A minimum compressive strength of at least 4500 psi, after 180 days of curing (aging) time, is specified for the concrete used in a bridge project. It is further specified that a water-cement ratio of 0.5, a slump of 1.5 inch, and an air entrainment of 4% be used. To provide a curing protocol that will produce the required compression strength, the concrete should be moist-cured and then cured: A. In air after 3 days B. In air after 7 days C. In air after 14 days D. A compressive strength of at least 4500 psi cannot be attained

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Have a greater impact on maintenance productivity than any other support group. (clo5) a)-the top management b)-inventory and purchasing c)-sub-contracting d)-cmms

Agas mixture consists of 8 kmol of h2 and 2 kmol of n2. determine the mass of each gas and the apparent gas constant of the mixture.