Answer:
Explanation:
Given
Temperature of solid ![T=500\ K](https://tex.z-dn.net/?f=T%3D500%5C%20K)
Einstein Temperature ![T_E=300\ K](https://tex.z-dn.net/?f=T_E%3D300%5C%20K)
Heat Capacity in the Einstein model is given by
![C_v=3R\left [ \frac{T_E}{T}\right ]^2\frac{e^{\frac{T_E}{T}}}{\left ( e^{\frac{T_E}{T}}-1\right )^2}](https://tex.z-dn.net/?f=C_v%3D3R%5Cleft%20%5B%20%5Cfrac%7BT_E%7D%7BT%7D%5Cright%20%5D%5E2%5Cfrac%7Be%5E%7B%5Cfrac%7BT_E%7D%7BT%7D%7D%7D%7B%5Cleft%20%28%20e%5E%7B%5Cfrac%7BT_E%7D%7BT%7D%7D-1%5Cright%20%29%5E2%7D)
![e^{\frac{3}{5}}=1.822](https://tex.z-dn.net/?f=e%5E%7B%5Cfrac%7B3%7D%7B5%7D%7D%3D1.822)
Substitute the values
![C_v=3R\times (\frac{300}{500})^2\times (\frac{1.822}{(1.822-1)^2})](https://tex.z-dn.net/?f=C_v%3D3R%5Ctimes%20%28%5Cfrac%7B300%7D%7B500%7D%29%5E2%5Ctimes%20%28%5Cfrac%7B1.822%7D%7B%281.822-1%29%5E2%7D%29)
![C_v=3R\times \frac{9}{25}\times \frac{1.822}{(0.822)^2}](https://tex.z-dn.net/?f=C_v%3D3R%5Ctimes%20%5Cfrac%7B9%7D%7B25%7D%5Ctimes%20%5Cfrac%7B1.822%7D%7B%280.822%29%5E2%7D)
Answer:
1. High friction
2. High extrusion temperature
Explanation:
Surface cracking on extruded products are defects or breakage on the surface of the extruded parts. Such cracks are inter granular.
Surface cracking defects arises from very high work piece temperature that develops cracks on the surface of the work piece. Surface cracking appears when the extrusion speed is very high, that results in high strain rates and generates heat.
Other factors include very high friction that contributes to surface cracking an d chilling of the surface of high temperature billets.
Answer: The energy system related to your question is missing attached below is the energy system.
answer:
a) Work done = Net heat transfer
Q1 - Q2 + Q + W = 0
b) rate of work input ( W ) = 6.88 kW
Explanation:
Assuming CPair = 1.005 KJ/Kg/K
<u>Write the First law balance around the system and rate of work input to the system</u>
First law balance ( thermodynamics ) :
Work done = Net heat transfer
Q1 - Q2 + Q + W = 0 ---- ( 1 )
rate of work input into the system
W = Q2 - Q1 - Q -------- ( 2 )
where : Q2 = mCp T = 1.65 * 1.005 * 293 = 485.86 Kw
Q2 = mCp T = 1.65 * 1.005 * 308 = 510.74 Kw
Q = 18 Kw
Insert values into equation 2 above
W = 6.88 Kw
Answer:
t = 6179.1 s = 102.9 min = 1.7 h
Explanation:
The energy provided by the resistance heater must be equal to the energy required to boil the water:
E = ΔQ
ηPt = mH
where.
η = efficiency = 84.5 % = 0.845
P = Power = 2.61 KW = 2610 W
t = time = ?
m = mass of water = 6.03 kg
H = Latent heat of vaporization of water = 2.26 x 10⁶ J/kg
Therefore,
(0.845)(2610 W)t = (6.03 kg)(2.26 x 10⁶ J/kg)
![t = \frac{1.362\ x\ 10^7\ J}{2205.45\ W}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B1.362%5C%20x%5C%2010%5E7%5C%20J%7D%7B2205.45%5C%20W%7D)
<u>t = 6179.1 s = 102.9 min = 1.7 h</u>