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Understanding Structure- Function Relationships in Biological Glass - - PowerPoint PPT Presentation
Understanding Structure- Function Relationships in Biological Glass - - PowerPoint PPT Presentation
Understanding Structure- Function Relationships in Biological Glass Fibers Michael Porter Project Mentor: James Weaver Faculty Advisor: Dan Morse Structural Diversity of Siliceous Sponge Skeletal Elements (Spicules) Hexactinellids
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Structural Diversity of Siliceous Sponge Skeletal Elements (Spicules)
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Hexactinellids
Haeckel, 1904
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Sponge Spicule Nomenclature
Generally classified into two major groups Microscleres: Typically less than 500µm
Small-scale skeletal support
Megascleres: Typically greater than 1mm
Large-scale skeletal support
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Skeletal System of Rhabdocalyptus dawsoni
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- R. dawsoni Spicule Cross-Sections
75µm
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Fracture Dynamics in Laminated Spicules
Energy Dissipating Organics
Applied Stress Stepped-Fracture No Catastrophic Failure!
Molecular Shock- Absorbers
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Structural Analysis of Euplectella aspergillum Spicules
50µm x 10cm
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Skeletal Lattice of E. aspergillum
100µm
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Etching of E. aspergillum Skeletal Lattice with HF
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- E. aspergillum Skeletal Lattice Cross-Sections
5mm 50µm
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Maximum Tension
Giant Anchor Spicule of Monorhaphis chuni
Maximum Compression
0.5m
1º 2º
5mm
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Maximum Tension
Giant Anchor Spicule of Monorhaphis chuni
Maximum Compression
35µm
1 3 2 4
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Skeletal System of Aphrocallistes vastus
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Spicules greater that a few millimeters in length exhibit a unique laminated architecture which effectively retards crack propagation through these materials. Layer number increases with spicule length and typically decreases in thickness outward from the core. Large spicules confronting uniaxial loading exhibit a unique graded architecture for enhanced fracture resistance.
Conclusions
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Identify the specific bio-macromolecules that direct the synthesis of these remarkable structures. Model the mechanics of these spicules. Apply the lessens learned in these studies toward the synthesis of more fracture-resistant composite materials.
Future Work
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