ENGINEERING COLLEGE

Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the reheat stage for a 100-mm-thick steel plate ( 7830 kg/m3 , c 550 J/kg K, k 48 W/m K), which is initially at a uniform temperature of Ti 200 C and is to be heated to a minimum temperature of 550 C. Heating is effected in a gas-fired furnace, where products of combustion at T 800 C maintain a convection coefficient of h 250 W/m2 K on both surfaces of the plate. How long should the plate be left in the furnace

Answers

Answer 1
Answer:

Answer:

T = 858.25 s

Explanation:

Given data:

Reheat stage for a 100-mm-thick steel plate ( 7830 kg/m3,  c 550 J/kg K, k 48 W/m K),

initial uniform temperature ( Ti ) = 200 c

Final temperature = 550 c

convection coefficient  = 250 w/m^2 k

products combustion temp = 800 c

calculate how long the plate should be left in the furnace ( to attain 550 c )

first calculate/determine the Fourier series Number ( Fo )

(T_(0)-T_(x) )/(T_(1)-T_(x) ) = C_(1) e^{(-0.4888^(2)*Fo )}

= 0.4167 = 1.0396e^(-0.4888*Fo)

therefore Fo =  3.8264

Now determine how long the plate should be left in the furnace

Fo = ((k)/(pc_(p) ) ) ( (t)/((L/2)^2) )

k = 48

p = 7830

L = 0.1

Input the values into the relation and make t subject of the formula

hence t = 858.25 s

Related Questions

When considering free energy change, biochemists usually define a standard state, the biochemical standard state, which is modified from the chemical standard state to fit biochemical applications. Determine which of the phrases describe the biochemical standard state, the chemical standard state, or both.
Why do we care about a material's ability to resist torsional deformation?(A) Because the angle of twist of a material is often used to predict its shear toughness(B) Because rotating shafts are used in engineering applications(C) We don't care - simply an academic exercise.(D) Because it can determine G and inform us of a materials ability to resist shear deformation
How much heat is lost through a 3’× 5' single-pane window with a storm that is exposed to a 60°F temperature differential?A. 450 Btu/hB. 900 Btu/hC. 1350 Btu/hD. 1800 Btu/h
An activated sludge plant is being designed to handle a feed rate of 0.438 m3 /sec. The influent BOD concentration is 150 mg/L and the cell concentration (MLVSS) is 2,200 mg/L. If you wish to operate the plant with a food-to-microorganism ratio of 0.20 day-1 , what volume of aeration tank should you use? Please give your answer in m3 .
Assignment 1: Structural Design of Rectangular Reinforced Concrete Beams for Bending Perform structural design of a rectangular reinforced concrete beam for bending. The beam is simply supported and has a span L=20 feet. In addition to its own weight the beam should support a superimposed dead load of 0.50 k/ft and a live load of 0.65 k/ft. Use a beam width of 12 inches. The depth of the beam should satisfy the ACI stipulations for minimum depth and be proportioned for economy. Concrete compressive strength f’c = 4,000 psi and yield stress of reinforcing bars fy = 60,000 psi. Size of stirrups should be chosen based on the size of the reinforcing bars. The beam is neither exposed to weather nor in contact with the ground, meaning it is subjected to interior exposure.• Use the reference on "Practical Considerations for Rectangular Reinforced Concrete Beams" • Include references to ACI code – see slides from second class • Include references to Tables from Appendix A • Draw a sketch of the reinforced concrete beam showing all dimensions, number and size of rebars, including stirrups.

Webster is giving a speech on the benefits of moving toward the use of windmill energy instead of having to rely on fossil fuels. Most likely, he will select which method of arrangement?

Answers

Answer:

the netuon arrangment

Explanation:

Which of the following results from the fact that skip signals refracted from the ionosphere are elliptically polarized?A. Digital modes are unusable

B. Either vertically or horizontally polarized antennas may be used for transmission or reception

C. FM voice is unusable

D. Both the transmitting and receiving antennas must be of the same polarization

Answers

Answer:

B

Explanation:

The fact that skip signals refracted from the ionosphere are elliptically polarized is a result of either vertically or horizontally polarized antennas may be used for transmission or reception.

If you are pouring a large concrete slab and wish to avoid random cracks caused by shrinkage, you would likely provideA. expansion joints
B. isolation joints
C. control joints
D. construction joints

Answers

If you are pouring a large concrete slab and wish to avoid random cracks caused by shrinkage, you would likely provide Control joints. The correct answer would be C.

Control joints are used to prevent random cracks from forming in large concrete slabs caused by shrinkage. These joints are placed at strategic locations in the slab to allow for the concrete to expand and contract without cracking. Expansion joints, on the other hand, are used to separate concrete from other structures or materials, and isolation joints are used to separate different sections of concrete.

Construction joints are used to connect two different pours of concrete. Therefore, the best option for preventing random cracks caused by shrinkage would be to use control joints.

Learn more about Control joints:

brainly.com/question/1992029

#SPJ11

A 15. μF capacitor is connected to a 50. V battery and becomes fully charged. The battery is removed and a slab of dielectric that completely fills the space between the plates is inserted. If the dielectric has a dielectric constant of 5.0, what is the voltage across the capacitor's plates after the slab is inserted?

Answers

Answer:

voltage across the capacitor's is 75 μF

Explanation:

given data

capacitor = 15 μF

voltage = 50V

dielectric constant k = 5

to find out

voltage across the capacitor's

solution

we will find here voltage across the capacitor's  by this formula

voltage across the capacitor's  = kC_(o)

here k is 5 and C_(o) = 15

put these value we get

voltage across the capacitor's  = kC_(o)

voltage across the capacitor's  = 5 ( 15 )  = 75 μF

so voltage across the capacitor's is 75 μF

A test bottle containing just seeded dilution water has its DO level drop by 0.8 mg/L in a 5-day test. A 300 mL BOD bottle filled with 30 mL of wastewater and the rest with seeded dilution water experiences a drop of 7.3 mg/L in the same period (5-day). Calculate the BOD5 of the wastewater.

Answers

Answer:

BOD_5 = =65.8 mg/l

Explanation:

dilution water DO level = 0.8 m/l

BOD level drop to 7.3 mg/l

we know that BOD at 5th day can be clculated by using following relationBOD_5 = ((D_1 -D_2) -(B_1-B_2)(1-P))/(P)

D_1 -D_2 - DO drop in BOD bottle

B_1-B_2 - dilution water drop

P= 30/300 = 0.1

BOD_5 = ((7.3) -(0.8)(1-0.1))/(0.1)

BOD_5 = =65.8 mg/l

In a TDM communication example, 15 voice signals are badlimited to 5kHz and transmitted simultaneously using PAM. What is a preliminary estimate for the required system bandwidth?(a) 10 kHz
(b) 75 kHz
(c) 80 kHz
(d) 160 kHz
(e) None of the above.

Answers

Answer:

Option D

160 kHz

Explanation:

Since we must use at least one synchronization bit, total message signal is 15+1=16

The minimum sampling frequency, fs=2fm=2(5)=10 kHz

Bandwith, BW required is given by

BW=Nfs=16(10)=160 kHz
Other Questions
If new research showed that the standard heights for crest vertical curve design were H1=3.0 ft and H2=1.5 ft, respectively, by what percent would the minimum length of curvature increase or decrease for a crest curve with a stopping sight distance of 500 ft and grades of +3% and -2%, respectively.
One piece of evidence that supports the Theory of Plate Tectonics is the discovery of what in both South America and Africa? The ancient atmosphere in both places was identical. The rates of weathering of rock are similar. Fossil remains of the same land-dwelling animal. Plants on both continents have similar flowers.
Young students show a preference for which modality?
A circuit contains a 40 ohm resistor and a 60 ohms resistor connected in parallel. If you test this circuit with a DMM you should read a total resistance