The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform

Gareth H. Mckinley - One of the best experts on this subject based on the ideXlab platform.

  • Improved rheometry of yield stress fluids using bespoke fractal 3D printed vanes
    Journal of Rheology, 2020
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed (3DP) using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3DP cup, which attaches to a standard rheometer base. We discuss general design criteria for 3DP rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

  • Improved Rheometry of Yield Stress Fluids Using Bespoke Fractal 3D Printed Vanes.
    arXiv: Soft Condensed Matter, 2019
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically-compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3D printed cup, which attaches to a standard rheometer base. We discuss general design criteria for 3D printed rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

Crystal E. Owens - One of the best experts on this subject based on the ideXlab platform.

  • Improved rheometry of yield stress fluids using bespoke fractal 3D printed vanes
    Journal of Rheology, 2020
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed (3DP) using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3DP cup, which attaches to a standard rheometer base. We discuss general design criteria for 3DP rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

  • Improved Rheometry of Yield Stress Fluids Using Bespoke Fractal 3D Printed Vanes.
    arXiv: Soft Condensed Matter, 2019
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically-compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3D printed cup, which attaches to a standard rheometer base. We discuss general design criteria for 3D printed rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

A. John Hart - One of the best experts on this subject based on the ideXlab platform.

  • Improved rheometry of yield stress fluids using bespoke fractal 3D printed vanes
    Journal of Rheology, 2020
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed (3DP) using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3DP cup, which attaches to a standard rheometer base. We discuss general design criteria for 3DP rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

  • Improved Rheometry of Yield Stress Fluids Using Bespoke Fractal 3D Printed Vanes.
    arXiv: Soft Condensed Matter, 2019
    Co-Authors: Crystal E. Owens, A. John Hart, Gareth H. Mckinley
    Abstract:

    To enable robust rheological measurements of the properties of yield stress fluids, we introduce a class of modified vane fixtures with fractal-like cross-sectional structures. A greater number of outer contact edges leads to increased kinematic homogeneity at the point of yielding and beyond. The vanes are 3D printed using a desktop Stereolithography Machine, making them inexpensive (disposable), chemically-compatible with a wide range of solvents, and readily adaptable as a base for further design innovations. To complete the tooling set, we introduce a textured 3D printed cup, which attaches to a standard rheometer base. We discuss general design criteria for 3D printed rheometer vanes, including consideration of sample volume displaced by the vanes, stress homogeneity, and secondary flows that constrain the parameter space of potential designs. We also develop a conversion from Machine torque to material shear stress for vanes with an arbitrary number of arms. We compare a family of vane designs by measuring the viscosity of Newtonian calibration oils with error

Lichun Lu - One of the best experts on this subject based on the ideXlab platform.

  • Poly(propylene fumarate) bone tissue engineering scaffold fabrication using Stereolithography: Effects of resin formulations and laser parameters
    Biomacromolecules, 2007
    Co-Authors: Kee Won Lee, Bradley C. Fox, Shanfeng Wang, Michael J. Yaszemski, Erik Leo Ritman, Lichun Lu
    Abstract:

    Stereolithography using photo-cross-linkable polymeric biomaterials is an effective technique for fabricating highly complex three-dimensional (3D) scaffolds with controlled microstructures for tissue engineering applications. In this study, we have optimized the UV curable polymer solution composition and laser parameters for the Stereolithography Machine. Poly(propylene fumarate) (PPF) was used as the biomaterial, diethyl fumarate (DEF) was used as the solvent, and bisacrylphosphrine oxide (BAPO) was used as the photoinitiator. Three different weight ratios of PPF/DEF and BAPO contents were characterized by measuring the viscosities and thermal properties of the un-cross-linked solutions and the mechanical properties of the formed scaffolds. After optimizing the resin composition by satisfying both the viscosity limitation and the mechanical requirement, laser parameters such as critical exposure (Ec) and penetration depth (Dp) were determined from the working curve and the relationship between laser speed and energy by measuring the thickness of predesigned windows fabricated in Stereolithography with different ranges of Ec and Dp. Three-dimensional scaffolds with various pore sizes, pore shapes, and porosities were designed in computer-aided design (CAD) software and were fabricated in Stereolithography. The fabricated scaffolds were characterized by measuring external dimensions, porosities, mean pore sizes, and compressive moduli and were compared to the CAD models. Feature accuracy in the xy-plane was achieved and overcuring of the resin in z-axis was minimized. The stereolithographically fabricated scaffolds with controlled microstructures can be useful in diverse tissue engineering applications.

Kee Won Lee - One of the best experts on this subject based on the ideXlab platform.

  • Poly(propylene fumarate) bone tissue engineering scaffold fabrication using Stereolithography: Effects of resin formulations and laser parameters
    Biomacromolecules, 2007
    Co-Authors: Kee Won Lee, Bradley C. Fox, Shanfeng Wang, Michael J. Yaszemski, Erik Leo Ritman, Lichun Lu
    Abstract:

    Stereolithography using photo-cross-linkable polymeric biomaterials is an effective technique for fabricating highly complex three-dimensional (3D) scaffolds with controlled microstructures for tissue engineering applications. In this study, we have optimized the UV curable polymer solution composition and laser parameters for the Stereolithography Machine. Poly(propylene fumarate) (PPF) was used as the biomaterial, diethyl fumarate (DEF) was used as the solvent, and bisacrylphosphrine oxide (BAPO) was used as the photoinitiator. Three different weight ratios of PPF/DEF and BAPO contents were characterized by measuring the viscosities and thermal properties of the un-cross-linked solutions and the mechanical properties of the formed scaffolds. After optimizing the resin composition by satisfying both the viscosity limitation and the mechanical requirement, laser parameters such as critical exposure (Ec) and penetration depth (Dp) were determined from the working curve and the relationship between laser speed and energy by measuring the thickness of predesigned windows fabricated in Stereolithography with different ranges of Ec and Dp. Three-dimensional scaffolds with various pore sizes, pore shapes, and porosities were designed in computer-aided design (CAD) software and were fabricated in Stereolithography. The fabricated scaffolds were characterized by measuring external dimensions, porosities, mean pore sizes, and compressive moduli and were compared to the CAD models. Feature accuracy in the xy-plane was achieved and overcuring of the resin in z-axis was minimized. The stereolithographically fabricated scaffolds with controlled microstructures can be useful in diverse tissue engineering applications.