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3 years ago

6

Ferroconcrete is reinforced concrete that combines concrete and ________. A. Lead c. Copper b. Iron d. Aluminum.

1 answer:

Sveta_85 [38]3 years ago

6 0

Answer:

b. Iron

Explanation:

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Consider the gas carburizing of a gear of 1018 steel (0.18 wt %) at 927°C (1700°F). Calculate the time necessary to increase the

Artyom0805 [142]

Answer:

t = 56.6 min

Explanation:

Fick's second law is used to calculate time required for diffusion

$\frac{C_s - C_x}{C_s - C_o} = erf( \frac{x}{2\sqrt{Dt}})$

where

$C_s$ = 1.15%

$C_o$ = 0.18%

$C_x$ = 0.35%

x = 0.40 mm = 0.0004 n

$D_{927^O\ C } = 1.28\times 10^{11} m^2/s$

therefore we ahave

$\frac{1.15-0.35}{1.15- 0.18} = erf[\frac{4\times 10^{-4}}{2\sqrt{1.28\times 10^{-11} t}}]$

$0.8247 = erf [\frac{55.90}{\sqrt{t}}] = erf z$

from error function table we hvae following result

for erf z z

0.8209 0.95

0.8247 x

0.8427 1

therefore

$\frac{0.8247 - 0.8209}{0.8427 - 0.8209} = \frac{x - 0.95}{1 - 0.95}$

x = 0.959

thus

$z = \frac{55.90}{\sqrt{t}}$

$0.959 = \frac{55.90}{\sqrt{t}}$

t = 56.6 min

5 0

3 years ago

The ruler game, HELPPPP PLS

Rasek [7]

Answer:

C

Explanation:

8 0

3 years ago

Read 2 more answers

Liquid water is fed to a boiler at 24°C and 10 bar is converted at a constant pressure to saturated steam.

zepelin [54]

We can find the change in the enthalpy through the tables A5 for Saturated water, pressure table.

For 1bar=1000kPa:

$T_{sat}=179.88\°c$

$H_{fg} = 2014.6kJ/kg$

$c_p=4.18 kJkg^{-1}{K^{-1}$

$\nu_g = 0.19436m^3/kg$

Replacing,

$\Delta h = h_{fg}+c_p(T_{sat}-T_{inlet})$

$\Delta h = 2014.6+4.18(179.88-24)$

$\Delta h=2666.17kJ/kg$

With the specific volume we know can calculate the mass flow, that is

$\dot{m}=\frac{\frac{15000}{3600}}{0.19436}$

$\dot{m} = 21.4378kg/s$

Then the heat required in input is,

$Q=\dot{m}\Delta h$

$Q=21.4378*2666.17$

$Q=57157.036kW$

With the same value required of 15000m^3/h, we can calculate the velocity of the water, that is given by,

$V= \frac{\dotV}{A}$

$V = \frac{\frac{15000}{3600}}{\pi /4 *(0.15)^2}$

$V=235.79m/s$

Finally we can apply the steady flow energy equation, that is

$\dot{m}(h_1+\frac{V^2}{2000})+Q = \dot{m}h_2$

Re-arrange for Q,

$Q=\dot{m}(h_2-h_1-\frac{V^2}{2000})$

$Q=\dot{m}(\Delta h-\frac{V^2}{2000})$

$Q= (21.4378)(2666.17-\frac{235.79^2}{2000})$

$Q= 56560.88kW$

We can note that consider the Kinetic Energy will decrease the heat input.

4 0

3 years ago

Air within a piston cylinder assembly executes a Carnot refrigeration cycle between hot and cold reservoirs at TH=600 K and TC=3

Nataly [62]

Answer:

See explaination

Explanation:

for a reverse carnot cycle T-S diagram is a rectangle which i have shown

net work for a complete cycle must be equal to net heat interaction.

Kindly check attachment for the step by step solution of the given problem.

5 0

3 years ago

Air flows through a 0.25-m-diameter duct. At the inlet the velocity is 300 m/s, and the stagnation temperature is 90°C. If the M

Naddika [18.5K]

Answer:

a. 318.2k

b. 45.2kj

Explanation:

Heat transfer rate to an object is equal to the thermal conductivity of the material the object is made from, multiplied by the surface area in contact, multiplied by the difference in temperature between the two objects, divided by the thickness of the material.

See attachment for detailed analysis

7 0

3 years ago