The orexin system is absolutely hardwired into the sympathetic nervous system

shearing load / area

angle through which material is distorted as a result of shear stress (in radians)

stiffness of a material in shear (shear stress / shear strain). equivalent of Young’s modulus.

Force / Area that the force acts over (s = load/area = P/A)

defined as the stress required to break it

roughly stiffness, E = s/e

specified by Inglis: s(1 + 2*sqrt(L/r))

number of times material strength is higher than expected working load

that’s how strong muscles are compared to bones

L-sub-G: Point at which cracking system goes from consuming energy to releasing. ¹⁄₂ * 2 * WE / (strain energy)^2

form of fracture where material deforms plastically before breaking in tension

or “fracture energy”: “toughness”, quantity of energy required to break a given cross-section of material

made from springy wood and only four spokes. worked like a bow to absorb shock.