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3 years ago

15

For some transformation having kinetics that obey the Avrami equation (Equation 11.17), the parameter n is known to have a value

of 2.1. If, after 112 s, the reaction is 50% complete, how long (total time) will it take the transformation to go to 90% completion

1 answer:

Nastasia [14]3 years ago

5 0

Explanation:

Below is an attachment containing the solution.

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. Air at 200 C blows over a 50 cm x 75 cm plain carbon steel (AISI 1010) hot plate with a constant surface temperature of 2500 C

MrRissso [65]

Answer:

The inside temperature, $T_{in}$ is approximately 248 °C.

Explanation:

The parameters given are;

Temperature of the air = 20°C

Carbon steel surface temperature 250°C

Area of surface = 50 cm × 75 cm = 0.5 × 0.75 = 0.375 m²

Convection heat transfer coefficient = 25 W/(m²·K)

Heat lost by radiation = 300 W

Assumption,

Air temperature = 20 °C

Hot plate temperature = 250 °C

Thermal conductivity K = 65.2 W/(m·K)

Steady state heat transfer process

One dimensional heat conduction

We have;

Newton's law of cooling;

q = h×A×( $T_s$ - $T_{\infty$ ) + Heat loss by radiation

= 25×0.325×(250 - 20) + 300

= 2456.25 W

The rate of energy transfer per second is given by the following relation;

$P = \dfrac{K \times A \times \Delta T}{L}$

Thermal conductivity K = 65.2 W/(m·K)

Therefore;

$2456.25 = \dfrac{65.2 \times 0.375 \times (250 - T_{in})}{0.02}$

$T_{in} = 250 - \dfrac{2456.25 \times 0.02}{65.2 \times 0.375} = 247.99 ^{\circ}C$

The inside temperature, $T_{in}$ = 247.99 °C ≈ 248 °C.

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4 years ago

Angelina_Jolie [31]

Answer:

The correct option is;

B) Metamorphic Rocks

Explanation:

Zoisite, which is also referred to saualpite, is a metamorphic rock which is a hydroxy sorosilicate mineral formed from other types of rocks such as sedimentary, metamorphic and ingenious rocks in the process of their metamorphism under the presence high temperatures and pressures and mineral fluids which are hot

Zoiste is named after Sigmund Zois by Abraham Gottlob Werner in 1805 when Sigmund Zois sent Abraham Gottlob Werner the mineral specimen from Saualpe in 1805

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3 years ago

What is differentiation

oksian1 [2.3K]

Answer:

the action or process of differentiating or distinguishing between two or more things or people.

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3 years ago

Drivers education - Unit 3

melamori03 [73]

The following scenarios are pertinent to driving conditions that one may encounter. See the following rules of driving.

<h3>What do you do when the car is forced into the guardrail?</h3>

Best response:

I'll keep my hands on the wheel and slow down gradually.
The reason I keep my hands on the steering wheel is to avoid losing control.
This will allow me to slowly back away from the guard rail.
The next phase is to gradually return to the fast lane.
Slamming on the brakes at this moment would result in a collision with the car behind.

Scenario 2: When driving on a wet road and the car begins to slide

Best response:

It is not advised to accelerate.
Pumping the brakes is not recommended.
Even lightly depressing and holding down the brake pedal is not recommended.
The best thing to do is take one foot off the gas pedal.
There should be no severe twists at this time.

Scenario 3: When you are in slow traffic and you hear the siren of an ambulance behind

Best response:

The best thing to do at this moment is to go to the right side of the lane and come to a complete stop.
This helps to keep the patient in the ambulance alive.
It also provide a clear path for the ambulance.
Moving to the left is NOT recommended.
This will exacerbate the situation. If there is no place to park on the right shoulder of the road, it is preferable to stay in the lane.

Learn more about rules of driving. at;

brainly.com/question/8384066

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2 years ago

A furnace wall composed of 200 mm, of fire brick. 120 mm common brick 50mm 80% magnesia and 3mm of steel plate on the outside. I

Liula [17]

Answer:

fire brick / common brick : 1218 °C
common brick / magnesia : 1019 °C
magnesia / steel : 90.06 °C
heat loss: 4644 kJ/m^2/h

Explanation:

The thermal resistance (R) of a layer of thickness d given in °C·m²·h/kJ is ...

R = d/k

so the thermal resistances of the layers of furnace wall are ...

R₁ = 0.200/4 = 0.05 °C·m²·h/kJ

R₂ = 0.120 2.8 = 3/70 °C·m²·h/kJ

R₃ = 0.05/0.25 = 0.2 °C·m²·h/kJ

R₄ = 0.003/240 = 1.25×10⁻⁵ °C·m²·h/kJ

So, the total thermal resistance is ...

R₁ +R₂ +R₃ +R₄ = R ≈ 0.29286 °C·m²·h/kJ

__

The rate of heat loss is ΔT/R = (1450 -90)/0.29286 = 4643.70 kJ/(m²·h)

__

The temperature drops across the various layers will be found by multiplying this heat rate by the thermal resistance for the layer:

fire brick: (4543.79 kJ/(m²·h))(0.05 °C·m²·h/kJ) = 232 °C

so, the fire brick interface temperature at the common brick is ...

1450 -232 = 1218 °C

For the next layers, the interface temperatures are ...

common brick to magnesia = 1218 °C - (3/70)(4643.7) = 1019 °C

magnesia to steel = 1019 °C -0.2(4643.7) = 90.06 °C

_____

<em>Comment on temperatures</em>

Most temperatures are rounded to the nearest degree. We wanted to show the small temperature drop across the steel plate, so we showed the inside boundary temperature to enough digits to give the idea of the magnitude of that.

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3 years ago