Now showing items 1-12 of 12

    • Complex Polymer Orientation 

      Gilbert, Peter H. (2015-07)
      Previously, we explored the dynamics of a dilute suspension of rigid dumbbells as a model for polymeric liquids in large-amplitude oscillatory shear (LAOS) flow. We derived the expression for the polymer orientation ...
    • Die Drool and Polymer Degradation 

      Hoy, Geoffrey S.; Giacomin, A. Jeffrey; Gilbert, Peter H. (2015-06-24)
      Die drool is an operational problem associated with polymer extrusion. Extrudate collects outside of the die, necessitating periodic disruptions for cleaning. There exists some debate as to the mechanism that produces ...
    • Fourier Decomposition of Polymer Orientation in Large-Amplitude Oscillatory Shear Flow 

      Giacomin, A. Jeffrey; Gilbert, Peter H.; Schmalzer, Andrew M. (2015-03-17)
      In our previous work, we explored the dynamics of a dilute suspension of rigid dumbbells as a model for polymeric liquids in large-amplitude oscillatory shear flow, a flow experiment that has gained a significant following ...
    • Large-Amplitude Oscillatory Shear: Comparing Parallel-Disk with Cone-Plate Flow 

      Giacomin, A. Jeffrey; Gilbert, Peter H.; Merger, Dimitri; Wilhelm, Manfred (2014-09-30)
      We compare the ratio of the amplitudes of the third to the first harmonic of the torque, |T3|/|T1|, measured in rotational parallel-disk flow, with the ratio of the corresponding harmonics of the shear stress, |T3|/|T1|, ...
    • Macromolecular Origins of Fifth Shear-Stress Harmonic in Large-Amplitude Oscillatory Shear Flow 

      Jbara, Layal M.; Gilbert, Peter H.; Giacomin, A. Jeffrey (2016-08)
      This study examines the simplest relevant molecular model of a polymeric liquid in large-amplitude oscillatory shear (LAOS) flow: the suspension of rigid dumbbells in a Newtonian solvent. For such suspensions, the viscoelastic ...
    • Molecular Origins of Higher Harmonics in Large-Amplitude Oscillatory Shear Flow: Shear Stress Response 

      Gilbert, Peter H.; Giacomin, A. Jeffrey (2016-11-01)
      Recent work has focused on deepening our understanding of the molecular origins of the higher harmonics that arise in the shear stress response of polymeric liquids in large-amplitude oscillatory shear flow. For instance, ...
    • Reflections on Inflections 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Gilbert, Peter H.; Kolitawong, Chanyut (2015-11-11)
      In plastics processing, the single most important rheological property is the steady shear viscosity curve: the logarithm of the steady shear viscosity versus the logarithm of the shear rate. This curve governs the volumetric ...
    • Slip Heating in Die Drool 

      Gilbert, Peter H.; Giacomin, A. Jeffrey (2014-05-14)
      When molten plastic is extruded from a die, it can collect on the open die face. Called die drool, this phenomenon costs plastics manufacturers by requiring shutdown for die cleaning. This has been attributed to cohesive ...
    • Slip Heating in Die Drool with Viscous Dissipation 

      Gilbert, Peter H.; Giacomin, A. Jeffrey (2014-10-06)
      Plastics can build-up on the die lip during extrusion. This phenomenon is called die drool and can be costly for plastics producers, requiring periodic shutdowns for die cleaning. Die drool has been attributed to the ...
    • Temperature Rise in a Verging Annular Die 

      Younes, Georges R.; Giacomin, A. Jeffrey; Gilbert, Peter H. (2015-12-07)
      Plastic pipes, tubes or catheters are extruded by pressure‑driven flows through annular dies. Whereas die lands are straight, the section connecting the die land to the extruder either converges or diverges, converging ...
    • Transport Phenomena in Eccentric Cylindrical Coordinates 

      Gilbert, Peter H.; Saengow, Chaimongkol; Giacomin, A. Jeffrey (2016-09)
      Studies in transport phenomena have been limited to a select few coordinate systems. Specifically, Cartesian, cylindrical, spherical, Dijksman toroidal, and bipolar cylindrical coordinates have been the primary focus of ...
    • Wall Slip Heating 

      Gilbert, Peter H.; Giacomin, A. Jeffrey (2015-01-05)
      When molten plastic is extruded, the upper limiting throughput is often dictated by fine irregular distortions of the extrudate surface. Called sharkskin melt fracture, plastics engineers spike plastics formulations with ...