Two CU triaxial tests are performed on a clay specimen. At failure, the results are: Test 1: σ3 = 30 kPa, P = 0.45 kN, Area of specimen = 0.01 m2 , u = 10 kPa Test 2: σ3 = 60 kPa, P = 0.70 kN, Area of specimen = 0.01 m2 , u = 20 kPa a) Find σ1, σ3, σ'1, and σ'3 at failure for both tests. b) Draw the effective stress Mohr's circle for both tests and draw the Mohr-Coulomb failure envelope for the clay. What are ' and c' for the clay? Write the equation for the MohrCoulomb failure envelope.

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?