplée ICP-MS. La structure optimisée de l'entité [PaO(C2O4)3] se caractérise par une coordination bidentate des trois oxalates, dont deux se situent dans le plan “équatorial” de la liaison Pa=O. Les constantes de formation des différents complexes successifs conduisant à PaO(C2O4)33– ont été déterminées à partir de l'analyse des variations du coefficient de partage D de Pa(V) en fonction de la concentration de ligand, dans le système TTA/toluène/H2O/NaClO4/HClO4/H2C2O4 à différentes températures pour une force ionique de 3 M. L'influence de la température a révélé une forte contribution entropique (excepté lors de la formation de PaO(C2O4)2–). La variation enthalpique relative aux équilibres successifs, accompagnant la formation des complexes est favorable pour les deux premiers complexes mais légèrement défavorable pour la formation du complexe limite. Avec le DTPA, les expériences d'électrophorèse capillaire ont clairement montré la formation d'un complexe neutre ; d'après les expériences d'extraction par solvant, il s'agit d'un complexe (1:1), pouvant donc correspondre à la formulation Pa(DTPA). L'arrangement le plus stable, issu de calculs de type DFT, montre que la coordination du protactinium est assurée par l'ensemble des atomes donneurs de la molécule de DTPA : les 3 atomes d'azote et les 5 atomes d'oxygène de chacune des fonctions carboxyliques. La constante de stabilité βapp de ce complexe a été déterminée pour différentes valeurs de force ionique et de température. La température s'est révélée sans influence sur les constantes de complexation entrainant l'hypothèse d'une variation enthalpique nulle et donc de la formation de Pa(DTPA) gouvernée par l'entropie.

Charged particle beam source problems are difficult to simulate because of the extremely large and anisotropic scattering cross sections, and the associated singularities in angle and space. To overcome these difficulties the Extended First Collision Source method and the SMART (Simulation of Many Accumulative Rutherford Trajectories) scattering method have been developed. In this study, the extended first collision source calculation was improved in the SN code using the SMART scattering method which produces smoother and smaller effective cross sections. To determine the uncollided flux which was necessary for the first collision source calculation, the SMART scattering cross sections were used instead of screened Rutherford scattering cross sections. After the SN code was modified, it produced results that approached those obtained using the benchmark Monte Carlo code.

<p> Patients receiving Intensity Modulated Radiation Therapy (IMRT) for late stage head and neck (HN) cancer often experience anatomical changes due to weight loss, tumor regression, and positional changes of normal anatomy (1). As a result, the actual dose delivered may vary from the original treatment plan. The purpose of this study was (a) to evaluate the dosimetric consequences of the parotid glands during the course of treatment, and (b) to determine if there would be an optimal timeframe for replanning. Nineteen locally advanced HN cancer patients underwent definitive IMRT. Each patient received an initial computerized tomography simulation (CT-SIM) scan and weekly cone beam computerized tomography (CBCT) scans. A Deformable Image Registration (DIR) was performed between the CT-SIM and CBCT of the parotid glands and Planning Target Volumes (PTVs) using the Eclipse treatment planning system (TPS) and the Velocity deformation software. A recalculation of the dose was performed on the weekly CBCTs using the original monitor units. The parameters for evaluation of our method were: the changes in volume of the PTVs and parotid glands, the dose coverage of the PTVs, the lateral displacement in the Center of Mass (COM), the mean dose, and Normal Tissue Complication Probability (NTCP) of the parotid glands. The studies showed a reduction of the volume in the PTVs and parotids, a medial displacement in COM, and alterations of the mean dose to the parotid glands as compared to the initial plans. Differences were observed for the dose volume coverage of the PTVs and NTCP of the parotid gland values between the initial plan and our proposed method utilizing deformable registration-based dose calculations.</p>