close

Memorial University Research Repository

The Memorial University Research Repository is an open access initiative to showcase and preserve Memorial University's creative and intellectual output, including theses, journal articles, conference papers, lectures, presentations, reports, and performances.

Communities in Memorial University Research Repository

Select a community to browse its collections.

Recent Submissions

  • Thumbnail Image
    Item type: Item , Access status: Open Access ,
    AI Literacy for Graduate Students & Researchers
    (Memorial University of Newfoundland, Grenfell Campus, 2026-07-30) Humphries, Chelsea
  • Thumbnail Image
    Item type: Item , Access status: Open Access ,
  • Thumbnail Image
    Item type: Item , Access status: Open Access ,
    Exploring the effect of installing collars on snow crab (Chionoecetes opilio) pots in Newfoundland and Labrador: Do collars improve size selectivity?
    (Elsevier B.V, 2026-06-30) Brown, Peter Wilfred; Araya-Schmidt, Tomas; Bayse, Shannon M.; Winger, Paul D.
    The snow crab (Chionoecetes opilio) fishery is the province of Newfoundland and Labrador’s most valuable fishery. The snow crab fishery is limited to land only hardshell (inter-molt) male adult crabs with a carapace width (CW) ≥ 95 mm. Bycatch consists of sublegal male (CW < 95 mm), softshell (post-molt), and rarely, female snow crabs. This manuscript documents a comparative fishing experiment evaluating the effects of installing external plastic collars on the tops of typically used conical pots. The goal of this work is to improve size selectivity by restricting the entry of bycatch while maintaining or improving the capture of target-sized snow crabs. Smaller (female and sublegal) or weaker (softshell) crabs were hypothesized to be unable to reach or climb beyond the distance of the collar. Four experimental conical pots with non-selective, small mesh jackets (40.5 mm mean; s. d. = ±1.4 mm; measured inside the knots) and collars of 180 mm, 240 mm, 300 mm, and 180 mm with a 51 mm lip, were compared with small mesh pots with no collar and traditional pots with traditional mesh (137.0 mm mean; s. d. = ±1.9 mm; measured inside the knots) and used in the fishery. Generally, results showed that adding a smaller collar to snow crab pots produced similar catches to traditional snow crab pots for target-sized snow crab, and that large amounts of target-sized snow crab were lost with the larger collars tested. Conversely, sublegal-sized crabs were generally caught more (except for the 300 mm collar) and had high retention for the smaller collars tested. The design, as tested, requires additional refinement as small male and female crabs were unable to escape once they entered the pot. Future research could investigate the additional use of escape gaps to assist the egress of these small crabs.
  • Thumbnail Image
    Item type: Item , Access status: Open Access ,
    Acoustic phonon dynamics of polycrystalline tin selenide by brillouin light scattering spectroscopy
    (Memorial University of Newfoundland, 2026-05) Penney, Jenna; Andrews, G. Todd
    Tin Selenide (SnSe) is a layered semiconducting material that has recently gained popularity due to its potential in the field of thermoelectricity. Single-crystal SnSe has been found to have the highest reported value for the thermoelectric figure of merit, due to an extremely low value for thermal conductivity. Since heat travels in solids through lattice vibrations known as phonons, a measurement of the phonon dynamics, such as velocities or attenuation, will give further insight to the thermal properties of the material. There has been little study done to investigate the thermal conductivity in single-crystal samples of SnSe, and even less for polycrystalline SnSe, which is expected to be more favourable in terms of thermoelectric applications. Furthermore, the few results that have been reported for phonon velocities show wide variation. To fill this void, Brillouin scattering spectroscopy was used to probe acoustic surface phonons in two samples of polycrystalline SnSe to determine acoustic phonon velocities and attenuation. Material characterization of the samples was done through X-ray diffraction, energy dispersive X-ray spectroscopy, and elemental mapping. The results of which indicated that the sample was polycrystalline and composed of ∼ 50% Tin and ∼ 50% Selenium, with elements evenly dispersed across the sample. The precise direction of propagation is unknown, but is known to be parallel to the bc plane. Brillouin spectra contained peaks due to a Rayleigh mode and a longitudinal resonance mode. The Rayleigh surface mode velocity was found to be independent of direction of propagation in the sample surface plane, and the associated spectral peak was sharp and narrow, indicating low attenuation. In contrast, the longitudinal resonance peak was over an order of magnitude wider, indicating high attenuation and by extension a short lifetime and lower thermal conductivity. For the first sample, velocities were found to be 1640±50 m/s for the Rayleigh mode, and 3700±100 m/s for the longitudinal resonance. For the second sample, velocities were found to be 1650 ± 50 m/s for the Rayleigh mode, and 3800 ± 100 m/s for the longitudinal resonance. It was found that, on average, both the Rayleigh and longitudinal resonance velocities for polycrystalline SnSe fell within the range of reported velocities for single-crystal SnSe, perhaps indicating a similar thermal conductivity in polycrystalline samples. Finally, two estimated elastic constants were calculated for the polycrystalline sample using the acoustic phonon velocities. From the longitudinal resonance velocities, it was found that for the first sample Cʟʀ = 83 ± 9 GPa, and for the second, Cʟʀ = 87 ± 9 GPa. From the Rayleigh velocities, it was found that for the first sample Cʀ = 20 ± 2 GPa, and for the second Cʀ = 20 ± 2 GPa.
  • Thumbnail Image
    Item type: Item , Access status: Open Access ,
    Investigating electrohydrodynamic droplet deformations using 2D finite-volume simulations
    (Memorial University of Newfoundland, 2026-05) Pollett, Andrew; Fitzgerald, Joseph; Yethiraj, Anand
    A liquid droplet suspended in an immiscible fluid has a spherical equilibrium shape but will deform in the presence of an applied external electric field. This phenomenon is studied under electrohydrodynamics (EHD), a field that examines fluid flows driven by electric forces. One common way to study these phenomena is through oil-inoil emulsions, where droplets of one oil type are suspended in another, typically using castor and silicone oils due to their immiscibility. Depending on the material properties of the fluids, this deformation may align with the electric field (prolate deformation) or the plane perpendicular to the electric field (oblate deformation). As the external electric field strength increases, more complex behaviours are observed, such as stable tilting, rotation, and breakup. Despite these behaviours being well documented experimentally, the physical mechanisms governing them are not fully understood. Numerical simulations are widely used to study this EHD droplet system, often using a two-dimensional (2D) computational domain due to computational limitations. Previously, 2D simulations have shown good agreement with theoretical analysis in the small deformation limit, which corresponds to weak electric fields. However, as the strength of the external field and deformation increase, simulation results increasingly deviate from theoretical analysis. This deviation is commonly attributed to comparisons with first-order theory, which is only valid for small deformations. This study uses simple electrostatic problems to identify limitations of a 2D approximation. Simulations of these test cases show that the reduced dimensionality alters the form of the electric field. For example, for a point charge, this changes field expressions from 𝑟⁻² in 3D to 𝑟⁻¹ in 2D. Accounting for this difference, a revised analysis of the small deformation limit is performed. Comparisons between simulation results and current 3D first-order theory show good agreement for small deformations but deviate as the deformation increases, highlighting the limitations of comparing 3D theory with 2D simulations. Finally, a new 2D first-order theory is initiated, following the procedure used for the 3D case. i