Engineering Answers

According to ASTM C94, are there other tests to be performed to evaluate the suitability of that water? Discuss briefly

The water-cement ratio is important because it influences all of the desirable qualities of concrete. Briefly describe how super high strength concrete (f'c = 15 ksi) can be made?

The water-cement ratio is important because it influences all of the desirable qualities of concrete. Why is the extra water necessary

The water-cement ratio is important because it influences all of the desirable qualities of concrete. What is the minimum water-cement ratio for hydration only?

The water-cement ratio is important because it influences all of the desirable qualities of concrete. What is the typical water-cement ratio for normal strength concrete?

Show that when a Bingham plastic fluid flows under laminar condition through a tube of radius R and length L the volumetric flow rate, Q is given by 4 4 0 0 0 0 ( ) 4 1 1 8 3 3 L R R P P R Q L         −     = − +               Where 0  and R  are the yield stress and shear stress at the tube wall, respectively.

In a gas absorption experiment a viscous fluid flows upward through a small circular tube and then downward in laminar flow on the outside. Set up a momentum balance over a shell of thickness r in the film, as shown in figure 1 (Appendix A). Note that the “momentum in” and “momentum out” arrows are always taken in the positive coordinate direction, even though in this problem the momentum is flowing through the cylindrical surfaces in the negative r direction. i. Show that the velocity distribution in the falling film (neglecting end effects) is 2 2 2 1 2 ln 4 z gR r r v a R R         = − +               ii. Show that the mass rate of flow in the film is given by 2 4 2 4 4 1 4 3 4 ln 8 gR w a a a a   = − + − +     iii. Show that the result in (b) simplifies to the following equation, if the film thickness is very small ( Use a = +  1 , 1   ) 2 3 cos 3 gW w     = , Where W R = 2 and   = R .

A solid sphere of radius R is rotating slowly at a constant angular velocity '  ' in a large body of quiescent fluid as shown in figure 2 (Appendix-I). Develop expressions for the pressure and velocity distributions in the fluid using shell momentum balances (refer figure 3). Also find out the torque required to maintain the motion. Assume that the sphere rotates sufficiently slowly so that one can conveniently use the creeping flow assumption. Appendix-A Figure 1: Velocity distribution and z-momentum Balance for the flow of a falling film on the outside of a circular tube. Figure 2: A slowly rotating sphere in an infinite expanse of fluid Figure 3: Differential Volume Elemen

Find the new location of point G, initially at G = [3 0 -1] If, (i) it is rotated by 60deg. about z-axis and then translated by 3 units along y-axis, and (ii) it is first translated by 3 units along y-axis and then rotated by 60deg bout z-axis. Are the two locations same? Check and justify, whether the final position in two cases is same or different.