African University of Science and Technology: Recent submissions

Now showing items 721-740 of 4790

  • Mixing and internal dynamics of droplets impacting and coalescing on a solid surface 

    Castrejón-Pita, JR; Kubiak, KJ; Castrejón-Pita, AA; Wilson, MCT; Hutchings, Ian Michael (American Physical SocietyPhysical Review E, 2013-08-26)
    The coalescence and mixing of a sessile and an impacting liquid droplet on a solid surface are studied experimentally and numerically in terms of lateral separation and droplet speed. Two droplet generators are used to ...

  • Shear strength of reinforced concrete wall-beam structures: upper- bound analysis and experiments 

    Bin Mohamed, Zainai (University of CambridgeDowning CollegeDepartment of Engineering, 1987-10-27)
    This study presents rigid-plastic methods of analysis of shear failure in reinforced concrete (R. C.) wall-beam type structures when subjected to in-plane loading. The upper-bound approach is emphasised. Present shear ...

  • Precracked RC T-beams Repaired in Shear with Externally Bonded CFRP Sheets 

    Dirar, Samir; Lees, Janet M.; Morley, Chris T. (American Concrete InstituteACI Structural Journal, 2012-03-01)
    This study investigates the structural behavior of precracked reinforced concrete (RC) T-beams strengthened in shear with externally bonded carbon fiber-reinforced polymer (CFRP) sheets. It reports on seven tests on ...

  • Precracked RC T-beams Repaired in Shear with Prestressed CFRP Straps 

    Dirar, Samir; Lees, Janet Marillyn; Morley, Chris T (American Concrete InstituteACI Structural Journal, 2013-09-01)
    The results of an experimental and numerical investigation involving unstrengthened reinforced concrete (RC) T-beams and precracked RC T-beams strengthened in shear with prestressed carbon fiber-reinforced polymer (CFRP) ...

  • CFRP prestressed concrete lighting columns 

    Terrasi, GP; Lees, Janet Marillyn (American Concrete InstituteField Applications of FRP Reinforcement: Case Studies, 2003)

  • Non-laminated FRP Strap Elements for Reinforced Concrete, Timber and Masonry Applications 

    Lees, Janet Marillyn; Winistörfer, AU (American Society of Civil EngineersJournal of Composites for Construction, 2010-05-11)
    Advances in material technology allow for the exploration of new structural forms and systems. In recent years, fiber-reinforced polymers (FRPs) have emerged as candidate materials for civil engineering applications, and ...

  • 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 ...