Acomposite wall consists of a 10-cm-thick layer of building brick of thermal conductivity k = 0.7 w/(m • °c) and 3-cm-thick plaster of thermal conductivity k = 0.5 w/(m • °c). an insulating material of thermal conductivity k = 0.08 is to be added to reduce the heat transfer through the wall by 70 percent. determine the thickness of the insulating layer.

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

What precautions should you take to prevent injuries when dealing with heavy loads?

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?