Inaug.-diss.--Göttingen. / Lebenslauf.

This thesis studies in detail: formation, developmen and instability of the vortex ring; associated surface pressure distribution; and drag for a family of spheres in the Reynolds number range of 30-2000 and the blockage ratio of 3-30%. In the beginning, a glycerol-water solution tunnel used in the experimental program is briefly described followed by an explanation of the model support system, pressure measuring instrumentation, drag balance and test procedures. An approach to the data reduction, so critical at low Reynolds number, is discussed and a new definition of the pressure coefficient which promises to be less dependent on test facilities and pressure gradients is evolved. Finally, the test data are analyzed as functions of the confinement condition and Reynolds number. The results suggest that the ratio of the model to vertical stem support should be at least 10 to make stem effects negligible. Influence of Reynolds number on the surface pressure distribution is primarily confined to the range R[sub n] < 1000. However, for the model with the highest blockage ratio of 30.6%, the pressure continues to show Reynolds number dependency for R[sub n] as high as 2300 (limit of the tunnel capability for a glycerol-water concentration used). In general, the effect of Reynolds number is to increase the minimum as well as the wake pressure. On the other hand, the effect of an increase in the blockage ratio is just the opposite. The wall confinement tends to increase the drag coefficient, however, the classical dependence of skin friction on the Reynolds number, C[sub d],[sub f]αR[sub n][sup ½] , is maintained. The results vividly a, r n showed inadequacy of Maskell's correction procedure particularly at higher blockage (S/C > 5%). An extensive flow visualization study using dye injection in conjunction with high speed photography complements the test program. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

by Fung Siu-kwong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 61-62). / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Independently distributed spheres with constant radius --- p.5 / Chapter 2.1 --- The method of moment estimator of R --- p.6 / Chapter 2.2 --- Maximum likelihood estimator of R --- p.7 / Chapter 2.3 --- Mean squared errors of the estimators of R --- p.7 / Chapter 2.4 --- Confidence interval of R .。 --- p.14 / Chapter 3 --- Dependently distributed spheres with the constant radius --- p.17 / Chapter 3.1 --- Gibbs Sampler --- p.18 / Chapter 3.2 --- Model based on simulating spatial patterns --- p.20 / Chapter 3.3 --- Algorithm --- p.23 / Chapter 3.4 --- Explanation of the algorithm --- p.24 / Chapter 3.5 --- Posterior distribution of R --- p.28 / Chapter 3.6 --- The number of spheres is unknown --- p.30 / Chapter 3.7 --- Boundary Effect --- p.31 / Chapter 4 --- Simulation Study --- p.32 / Chapter 4.1 --- Determination of the convergence of the Gibbs sequence --- p.33 / Chapter 4.2 --- Comparison between Rbay and RadjMLE --- p.35 / Chapter 4.2.1 --- The number of spheres is known --- p.37 / Chapter 4.2.2 --- The number of sphere is unknown --- p.41 / Chapter 4.2.3 --- Boundary effect --- p.45 / Chapter 5 --- Extension and Conclusion --- p.53 / Chapter 5.1 --- Extension on the simulation algorithm --- p.53 / Chapter 5.2 --- Extension to the case of varied radius --- p.56 / Chapter 5.2.1 --- Modified Algorithm --- p.57 / Chapter 5.2.2 --- An artificial example --- p.58 / Bibliography --- p.61

The purpose with this thesis is divided. First, it is to examine the online information traffic trends related to political communication and if the Internet is considered to be under surveillance. Second, it is to examine if the Internet can be regarded as a medium for Public Spheres. The thesis only focuses on the Philippines and takes the approach of the Internet users with focus on young Filipinos that are engaged citizens in the society.      The method of the study has been qualitative semi-structured interviews. A total amount of eight interviews have been conducted.   Using Bordewijk’s and Van Kaams model and terminology, the study’s results show that the users exhibit strong allocution and consolation trends but vaguer conversation and registration trends. The Internet was not thought to be under surveillance or monitored. Internet does not work as a medium for creating one holistic, or several smaller, Public Spheres in the Philippines today – foremost due to the harsh Internet environment that for example includes cyber bulling.

This thesis concentrates on a set of problems and approaches relating to the generation and analysis of spherical codes. The work was conducted at the University of New South Wales between 2002 and 2006, during a short visit to Vanderbilt University in 2004, and at the University of Sydney in 2006. The key results include: 1. A description of an equal area partition of the unit sphere Sd called the EQ partition. 2. A detailed description of the EQ algorithm which produces the EQ partition. 3. Proofs that EQ partitions are equal area partitions with small diameter. 4. A detailed description of the construction of a spherical code called the EQ code, based on the EQ partition. 5. A proof that the sequence of EQ codes is well separated. 6. An examination of the suitability of the EQ codes for polynomial interpolation. 7. An examination of the packing density of the EQ codes. 8. Modified constructions of the EQ codes to allow nesting or to maximize the packing radius. 9. A scheme to use the EQ partitions and EQ codes for spherical coding and decoding. 10. A proof that for 0 < s < d a sequence of Sd codes which is well separated and weak star convergent has a Riesz s energy which converges to the corresponding energy double integral. 11. A bound on the rate of convergence of Riesz s energy given the rate of convergence to zero of the spherical cap discrepancy. 12. A comparison of Coulomb energy estimate for S2 spherical designs given in [73] with estimates obtained using only the separation and the estimated spherical cap discrepancy of the spherical designs. 13. A proof that the EQ codes are weak star convergent. 14. Estimates of the rate of convergence to zero of the spherical cap discrepancy of EQ codes. 15. Estimates of the rate of convergence of Riesz s energy of EQ codes to the energy double integral.

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves [83]-84). Also available in electronic version. Access restricted to campus users.

The object of this thesis is to cover the results of [1] from a piecewise linear point of view. The principal result of [1] is the theorem on the homogeneity of spheres, i.e. the complement of a combinatorial n-cell in a combinatorial n-sphere is a combinatorial n-cell. A piecewise linear proof of this theorem by a "long induction" using regular neighbourhoods and collapsing was given in [4]. A direct piecewise linear proof appeared recently in [2]; it is based on the existence of a "collar" for the boundary of a combinatorial manifold with boundary. Our proof is similar to the proof in [2]. We proceed by induction on dimensions, proving simultaneously the existence of a collar for the boundary of a combinatorial manifold with boundary and the homogeneity theorem. From [2] we adopted an argument which eliminates a certain combinatorial technique applied in [1] and involving induction on the length of stellar subdivisions. The results of [1] were previously interpreted in piecewise linear topology by use of a theorem in [3] stating that piecewise linearly homeomorphic simplicial complexes have subdivisions which are combinatorially equivalent in the sense of [1]. The thesis is divided into three parts. The first gives definitions and basic properties relating to simplicial complexes. The second concerns combinatorial manifolds, and in the third we present our proof of the piecewise linear homogeneity of spheres. / Science, Faculty of / Mathematics, Department of / Graduate

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