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3 years ago

Air entrainment is used in concrete to: __________.

Engineering

1 answer:

Dahasolnce [82]3 years ago

5 0

The answer is number 2) Increase the resistance of the concrete to freeze-thaw damage.

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Ball Throws

professor190 [17]

Jake because the more speed, the more kinetic energy which = force.

3 0

3 years ago

Steam enters a turbine operating at steady state with a mass flow of 10 kg/s, a specific enthalpy of 3100 kJ/kg, and a velocity

likoan [24]

Answer:7989.86KW

Explanation:

Given data

$h_1$ =3100 KJ/kg

$\dot{m}$ =10kg/s

$V_1$ =30m/s

$Z_1$ =3m

$h_2$ =2300KJ/kg

$V_2$ =45m/s

$Z_2$ =0

using steady flow energy equation which is

$\dot{m}$ $\left (h_1+gZ_1+\frac{V_1^2}{g}\right )$ + $\dot{Q}$ = $\dot{m}$ $\left (h_2+gZ_2+\frac{V_2^2}{g}\right )\+$ $\dot{W}$

$10\left (3100+\frac{9.81\times 3}{1000}+\frac{30^2}{9.81\times 1000}\right )$ + $\dot{Q}$ = $10\left (2300+\frac{9.81\times 0}{1000}+\frac{45^2}{9.81\times 1000}\right )$ + $\dot{W}$

$10\left ( \left ( 3100-2300\right )+\frac{30^{2}-45^{2}}{2\times 9.81\times 1000}+\frac{9.82\times 3}{1000}\right )$ - $1.1\times 10$ = $\dot{W}$

$\dot{W}$ =7989.8673 KW

7 0

4 years ago

A 8-core machine has 4 times the performance of a single-core machine of the same frequency. Performance is proportional to freq

tankabanditka [31]

Answer: The 8-core machine saves 87.5% of the dynamic power.

Explanation:

Let Fold = f , Vold = V , Cold = Capacitance

Old Dynamic power = Cold × (Vold × Vold) × f

therefore for the 8-core machine

Fnew / Fold = 1/4

Fnew = Fold/4

we were told that Voltage decreases proportional to frequency,

Vnew / Vold = 1/4

Vnew = V / 4

So New Capacitance will be;

Cnew = Cold

Thus, New Dynamic power = 8 × Cnew × ( Vnew × Vnew ) × Fnew

= 8 × Cold × (Vold × Vold/16) × ( f/4 )

= 8 × ( Cold ) × ( Vold × Vold ) × ( f ) / 64

= (Old Dynamic Power) / 8

therefore

Old Dynamic Power / New Dynamic Power = 8

Thus, Percentage of power saved will be;

Percentage power saved = 100 × ( Old Dynamic Power - New Dynamic Power ) / Old Dynamic Power

= 100 × (8-1) / 8

= 87.5 %

Therefore The 8-core machine saves 87.5% of the dynamic power.

6 0

4 years ago

An undeformed specimen of some alloy has an average grain diameter of 0.050 mm. You are asked to reduce its average grain diamet

aleksandrvk [35]

Answer:

Yes it is possible

Explanation:

Procedures to be taken:

Step 1:

I will deform the specimen, that is, I will subject the specimen to plastic deformation at room temperature.

Step 2:

Also, I will anneal the deformed specimen at a high temperature.

Step 3:

Then, recrystallize the annealed specimen

Step 4:

Finally, I will facilitate the grain growth until the average grain diameter becomes 0.02mm.

5 0

3 years ago

Two gage marks are placed exactly 250 mm apart on a 12-mm-diameter aluminum rod with E 5 73 GPa and an ultimate strength of 140

NNADVOKAT [17]

Answer:

81.76 N/mm² ( MPa), 1.71233

Explanation:

Modulus of elasticity = stress / strain

stress = modulus of elastic × strain

strain = ΔL / L = 250.28 mm - 250 mm / 250 mm = 0.00112

Modulus of elasticity E = 73 GPa = 73 × 10³ MPa where 1 MPa = 1 N/mm²

E = 73 × 10³N/mm²

stress = 73 × 10³N/mm²× 0.00112 = 81.76 N/mm² ( MPa)

b) Factor of safety = maximum allowable stress / induced stress = 140 MPa / 81.76 MPa = 1.71233

8 0

4 years ago