African University of Science and Technology: Recent submissions

Now showing items 1281-1300 of 4828

  • Scattering of biflagellate micro-swimmers from surfaces 

    Lushi, E; Kantsler, V; Goldstein, Raymond Ethan (American Physics SocietyPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics, 2017-08-10)
    We use a three-bead-spring model to investigate the dynamics of bi-flagellate micro-swimmers near a surface. While the primary dynamics and scattering are governed by geometric-dependent direct contact, the fluid flows ...

  • Alternating Direction Implicit (ADI) schemes for a PDE-based image osmosis model 

    Calatroni, L; Estatico, C; Garibaldi, N; Parisotto, Simone (Journal of Physics: Conference Series, 2017-10-22)
    © Published under licence by IOP Publishing Ltd. We consider Alternating Direction Implicit (ADI) splitting schemes to compute efficiently the numerical solution of the PDE osmosis model considered by Weickert et al. in ...

  • X-Switch: An Efficient Multi-User Multi-Language Web Application Server. 

    Nyirenda, Mayumbo (University of Cape TownFaculty of ScienceDept. of Computer Science, 2010)
    Web applications are usually installed on and accessed through a Web server. For security reasons, these Web servers generally provide very few privileges to Web applications, defaulting to executing them in the realm of ...

  • A Balanced Approach to IT Project Management 

    Smith, Derek (University of Cape TownFaculty of CommerceDept. of Information Systems, 2007)
    The primary objectives of this study were to identify how IT projects can be managed using the Balanced Scorecard approach. Although the research is positioned to have potential application within international project ...

  • Homological stability for automorphism groups 

    Randal-Williams, Oscar; Wahl, N (Academic PressAdvances in Mathematics, 2017-10-01)
    Given a family of groups admitting a braided monoidal structure (satisfying mild assumptions) we construct a family of spaces on which the groups act and whose connectivity yields, via a classical argument of Quillen, ...

  • On the local well-posedness of Lovelock and Horndeski theories 

    Papallo, Giuseppe; Reall, Harvey Stephen (American Physical SocietyPhysical Review D - Particles, Fields, Gravitation and Cosmologyhttp://dx.doi.org/10.1103/PhysRevD.96.044019, 2017-08-15)
    We investigate local well-posedness of the initial value problem for Lovelock and Horndeski theories of gravity. A necessary condition for local well-posedness is strong hyperbolicity of the equations of motion. Even weak ...

  • Taylor's swimming sheet in a yield-stress fluid 

    Hewitt, Duncan; Balmforth, NJ (Cambridge University PressJournal of Fluid Mechanics, 2017-10-10)
    A yield stress is added to Taylor’s (1951, Proc. Royal Soc. A, 209, 447-461) model of a two-dimensional flexible sheet swimming through a viscous fluid. Both transverse waves along the sheet, as in Taylor’s original model, ...

  • Analytical solutions to slender-ribbon theory 

    Koens, Lyndon Mathijs; Lauga, Eric Jean-Marie (Physical Review Fluids, 2017-08-01)

  • Bounded Height in Families of Dynamical Systems 

    DeMarco, L; Ghioca, D; Krieger, Holly Christine; Dang Nguyen, K; Tucker, T; Ye, H (Oxford University PressInternational Mathematics Research Notices, 2017-08-29)
    Let a, b ∈ $\bar{\mathbb{Q}}$ be such that exactly one of a and b is an algebraic integer, and let f$_{t}$(z) := z$^{2}$ + t be a family of polynomials parameterized by t ∈ $\bar{\mathbb{Q}}$. We prove that the set of all ...

  • Pro-p subgroups of profinite completions of 3-manifold groups 

    Wilton, Henry John; Zalesskii, P
    We completely describe the finitely generated pro-$p$ subgroups of the profinite completion of the fundamental group of an arbitrary 3-manifold. We also prove a pro-$p$ analogue of the main theorem of Bass–Serre theory for ...

  • Hydrogel as a Medium for Fluid-Driven Fracture Study 

    O'Keeffe, Niall; Linden, Paul Frederick
    In this paper we describe how to construct polyacrylamide hydrogels to study the processes linked with hydraulic fracturing. These transparent, linearly elastic and brittle gels permit fracturing at low pressures and speeds ...

  • The Complexity of Translationally Invariant Spin Chains with Low Local Dimension 

    Bausch, Johannes; Cubitt, Toby; Ozols, Maris (Annales Henri Poincaré, 2017-11)
    We prove that estimating the ground state energy of a translationally-invariant, nearest-neighbour Hamiltonian on a 1D spin chain is QMAEXP-complete, even for systems of low local dimension (roughly 40). This is an improvement ...

  • Cool and hot emission in a recurring active region jet 

    Mulay, Sargam; Del, Giulio; Mason, Helen Elizabeth
    Aims. We present a thorough investigation of the cool and hot temperature components in four recurring active region jets observed on July 10, 2015 using the Atmospheric Imaging Assembly (AIA), X-ray Telescope (XRT), and ...

  • High-dimensional change point estimation via sparse projection 

    Wang, T; Samworth, Richard John
    Changepoints are a very common feature of Big Data that arrive in the form of a data stream. In this paper, we study high-dimensional time series in which, at certain time points, the mean structure changes in a sparse ...

  • Mesoscale and Submesoscale Effects on Mixed Layer Depth in the Southern Ocean 

    Bachman, Scott Daniel; Taylor, John Ryan; Adams, KA; Hosegood, P (American Meteorological SocietyJournal of Physical Oceanography, 2017-09-01)
    Submesoscale dynamics play a key role in setting the stratification of the ocean surface mixed layer and mediating air–sea exchange, making them especially relevant to anthropogenic carbon uptake and primary productivity ...


  • Fractional Calabi-Yau Categories from Landau-Ginzburg Models 

    Kelly, Tyler Lee; Favero, D
    We give criteria for the existence of a Serre functor on the derived category of a gauged Landau-Ginzburg model. This is used to provide a general theorem on the existence of an admissible (fractional) Calabi-Yau subcategory ...

  • Pauli-Lubanski, supertwistors, and the superspinning particle 

    Arvanitakis, AS; Mezincescu, L; Townsend, Paul Kingsley (Springer NatureJournal of High Energy Physics, 2017-06-28)
    We present a novel construction of the super-Pauli-Lubanski pseudo-vector for 4D supersymmetry and show how it arises naturally from the spin-shell constraints in the supertwistor formulation of superparticle dynamics. We ...

  • Uniform and high-order discretization schemes for Sturm–Liouville problems via Fer streamers 

    Ramos, Alberto Gil Couto Pimentel
    The current paper concerns the uniform and high-order discretization of the novel approach to the computation of Sturm–Liouville problems via Fer streamers, put forth in Ramos and Iserles (Numer. Math. 131(3), 541—565 ...

  • An Efficient Fill Estimation Algorithm for Sparse Matrices and Tensors in Blocked Formats 

    Unknown author (2017-06-09)
    Tensors, linear-algebraic extensions of matrices in arbitrary dimensions, have numerous applications in computer science and computational science. Many tensors are sparse, containing more than 90% zero entries. Efficient ...