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

Burgers vector is generally parallel to the dislocation line. a)-true b)-false

Ahot wire operates at a temperature of 200°c while the air temperature is 20°c. the hot wire element is a tungsten wire of 5 um diameter and 2 mm in length. plot using excel current, heat transfer and heat generated by the wire for air velocity varying from 1-10 m/s in steps of lm/s? matlab the sensor voltage output, resistance, or assume nu 0.989 re033pr13 take air properties at tr (200°c20°c)/2 = 110°c properties of tungsten: c 0.13 kj/kg. k 3 p 19250 kg/m k (thermal conductivity) = 174 w/m. k

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?