Calculate the diffusion current density for the following carrier distributions. For electrons, use Dn = 35 cm2/s and for holes, use Dp = 10 cm2/s. a. ; Jn = b. , at x = 0: Jp (0) = c. , at x = 2.5 µm: Jp (2.5 µm) = d. , at x = 20 µm: Jp (20 µm) = e. , at x = 5 µm: Jn (5 µm) = n (x) = (1010 cm−3 ) 5 μm − x 5 μm

The power source in a certain welding setup generates 3500w that is transferred to the low carbon steel work with a heat transfer factor of 0.85. the melting factor in the operation is 0.45. a continuous fillet weld is to be made with a cross-sectional area of 23 mm2 determine the travel speed at which the welding can be accomplished.