Dissertations / Theses: 'Calculations model'

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Karlsen, John Amund. "Performance Calculations for a Model Turbine." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12887.

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En modell av en vindturbin er studert numerisk og eksperimentelt. Dette er gjort for å verifisere at modellen fungerer i henhold til de beregninger som ble lagt til grunn i designprosessen. Vindturbinen har en diameter på 0.9m. Numeriske beregniner av vindturbinens effekt- og dragkoeffisient har blitt kalkulert under forskjellige driftsbetingelser. Både en Bladelementmetode (BEM) og en fullstendig løsning av bevegelseslikningene (CFD) har blitt benyttet. Eksperimentelle målinger ble deretter utført i vindtunnelen for å ha et sammelikningsgrunnlag.Modellturbinen benytter et NREL s826 profil langsmed hele bladet. Grundige todimensjonale undersøkelser av dette profilet ble gjennomført, et studie som resulterte i løft og dragkurver for BEM-beregningene, samt anbefalinger for gridoppløsning i det tredimensjonale gridet som skulle bli konstruert.Et hybridgrid bestående av 3.54 millioner celler ble benyttet i CFD-simuleringen. Strømingen ble antatt å være rotasjonsmessig periodisk, og Menters SST modell ble benyttet for å modellere de turbulente størrelsene.Det ble observert god overensstemmelse mellom eksperimentelle og numeriske resultater. CFD-resultatene viste seg å stemme best overens med den målte effektkoeffisienten, med avvik under 5%.Det ble oppdaget at strømingen rundt vindturbinen ble svært tredimensjonal ved lave tupphastighetsrater. Denne tredimensjonaliteten synes å oppstå når roten av bladet steiler, og forplanter seg langsmed dette i det tupphastighetsraten senkes ytterligere. BEM-metoden er ikke i stand til å beskrive denne prosessen, men viste seg å predikere bladets steiling svært bra.Det viste seg at vindturbinen opplever en rotasjonsmessig forsterking av løftekraften på vingeseksjoner nær roten på grunn av disse tredimensjonale effektene. De tredimensjonale effektene antas å være avhengige av vingerotens geometriske utforming.I eksperimentet ble det observert kraftige dynamiske effekter ved begynnene steiling. Disse kan være knyttet til regulær steiling av bladet, men det er indikasjoner på at laminære effekter kan være involvert. Disse effektene ble ikke observert i CFD-simuleringene da en fullturbulent beskrivelse ble benyttet. Effekten rotasjon har på transisjon i grensesjiktet bør studeres videre, da dette kan ha betydning for dynamiske krefter på vindturbiner. Videre er fysikken bak rotasjonsmessig løftforsterkning utilstrekkelig beskrevet, noe som inviterer til videre studier.

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Hussain, A. R. Q. "Model calculations of gap and local modes in alkali halides." Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373469.

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Beck, Christopher A. "Diffusion-collision model calculations of protein folding /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2001.

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Thesis (Ph.D.)--Tufts University, 2001.
Adviser: David L. Weaver. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 148-149). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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Zenia, Hand. "First-principles and model calculations of manganites." Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434510.

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Fiase, J. O. "Effective interactions for SD shell model calculations." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233319.

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Slavich, P. "Precision calculations in supersymmetric extensions of the Standard Model." Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00824019.

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Perantonis, S. J. "Model calculations in quantum chromodynamics and other field theories." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379929.

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Palmer, Jonathan. "Computer assisted loop calculations in the dualized standard model." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425890.

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Aerts, Catherine. "Model Calculations with the Relativistic Bogoliubov - de Gennes Equations." Thesis, University of Kent, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499712.

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Theys, Nicolas. "Atmospheric bromine monoxide: multi-platform observations and model calculations." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210185.

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Bromine compounds play an important role as catalyst of the ozone destruction in both the stratosphere and troposphere. While the impact of bromine species on the chemistry of the stratosphere is known to a large extend, a number of uncertainties remain regarding the sources and sinks of atmospheric bromine as well as the chemistry and impact of bromine species on the troposphere.

This work describes remote-sensing observations of bromine monoxide (BrO) derived from scattered sunlight spectra in the ultraviolet region measured by ground-based multi-axis and satellite nadir viewing instruments (GOME and GOME-2). The method of differential optical absorption spectroscopy is used to retrieve the columnar concentration of BrO along the effective light path through the atmosphere. New algorithms to derive vertical columns of BrO resolved into their stratospheric and tropospheric contributions are developed and described. For the ground-based geometry a way was found to determine independently the stratospheric and tropospheric BrO columns from the diurnal variation of the BrO measurements. For the satellite observations, the contribution of the stratospheric BrO to the measured column is estimated using an innovative stratospheric BrO climatology. This climatology is based on a state-of-the-art stratospheric chemical transport model, and explicitly accounts for the impact of atmospheric dynamics and photochemistry on the stratospheric BrO distribution. As for the tropospheric fraction of the measured total BrO column, it is derived using a residual technique accounting for the effects of clouds and surface reflectivity.

Supported by an extensive set of correlative data, the results presented here allow to study properly the spatial and temporal evolution of atmospheric BrO at the global scale and enable to better assess the significance of BrO in the polar planetary boundary layer and free-troposphere as well as the contribution from very short-lived brominated sources gases to the stratospheric bromine budget. We also report on the first satellite detection of BrO in a volcanic plume, using GOME-2 measurements.

Les composés bromés jouent un rôle important dans la stratosphère et la troposphère en tant que catalyseurs de la destruction d’ozone. Bien que l’impact des espèces bromées sur la chimie de la stratosphère soit largement compris, il reste de nombreuses incertitudes en ce qui concerne les sources et les pertes de brome dans l’atmosphère ainsi qu’à propos de la chimie et de l’impact des espèces bromées sur la troposphère.

Le travail présenté dans ce manuscrit porte sur la télédétection du monoxyde de brome (BrO) à partir de spectres du rayonnement solaire diffusé, mesurés dans l’ultraviolet à partir d’instruments au sol de type multi-axis et satellitaires à visée nadir (GOME et GOME-2). La méthode de spectroscopie d’absorption optique différentielle est utilisée pour inverser la colonne intégrée de BrO le long du chemin optique effectif dans l’atmosphère. Nous avons développé de nouveaux algorithmes afin de dériver les colonnes verticales de BrO résolues en leurs contributions stratosphérique et troposphérique. Pour la géométrie d’observation au sol, un moyen a été trouvé pour déterminer indépendamment les colonnes de BrO stratosphérique et troposphérique, et cela à partir de la variation diurne des mesures de BrO. Pour les observations satellitaires, la contribution de la stratosphère à la colonne mesurée de BrO est estimée à partir d’une climatologie innovante de BrO stratosphérique. Cette climatologie est basée sur un modèle de pointe de la chimie et du transport de la stratosphère; par ailleurs, elle tient compte explicitement de l’impact de la dynamique atmosphérique et de la photochimie sur la distribution du BrO dans la stratosphère. La fraction troposphérique de la colonne totale mesurée de BrO est quant à elle dérivée à partir d’une technique résiduelle tenant compte des effets des nuages et de la réflectivité de la surface.

Soutenus par un vaste jeu de données corrélatives, les résultats présentés dans ce travail permettent d’étudier de manière appropriée l’évolution spatiale et temporelle du BrO atmosphérique à l’échelle globale. Ces résultats permettent également de mieux estimer l’importance du BrO dans la couche limite planétaire polaire et dans la troposphère libre ainsi que la contribution des précurseurs bromés à temps de vie court sur le budget de brome dans la stratosphère. Nous présentons également la première détection satellitaire de BrO dans un panache volcanique, à l’aide de mesures effectuées avec l’instrument GOME-2.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Askin, Muharrem Kemal. "Calculations of Wind Turbine Flow in Yaw using the BEM Technique." Thesis, KTH, Energiteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187238.

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The earlier EU-sponsored project MEXICO (model experiments in controlled conditions) provided a huge database for flows past an experimental rotor in standard and yaw conditions. This study aims to determine the eligibility of different models under various conditions by using the MEXICO data. The main purpose of this project is to improve the BEM technique for yawed flows by using the new yaw model. Additionally, the BEM technique with new yaw model is compared with the CFD and measurement results. The Glauert’s yaw model is also applied in BEM model to compare the effectiveness of the new yaw model. It is proved that the CFD technique is still better than the BEM technique except at the high yaw and wind conditions. Furthermore, new yaw model is favored against Glauert’s yaw model. This project also aims to implement the new tip loss correction model in the BEM code and the results are validated with the CFD results.

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Pedersen, Robert Fossmark. "Prospective and Efficient Techniques for Model Reduction in Reliability Calculations." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22881.

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A reliable electric power supply is essential for modern society. Recently, severe blackouts worldwide have attracted attention to reliability studies in power system planning and operation. The relevance of the traditional N-1 criterion has been discussed, and much focus has been directed towards developing satisfactory probability based reliability tools. Goodtech Project & Services has developed a methodology for calculation of online power delivery reliability for use in power system operation and planning. The method, based on Markov models, analyzes the entire network for a large number of fault combinations, a useful approach for relatively small networks. However, the computation time increases polynomial with increasing system size. Because the impact of an outage has a limited geographical extent, it is desirable to reduce the system to be simulated, so that it only includes the affected area. The objective of this project is to develop methods for identifying the components that can be considered influenced by a fault. The focus of the pre-study was to evaluate which post-processing method best suited for developing a reduced network system. In the pre-study, power flow results from the standard DC load flow were used. The main focus of this thesis has been on developing and implementing fast methods for obtaining the necessary power flow data needed in order to use the post-processing methods. Three approaches have been investigated and tested, namely AC load flow based on the fast decoupled load flow with compensation techniques for obtaining the post- contingency power flows, DC load flow with compensation techniques and the efficient bounding method. The key principle of the compensation methods is that the effect of outages can be calculated by introducing simple compensation terms, thus avoiding the need to rebuild and factorize the system matrices for every contingency case. The bounding method is based on the principle of sensitivity factors and the fact that given knowledge about changes inside a boundary certain conclusions can be made regarding the changes outside it, thus eliminating the need for studying the entire system. The method based on the fast decoupled load flow is the only method that gives the possibility to provide an exact solution, and is also the only method that includes reactive power and voltage magnitudes. It is therefore recommended used in cases where a high degree of accuracy is important, or if reactive power and voltages are of interest. Tests show that the DC load flow is fastest. The accuracy is assumed sufficient for most intended purposes, and should therefore the preferred choice in most cases. Bounding methods are especially useful in highly meshed grids, and if only the largest changes are of interest.

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Lorenzo, Martín Francisco. "Time-dependent crustal deformation after strong earthquakes rheological model calculations /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=984503889.

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Paulley, Alan. "Model calculations of the optical absorption of poly(p-phenylene)." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301470.

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Lundin, Urban. "Physics of Strong Correlations in Electronic Structure and Model Calculations." Doctoral thesis, Uppsala (Suède) : Acta universitatis upsaliensis, 2000. http://catalogue.bnf.fr/ark:/12148/cb39299111x.

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Sahin, Pinar. "Navier-stokes Calculations Over Swept Wings." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607618/index.pdf.

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In this study, the non-equilibrium Johnson and King Turbulence Model (JK model) is implemented in a three-dimensional, Navier-Stokes flow solver. The main program is a structured Euler/Navier-Stokes flow solver in which spatial discretization is accomplished by a finite volume formulation and a multigrid technique is used as a convergence accelerator. The aim is the validation of this in-house developed CFD (Computational Fluid Dynamics) tool with this enhanced enlarged capability in order to obtain a reliable flow solver that can solve flows over swept wings accurately. Various test cases were evaluated against reference solutions in order to demonstrate the accuracy of the newly implemented JK turbulence model. The selected test cases are NACA 0012 airfoil, ONERA M6 wing, DLR-F4 wing and two wings taken from the 3rd Drag Prediction Workshop. The solutions were analyzed and discussed in detail. The results show appreciably good agreement with the experimental data including force coefficients and surface pressure distributions.

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Datta, Alakabha, Saeed Kamali, Stefan Meinel, and Ahmed Rashed. "Phenomenology of Λb → Λcτν¯τ using lattice QCD calculations." SPRINGER, 2017. http://hdl.handle.net/10150/625760.

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In a recent paper we studied the effect of new-physics operators with different Lorentz structures on the semileptonic Λb → Λcτν¯τ decay. This decay is of interest in light of the R(D(∗)) puzzle in the semileptonic B¯ → D(∗)τν¯τ decays. In this work we add tensor operators to extend our previous results and consider both model-independent new physics (NP) and specific classes of models proposed to address the R(D(∗)) puzzle. We show that a measurement of R(Λc) = B[Λb → Λcτν¯τ ]/B[Λb → Λcℓν¯ℓ] can strongly constrain the NP parameters of models discussed for the R(D(∗)) puzzle. We use form factors from lattice QCD to calculate all Λb → Λcτν¯τ observables. The Λb → Λc tensor form factors had not previously been determined in lattice QCD, and we present new lattice results for these form factors here.

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Siddiki, Afif. "Model calculations of current and density distributions in dissipative Hall bars." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=980715725.

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Nowak, Daniela. "Radiation and clouds: observations and model calculations for Payerne BSRN site /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17687.

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Fink, Stephen J. "A programming model for block-structured scientific calculations on SMP clusters /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9835374.

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Summ, Benjamin. "Higgs mass calculations in the Next-to-Minimal Supersymmetric Standard Model." Thesis, KTH, Fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-212725.

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Jaqua, Lene Mahler. "Improved shell-model effective interaction calculations and their applications to light nuclei." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186220.

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We calculate two-body effective interactions starting from a free nucleon-nucleon interaction and apply these interactions in shell-model calculations for no-core model spaces where all particles of the nucleus are active. The spurious center-of-mass motion is explicitly removed from the Hamiltonian. The role of the kinetic-energy operator is examined for ¹⁶O and ¹⁷O. Convergence properties of no-core model spaces are shown for ⁴He and ¹⁸O. The starting-energy dependence is removed by employing the effective Hamiltonian approach of Lee and Suzuki, and the results are applied to the deuteron. Different single-particle wavefunctions are applied to formfactor calculations for ¹⁷O in the extreme single-particle model and the results for high-momentum transfer are compared with the experimental data.

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Thoresen, Michael Joseph 1965. "Nuclear shell model calculations of the effective interaction and other effective operators." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282364.

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Recent breakthroughs in effective interaction and effective operator techniques allow us to take a new look at this field that has seen limited progress in the past twenty years. A comparison of the old and new techniques will shed some new light on the use of effective interactions and effective operators in shell model calculations of light nuclei. Three different methods of calculating the effective interaction and effective operators are described and compared. A large model-space no-core shell-model calculation for ⁶Li is used as the basis for comparison. In the no-core calculation all nucleons are active in a model space involving all configurations with energies up to 8ħΩ. The second method is a perturbation expansion for the effective interaction and effective operators, using an inert ⁴He core and two valence particles. In particular, the electric quadrupole and magnetic dipole operators are studied to determine the effective charges to be used in connection with one-body operators in this shell-model space. The third method is a model-space truncation scheme, which maps operators in a large model space into operators in smaller, truncated model spaces. The effect of going to larger excitation spaces will be examined as well as the convergence trends regarding increases in the excitation space. The results from these three approaches are compared in order to gain new insight into the nature of effective interactions and operators in truncated model spaces. We find that by going to energies of 8ħΩ we can accurately reproduce the experimental values for the binding energy, excitation spectrum, electric quadrupole moment and magnetic dipole moment of ⁶Li and that there is a definite model-space dependence for these operators. To obtain results similar to the 8ħΩ ones in a truncated 2ħΩ model space we use effective operators and effective charges. Effective charges of approximately 1.1e for the effective proton charge and 0.3e for the effective neutron charge are obtained in the perturbation-expansion technique, while the model-space truncation calculations yield effective charges of 1.5e for the proton and.36e for the neutron. These values can be compared with empirically obtained values of eᵖ(eff) ≈ 1.5e and eⁿ(eff) ≈ 0.5e.

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Ackler, Harold D. (Harold Dale) 1964. "Thermodynamic calculations and model experiments on thin intergranular amorphous films in ceramics." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10423.

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Jäderlund, Thom. "A scaling approach to critical exponent calculations for the 2D Ising model." Thesis, KTH, Fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-274382.

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Bumgardner, Jacob Dharma. "Feasibility of Cathodic Protection in Grouted Post Tensioned Tendons - Exploratory Model Calculations." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5918.

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Recent corrosion related failures of grouted post tensioned tendons, even after the introduction of improved grouts, have led to renewed interest in supplemental or backup means of corrosion control for these systems. A finite element model is presented to explore feasibility of impressed current cathodic protection of strand in grouted tendons. The model examines polarization evolution as function of service time and includes consideration of anode placement and size, grout porosity, pore water alkalinity, electrochemical species diffusivity and applied voltage on the polarization efficacy and durability of such a system. The exploratory model projections suggested that, within the context of the design parameters assumed, an impressed current cathodic protection system installed internally into a grouted duct for the purpose of cathodic protection of steel tensioning strand may be feasible for the case of initially passive steel.

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Karlsson, Axel. "Framtagning av beräkningsmall för rullaxlar." Thesis, Högskolan Väst, Avdelningen för maskinteknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-7973.

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Möjligheter att förbättra Hofpartner ABs beräkningsmall för rullaxlar har undersökts. Undersökningen har fokuserat på användarvänlighet, ekonomi samt hållfasthet. Målet var att göra mallen mer lättanvänd. Nuvarande mall undersöks med resultat att den är väldigt svår att följa samt att dess värden inte överensstämmer särskilt bra med verkligheten i de flesta avseenden. Arbetet koncentreras därmed på att identifiera de existerande problemen och att åtgärda dem. Mallens funktioner utvärderas och beslut fattas om att reducera mallen till att endast hantera information som regelbundet används av företaget. Genom att minska mängden data ses möjligheter att göra mallen enklare att följa och mer lättanvänd med mindre krav på förkunskaper. Nya formler för hållfasthetsberäkningar framställs och implementeras i en nyskapad mall. Formlerna kontrolleras med analyser i FEM. Analyserna visar att de nya beräkningarna ger resultat närmare verkligheten. Kostnadsberäkningarna har konstruerats som en grund till Hofpartner att bygga vidare på. Formler är implementerade men en undersökning av företagets produktion krävs för att uppnå korrekta resultat. Undersökningen behöver utföras för att kartlägga tidsåtgång för företagets produktion, arbetet har endast lett till uppskattningar. Om undersökningen utförs har Hofpartner möjlighet att åstadkomma mycket rimliga resultat i mallen.
In this project the possibilities to improve Hofpartner AB's calculation model for reel shafts has been investigated. The investigation has focused on user friendliness, economy and strength calculations. The goal was to make the model easier to use. An investigation of the current model shows that it is difficult to follow the calculations and that the results in most cases are not particularly accurate. Thus the work is focused on identifying the existing problems and improving on them. Several of the functions in the model are removed and the model now only handles information that are used with some regularity. By reducing the amount of data covered by the model possibilities is seen to simplify usage and to reduce the amount of necessary prior knowledge. New formulas for the strength calculations are presented and implemented in a new model. The formulas are verified by analysis with FEM. The analysis shows that the model is providing results close to the real values. The economical calculations are constructed as a basis for Hofpartner to continue developing. The necessary formulas are implemented but an investigation of the company's production process is necessary to achieve correct results. The newly constructed model mostly contains estimates of costs related to production time and material. If these estimates are updated with correct values Hofpartner has the possibility to achieve very reasonable results in their model.

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Gjerde, Tony. "A heavy tailed statistical model applied in anti-collision calculations for petroleum wells." Thesis, Norwegian University of Science and Technology, Department of Mathematical Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9698.

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Anti-collision calculations are done during the planning of a new petroleum well. These calculations are required in order to control the risk of having a well-collision, which is an unwanted event at any cost. The risk of having a well-collision is closely related to the position uncertainty both of the well that is planned and of the existing wells in the given region. Earlier literature has indicated that the distribution of the position errors are more heavy-tailed than a normal distribution, which leads to the question whether the current methods are accurate enough. The currently used industry standard calculates the standard deviation of the centre to centre distance by an approximation, and assumes that the centre to centre distance is normally distributed. In this thesis we use a heavy-tailed Normal Inverse Gaussian (NIG) distribution for the declination error source in MWD magnetic directional surveying, which lead to a position uncertainty that is heavy-tailed relative to the multivariate normal distribution. The parameters of the NIG-distribution are estimated from processed magnetic field data from the Tromsø geomagnetic observation station. The NIG-distribution requires the use of Monte Carlo simulations in order to apply the currently used industry approach. Other error sources are also included in the error model to give a more realistic position uncertainty. Three different anti-collision cases demonstrate the differences in using the NIG error model and the normal error model. We compare the simulation based results against the currently used methodology. The results are very dependent on the well geometries. The results differ significantly, and the NIG error model is the most conservative distribution in most cases, with respect to whether a wellplan should be realized or not. However, there are cases where a normally distributed declination error gives more conservative decisions than the NIG-distribution. As an alternative to change the distribution of the declination error, we propose two corrective actions to improve the existing anti-collision methodology. One action is to exchange one of the approximations in the current methodology with simulations or analytical computations. The other action is to correct for bias in the expected position, which is caused by the NIG error model.

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Burrows, Matthew. "Translationally Invariant Local Densities for Light Nuclei from No-Core-Shell-Model Calculations." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1477569906766884.

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Preval, S. P., M. A. Barstow, N. R. Badnell, I. Hubeny, and J. B. Holberg. "Hot DA white dwarf model atmosphere calculations: including improved Ni PI cross-sections." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/623044.

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To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages need to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni IV-VI bound-bound and bound-free atomic data on model atmosphere calculations. Models including photoionization cross-section (PICS) calculated with AUTOSTRUCTURE show significant flux attenuation of up to similar to 80 per cent shortward of 180 angstrom in the extreme ultraviolet (EUV) region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of these atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including AUTOSTRUCTURE PICS were found to change the abundances of N and O by as much as similar to 22 per cent compared to models using hydrogenic PICS, but heavier species were relatively unaffected. Models including AUTOSTRUCTURE PICS caused the abundances of N/O IV and V to diverge. This is because the increased opacity in the AUTOSTRUCTURE PICS model causes these charge states to form higher in the atmosphere, more so for N/O V. Models using an extended line list caused significant changes to the Ni IV-V abundances. While both PICS and an extended line list cause changes in both synthetic spectra and measured abundances, the biggest changes are caused by using AUTOSTRUCTURE PICS for Ni.

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Tang, Koon T. "Studies of '1'5'8Gd by thermal neutron capture reactions and by IBA-1 model calculations." Thesis, University of Brighton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361584.

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Pellen, Mathieu [Verfasser], Michael [Akademischer Betreuer] Krämer, and Margarete [Akademischer Betreuer] Muhlleitner. "Precision calculations for physics beyond the standard model / Mathieu Pellen ; Michael Krämer, Margarete Muhlleitner." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1129261646/34.

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Chaves, Rogerio de Queiroz. "Perturbative calculations to two loops and some topological considerations in the dualized standard model." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424757.

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Knapp, Michael James. "Spectroscopic properties of iron-sulfur model systems : high-field EPR and electronic structure calculations /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9908499.

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Hoshmeh, Abdullah, Uwe Schmidt, and Akif Gürlek. "Investigations on the Developed Full Frequency-Dependent Cable Model for Calculations of Fast Transients." MDPI AG, 2018. https://monarch.qucosa.de/id/qucosa%3A31827.

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The knowledge about the behavior of cables is substantial in cases of transients or in cases of faults. However, there are only a few models that are tailored to the current requirements for calculations of transient phenomena in three-phase cable systems. These models are based on complex structures. PI-section cable models with simple structures were previously qualified only for calculations in the frequency domain. A new full frequency-dependent cable model to simulate transient phenomena is introduced and validated. The model is based on lumped parameters with cascaded frequency-dependent PI-sections. For the implementation and the integration in simulation tools, it is important to investigate the impact of the PI-section parameters to the accuracy, the stability and the mathematical robustness. In this work, the impact of the frequency dependence of cable parameters, the length distribution and the number of PI-sections on the results of the developed three-phase cable model have been discussed. For simulations in the time domain, two algorithms have been presented to optimize the number of PI-sections based on a specified accuracy.

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Thomas, Evan Cameron. "Calculations in modified gauge theory : testing some ideas from QCD in a toy model." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63841.

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We use a deformed “center-stablised” gauge theory, which can be brought into a weak coupling regime while remaining confined and gapped, as a toy model to study some ideas from real QCD. The deformed model has the correct nontrivial θ-dependence and degeneracy of topological sectors conjectured for QCD, and is, apparently, smoothly connected to the strongly coupled undeformed Yang-Mills, so that we can perhaps expect to get some qualitative insights into QCD. We demonstrate the presence of a nondispersive contact term in the topological susceptibility, which contributes with the opposite sign to normal dispersive contributions coming from physical propagating degrees of freedom. We further show that, despite the system being completely gapped with no massless physical degrees of freedom, the system has a Casimir-like, power scaling, dependence on boundaries, in contrast with the naive expectation that a system with only massive degrees of freedom should have a weak (exponentially small) dependence on long distance effects. This behaviour suggests the possibility for a solution for the cosmological dark energy problem coming from the strongly coupled QCD sector on a manifold with a boundary, which would have the correct sign and be of the correct order of magnitude. Next, we investigate the interaction between point-like topological charges (monopoles) and extended sheet-like topological defects (domain walls) in attempt to explain some recent lattice QCD results suggesting that extended topological objects are more important to understanding the relevant field configurations in QCD than the instantons traditionally expected. Finally, we derive the existence of excited metastable vacuum states and calculate their decay rate to the true ground state of the theory, comparing with the expected results discussed years ago in proper QCD. The presence of metastable vacuum states with a nonzero effective θ parameter, like those present in the deformed model, could explain P and CP violation in heavy ion collisions observed on an event by event basis, which seem to average away over many events.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

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Deutschmann, Nicolas. "Precision calculations in effective theories for Higgs production." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1142/document.

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Après une introduction générale, ce manuscrit contient deux chapitres préliminaires, l'un décrivant le contexte physique et l'autre les techniques mathématiques utilisées lors de cette thèse.Nous présentons ensuite les travaux développés au cours de cette thèse. Nous commençons par l'extraction de la correction du couplage de Yukawa du quark bottom dans la théorie effective du boson de Higgs par un calcul de correspondance à deux boucles entre cette théorie effective et le modèle standard. Cette correction était la pièce manquante pour l'amélioration de la prédiction de la section efficace de production du boson de Higgs en association avec deux quarks bottom.Les deux chapitres suivants couvrent différents aspects du calcul de la correction au deuxième ordre de la section efficace de production d'un boson de Higgs par fusion de gluon dans la théorie effective du modèle standard. Nous présentons d'abord le calcul des corrections virtuelles de ce processus et exploitons la structure établie des divergences ultraviolettes à une boucle et des divergences infrarouges pour extraire un contre terme à deux boucles qui nous a permis de renormaliser l'amplitude, que nous avons ensuite prolongé analytiquement aux régions physiques.Nous combinons alors ce résultat avec le calcul automatique des corrections par émission réelles par le logiciel Madgraph5_aMC@NLO, qui a permis l'intégration de la section efficace. Nous présentons les résultats pour la section efficace totale et deux distributions de variables cinématiques et commentons l'impact des corrections radiatives sur ces prédictions
After a general introduction, this manuscript presents two preliminary chapters, describing first the physics context and the mathematical techniques used in this thesis.We then present the work performed in this thesis. We start with extraction of the power-suppressed of the Yukawa coupling of the bottom quark in the Higgs Effective Field Theory (HEFT) by a two-loop matching calculation between the Standard Model and the HEFT. This correction was the missing piece to improve the prediction of the production cross section of a Higgs boson in association to a pair of bottom quarks.The two next chapters present different aspects of the NLO corrections to Higgs boson production through gluon fusion in the standard model effective field theory. We first present the evaluation of the virtual corrections to this process and use the known one-loop ultraviolet and infrared divergence structure to extract a two-loop counterterm that allowed us to renormalize the amplitude, which we then analytically continued to the physical regions.We then combine this result with the automatic calculation of the real emission corrections in the program Madgraph5_aMC@NLO. The results are presented for the total cross section and differential distributions and comment on the effect of radiative corrections on these predictions

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Burk, David Edward. "Forward model calculations for determining isotopic compositions of materials used in a radiological dispersal device." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2366.

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In the event that a radiological dispersal device (RDD) is detonated in the U.S. or near U.S. interests overseas, it will be crucial that the actors involved in the event can be identified quickly. If irradiated nuclear fuel is used as the dispersion material for the RDD, it will be beneficial for law enforcement officials to quickly identify where the irradiated nuclear fuel originated. One signature which may lead to the identification of the spent fuel origin is the isotopic composition of the RDD debris. The objective of this research was to benchmark a forward model methodology for predicting isotopic composition of spent nuclear fuel used in an RDD while at the same time optimizing the fidelity of the model to reduce computational time. The code used in this study was Monteburns-2.0. Monteburns is a Monte Carlo based neutronic code utilizing both MCNP and ORIGEN. The size of the burnup step used in Monteburns was tested and found to converge at a value of 3,000 MWd/MTU per step. To ensure a conservative answer, 2,500 MWd/MTU per step was used for the benchmarking process. The model fidelity ranged from the following: 2-dimensional pin cell, multiple radial-region pin cell, modified pin cell, 2D assembly, and 3D assembly. The results showed that while the multi-region pin cell gave the highest level of accuracy, the difference in uncertainty between it and the 2D pin cell (0.07% for 235U) did not warrant the additional computational time required. The computational time for the multiple radial-region pin cell was 7 times that of the 2D pin cell. For this reason, the 2D pin cell was used to benchmark the isotopics with data from other reactors. The reactors from which the methodology was benchmarked were Calvert Cliffs Unit #1, Takahama Unit #3, and Trino Vercelles. Calvert Cliffs is a pressurized water reactor (PWR) using Combustion Engineering 14??14 assemblies. Takahama is a PWR using Mitsubishi Heavy Industries 17??17 assemblies. Trino Vercelles is a PWR using non-standard lattice assemblies. The measured isotopic concentrations from all three of the reactors showed good agreement with the calculated values.

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Aumond, João Paulo. "A model for the calculations of solvent effects on reaction rates for process design purposes." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85280.

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Wigmore, Ioan Tomos. "Automated calculation of one-loop processes within MadGolem." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7967.

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In the current LHC era, a vast number of models for BSM physics are being tested. For predictions accurate enough to match experimental errors, theoretical calculations have to go beyond LO estimates. However, calculating one-loop corrections in BSM models involves many new particles with specific model dependent properties. Therefore, they are done largely by hand, or in partially–automated ways. I present a fully automated tool for the calculation of generic massive one-loop Feynman diagrams with four external particles, implemented as a module within the fully automated MadGolem framework. With this one can compute the NLO–QCD corrections to generic BSM heavy resonance production processes, for example in the context of supersymmetric theories.

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41

Anpalahan, Peethamparam. "Design of transverse flux machines using analytical calculations&finite element Analysis." Licentiate thesis, KTH, Electrical Systems, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1227.

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Neumann, Tobias [Verfasser]. "Perturbative calculations for Standard Model precision physics: Higgs production and Yang-Mills gradient flow / Tobias Neumann." Wuppertal : Universitätsbibliothek Wuppertal, 2015. http://d-nb.info/1078321795/34.

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Oram, David Edward. "Trends of long-lived anthropogenic halocarbons in the Southern Hemisphere and model calculations of global emissions." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323346.

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Turkoglu, Danyal J. "Evaluation of Prompt Gamma-ray Data and Nuclear Structure of Niobium-94 with Statistical Model Calculations." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417737555.

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45

Maroteaux, Anaïs. "Study of Analytical Models for Harmonic Losses Calculations in Traction Induction Motors." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187662.

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This Master Thesis deals with the study of analytical and finite-element (FE) models for calculation of losses in traction induction motors. Motors are fed through inverters for this type of application. Therefore, both fundamental and harmonic losses are considered. The study is done with one particular motor and one initial analytical model. In order to validate the model and improve it, a FE model is developed with the tool FLUX 2D. Several chosen operating points with different modulation patterns are simulated both with FE and analytical models and results are compared. Stator and rotor Joule losses are studied first. A model to calculate stator Joule losses at strand level is proposed as an improvement to the current analytical model. Then iron losses, both in stator and rotor, are calculated. Two different computations methods with data extraction from FE are studied: the Bertotti model and a recently developed method called MVPRS in the report. It is based on a mathematical model for curve fitting of the core loss material data. Results with the two methods are compared with the ones from ana-lytical model. Finally total fundamental and harmonic losses are compared with measurements and conclusions are drawn on the quality and accuracy of the analytical model.
Detta examensarbete handlar om analytiska och Finita Element (FE) modeller för beräkning av förluster i asynkronmotorer för traktion. Motorer matas genom växelriktare för denna typ av applikation. Därför är det nödvändigt att både grundläggande och harmoniska förluster beaktas. Studien görs för en särskild motor och en redan existerande analytisk modell. För att validera modellen och förbättra den, utvecklats en FE modell med verktyget FLUX 2D. Flera arbetspunkter med olika moduleringsmönster simuleras både med FE och analytiska modeller och resultaten jämförs. Först studeras stator och rotor Joule förluster. En modell för att beräkna stator Joule förluster i varje ledare föreslås som en förbättring av den nuvarande analytiska modellen. Sedan beräknas järnförluster, både i stator och rotor, beräknas. Två olika metoder baserad på flödestäthet variationer i tid och rum från FE simuleringar studeras med Bertottis modell och en nyutvecklad metod som kallas MVPRS. Den är baserat på en matematisk modell för kurvanpassning av materialet förlust data. Resultaten med de två metoderna jämförs med de från analytiska modellen. Slutligen jämförs totala fundamentala och harmoniska förluster med mätningar och slutsatser dras om kvalitet och noggrannhet av analytiska modellen.

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46

Chen, Yuhua. "Model calculations of radiation induced damage in 1-methylthymine:9-methyladenine and in 1-methyluracil:9-ethyladenine." [Johnson City, Tenn. : East Tennessee State University], 2001. http://etd-submit.etsu.edu/etd/theses/available/etd-0525101-132606/restricted/cheny0709.pdf.

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Capozi, Matteo [Verfasser], and Gerhard [Akademischer Betreuer] Buchalla. "Precision calculations in the Higgs sector within and beyond the Standard Model / Matteo Capozi ; Betreuer: Gerhard Buchalla." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1222436612/34.

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48

Denis, Malika. "Probing physics beyond the standard model in diatomic molecules." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30059/document.

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De nos jours, l'incomplétude du modèle standard des particules est largement reconnue. L'une de ses failles les plus évidentes est le manque d'explication de l'énorme excédent de matière par rapport à l'antimatière dans l'univers, que l'on appelle l'asymétrie baryonique de l'univers. De nouvelles violations de CP (conjugaison de charge et parité spatiale) absentes dans le modèle standard sont supposées être responsables de cette asymétrie. Une telle violation pourrait être observée dans la matière ordinaire à travers un ensemble d'interactions violant les symétries de parité et de renversement du temps (impaires pour P,T) dont les prépondérantes sont les interactions du moment dipolaire électrique de l'électron (eEDM), électron-nucléon scalaire-pseudoscalaire (enSPS) et du moment quadripolaire magnétique nucléaire (nMQM). Ainsi, une preuve expérimentale d'une constante d'interaction impaire pour P,T serait une preuve de cette nouvelle physique au-delà du modèle standard. Le calcul des paramètres moléculaires correspondants est réalisé en utilisant une approche d'interaction de configurations relativiste à quatre composantes dans des molécules diatomiques polaires contenant un actinide, qui sont des systèmes particulièrement appropriés pour les expèriences eEDM, tels que ThO qui a permis d'assigner à l'eEDM la borne supérieure la plus contraignante et ThF+ qui sera utilisé dans une expérience à venir. Ces résultats sont d'une importance cruciale dans l'interprétation des mesures puisque les constantes fondamentales ne peuvent être évaluées que si l'on associe les mesures de décalages énergétiques et les paramètres moléculaires théoriques
Nowadays, the incompleteness of the Standard Model of particles is largely acknowledged. One of its most obvious shortcomings is the lack of explanation for the huge surplus of matter over antimatter in the universe, the so-called Baryon Asymmetry of the Universe. New CP (Charge conjugation and spatial Parity) violations absent in the SM are assumed to be responsible for this asymmetry. Such a violation could be observed in ordinary matter through a set of interactions violating both parity and time-reversal symmetries (P,T-odd), among which the preponderant ones are the electron Electric Dipole Moment (eEDM), the electron-nucleon scalar-pseudoscalar (enSPS) and the nuclear magnetic quadrupole moment (nMQM) interactions. Hence, an experimental evidence of a non-zero P,T-odd interaction constant would be a probe of this New Physics beyond the Standard Model. The calculation of the corresponding molecular parameters is performed by making use of an elaborate four-component relativistic configuration interaction approach in polar diatomic molecules containing an actinide, that are particularly adequate systems for eEDM experiments, such as ThO that allowed for assigning the most constraining upper bound on the eEDM and ThF+ that will be used in a forthcoming experiment. Those results will be of crucial importance in the interpretation of the measurements since the fundamental constants can only be evaluated if one combines both experimental energy shift measurements and theoretical molecular parameters

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Wang, Yangi [Verfasser]. "Model Calculations and Implementation of Filters and Hybrid Green VCSELs based on Optical Thin Film Stacks / Yangi Wang." Kassel : Universitätsbibliothek Kassel, 2010. http://d-nb.info/1004257686/34.

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Gebrerufael, Eskendr [Verfasser], Robert [Akademischer Betreuer] Roth, and Jens [Akademischer Betreuer] Braun. "In-Medium No-Core Shell Model for Ab Initio Nuclear Structure Calculations / Eskendr Gebrerufael ; Robert Roth, Jens Braun." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1143125142/34.

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Dissertations / Theses on the topic 'Calculations model'

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