Nitrogen from a gaseous phase is to be diffused into pure iron at 675°C. If the surface concentration is maintained at 0.1 wt% N, what will be the concentration 2 mm from the surface after 25 h? The diffusion coefficient for nitrogen in iron at 675°C is 2.8 × 10–11 m2/s. Use the supplemental information. Initial concentration of N in iron is 0%

Which of the following is true for secondary creep?

  How would the plane strain fracture toughness of a metal be expected to change with rising temperature?

With increasing the number average molecular weight, the tensile strength of polymers typically 

  A three-point bending test is performed on a cylindrical specimen (radius = 5 mm); the distance between support points is 15 mm. Compute the flexural strength if the load at fracture is 7500 N.

A 150 mm long cylindrical sample with a 20 mm diameter is stretched by a force until the diameter is decreased by 0.0023 mm. What is the applied force that causes this deformation? E = 104 GPa and v = 0.34. Assume the deformation is elastic.

A 100 mm long sample with a square cross-section (side length 10 mm) is stretched by  force until the side length is decreased by 0.002 mm. What is the applied force that causes this deformation?  E=80GPa and v=0.33. Assume the deformation is elastic.

DRG Inc. makes many types of guitar strings.  One type of string (Type 008) has fallen out of favor with guitar players and is no longer able to be sold at a profit.  DRG has 1,000 cases of the Type 008 string that they are considering selling at a deep discount or giving to a middle school music program.  Which of the following factors would be relevant in DRG’s decision to either sell the strings at a deeply reduced price or just give the strings away to middle school music programs?    

Jax Co. makes weightlifting shoes. The Champ is a shoe that Jax has made for many years but sales are waning. Jax has developed a new shoe called The Legend that the shoe market is eargerly awaiting, but Jax hasn’t yet began production on the Legend yet. Jax still has 2,500 pairs of The Champ shoes in its warehouse. Jax estimates it would take another four months to sell the remaining stock of The Champ shoe. Jax knows that if they introduce the Legend shoe, it will not be able to sell the remaining inventory of The Champ shoes.  Jax is trying to decide whether to sell the remaining 2,500 pairs of the Champ before producing the Legend, or, beginning production on the Legend immediately so that the Legend shoe can be on sale next week. Indicate whether each item listed below is relevant to the decision of continuing to sell the Champ until the inventory runs out, or, immediately begin the production and sale of the Legend, leaving the remaining inventory of the Champ unsold.  The Champ (old style) The Legend (new style) Selling Price $149 [spc] $219 [spl] Variable cost per unit (materials and labor required to make the shoe) 30 [mc] 45 [ml] Development cost (the total cost of designing the shoe divided by the anticipated number of shoes to be sold) 15 [dc] 19 [dl] Marketing cost (fixed cost incurred to support all marketing, allocated to products based on the budgeted selling price of the products) 4 [mktc] 6 [mktl]  

Atlas Manufacturing is trying to decide between buying a part or continuing to make the part themselves. Which of the following is a qualitative factor that Atlas Manufacturing should consider when deciding whether to buy or make a part? (select all that apply)