Engineering, 26.11.2019 03:31 ShexSmart1646
Answer true of false to the following statements. above its glass transition temperature, a polymer is glassy and brittle. below the glass transition temperature, polymer chains lose their mobility (they are less capable of bending, flexing, raveling, and rotating about covalent bonds along the backbone. the glass transition temperature of a material is normally above its melting temperature. the elastic modulus of a polymer decreases when it is heated above its glass transition temperature
Answers: 3
Engineering, 04.07.2019 18:20, maciemarklin79981
A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?
Answers: 3
Engineering, 06.07.2019 03:20, crazylife77
What is the strain energy stored in a solid uniformly circular shaft of length 3.0 m and diameter 120 mm when subject to pure torsion if the maximum shear stress is 40 mpa? g-80gpa
Answers: 1
Answer true of false to the following statements. above its glass transition temperature, a polymer...
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