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Dissertations / Theses on the topic 'Cross sections'

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Author: Grafiati

Published: 4 June 2021

Last updated: 9 March 2023

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1

Griesenauer, Erin. "Algebras of cross sections." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2086.

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My research studies algebras of holomorphic functions from $d$-tuples of $n\times n$- matrices, $M_n(\bC)^d$, to $M_n(\bC)$. In particular, I study the holomorphic functions that can be approximated by \emph{polynomial matrix concomitants}, that is polynomial maps from $M_n(\bC)^d$ to $M_n(\bC)$ that satisfy the relationship \[ f(g^{-1}\fz g) = g^{-1}f(\fz)g \] for every $\fz \in M_n(\bC)^d$ and $g\in GL_n(\bC)$. In a sense, these are the polynomial maps that “remember” the structure of the $d$-tuple $\fz$. My first result is that these holomorphic matrix concomitants can be identified with holomorphic cross sections of certain matrix bundles. A holomorphic matrix bundle is a fibred space in which every fibre is $M_n(\bC)$ and the fibres are glued together in such a way that the total space has a holomorphic structure. Once the identification between holomorphic cross sections and holomorphic concomitants is established, the structure of the matrix bundle is used to endow the algebra of continuous cross sections with a $C^*$-algebra structure. Then we study the subalgebra of cross sections that can be approximated by polynomial concomitants. By identifying the matrix concomitants with cross sections, we are able to prove interesting results about these algebras.

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2

Bhargava, Prarit. "The ¹²C pion absorption cross sections." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq30446.pdf.

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3

Pelzer, Bernard Joseph. "Recovering transitions from repeated cross sections." [S.l. : Nijmegen : s.n.] ; UB Nijmegen [Host], 2006. http://webdoc.ubn.ru.nl/mono/p/pelzer_b/recotrfrr.pdf.

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4

Egyed, Peter 1962. "Hidden-surface removal in polyhedral-cross-sections." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63763.

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5

Leslie, Dawn Elizabeth. "Positronium beam production and scattering cross-sections." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444932/.

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In this work, the efficiency for the production of a monoenergetic positronium beam via the charge-exchange reaction of a positron beam in a gaseous target has been determined for molecular hydrogen and molecular nitrogen. In the case of molecular nitrogen, it has been found that the energy range over which a useful intensity of collimated positronium may be produced can be extended to 250eV, 100eV higher than previously achieved. This should enable measurements of the total and partial positronium cross-sections at correspondingly higher energies, where target inelastic effects are expected to be significant A recent measurement of the integrated positronium formation cross-section for xenon found a larger yield of positronium atoms compared to the other noble gases. A shoulder was also seen 10eV above the peak and it was suggested that this might be due to the production of positronium in an excited state. These findings have provided an incentive to investigate the collimated positronium production efficiency from xenon, which has been found to be surprisingly low. The quantum state of the beam atoms has also been found to be dominantly ground state. Possible reasons for these findings are discussed Total cross-sections for positronium-gas scattering have been extracted from the measurements of the positronium beam production efficiency for both molecular nitrogen and xenon. These quantities have also been determined directly by measuring the intensity of the positronium beam transmitted through a gas cell via the Beer-Lambert Law. A good consistency is found between the values obtained using this method and those determined indirectly. Recently, measurements have been made of the absolute integrated cross-section for the fragmentation of positronium in collision with helium atoms, along with the longitudinal energy distributions of the residual positrons in the energy range -Ep/=13-33eV. Measurements of the latter indicate a peak close to half the residual positronium energy, suggesting that they continue to move in a correlated fashion with the emitted electrons. In the present work, these results have been confirmed using a different method, which enables the energy range of investigation to be extended both to higher and lower values. Preliminary results have also been obtained at Epx=60eV for the ejected positrons and for the ejected electrons at Ep/= 33eV.

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6

Ross, Martin James. "Effective cross-sections from transport property measurements." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47232.

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7

Saltzer, Sarah Dawn. "Applications of computers to balanced cross-sections." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/58330.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1986.
Microfiche copy available in Archives and Science.
Bibliography: leaves [54]-[55].
by Sarah Dawn Saltzer.
M.S.

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8

Wakely, Anthony B. "Glueball wave functions and production cross sections." W&M ScholarWorks, 1994. https://scholarworks.wm.edu/etd/1539623854.

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Three topics are studied in this dissertation.;Using QCD sum rules, I first calculate the first few moments of the distribution amplitude of the pseudoscalar glueball, a bound state of gluons. The distribution amplitude is the momentum wave function integrated over the transverse momentum. QCD sum rules are a method of finding hadronic parameters using perturbative QCD. I use an approximation in which the glueball is treated as a narrow resonance. The moments of the distribution amplitude then give the corresponding first few coefficients of the distribution amplitude for the glueball expanded in Gegenbauer polynomials. The distribution amplitude is rather close to its asymptotic form, and the glueball's "decayconstant" is about 105 MeV for a pseudoscalar glueball mass of 2.0 GeV.;Using the previously calculated distribution amplitude, I calculate the normalized differential cross section for two-photon pseudoscalar glueball plus meson production, {dollar}\gamma + \gamma\to G + \pi\sp0{dollar}. I compare to a previous calculation and to {dollar}\gamma + \gamma\to\pi\sp0 + \pi\sp0{dollar}.;Lastly, I show that very high momentum transfer semi-inclusive photoproduction of pions from nucleons, {dollar}\gamma p\to\pi X{dollar}, is dominated by a subprocess where the pions are produced directly. Although the "direct subprocess" may be thought of as a limiting case of a quark fragmentation subprocess, it is an exclusive process at the quark level, fully calculable using perturbative QCD, and thus distinct from the usual thinking about fragmentation processes. The numerical results, concentrating on neutral pions, indicate that the direct subprocess is dominant at pion transverse momenta slightly higher than those already measured. Incidentally, the integral over the pion distribution amplitude in the present case is the same as that for the pion electromagnetic form factor, but the momentum transfers involved correspond to measuring the pion form factor at momentum transfers up to several hundred GeV{dollar}\sp2{dollar}. These calculations can now be extended to glueball production at high transverse momentum.

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9

Bart, Mark. "Electron impact ionization: Measurements of absolute cross-sections and cross-beam studies." Thesis, University of Canterbury. Chemistry, 2003. http://hdl.handle.net/10092/5712.

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Absolute total electron impact ionization cross-sections have been measured and calculations performed for C1 to C4 perfluorocarbons, C1 to C5 chlorocarbons and a number of mixed halo carbons and nitriles. Measured and calculated cross-sections using several different models have been analyzed using empirically and theoretically determined functions in terms of fundamental molecular parameters. A series of bond contributions to the total electron impact ionization cross-section have been determined and shown to reproduce total cross-sections for all of the molecules investigated with a high degree of confidence. An instrument has been constructed for the measurement of pseudo-absolute partial electron impact ionization cross-sections using the NIST standard mass spectrum database as a reference. Measurements were carried out for CF4, C2F6, C3F8, C3F6, F2C=CF-CF=CF2 and F3C-C=C-CF3 Theoretical models of electron impact ionization cross-sections have been critically assessed and a correction factor has been devised and applied to the binary encounter Bethe model of electron impact ionization resulting in a significant improvement in the performance of that model such that it can now be used for molecules comprising of atoms in rows 1 to 4 of the periodic table with a high degree of confidence. Ion imaging has been applied for the first time to crossed-beam electron impact ionization in an attempt to measure angular scattering patterns and energy disposal in a one step process. The instrument and the ion imaging process are described in detail and preliminary results reported in this thesis. A feasibility study has been carried out on the use of a capacitance manometer to measure neutral molecular beam fluxes directly and recommendations made for the future development of a usable device.

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10

Kebadze, Elizbar. "Theoretical modelling of unbonded flexible pipe cross-sections." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326762.

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11

Miller, Janice E. "Representation theory, Borel cross-sections, and minimal measures." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/38643.

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12

Mosconi, Marita. "Re/Os Cosmochronometer Measurement of neutron cross sections /." [S.l. : s.n.], 2007. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000007503.

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13

Andrews, Mike C. 1949. "L- and M-Shell X-Ray Production Cross Sections of Neodymium Gadolinium, Holmium, Ytterbium, Gold and Lead by 25-MeV Carbon and 32-MeV Oxygen Ions." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc330892/.

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L- and M-shell x-ray production cross sections have been measured for thin solid targets of neodymium, gadolinium, holmium, ytterbium, gold, and lead by 25 MeV 12/6C^q+ (q=4,5,6) and by 32 MeV 16/8O^q+ (q=5,7,8). The cross sections were determined from measurements made with thin targets (< 2.5 μg/cm2). For projectiles with one or two K-shell vacancies, the target x-ray production cross sections were found to be enhanced over those for projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) plus electron capture (EC) to the L, M, N... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories, i.e., plane wave Born approximation for DI and Oppenheimer-Brinkman-Kramers formula of Nikolaev for EC and to the ECPSSR approach that accounts for Energy loss and Coulomb deflection of the projectile as well as for Relativistic and Perturbed Stationary States of inner shell electrons.

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14

Chatzigeorgiadis, Filippos. "Development of Code for a Physical Optics Radar Cross Section prediction and analysis application." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sept%5FChatzigeorgiadis.pdf.

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Thesis (M.S. in Systems Engineering and M.S. in Electrical Engineering)--Naval Postgraduate School, Sept. 2004.
Thesis advisor(s): David C. Jenn, D. Curtis Schleher. Includes bibliographical references (p. 125). Also available online.

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15

Yuzcelik, Cihangir Kemal. "Radar absorbing material design." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FYuzcelik.pdf.

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16

Johansson, Anders. "Shape functions in calculations of differential scattering cross-sections." Thesis, Uppsala University, Department of Physics and Astronomy, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-126674.

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Two new methods for calculating the double differential scattering cross-section (DDSCS) in electron energy loss spectroscopy (EELS) have been developed, allowing for simulations of sample geometries which have been unavailable to earlier methods of calculation. The new methods concerns the calculations of the thickness function of the DDSCS. Earlier programs have used an analytic approximation of a sum over the lattice vectors of the sample that is valid for samples with parallel entrance and exit surfaces.The first of the new methods carries out the sum explicitly, first identifying the unit cells illuminated by the electron beam, which are the ones needed to be summed over. The second uses an approach with Fourier transforms, yielding a final expression containing the shape amplitude, the Fourier transform of the shape function defining the shape of the electron beam inside the sample. Approximating the shape with a polyhedron, one can quickly calculate the shape amplitude as sums over it’s faces and edges. The first method gives fast calculations for small samples or beams, when the number of illuminated unit cells is small. The second is more efficient in the case of large beams or samples, as the number of faces and edges of the polyhedron used in the calculation of the shape amplitude does not need to be increased much for large beams. A simulation of the DDSCS for magnetite has been performed, yielding diffraction patterns for the L₃ edge of the three Fe atoms in its basis.

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17

Hargreaves, Leigh Randall, and harg0032@flinders edu au. "Absolute Electron Scattering Cross Sections for the CF2 Radical." Flinders University. School of Chemsitry, Physics and Earth Sciences, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20080430.103821.

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This thesis describes an experimental study of elastic electron scattering from CF2 radicals, in the intermediate energy regime. Measurements of the absolute differential, integral and momentum transfer cross sections for CF2 are presented. These measurements were performed using a new crossed beam spectrometer, incorporating a supersonic gas source and normalised using a new technique, with both of these features being extensively developed as a major part of this study. The organisation of this thesis is as follows: A brief justification for this research is presented in Chapter 1, together with a review of the spectroscopy and electron collision cross sections which are currently available for the CF2 radical. The crossed beamed apparatus and experimental techniques used to perform the present cross section measurements are then described in detail in Chapter 2, and the theory behind the new normalisation technique is subsequently presented in Chapter 3. Results from the present study are given in Chapter 4. Firstly, differential cross sections measurements for stable molecules are presented, to validate the new normalisation method. Characterisation data for the dissociation dynamics of C2F4 into CF2 radicals are then presented and, finally, differential cross section measurements for the CF2 radical are explored. Where possible, the measured data for CF2 are compared against results from theoretical calculations and the implications of the present results are discussed. The major findings of this research are then summarised in Chapter 5, and directions for future research using the present apparatus are also discussed here. Finally, some additional findings from this research and calibration data for the current apparatus are given in the appendices.

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18

Lantz, Mattias. "Investigations of Reaction Cross Sections for Protons and 3He." Doctoral thesis, Uppsala universitet, Institutionen för kärn- och partikelfysik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5813.

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The reaction cross section gives the probability that a particle will undergo a nonelastic process when passing through a nuclear medium. Therefore reaction cross section data are of importance both for theoretical studies and for applications in such diverse fields as medicine, biology, astrophysics and accelerator-driven transmutation of nuclear waste. There exist many data sets with angular distributions of elastic scattering, but very few measurements of the complementary reaction cross section have been performed. The measurement is in principle simple but has in practice proved to be very difficult to perform, and the relatively limited amount of experimental data displays some serious inconsistencies. Results from measurements of reaction cross sections are presented for: • 3He on 9Be, 12C, 16O, 28Si, 40Ca, 58,60Ni, 112,116,118,120,124Sn and 208Pb at 96, 138 and 167 MeV • protons on 12C, 40Ca, 90Zr and 208Pb at six energies in the energy range 80-180 MeV, and on 58Ni at 81 MeV. Experimental uncertainties were 3-9% for 3He and 1.5-8% for protons. The apparatus and the experimental method used for the measurements of reaction cross sections, using a modified attenuation technique, is described. The detection method enables simultaneous measurements of reaction cross sections for five different sizes of the solid angles in steps from 99.0 to 99.8% of the total solid angle. The final results are obtained by extrapolation to the full solid angle. Experimental results are compared with predictions from optical model calculations using phenomenological global optical potentials. Phenomenological parametrizations of reaction cross sections for scattering of projectiles on targets are presented. The parametrizations show that reaction cross sections are very sensitive to matter distributions at very large radii of both the projectile and the target. For protons the derived relations makes it possible to predict the reaction cross sections on targets for which no experimental data exist.

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19

Harris, Allison Lynn. "Fully differential cross sections for four-body scattering processes." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Harris_09007dcc806c3b59.pdf.

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Thesis (Ph. D.)--Missouri University of Science and Technology, 2009.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed August 25, 2009) Includes bibliographical references (p. 84-92).

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20

Nurmela, Arto. "Non-Rutherford elastic scattering cross sections for materials analysis." Helsinki : University of Helsinki, 2001. http://ethesis.helsinki.fi/julkaisut/mat/fysii/vk/nurmela/.

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21

Cockburn, James David. "Subleading corrections to hadronic cross-sections at high energies." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29519.

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The Large Hadron Collider (LHC) has provided, and will continue to provide, data for collisions at the highest energies ever seen in a particle accelerator. A strong knowledge of the properties of amplitudes for Quantum Chromodynamics in the High Energy Limit is therefore important to interpret this data. We study this limit in the context of the High Energy Jets (HEJ) formalism. This formalism resums terms in the perturbative expansion of the cross-section that behave like αn/s log (s/-t)ⁿ¯¹, which are enhanced in this limit. Understanding this region is particularly important in certain key analyses at the LHC: for example, Higgs-boson- plus-dijet analyses where cuts are applied to pick out events with a large mjj and in many searches for new physics. In this thesis, we discuss two directions in which HEJ's accuracy has been improved. Firstly, we look at adding descriptions of partonic subprocesses which are formally sub-leading in the jet cross-section but Leading Logarithmic (LL) in the particular subprocess itself. This required the derivation of new effective vertices that describe the emission of a quark/anti-quark pair in a way that is consistent with the resummation procedure. The inclusion of such processes reduces HEJ's dependence on fixed-order calculations and marks an important step towards full Next-to-Leading Logarithmic (NLL) accuracy in the inclusive dijet cross-section. The second extension was to improve our description of events involving the emission of a Higgs boson along with jets. Specifically, we derive new effective vertices which keep the full dependence on the quark mass that appears in the loops that naturally arise in such amplitudes. The formalism is also simple enough to allow for any number of extra nal state jets in the process. Therefore, HEJ is unique in its ability to provide predictions for high-multiplicity Higgs-plus-jets processes with full nite quark mass e ects. Such a calculation is far beyond the reach of any xed order approach.

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22

Jia, Bicen. "Resistance of Polygonal Cross Sections of Lattice Wind Tower." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63487.

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Wind energy is one of the most efficient renewable energies. The most used wind towers are tubularand lattice wind towers. Parts of lattice are easier to transfer, especially in the inland areas. Also, it is easier to build higher lattice tower in order to have more efficient energy conversion in inland areas.However, most of the cross sections for lattice tower are tubular cross sections.This thesis represents the parametric study of polygonal cross section of lattice tower. It consists ofthe numerical analysis based on finite element method (ABAQUS) and analysis based on EN 1993-1-3. The objective of this thesis is to find regular patterns of parametric influences on polygonal crosssection, and to compare them against calculation based on EN 1993-1-3. Also, to find regular patternsof parametric influences on the stiffness of the bolts on the lips.

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23

Arsenault, Caroline. "Development of a new design method for the cross-section capacity of steel slender I-sections." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/33548.

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Ce mémoire présente la recherche effectuée concernant le développement d’une nouvelle méthode de dimensionnement spécifiquement dédiée aux sections en acier en I très élancées par l’entremise de l’Overall Interaction Concept (O.I.C.). Le comportement en section est défini par deux comportements extrêmes, soit la résistance et l’instabilité pure. Les méthodes de calculs couramment utilisées dans les normes nécessitent d’abord de classer la section pour ensuite calculer les propriétés de la section efficace. Ces méthodes comportent quelques incohérences ainsi qu’un manque de précision. Une nouvelle méthode de dimensionnement qui considère la section entière – qui ne requiert donc plus de calculer les propriétés efficaces – et l’interaction entre les plaques peut et doit être développée. La considération des imperfections tant géométriques que matériels permet d’atteindre une plus grande précision, et l’utilisation d’outils numériques performants permet également d’augmenter l’efficacité des calculs. L’Overall Interaction Concept permet de calculer rapidement la résistance en section en fonction de l’élancement relatif généralisée, au moyen de courbes d’interaction. L’objectif principal de cette maîtrise est donc d’adapter l’O.I.C. aux sections ouvertes en I très élancées, comme celles utilisées dans le domaine des ponts, soumises à des cas de chargement simples (compression pure ou flexion d’axe fort seulement). Un modèle numérique a d’abord été développé en réalisant entre autres une étude de densité de maillage et des études sur les imperfections géométriques et matérielles à utiliser. Cette dernière étude doit être fait minutieusement et les choix effectués doivent être justifiés convenablement puisqu’aucune donnée expérimentale n’est disponible pour calibrer le modèle. Une fois le modèle fiable développé, une campagne numérique comptabilisant plus de 3500 simulations a été faite, permettant ainsi d’analyser l’effet de certains paramètres sur la résistance en section. Sur la base de ces simulations numériques, une proposition de méthode de dimensionnement a été faite en fonction des paramètres déterminants, c’est-à-dire le choix des contraintes résiduelles, du type de chargement et des propriétés géométriques géométrique de la section par l’entremise du paramètre μ. La formulation d’Ayrton-Perry a été adaptée pour définir les courbes d’interaction servant à prédire la résistance. En parallèle au développement de la méthode, des études ont été effectuées pour comparer les résultats obtenus pour la résistance en section selon les normes canadiennes, américaines et européennes avec les résultats obtenus numériquement. Ainsi, il a été possible d’observer la capacité d’amélioration des méthodes couramment utilisées tant en termes de précision que de simplicité.
This dissertation presents research developments related to the design of very slender open steel sections through the Overall Interaction Concept (O.I.C.). The cross-sectional behaviour is defined by two extreme, ideal behaviours: pure resistance and pure instability. Methods used in the current standards need to classify the section, and, in the case of bridge sections, to calculate effective properties. This method presents some inconsistencies, as well as accuracy issues. A new design approach considering the whole section – and by that interaction between plates – was developed. By including the geometrical and material imperfections, more accuracy can be reached, and using numerical tools can increase the efficiency as well. The Overall Interaction Concept allows to calculate fast the resistance of a cross-section by using a generalized relative slenderness, so-called interaction curves. The main aim of this master is to adapt the O.I.C. to very slender open I-sections subjected to simple load cases (major-axis bending moment and pure compression). A numerical model has been developed by carry out mesh density study, and imperfections studies. This part had to be carefully detailed and assessed since no experimental data can be available to calibrate the numerical models. Once a reliable model was settled, a numerical campaign of more than 3500 simulations has been undertaken, allowing to analyse the effects of many key parameters. Based on these numerical simulations, design proposals were made as based on the identified governing parameters, i.e. the residual stresses pattern, load case and geometrical properties by means of newly-proposed parameter μ. An extension of the Ayrton-Perry formulation is finally used to define crosssection interaction curves. Besides, systematic comparison with Canadian, American and European Standards are done with the results from numerical simulations allowing to observe the improvement capacity of the current methods, in terms of accuracy and simplicity.

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24

Symonds, Philip. "Top pair production cross sections and differential cross sections in the semi-leptonic channel using the CMS detector at √s = 7 and 8 TeV." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/10917.

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The top quark has been extensively studied since the Large Hadron Collider (LHC) began operating in 2010. The excellent performance of both the LHC and the Compact Muon Solenoid (CMS) detector has enabled complex analyses of many properties of the top quark. In this thesis inclusive and differential top pair (tt) production cross sections have been measured. Inclusive tt cross sections of 145.6 ± 8.2 (stat.) +38.1/28.3 (syst.) pb and 237.4 ± 1.9 (stat.) +20.4/-16.9 (syst.) pb were measured at 7 TeV and 8 TeV center-of-mass collision energies using luminosities of 1 fb⁻¹ and 19.7 fb⁻¹, respectively. These measurements were performed in the semi-leptonic channel by means of a maximum likelihood t of the lepton's pseudorapidity. The work in this thesis focuses specifically on the muon-plus-jets channel. The methods used for measuring the inclusive cross sections were built upon to measure differential cross sections with respect to event level observables. These observables include the missing transverse energy (Emiss T ) as well as some other kinematic distributions involving the jets, lepton and Emiss T in the decay. These results are unfolded to remove detector and selection effects and have uncertainties in the range of 3% to 15%. A low uncertainty is achieved by normalising the differential cross section using the total cross section. This leads to cancellations of some uncertainties. The results were compared with different Monte Carlo generators and with different input parameters. No significant deviations from predictions of the Standard Model were observed. This thesis also contains test beam results on CMS ECAL Endcap Lead Tungstate (PbWO4) crystals. These crystals had been damaged using various doses of proton irradiation. The damage for some crystals is expected to be roughly equivalent to 300 fb-1 of integrated luminosity at √s = 14 TeV. The energy resolution for these crystals was seen to reduce by close to a factor of 20.

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25

Adamczyk, Anne Marie. "Electromagnetic nucleus - nucleus cross sections using energy dependent branching ratios." Worcester, Mass. : Worcester Polytechnic Institute, 2009. http://www.wpi.edu/Pubs/ETD/Available/etd-042109-191434/.

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Reiter, Andreas J. H. "Differential photoneutron cross sections of light nuclei for neutron dosimetry." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400697.

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27

Yasuhara, Akira. "Surfaces in simply connected 4-manifolds and their cross-sections /." Electronic version of summary, 1994. http://www.wul.waseda.ac.jp/gakui/gaiyo/2010.pdf.

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28

Kanda, Hiroki. "Measurement of the cross sections of Σ[+]p elastic scattering." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136965.

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29

Hirlinger-Saylor, Nicholas. "A measurement of unpolarized cross sections and polarized cross section differences of deeply virtual compton scattering on the proton at Jefferson Laboratory using Clas." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00913906.

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Cette thèse a pour sujet l'étude de la réaction de la Diffusion Compton Profondément Virtuelle (DVCS) sur le proton e + p -> e' + p' + gamma (DVCS). Cette réaction est mesurée en analysant l'expérience e1-dvcs2 qui a eu lieu dans le Hall B du Jefferson Laboratory avec CLAS. La prise de données s'est déroulée du 22 octobre 2008 jusqu'au 23 janvier 2009. Cette analyse a pour but la détermination des sections efficaces non polarisées et les différences de sections efficaces polarisées du DVCS, dans divers bins en xB, Q^2, t et phi. Cette analyse compare les sections efficaces avec plusieurs mesures existantes du DVCS: une analyse parallèle de e1-dvcs2 et une analyse de e1-dvcs1. En factorisant l'élément de matrice qui correspond au DVCS en deux parties, calculables en QCD perturbative et non perturbative, on peut accéder aux Distributions de Partons Généralisées (GPDs) du proton, et ainsi obtenir une vue en 3D des distributions spatiales et en impulsion des quarks et des gluons dans le proton.

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Mira, Joele Paulus. "Production of Li, Be and B nuclei in the interaction of 12C with 12C at incident energies of 200 and 400 MeV." Thesis, Online Access, 2008. http://etd.uwc.ac.za/usrfiles/modules/etd/docs/etd_gen8Srv25Nme4_7059_1260783023.pdf.

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Weisberg, Adam. "A preliminary cross section measurement for K⁰*[Sigma]⁺ electroproduction." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1000211618.

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Blackie, Douglas Sinclair. "Sulphur dioxide : high resolution UV photoabsorption cross sections at 198 K." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508327.

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Goudet, Catherine A. "Finite element analysis of diseased cross-sections of human carotid arteries." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/16816.

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Tsai, Wei-heng. "Charring Rates for Different Cross Sections of Laminated Veneer Lumber (LVL)." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2010. http://hdl.handle.net/10092/5017.

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Current research at the University of Canterbury is investigating the performance of a new type of timber floor system made of a timber-concrete composite. This newly proposed timber floor system uses double LVL members connected together with screwed connections to form one larger LVL member. Recent large scale fire tests showed that the joint between these two screwed LVL members opened up during fire exposure. This opening phenomenon causes concerns as the overall charring rate of the joint LVL members is subsequently increased. The main focus of this research, therefore, was to examine the charring rate for different cross sections of single and double LVL members, with different connection types for the double members. The single LVL member examined was 63mm width whereas the double LVL members examined were 90mm and 126mm width. Three connection types were investigated which were nails, screws and glue. Their corresponding charring rates and burning characteristics were examined both in the small furnace provided by the University of Canterbury and in the pilot furnace at the Building Research Association of New Zealand (BRANZ) in Wellington. The overall finding from the small furnace testing shows that the overall average side charring rate for a 30 minute fire exposure was 0.76mm/min; whereas the overall average side charring rate for a 60 minute fire exposure was 0.66mm/min. Moreover for a 30 minute fire exposure, the average bottom charring rates for nail, screw and glue connected double LVL members were 1.00mm/min, 0.83mm/min and 0.83mm/min, respectively. For a 60 minute fire exposure, the average bottom charring rates for screw and glue connected double LVL members were 0.97mm/min and 0.57mm/min, respectively. The nail connected double LVL members experienced the highest bottom charring rate as it suffered the largest bottom separation which allowed the heat to travel into the mid-span resulting in a higher bottom charring rate. Out of these three connection types, the glued connection was the best connection type. Experimental findings were compared with the simulated results generated by the SAFIR finite element program. Experimental findings were also used to modify the spreadsheet design tool which predicts the fire resistance rating of a timber-concrete composite floor under user defined load conditions and floor geometries.

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Roodbaraky, K. "Finite element modelling of tubular cross joints in rectangular hollow sections." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384702.

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Collins, Timothy L. D. "Inelastic rotational transfer differential cross-sections for Li2-rare gas collisions." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282082.

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Sousa, Yuri Teixeira e. "Kinematically exact elastoplastic analysis of steelo rods with compact cross sections." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-05122017-134523/.

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In this work, we present the formulation and implementation of two elastoplastic constitutive equations for kinematically exact thin-walled rod models. The first uses the fact that first order strains due to cross sectional shear stresses and warping are considered to formulate a small strains three-dimensional elastoplastic constitutive model. Given the kinematical hypothesis of non-deformability of the cross section in the projection of its plane, we may also assume that plastic deformations may occur due only to the cross sectional normal stresses, thereby allowing us to formulate a second, simple one-dimensional framework. Our approach adopts a standard additive decomposition of the strains together with a linear elastic relation for the elastic part of the deformation. Both ideal plasticity and plasticity with (linear) isotropic hardening are considered. The models have a computational implementation within a finite element thin-walled rod model and, following the kinematics adopted, we implement this equation on models with consideration of the warping of the cross sections, having 7 degrees of freedom. The formulation and implementation presented is validated by the analysis of problems known in the literature and comparison of the results. We believe that simple elastoplastic models combined with robust thin-walled rod finite element may be a useful tool for the analysis of thin-walled rod structures, such as, e.g., steel structures.
Neste trabalho, apresentamos a formulação e implementação de duas equações constitutivas elastoplásticas simples para modelos de barra de parede fina cinematicamente exatos. O primeiro usa o fato de deformações de primeira ordem devido a esforço cortante na seção transversal e empenamento serem considerados para formular um modelo constitutivo elastoplástico tridimensional para pequenas deformações. Dada a hipótese cinemática de não deformabilidade da seção transversal da barra na projeção de seu plano, podemos também assumir que deformações plásticas ocorrem devido apenas às tensões normais à seção transversal, nos permitindo formular um segundo modelo unidimensional simples. Nossa abordagem adota uma decomposição aditiva padrão das deformações com uma relação elástica linear para a parte elástica das deformações. Tanto plasticidade ideal quanto plasticidade com encruamento isótropo (linear) são considerados. Os modelos resultantes têm uma implementação computacional com elementos finitos de barras e, de acordo com a cinemática adotada, implementamos esta equação com consideração do empenamento das seções transversais, possuindo 7 graus de liberdade. A formulação e implementação apresentadas são validadas pela análise de problemas conhecidos na literatura e comparação dos resultados. Acreditamos que modelos elastoplásticos simples combinados com um elemento finito de barras robusto podem ser uma ferramenta útil para a análise de estruturas reticuladas como, por exemplo, estruturas de aço.

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Guerra, Mauro António Moreira. "Electron impact ionization cross sections and analysis of X-ray spectra." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/9141.

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Leclère, Anne-Sophie T. "An evaluation of bremsstrahlung cross-sections for keV to GeV electrons." [Gainesville, Fla.] : University of Florida, 2001. http://etd.fcla.edu/etd/uf/2001/anp4086/thesis.pdf.

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Thesis (M.S.)--University of Florida, 2001.
Title from first page of PDF file. Document formatted into pages; contains x, 56 p.; also contains graphics. Vita. Includes bibliographical references (p. 53-55).

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Verzani, Christopher J. "Single and double electron capture cross sections at very low energies /." Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.

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41

Kovačíková, Petra. "Hard scattering cross sections and parton distribution functions at the LHC." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16806.

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Über einen Mellinraumzugang werden Methoden zur Auswertung von Wirkunsquerschnitten für verschiedene Prozesse mit Hadronen im Anfangszustand entwickelt. Die Arbeit geschieht im Hinblick auf drei Prozesse, für die die analyischen Ergebnisse für perturbative QCD Korrekturen zu “next-to-next-to-leading order” bekannt sind; diese sind: die Produktion der Vektorbosonen Z0 und W± über einen Drell-Yan-Prozess in der “narrow width”-Näherung, die Produktion eines Standardmodell-Higgs-Bosons über die Fusion zweier Gluonen im Grenzfall schwerer Top-Quark-Massen und die tiefinelastische Lepton-Hadron-Streuung über neutrale und geladene Ströme. Die Implementierung der Mellinraumtechniken erfolgt in dem c++ Paket sbp. Das Programm ermöglicht auf elegante Weise eine schnelle und präzise Auswertung von inklusiven Wirkungsquerschnitten. Wir vergleichen sbp mit den herkömmlichen Impulsraumtechniken, und präsentieren Studien der asymptotischen Konvergenz den perturbativen Reihen und von Skalenabhängigkeiten. Als Anwendung untersuchen wir welchen Einfluss die Behandlung der Faktorisierungs- und Renormierungsskala auf den Wirkungsquerschnitt hat.
In this thesis we will explore a Mellin space approach to the evaluation of precision cross-sections at hadron colliders. We consider three processes with known analytic results for perturbative QCD corrections up to the next-to-next-to-leading order, namely: the production of vector bosons Z0, W± via the Drell-Yan mechanism in the narrow width approximation; the production of the standard model Higgs boson via gluon-gluon fusion using the large top quark mass limit and the neutral and charged current deep inelastic lepton-hadron scattering. We develop a c++ package sbp that implements the Mellin space technique. The resulting program provides an elegant, fast and accurate solution for the evaluation of inclusive cross sections. We compare our program with available results that use standard momentum space techniques. We present studies of asymptotic convergence and scale dependence of the perturbative series. We use the package to study different treatments of factorisation and renormalisation scales in cross sections.

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Paquet, Jeanne. "Development of a new design method for the cross-section capacity of steel open sections at high temperatures." Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/69308.

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À hautes températures, les propriétés de l’acier sont affectées et sa résistance est donc moindre que sa résistance à température ambiante. Des méthodes de calculs différentes doivent donc être utilisées pour prédire la résistance dans la situation exceptionnelle d’incendie. Les normes actuelles proposent des méthodes simplifiées pour prédire la résistance de l’acier à haute température. Toutefois, ces méthodes sont inspirées des méthodes de dimensionnement à froid et ne sont donc généralement pas adéquates pour prédire de façon précise la résistance des éléments en situations d’incendie. Ce mémoire présente les recherches effectuées pour la proposition d’une nouvelle méthode de calcul pour les sections d’acier ouvertes soumises à de hautes températures en utilisant l’Overall Interaction Concept (O.I.C). Cette méthode est basée sur l’interaction entre la résistance et la stabilité et permet de considérer les imperfections géométriques et matérielles. Entre autres choses, l’avantage de cette nouvelle méthode est qu’elle permet d’obtenir des résultats précis et de conserver une continuité entre les prédictions. Un modèle numérique a été utilisé pour prédire la résistance de l’acier à hautes températures. Ce modèle a été validé en comparant les résultats avec des résultats expérimentaux. À la suite de la validation, le modèle a été utilisé pour conduire des simulations dans lesquelles plusieurs géométries, températures, limites élastiques et cas de chargement ont été considérés. Les résultats ont ensuite été utilisés pour proposer de nouvelles équations dans le format O.I.C. La performance de la nouvelle proposition a été évaluée et comparée avec la performance de normes existantes. Cette évaluation a permis de conclure que la proposition donne des résultats beaucoup plus précis. Finalement, l’évolution du comportement de l’acier entre la température ambiante et les hautes températures a brièvement été analysé. Puisque ce point est abordé de façon sommaire, il ouvre la porte vers de futures études sur le sujet.
At high temperatures, steel suffers from great lossesin strength and stiffness. Different design methods must therefore be considered to predict the resistance of steel in the exceptional situation of fire. Current standards propose simplified methods to predict the resistance of steel at high temperatures. However, these methods are inspired by steel design equations used at room temperature and are therefore generally not suitable to predict accurately the resistance of steel elements in fire situation. This thesis presents research investigations pursued to propose a new design method for open steel cross-sections subjected to high temperatures by means of the Overall InteractionConcept (O.I.C.). This calculation method is based on the interaction between resistance and stability and allows to consider geometrical and material imperfections. The advantage of this new calculation method is that it allows to obtain precise results and to keep continuity between predictions contrarily to standards that use the cross-section classification. A numerical model, initially developed for open steel cross-sections at ambient temperature,was improved to predict the resistance of steel at high temperatures. It was then verified against experimental test results to ensure its accuracy. After validation, the numerical model was used to conduct simulations using different geometries, temperatures, yield limits andload cases. Results were then used to formulate new design proposals for cross-sections at high temperatures in the O.I.C. format. The performance of the new proposal was then evaluated et compared with the performance of existing standards. This evaluation allowed to conclude that the proposition is much more accurate than existing standards. Finally, the evolution of the behaviour of steel between cold and high temperature was briefly analysed. As this point was only briefly discussed, it opens the door for future studies on the subject.

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Botes, Danniëll. "Few group cross section representation based on sparse grid methods / Danniëll Botes." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8845.

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This thesis addresses the problem of representing few group, homogenised neutron cross sections as a function of state parameters (e.g. burn-up, fuel and moderator temperature, etc.) that describe the conditions in the reactor. The problem is multi-dimensional and the cross section samples, required for building the representation, are the result of expensive transport calculations. At the same time, practical applications require high accuracy. The representation method must therefore be efficient in terms of the number of samples needed for constructing the representation, storage requirements and cross section reconstruction time. Sparse grid methods are proposed for constructing such an efficient representation. Approximation through quasi-regression as well as polynomial interpolation, both based on sparse grids, were investigated. These methods have built-in error estimation capabilities and methods for optimising the representation, and scale well with the number of state parameters. An anisotropic sparse grid integrator based on Clenshaw-Curtis quadrature was implemented, verified and coupled to a pre-existing cross section representation system. Some ways to improve the integrator’s performance were also explored. The sparse grid methods were used to construct cross section representations for various Light Water Reactor fuel assemblies. These reactors have different operating conditions, enrichments and state parameters and therefore pose different challenges to a representation method. Additionally, an example where the cross sections have a different group structure, and were calculated using a different transport code, was used to test the representation method. The built-in error measures were tested on independent, uniformly distributed, quasi-random sample points. In all the cases studied, interpolation proved to be more accurate than approximation for the same number of samples. The primary source of error was found to be the Xenon transient at the beginning of an element’s life (BOL). To address this, the domain was split along the burn-up dimension into “start-up” and “operating” representations. As an alternative, the Xenon concentration was set to its equilibrium value for the whole burn-up range. The representations were also improved by applying anisotropic sampling. It was concluded that interpolation on a sparse grid shows promise as a method for building a cross section representation of sufficient accuracy to be used for practical reactor calculations with a reasonable number of samples.
Thesis (MSc Engineering Sciences (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2013.

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Denz, Holger. "Differential cross sections in p±p [pi ± p] scattering at low energies." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972028021.

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Kaya, Halil. "Aerodynamic Analysis Of Long-span Bridge Cross-sections Using Random Vortex Method." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615072/index.pdf.

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In this thesis, two dimensional, incompressible, viscous flow past bluff bodies and a bridge section, in which strong vortex shedding and unsteady attribute of flow are generally found, is simulated by means of random vortex method. The algorithm and method are described in detail. The validation and applicability of the developed numerical implementation to general wind engineering problems is illustrated by solving a number of classical problems, such as flow past circular and square cylinders. An application of the numerical implementation in the area of computational wind engineering is performed by analyzing a bridge deck section. Moreover, all results are compared with experimental and numerical studies in literature.

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Lantz, Mattias. "Investigations of Reaction Cross Sections for Protons and ³He." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5813.

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47

Hassan, Rusul. "Distortional Lateral Torsional Buckling Analysis for Beams of Wide Flange Cross-sections." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24008.

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Structural steel design standards recognize lateral torsional buckling as a failure mode governing the capacity of long span unsupported beams with wide flange cross-sections. Standard solutions start with the closed form solution of the Vlasov thin-walled beam theory for the case of a simply supported beam under uniform moments, and modify the solution to accommodate various moment distributions through moment gradient expressions. The Vlasov theory solution is based on the assumption that cross-sectional distortional effects have a negligible effect on the predicted elastic critical moment. The present study systematically examines the validity of the Vlasov assumption related to cross-section distortion through a parametric study. A series of elastic shell finite element eigen-value buckling analyses is conducted on simply supported beams subject to uniform moments, linear moments and mid span point loads as well as cantilevers subject to top flange loading acting at the tip. Cross-sectional dimensions are selected to represent structural steel cross-section geometries used in practice. Particular attention is paid to model end connection details commonly used in practice involving moment connections with two pairs of stiffeners, simply supported ends with a pair of transverse stiffeners, simply supported ends with cleat angle details, and built in fixation at cantilever roots. The critical moments obtained from the FEA are compared to those based on conventional critical moment equations in various Standards and published solutions. The effects of web slenderness, flange slenderness, web height to flange width ratio, and span to height ratios on the critical moment ratio are systematically quantified. For some combinations of section geometries and connection details, it is shown that present solutions derived from the Vlasov theory can overestimate the lateral torsional buckling resistance for beams.

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Mirjalili, Vahid. "Modelling the structural efficiency of cross-sections in limited torsion stiffness design." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99780.

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Most of the current optimization techniques for the design of light-weight structures are unable to generate structural alternatives at the concept stage of design. This research tackles the challenge of developing an optimization method for the early stage of design. The main goal is to propose a procedure to optimize material and shape of stiff shafts in torsion.
Recently introduced for bending stiffness design, shape transformers are presented in this thesis for optimizing the design of shafts in torsion. Shape transformers are geometric parameters defined to classify shapes and to model structural efficiency. The study of shape transformers are centered on concept selection in structural design. These factors are used to formulate indices of material and shape selection for minimum mass design. An advantage of the method of shape transformers is that the contribution of the shape can be decoupled from the contribution of the size of a cross-section. This feature gives the designer insight into the effects that scaling, shape, as well as material have on the overall structural performance.
Similar to the index for bending, the performance index for torsion stiffness design is a function of the relative scaling of two cross-sections. The thesis examines analytically and graphically the impact of scaling on the torsional efficiency of alternative cross-sections. The resulting maps assist the selection of the best material and shape for cross-sections subjected to dimensional constraints. It is shown that shape transformers for torsion, unlike those for bending, are generally function of the scaling direction.
The efficiency maps ease the visual contrast among the efficiency of open-walled cross-sections and that of close-walled cross-sections. As expected, the maps show the relative inefficiency of the former compared to the latter. They can also set the validity range of thin- and thick-walled theory in torsion stiffness design. The analytical results are validated with the numerical data obtained from ANSYS to guarantee the consistency of the models. The thesis concludes with three case studies that demonstrate the method.

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Chapman, Christopher Weeks. "The MANE process of generating continuous energy hot-operating temperature cross sections." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53037.

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MANE (MCNP ACE from NJOY & ENDF), a code for generating continuous energy cross sections at arbitrary temperatures, was created. Cross sections were evaluated using NJOY99 such that they would agree with the cross sections provided by MCNP5. The MANE cross sections were found to be in very good agreement with those provided by MCNP5 with some minor exceptions caused by round-off errors and some differences in the unresolved resonance region. Differences in the resonance region are caused by differences in the random number generator used to start the cross section calculations. The MANE cross sections were verified against the MCNP5 cross sections in five unique MCNP configurations: an 8.7% enriched MOX fuel pin cell, a UO₂ assembly (controlled and uncontrolled), a MOX assembly, and a whole core configuration containing the 3 assemblies. In each of these cases, eigenvalue and tally density results were found to be in very good agreement with one another.

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Ayling, Stephen Gerard. "Cross-sections and electron distributions relating to hot electron impact excitation efficiencies." Thesis, University of St Andrews, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328092.

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