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==Paddlefish Characteristics==
[[File:Student11-fig1.png|thumb|right|9999x300px|Figure 1: The Paddlefish.]]

From the basic laws of physics, everything in nature has a tendency to evolve to a state where survival is possible with the minimum possible expenditure of energy. Rostrum of the Paddlefish is a very good example of this phenomenon. The paddlefish (Polyondon spathula) can be easily distinguished by the presence of its elongated rostrum Figure 1. It is among the most primitive of bony-finned fishes (Osteichthyes, Actinopterygil) and together with sturgeon, comprises an order of secondary cartilaginous fishes, the Acipenseriformes <ref name="ref1">J.D. Pettigrew, L. Wilkens, Paddlefish and Platypus: Parallel Evolution of Passive Electroreception in a Rostral Bill Organ, Sensory Processing in Aquatic Environments, 2003, pp. 420-433.</ref>. Presently, they constitute the most endangered group of species in North America. Their population decline is attributed to habitat loss and degradation, overharvest <ref name="ref2">D.F. Williamson, Caviar and conservation – Status, management, and trade of North American sturgeon and Paddlefish, TRAFFIC North America, Washington, D. C.: World Wildlife Fund, 2003.</ref>, alterations to natural river flow regimes, and the construction of navigation dams on the Mississippi River and the most common waterways in the mid-west, which limit or eliminate spawning migrations.

The rostrum of paddlefish is a unique structure, comprising of a network of cartilage, tissue, and interlocking star shaped bones called the stellate bones. Figure 2 shows the stellate bone arrangement in a rostrum of paddlefish. The function of the long, paddle-shaped snout has received considerable attention. The sensory function of the rostrum enables them to detect the type of flows <ref name="ref3">C. Gurgens, D.F. Russell, L.A. Wilkens,  Electrosensory avoidance of metal obstacles by the Paddlefish.  Journal of Fish Biology, 57 (2000) 277-290.</ref> that allows them feed efficiently in both laminar and turbulent currents. Additionally, the sensory function allows the paddlefish to detect tiny zooplanktons without the benefit of using their visual, chemical, or hydrodynamic senses <ref name="ref4">L.A. Wilkens, D. F. Russell, X. Pei, C. Gurgens,  The Paddlefish Rostrum functions as an electrosensory antenna in plankton feeding.  Proc. R. Soc. Lond. B 264 (1997) 1723-1729. </ref>. 

[[File:Student11-fig2.png|right|thumb|480px|Figure 2: Paddlefish rostrum and Stellate bone arrangement.]]

Naturally occurring material are made from the simplest materials readily available in nature. They gain their strength from the unique hierarchical structure. Rostrum shows an incredible load transfer mechanism when it was subjected to blast and penetration loads. Several materials have been considered to reverse engineer the unique load resistance characteristics of the Rostrum to engineer superior materials that could be used for making blast resistant walls, bullet proof vests for soldiers etc.

==ICME Approach for designing superior Bio-Inspired Materials==

[[File:Student11-fig3.png|thumb|right|9999x300px|Figure 1: ICME approach for designing novel bio-inspired energy dissipating material.]]

Multi-scale simulations integrate the existing methods from different branches of science to fill the bridge of length and time that is inherent in designing new materials with superior properties. The design requirements are defined at the continuum application level. These design requirements are scaled down to the atomistic level where the structure of the matter is understood. The requirements of the end product are the beginning point of the ICME process. The entire process is based on the design requirements sent down from the continuum level internal state variables. Several studies have been carried out that use the multiscale approach. <ref name="ref5">S. J. V. Frankland, J. C. Riddick and T. S. Gates, Multi-scale Rule-of-Mixtures Model of Carbon Nanotube/Carbon Fiber/Epoxy Lamina. </ref><ref name="ref6">J F. Peters, J P. Allen, P G. Allison,T A. Carlson,M Q.Chandler, C F. Cornwell, B D. Devine, F C. Hill, N. Jabari Lee, C P. Marsh,P B. Stynoski, Laura Walizer, and C R. Welch, Towards Development of a Super Ceramic Composite - Initial Investigation into Improvement of Strength and Toughness of Polycrystalline Ceramics, Aug 2012. </ref>. Figure 3 shows the proposed skeleton of the ICME approach that will be employed to develop superior strength materials.

==Transmission of information between the different length scales ==

Electronics Scale (0.1-10 nm)

Downscaling: Energy and elastic moduli needed. 

Upscaling:  Continuum Scale: Energy and elastic moduli information passed. 
	     Atomic Scale: Interfacial Energy/Elasticity

Atomistic Scale (10-100nm)

Downscaling: Information required from electronics scale, heat of formation, elastic moduli etc. 

Upscaling:	Micro scale: Crack initiation criteria, bond strength information
		Continuum Scale: Penetration and high rate mechanism information

Microscale (1-200μm)

Downscaling: Information required from atomic scale. Crack initiation criteria, bond strength information

Upscaling: Meso Scale: Particle interaction information,
	   Continuum Scale: Void crack/nucleation information

Mesoscale (100-500 μm)

Downscaling: Information required from microscale. Particle interaction information. 

Upscaling: Macro scale: Particle/void interactions,Continuum scale: Void/crack growth

MacroScale:

Downscaling: Information required from meso scale. Particle void interactions

Upscaling: Continuum Scale: Layer interaction

Continuum Scale:

Downscaling: Information received from various scales mentioned above.

Upscaling: Provide information about the material used at the production level from the data received from various length and time scales. Provide a constitutive model for the FEM simulations.

==References==
<references/>


[[Category: ICME Class]]
[[Category: Multiscale Simulations]]
[[Category: Biomaterials]]