The proportioning of a concrete mixture has resulted in the following SSD weights. Material WSSD (Ib/yd^3) Other Info
Cement 739 Gs=3.15
Rock (coarse) 1550 Gs(SSD)= 2.7, % tot= 6%, % abs= 0.8%
Sand (fine) ? SSD =2.6, % tot=1.4%, % abs= 1.4%
Water 325
Air ___ % Air =7%

1. What is the volume of sand required?

a. 6.45 ft^3
b. 6.94 ft^3
c. 8.83 ft^3
d. 9.66 ft^3

2. What is the batch water weight?

a. 230 lbs
b. 245 lbs
c. 325 lbs
d. 405 lbs

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Refrigerant 134a enters an insulated compressor operating at steady state as saturated vapor at -26°c with a volumetric flow rate of 0.18 m3/s. refrigerant exits at 9 bar, 70°c. changes in kinetic and potential energy from inlet to exit can be ignored. determine the volumetric flow rate at the exit, in m3/s, and the compressor power, in kw.

Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.