Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 336 for “"discs"”.
-
The vibration of rolling discs
The study presented is a fundamental investigation into the vibration of a rolling disc and an analysis of the sound which is then produced by the disc response. In order to characterise the disc's behaviour the free and forced vibration of a thin disc is analysed with the additional conditions …
-
Magnetic Fields in Protoplanetary Discs
Protoplanetary discs are flattened discs of gas and dust surrounding young stars that are believed to be the sites of planet formation. They are believed to be threaded by large-scale magnetic fields, which significantly affect their dynamics through processes such as the magneto-rotational …
-
Extremal Discs and CR Geometry
… of the dimension of the set of extremal discs attached to a CR strictly pseudoconvex manifold of codimension two in C 4: we prove that, for such a manifold, extremal discs depend on 15 parameters, one more than the parameters needed to describe extremal discs attached to a quadric. We …
-
The aerodynamic response of airborne discs
… free-flying disc. In this study, three types of discs are analyzed in a series of stationary experiments, and a single disc is analyzed in a spinning experiment. Two dimensionless parameters dominate the experiments, the Reynolds number and the tip speed ratio. The first experiment measured the …
-
The Dynamics of Magnetised Warped Discs
The study of warped discs and the study of magnetised discs have generally been performed in relative isolation, and comparatively little attention has been given to the complex interplay between these two aspects of accretion disc physics. This thesis aims to provide a synthesis of these disparate …
-
Dynamics of spinning discs in fluids
… aims to investigate the dynamics of spinning discs on the water surface. The focus of the study are the vortex structure generated by a spinning disc, and the forces acting on the discs on the surface of a liquid at rest and in a nonuniform flow. During the thesis, we report on the self-guided …
-
Dynamics of spinning discs in fluids
… aims to investigate the dynamics of spinning discs on the water surface. The focus of the study are the vortex structure generated by a spinning disc, and the forces acting on the discs on the surface of a liquid at rest and in a nonuniform flow. During the thesis, we report on the self-guided …
-
Disc-planet interactions in inviscid discs
Planets are born in protoplanetary discs (PPDs), made of gas and dust, which surround newly formed stars. Gravitational coupling provides planets with means to interact with their birth environment, leading to the excitation of global spiral density waves, which drive evolution of the disc (such as …
-
Nonlinear Dynamics of Warped Astrophysical Discs
The classical perspective of astrophysical discs models them as being flat, circular and coplanar. However, a wealth of observational evidence has highlighted the ubiquity of warped geometries in a variety of contexts. This has motivated theoretical efforts to explain the origins of such …
-
Evaluation of Concentrations in Penicillin Sensitivity Discs
… has become the most popular today. | These discs, prepared from a filter or blotter paper, are impregnated with a known concentration of antibiotic and dried. This gives a relatively stable form of the antibiotic, which can be tested in combination with other drugs in a single operation.
-
Hydromagnetic Oscillations and Instabilities in Astrophysical Discs
… of oscillations and instabilities in accretion discs, developing theoretical and numerical models to explore the physical nature of variability encountered in a variety of astrophysical contexts. Through linear theory and semi-analytical calculations, I first consider the physical properties of …
-
Protoplanetary discs across the stellar mass range
… studies concerned with modelling protoplanetary discs around stars from different ends of the stellar mass range. In Chapters 1 and 2, I give an introduction to the field of protoplanetary discs, both from an observational and a modelling point of view, and describe the radiative transfer methods …
-
Secular Dynamics of Self-gravitating Debris Discs
Debris discs are the leftovers from the epoch of planetary formation, akin to the Solar System's asteroid and Kuiper belts. They preserve a record of the physical processes at work throughout the system's age, not least planet--disc interactions. Deciphering this record has become a central focus …
-
On the Dynamics of Noncircular Accretion Discs
… for considering non-circular motion in accretion discs. In this thesis I study the dynamics of such non-circular accretion discs using a mix of analytical and semi-analytical methods. One such example of a non-circular accretion disc is an eccentric disc, where the dominant fluid motion consists …
-
Radio Observations of Discs around Young Stellar Objects
In this thesis we study the disc surrounding the Young Stellar Object DG Tau B. We present observations at both cm and mm wavelengths using e-MERLIN and the EVLA respectively. We study the cold dust in the disc of DG Tau B by looking at its spectral energy distribution (SED). We also analyse the …
-
Magnetohydrodynamics in the Inner Regions of Protoplanetary Discs
The inner regions of protoplanetary discs, which encompass the putative habitable zone, comprise a highly ionised, turbulent active region and a poorly ionised outer dead zone. The complex magnetohydrodynamic processes at this dead–active zone interface significantly impact the disc's evolution – …
-
Recycling of worn-out vehicular brake pads and discs
… all vehicles for braking. The brake pads and discs are usually replaced with new ones before being entirely worn out to maintain their tribological performance. This work highlights the significance of sustainable and environmentally friendly approaches in refurbishing and producing brake …
-
The migration of giant planets in massive protoplanetary discs
… migration patterns of giant planets in unstable discs using radiative hydrodynamic simulations. More specifically we examine the migration of planets within different mass discs and at different orbital radii. We find that planets initially migrate inwards quickly. They are able to open up a gap …
-
Nonlinear hydrodynamic instability and turbulence in eccentric astrophysical discs
… of inertial waves inherent to eccentric discs is studied by way of a new local numerical model. Mode coupling of tidal deformation with the disc eccentricity is known to produce exponentially growing eccentricities at mean-motion resonances, most prominently via the 3:1 eccentric Lindblad …
Page 1 of 17