African University of Science and Technology: Recent submissions

Now showing items 1481-1500 of 4824

  • Evaluation of in-fill Well Placement and Optimization Using Experimental Design and Genetic Algorithm 

    Agbauduta, Emamuzo Anthony (2014-12-12)
    Determination of optimal well locations for infill drilling is a challenging task because engineering and geologic variables affecting reservoir performance are often nonlinearly correlated and have some degree of uncertainty ...

  • Comparative Economics of Petroleum Production Optimization Techniques 

    Edwin, G. Barquoi (2014-12-15)
    Hydrocarbon production in the petroleum industry is often constrained by reservoir heterogeneity, deliverability and capacity of surface facilities, also optimization technique in the petroleum industry requires execution ...

  • Hydrodynamics Behaviour of Slug Flow in 80 0 off the Horizontal Pipe using Electrical Capacitance Tomography (ECT) Data 

    Dawuda, Ismael (2014-12-12)
    This study presents an investigation of the hydrodynamics behaviour of slug flow in an inclined (80 degree inclination) and 67 mm internal diameter pipe. The study provides a more rudimentary explanation into the physical ...

  • Evaluation of Oil Recovery Efficiency of Water-Flooding, Gas-Flooding and Wag Injection in a Turbidite Reservoir 

    Ayawah, Akansah Evaristus Prosper (2014-12-12)
    Worldwide awareness of thin-bedded reservoirs (including turbidites) has become increasingly important with about 30-40% of the world’s oil in-place resources confined within thin-bed laminated reservoirs (Tyagi et al. ...

  • Integrated Petrophysical Evaluation of Turbiditic Sands in Niger Delta Basin 

    Awejori, Gabriel Adua (2014-12-12)
    Large quantities of petroleum resources in the Niger Delta province are confined to unconsolidated turbiditic and silici-clastic rocks. These rocks are usually associated with high volumes of shale. The high volumes of ...

  • Enhanced Oil Recovery in High Viscous Reservoir using the Thermal Process 

    Appiah, Elizabeth Akonobea (2014-12-12)
    New sources of energy should be found to relieve the high demand of energy. Even though heavy oil and bitumen are difficult to produce due to their high viscosity which can be reduced by heating, with increased oil price, ...

  • Geometric tuning of self-propulsion for Janus catalytic particles 

    Michelin, S; Lauga, Eric Jean-Marie (Nature Publishing GroupScientific Reports, 2017-02-13)
    Catalytic swimmers have attracted much attention as alternatives to biological systems for examining collective microscopic dynamics and the response to physico-chemical signals. Yet, understanding and predicting even the ...

  • Random-projection ensemble classification 

    Cannings, Timothy Ivor; Samworth, Richard John
    We introduce a very general method for high-dimensional classification, based on careful combination of the results of applying an arbitrary base classifier to random projections of the feature vectors into a lower-dimensional ...

  • Tropical Amplitudes 

    Tourkine, Piotr
    In this work, we argue that the α′→0 limit of closed string theory scattering amplitudes is a tropical limit. The motivation is to develop a technology to systematize the extraction of Feynman graphs from string theory ...

  • Elliptic curves over Q$_{∞}$ are modular 

    Thorne, Jack Arfon
    We show that if $\textit{p}$ is a prime, then all elliptic curves de ned over the cyclotomic $\mathbb{Z}$$_{p}$-extension of Q are modular.

  • More Abelian dualities in 2 + 1 dimensions 

    Karch, A; Robinson, B; Tong, David (SpringerJournal of High Energy Physics, 2017-01-01)
    We expand on the recent derivation of 3d dualities using bosonization. We present in some detail a general class of Abelian duals.

  • Connective constants and height functions for Cayley graphs 

    Grimmett, Geoffrey Richard; Li, Z (American Mathematical SocietyTransactions of the American Mathematical Society, 2017-03-31)
    The connective constant $μ$($G$) of an infinite transitive graph $G$ is the exponential growth rate of the number of self-avoiding walks from a given origin. In earlier work of Grimmett and Li, a locality theorem was proved ...

  • Dynamical symmetries in Brans-Dicke cosmology 

    Papagiannopoulos, G; Barrow, John David; Basilakos, S; Giacomini, A; Paliathanasis, A (American Physical SocietyPhysical Review D, 2017-01-20)
    In the context of generalized Brans-Dicke cosmology we use the Killing tensors of the minisuperspace in order to determine the unspecified potential of a scalar-tensor gravity theory. Specifically, based on the existence ...

  • Non-diagonal four-dimensional cohomogeneity-one Einstein metrics in various signatures 

    Dunajski, Maciej Lukasz; Tod, P (ElsevierDifferential Geometry and its Application, 2016-11-11)
    Most known four-dimensional cohomogeneity-one Einstein metrics are diagonal in a basis defined by the left-invariant one-forms, though some essentially non-diagonal ones are known. We consider the problem of explicitly ...

  • K-stability for Kähler manifolds 

    Dervan, Ruadhai; Ross, Julius Andrew (International PressMathematical Research Letters, 2017-09)
    We formulate a notion of K-stability for Kähler manifolds, and prove one direction of the Yau–Tian–Donaldson conjecture in this setting. More precisely, we prove that the Mabuchi functional being bounded below (resp. ...

  • Propositional and Activity Monitoring Using Qualitative Spatial Reasoning 

    Unknown author (2016-12-14)
    Communication is the key to effective teamwork regardless of whether the team members are humans or machines. Much of the communication that makes human teams so effective is non-verbal; they are able to recognize the ...

  • Sound and Complete Runtime Security Monitor for Application Software 

    Unknown author (2016-12-15)
    We present a run-time security monitor that detects both known and unknown cyber attacks by checking that the run-time behavior of the application is consistent with the expected behavior modeled by an application ...

  • Low- and high-frequency oscillatory winds synergistically enhance nutrient entrainment and phytoplankton at fronts 

    Whitt, DB; Lévy, M; Taylor, John Ryan (AGU PublicationsJournal of Geophysical Research: Oceans, 2017-02-10)
    When phytoplankton growth is limited by low nutrient concentrations, full-depth-integrated phytoplankton biomass increases in response to intermittent mixing events that bring nutrient-rich waters into the sunlit surface ...

  • Viscoplastic boundary layers 

    Balmforth, NJ; Craster, RV; Hewitt, Duncan; Hormozi, S; Maleki, A (Cambridge University PressJournal of Fluid Mechanics, 2017-02-25)
    In the limit of a large yield stress, or equivalently at the initiation of motion, viscoplastic flows can develop narrow boundary layers that provide either surfaces of failure between rigid plugs, the lubrication between ...

  • Utilising optimised operators and distillation to extract scattering phase shifts 

    Woss, Antoni; Thomas, Christopher Edward (Proceedings of Science, 2016-01-01)
    In this investigation, we examine how the precision of energy spectra and scattering phase shifts, extracted in lattice QCD, depend upon the degree of distillation type smearing. We use the variational method to extract ...