African University of Science and Technology: Recent submissions

Now showing items 761-780 of 4824

  • The elastic and plastic behaviour of cellular materials 

    Gibson, Lorna Jane (University of CambridgeChurchill CollegeDepartment of Engineering, 1981-11-10)
    Cellular materials are widespread. Some, like wood and bone, occur in nature, while others, like polymeric foams, are manmade. Because of their cellular structure, they have unusual mechanical properties: they can be stiff, ...

  • Water, salt water and alkaline solution uptake in epoxy thin films 

    Scott, P; Lees, Janet Marillyn (WileyJournal of Applied Polymer Science, 2013-05-10)
    As a means of characterizing the diffusion parameters of fiber reinforced polymer (FRP) composites within a relatively short time frame, the potential use of short term tests on epoxy films to predict the long-term behavior ...

  • Uptake induced swelling and thermal expansion of CFRP tendons 

    Scott, P; Lees, Janet Marillyn (Institute of Civil EngineersProceedings of ICE, Structures and Buildings, 2009)
    Carbon-fibre-reinforced polymer (CFRP) tendons can be used as a corrosion-resistant alternative to steel for reinforcing or prestressing concrete in aggressive marine environments. The design lives of many civil marine ...

  • External prestressed carbon fiber-reinforced polymer straps for shear enhancement of concrete 

    Lees, Janet Marillyn; Winistoerfer, AU; Meier, U (American Society of Civil EngineersJournal of Composites for Construction (ASCE), 2002)
    The use of fiber-reinforced polymers (FRPs) for the strengthening and repair of existing concrete structures is a field with tremendous potential. The materials are very durable and, hence, ideally suited for use as external ...

  • Time-Dependent Behavior of RC Beams Retrofitted with CFRP Straps 

    Hoult, Neil A; Lees, Janet Marillyn (American Society of Civil EngineersJournal of Composites in Construction, 2010-07-16)
    A retrofitting technique that uses prestressed unbonded carbon-fiber-reinforced polymer (CFRP) straps to provide additional shear capacity has previously been shown to be successful under short-term static loading conditions. ...

  • Efficient CFRP strap configurations for the shear strengthening of RC T-beams 

    Hoult, Neil Anthony; Lees, Janet Marillyn (American Society of Civil EngineersASCE Journal of Composites for Construction, 2009)
    A prestressed carbon fiber-reinforced polymer (CFRP) strap retrofitting system has been found to significantly enhance the shear capacity of existing reinforced concrete beams. In previous studies, the CFRP straps were ...

  • Experimental behavior of reinforced concrete beams strengthened with prestressed CFRP shear straps 

    Kesse, GK; Lees, Janet Marillyn (American Society of Civil EngineersJournal of Composites for Construction (ASCE), 2007)
    One promising means of increasing the capacity of existing shear-deficient beams is to strengthen the structure using external prestressed carbon fiber reinforced polymer (CFRP) straps. In this system, layers of CFRP tape ...

  • Modelling of an unbonded CFRP strap shear retrofitting system for RC beams 

    Hoult, Neil Anthony; Lees, Janet Marillyn (American Society of Civil EngineersASCE Journal of Composites for Construction, 2009)
    A retrofitting technique has been developed that uses carbon fiber-reinforced polymer (CFRP) straps to increase the shear capacity of reinforced concrete beams. The vertical straps are not bonded to the beam but are instead ...

  • Phased Nonlinear Finite-Element Analysis of Precracked RC T-Beams Repaired in Shear with CFRP Sheets 

    Dirar, Samir; Lees, Janet Marillyn; Morley, Chris (American Society of Civil EngineersJournal of Composites for Construction, 2012-10-17)
    Phased nonlinear finite-element (FE) analyses were carried out to predict the behavior of precracked reinforced concrete (RC) T-beams repaired in shear with externally bonded (EB) carbon fiber–reinforced polymer (CFRP) ...

  • Rectangular Reinforced Concrete Beams Strengthened with CFRP Straps 

    Yapa, Hiran D; Lees, Janet Marillyn (American Society of Civil EngineersJournal of Composites for Construction, 2013-07-13)
    Shear deficient reinforced concrete (RC) structures can be effectively strengthened using external prestressed carbon fibre reinforced polymer (CFRP) straps. Due to the presence of the external elastic straps, a strengthened ...

  • Transfer bond stresses generated between FRP tendons and concrete 

    Lees, Janet Marillyn; Burgoyne, Christopher John (Institute of Civil EngineersMagazine of Concrete Research, 1999)
    There is a growing interest in the use of new materials in construction. Materials such as fibre-reinforced plastics (FRPs) are lightweight, strong, and, for the most part, non-corrodible. Hence, the use of FRPs as ...

  • Nonlinear FE analysis of cracks in tension and shear 

    Kesse, G; Lees, Janet Marillyn (Institute of Civil EngineersMagazine of Concrete Research, 2007-05-01)
    Smeared-crack finite element (FE) analyses of reinforced-concrete beams strengthened with prestressed carbonfibre-reinforced polymer (CFRP) shear straps have shown that, at high load levels, the stresses in the straps ...

  • Signal separation of musical instruments: simulation-based methods for musical signal decomposition and transcription 

    Walmsley, Paul Jospeh (University of CambridgeDepartment of EngineeringPembroke College, 2001-05-29)
    This thesis presents techniques for the modelling of musical signals, with particular regard to monophonic and polyphonic pitch estimation. Musical signals are modelled as a set of notes, each comprising of a set of ...

  • Effects of solution exposure on the combined axial-shear behaviour of unidirectional CFRP rods 

    Lees, Janet Marillyn; Scott, P (ElsevierComposites Part A: Applied Science and Manufacturing, 2012-04-06)
    In fibre reinforced polymer (FRP) prestressed concrete applications, an FRP tendon must sustain high axial tensile stresses and, if cracks occur, additional dowel forces. The tendon may also be exposed to solutions and so ...

  • Collapse of masonry structures 

    Ochsendorf, John Allen (University of CambridgeDepartment of EngineeringKing's College, 2002-07-16)
    TIlls dissertation examines the collapse of masonry structures in response to large support displacements and horizontal ground accelerations. There are two main classes of masonry structure: arches that thrust, and ...

  • Behaviour of GFRP adhesive pipe joints subjected to pressure and axial loadings 

    Lees, Janet Marillyn (ElsevierComposites Part A: Applied Science and Manufacturing, 2006)
    The corrosion resistance of glass-fibre reinforced polymers (GFRPs) is a key advantage in pipeline applications. Adhesive bonded joints are often used in tensile resistant GFRP pipe systems and the behaviour of small-diameter ...

  • Transmission capacity improvement for high speed multimode waveguide links using advanced optical launch and multilevel modulation schemes 

    Geng, Liang (University of CambridgeDepartment of Engineering, 2013-07-09)
    This dissertation investigates the potential technologies in both optical and electrical domains for transmission capacity improvement in multimode waveguide links. The first half of the dissertation focuses on the multimode ...

  • On the playability of stringed instruments 

    Galluzzo, Paul M. (University of CambridgeDepartment of EngineeringTrinity College, 2004-07-13)
    As first noticed by Helmholtz, strings vibrate in a “V-shape” when they are bowed correctly and a full tone is produced, where the vertex of the “V” shuttles back and forth along the visible envelope of the string’s motion. ...

  • Vortex flow around the bases of obstacles 

    Baker, Christopher James (University of CambridgeSt. Catharine's CollegeDepartment of Engineering, 1979-02-06)
    This thesis presents the results of experimental and theoretical investigations of the horseshoe vortex systems caused by boundary layer separation upstream of obstacles mounted on a wall. Flow visualization enabled these ...

  • Future, Opportunities and Challenges of Inkjet Technologies 

    Castrejon-Pita, J. R.; Baxter, W. R. S.; Morgan, J.; Temple, S.; Martin, G. D.; Hutchings, I. M. (2013-08-07)