9. Disposable forks are ordered by an environmentally-conscious pizza-house. The shape of each (and thus the length, width, and profile) are fixed, but the thickness is free: it is chosen to give enough bending-stiffness to cut and impale the pizza without excessive flexure. The pizzeria-proprietor wishes to enhance the greenness of his image by minimizing the energy content of his throw-away tableware. List the design requirements and establish an appropriate material index for selecting materials for stiff, but energy-economic environmental forks. Model the eating implement loaded in bending as shown below. Young's modulus, E (GPa) 10. By looking at the "Young's modules vs. volumetric embodied energy" chart given below, which material or materials would be your choice if the stiffness greater than 1 GPa is adequate for the disposable forks you studied in Q9? 103. 10 0.1 0.01 102 b Modulus - Energy/m Non-technical ceramics Stone Natural materials Loading Foams 10 99 Concrete Brick Technical ceramics Wood to grain Wood I to grain Cork Flexible polymer foams Borosilicate glass Bamboo Soda glass Rigid polymer foarns Silicon Silca glass SIC B,C AIN wc Carbon steels Al2O3 S O Cast trons Zinc alloys Composites GFRP Epoxies Phenolics PET PVC- PS PP PE O Stainless steels Leather O PEEK ABS PTFE lonomers EVA Acetal Nylons PC Polyurethanes Polyurethane Ni alloys Lead alloys elastomers O Polymers 105 104 105 Embodied energy per cubic meter, Hm-P (MJ/m3) Metals Al alloys Mg alloys Elastomers Ti alloys CFRP Walloys Cu alloys HmP Ta E 10 HmP E2 Guidelines for minimum energy design Hmp E MFA 09 11. You probably hit too many options in Q10. What other constraints would you apply by using your engineering knowledge to narrow down the list considering factors that might be needed for the design and use of disposable forks?