Bradford Scholars

Bradford Scholars is the University of Bradford online research archive. Access is free to anyone interested in research being conducted at Bradford. In the repository you will find a range of materials from journal articles and conference papers to research reports and theses.

Contact the repository team via openaccess@bradford.ac.uk with any queries about Open Access or how to deposit your research papers.

Communities in Bradford Scholars

Select a community to browse its collections.

Recent Submissions

  • PublicationOpen Access
    ‘Beyond the Binary’: Funerary Archaeology, Gendered Identity, and its Impact on Contemporary Society
    Newbury, Dulcie S.D.; Croucher, Karina; Curtis-Summers, Shirley; Koon, Hannah
    Sex and gender are considered fundamental aspects of identity. Funerary archaeology is used as the access point to identity in the past, with these materials providing the basis for conclusions. Within interpretations, the sex and gender binaries are often relied upon, causing issues with reliability and validity of conclusions as the categories of ‘male’ and ‘female’ do not account for identities outside this binary. This research challenges the analytical processes within funerary archaeology by demonstrating a unique approach to materials that does not rely on this binary model. The results, along with other archaeological and contemporary materials that challenge ideas around sex and gender were incorporated into workshops that determined the role that archaeological materials can play in discussions around sex and gender identity and improving mental health and wellbeing today. There are issues relating to sex and gender identity today, such as inequality and discrimination. These issues have a negative impact on wellbeing, with the LGBTQ+ community having a higher risk of developing mental health issues such as depression and anxiety. The analysis of the funerary remains removes the restrictions of sex categorisations, allowing for broader discussions of identity and allows other patterns of evidence to come to the forefront. These results used in the workshops showed that the past is a powerful instigator of conversation around identity and can challenge perceptions and biases. This can improve contemporary attitudes by providing a sense of history and heritage and providing marginalised groups a voice in constructing their pasts.
  • PublicationOpen Access
    A method for predicting geometric characteristics of polymer deposition during fused-filament-fabrication
    (2019-05) Hebda, Michael J.; McIlroy, C.; Whiteside, Benjamin R.; Caton-Rose, Philip D.; Coates, Philip
    In recent years 3D printing has gained popularity amongst industry professionals and hobbyists alike, with many new types of Fused Filament Fabrication (FFF) apparatus types becoming available on the market. A massively overlooked component of FFF is the requirement for a simple method to calculate the geometries of polymer depositions extruded during the FFF process. Manufacturers have so far achieved adequate methods to calculate tool-paths through so called slicer software packages which calculate the required velocities of extrusion from prior knowledge and data. Presented here is a method for obtaining a series of equations for predicting height, width and cross-sectional area values for given processing parameters within the FFF process for initial laydown on to a glass surface.
  • PublicationOpen Access
    An experimental and simulation comparison of a 3-D abrupt contraction flow using the Molecular Stress Function constitutive model
    (Maney Publishing, 2021) Olley, Peter; Gough, Tim; Spares, R.; Coates, Philip
    The Molecular Stress Function (MSF) constitutive model with convective constraint release mechanism has been shown to accurately fit a large range of viscometric data, and also shown to give strong vortex growth in flows of LDPE through planar and axisymmetric contractions. This work compares simulation and experimental results for 3-D flows of Lupolen 1840H LDPE through a contraction slit; 3-D effects are introduced by using a slit with a low upstream aspect ratio of 5:3. Comparisons are made with vortex opening angles obtained from streak photography, and also with stress birefringence measurements. The comparisons are made with two versions of the convective constraint release (CCR) mechanism. The simulated vortex angles for one version of the CCR mechanism are found to approach what is seen experimentally. The best-fit value for the stress optical coefficient was found to vary between CCRs and to decrease with flow rate. This is partially explained by different centreline elongational rates with the two CCRs, which in turn is related to different opening angles. A 3-D simulation is compared to the corresponding 2-D simulation. It is shown that both velocity vectors and birefringence show only small changes to around 60% of the distance to the side wall.
  • PublicationOpen Access
    Enhancing poly(lactic acid) microcellular foams by formation of distinctive crystalline structures
    (2020-04) Li, R.; Ye, L.; Zhao, X.; Coates, Philip; Caton-Rose, Philip D.
    By controlling the crystallization behavior of poly(lactic acid) (PLA) in the presence of a hydrazide nucleating agent (HNA), PLA-HNA foams with enhanced microcellular structures were prepared via supercritical CO2 foaming. It was found that HNA can self-assemble into fibrillar networks, inducing the crystallization of PLA on their surface, and "shish-kebab"crystalline structures with high crystallinity formed, which can be maintained during the whole foaming process. Incorporation of HNA promoted the formation of gt conformers, improved the amount of dissolved CO2, hindered the escape of CO2, and increased the viscoelasticity of PLA. Compared with neat PLA foam, for PLA-HNA foam, the average cell diameter decreased obviously, from 64.39 to 6.59 μm, while the cell density increased up to nearly three orders of magnitudes, from 6.82 × 106 to 4.44 × 109 cells/cm3. Moreover, lots of fibrillar structures appeared and entangled with each other on the cell wall of the foam. By forming such dense micropores and enhanced fibrillar structures, PLA foam was highly reinforced with significantly improved compressive strength.
  • PublicationOpen Access
    Experimental analysis of the tensile property of FFF-printed elastomers
    (2020-10) Lin, X.; Coates, Philip; Hebda, Michael J.; Wang, R.; Lu, Y.; Zhang, L.
    Designing and manufacturing functional parts with enhanced mechanical property is a major goal of fused filament fabrication (FFF) for polymeric elastomers, which exhibits major advantages in producing such parts with a range of structures. But the unsatisfactory mechanical performance constrains greatly its real application and there is yet no consensus in the mechanical characterization of printed samples. This work takes the nozzle height as the considered factor and tests the tensile property of FFF-printed thermoplastic polyurethane (TPU). Rheological property of the TPU melt, represented here by die swell behavior and shear viscosity, were measured initially to obtain a preliminary assessment of the material suitability and an optimization of melt extrusion conditions for FFF processing. Then correlation between the cross-section profile of deposited bead and the tensile performance of printed sample were evaluated. Both the shape of deposited bead and the bonding strength of two adjacent beads are emphasized when explaining the measured tensile strength. The significance of molecular permeation efficiency at bead-bead interfaces, and bonding-releasing patterns between adjacent beads to the tensile failure of printed objects is discussed.
Show more