1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ELEN [110]
3 years ago
8

An alloy is evaluated for potential creep deformation in a short-term laboratory experiment. The creep rate (ϵ˙) is found to be

1% per hour at 800 ∘C and 5.5×10−2% per hour at 700 ∘C. Calculate the activation energy for creep in this temperature range.
Engineering
1 answer:
cupoosta [38]3 years ago
3 0

Answer:

Activation energy for creep in this temperature range is Q = 252.2 kJ/mol

Explanation:

To calculate the creep rate at a particular temperature

creep rate, \zeta_{\theta} = C \exp(\frac{-Q}{R \theta} )

Creep rate at 800⁰C, \zeta_{800} = C \exp(\frac{-Q}{R (800+273)} )

\zeta_{800} = C \exp(\frac{-Q}{1073R} )\\\zeta_{800} = 1 \% per hour =0.01\\

0.01 = C \exp(\frac{-Q}{1073R} ).........................(1)

Creep rate at 700⁰C

\zeta_{700} = C \exp(\frac{-Q}{R (700+273)} )

\zeta_{800} = C \exp(\frac{-Q}{973R} )\\\zeta_{800} = 5.5 * 10^{-2}  \% per hour =5.5 * 10^{-4}

5.5 * 10^{-4}  = C \exp(\frac{-Q}{1073R} ).................(2)

Divide equation (1) by equation (2)

\frac{0.01}{5.5 * 10^{-4} } = \exp[\frac{-Q}{1073R} -\frac{-Q}{973R} ]\\18.182= \exp[\frac{-Q}{1073R} +\frac{Q}{973R} ]\\R = 8.314\\18.182= \exp[\frac{-Q}{1073*8.314} +\frac{Q}{973*8.314} ]\\18.182= \exp[0.0000115 Q]\\

Take the natural log of both sides

ln 18.182= 0.0000115Q\\2.9004 = 0.0000115Q\\Q = 2.9004/0.0000115\\Q = 252211.49 J/mol\\Q = 252.2 kJ/mol

You might be interested in
What are some common work contexts for Licensing Examiners and Inspectors? Select four options.
Akimi4 [234]

According to O*NET, the common work contexts for Licensing Examiners and Inspectors include:

  1. Telephone
  2. Face-to-face discussions
  3. Contact with others
  4. Importance of being exact or accurate.

O*NET is an acronym for occupational information network and it refers to a free resource center or online database that is updated from time to time with several occupational definitions, so as to help the following categories of people understand the current work situation in the United States of America:

  • Workforce development professionals
  • Students
  • Human resource (HR) managers
  • Job seekers
  • Business firms

On O*NET, work contexts are typically used to describe the physical and social elements that are common to a particular profession or occupational work. Also, the less common work contexts are listed toward the bottom while common work contexts are listed toward the top.

According to O*NET, the common work contexts for Licensing Examiners and Inspectors include:

1. Telephone

2. Face-to-face discussions

3. Contact with others

4. Importance of being exact or accurate.

Read more on work contexts here: brainly.com/question/22826220

6 0
3 years ago
Read 2 more answers
A 20-cm-long rod with a diameter of 0.250 cm is loaded with a 5500 N weight. If the diameter decreases to 0.210 cm, determine th
ss7ja [257]

Answer:

1561.84 MPa

Explanation:

L=20 cm

d1=0.21 cm

d2=0.25 cm

F=5500 N

a) σ= F/A1= 5000/(π/4×(0.0025)^2)= 1018.5916 MPa

lateral strain= Δd/d1= (0.0021-0.0025)/0.0025= -0.16

longitudinal strain (ε_l)= -lateral strain/ν = -(-0.16)/0.3

(assuming a poisson's ration of  0.3)

ε_l =0.16/0.3 = 0.5333

b) σ_true= σ(1+ ε_l)= 1018.5916( 1+0.5333)

σ_true = 1561.84 MPa

ε_true = ln( 1+ε_l)= ln(1+0.5333)

ε_true= 0.4274222

The engineering stress on the rod when it is loaded with a 5500 N weight is 1561.84 MPa.

7 0
3 years ago
Velocity components in an incompressible flow are: v = 3xy + x^2 y: w = 0. Determine the velocity component in the x-direction.
cupoosta [38]

Answer:

Velocity component in x-direction u=-\frac{3}{2}x^2-\frac{1}{3}x^3.

Explanation:

   v=3xy+x^{2}y

We know that for incompressible flow

   \frac{\partial u}{\partial x}+\frac{\partial v}{\partial y}=0

\frac{\partial v}{\partial y}=3x+x^{2}

So   \frac{\partial u}{\partial x}+3x+x^{2}=0

\frac{\partial u}{\partial x}= -3x-x^{2}

By integrate with respect to x,we will find

u=-\frac{3}{2}x^2-\frac{1}{3}x^3+C

So the velocity component in x-direction u=-\frac{3}{2}x^2-\frac{1}{3}x^3.

3 0
3 years ago
A tool chest has 650 N weight that acts through the midpoint of the chest. The chest is supported by feet at A and rollers at B.
erica [24]

Answer:

the value of horizontal force P is 170.625 N

the value of horizontal force at P = 227.5 N is that the block moves to right and this motion is due to sliding.

Explanation:

The first diagram attached below shows the free body diagram of the tool chest when it is sliding.

Let start out by calculating the friction force

F_f= \mu N_2

where :

F_f = friction force

\mu = coefficient of friction

N_2 = normal friction

Given that:

\mu = 0.3

F_f = 0.3 N_2

Using the equation of equilibrium along horizontal direction.

\sum f_x = 0

P - F_f = 0

P = 0.3 N_2   ----- Equation (1)

To determine the moment about point B ; we have the expression

\sum M_B  = 0

0 = N_2*70-W*35-P*100

where;

P = horizontal force

N_2 = normal force at support A

W = self- weight of tool chest

Replacing W = 650 N

0 = N_2*70-650*35-100*P

P = \frac{70 N_2-22750}{100} ----- equation (2)

Replacing  \frac{70 N_2-22750}{100}  for P in equation (1)

\frac{70N_2 -22750}{100} =0.3 N_2

N_2 = \frac{22750}{40}N_2 = 568.75 \ N

Plugging the value of N_2 = 568.75 \ N in equation (2)

P = \frac{70(568.75)-22750}{100} \\ \\ P = \frac{39812.5-22750}{100}  \\ \\ P = \frac{17062.5}{100}

P =170.625 N

Thus; the value of horizontal force P is 170.625 N

b)  From the second diagram attached the free body diagram; the free body diagram of the tool chest when it is tipping about point A is also shown below:

Taking the moments about point A:

\sum M_A = 0

-(P × 100)+ (W×35) = 0

P = \frac{W*35}{100}

Replacing 650 N  for W

P = \frac{650*35}{100}

P = 227.5 N

Thus; the value of horizontal force P, when the tool chest tipping about point A is 227.5 N

We conclude that the motion will be impending for the lowest value when P = 170.625 N and when P= 227.5 N

However; the value of horizontal force at P = 227.5 N is that the block moves to right and this motion is due to sliding.

5 0
3 years ago
java Your program class should be called RomanNumerals Write a program that asks the user to enter a number within the range of
Ann [662]

Answer:

// Scanner class is imported to allow program

// receive input

import java.util.Scanner;

// RomanNumerals class is defined

public class RomanNumerals {

   // main method that signify beginning of program execution

   public static void main(String args[]) {

       // Scanner object scan is created

       // it receive input via keyboard

       Scanner scan = new Scanner(System.in);

       // Prompt is display asking the user to enter number

       System.out.println("Enter your number: ");

       // the user input is stored at numberOfOrder

       int number = scan.nextInt();

     

           // switch statement which takes number as argument

           // the switch statement output the correct roman numeral

           // depending on user input

          switch(number){

           case 1:

               System.out.println("I");

               break;

           case 2:

               System.out.println("II");

               break;

           case 3:

               System.out.println("III");

               break;

           case 4:

               System.out.println("IV");

               break;

           case 5:

               System.out.println("V");

               break;

           case 6:

               System.out.println("VI");

               break;

           case 7:

               System.out.println("VII");

               break;

           case 8:

               System.out.println("VIII");

               break;

           case 9:

               System.out.println("IX");

               break;

           case 10:

               System.out.println("X");

               break;

           // this part is executed if user input is not between 1 to 10

           default:

               System.out.println("Error. Number must be between 1 - 10.");

     }

   }

}

Explanation:

The program is well commented. A sample image of program output is attached.

The switch statement takes the user input (number) as argument as it goes through each case block in the switch statement and match with the corresponding case to output the roman version of that number. If the number is greater 10 or less than 1; the default block is executed and it display an error message telling the user that number must be between 1 - 10.

6 0
3 years ago
Read 2 more answers
Other questions:
  • What is the difference between absolute and gage pressure?
    11·1 answer
  • In a fluid power system, if energy is not transferred to work, what form does it take?
    6·1 answer
  • What happens to a commercial airline at cruising altitude if the pilot does not touch the throttles?
    12·1 answer
  • A 0.25" diameter A36 steel rivet connects two 1" wide by .25" thick 6061-T6 Al strips in a single lap shear joint. The shear str
    12·1 answer
  • Harlin is designing a new car engine that does not create pollution. Which technological design factor is probably the most
    8·1 answer
  • In your opinion...
    5·1 answer
  • Define Mechanism and mechanics.​
    15·2 answers
  • Jade wanted to test the effect of ice on the weathering of rocks. She filled two containers with gypsum and placed a water ballo
    12·1 answer
  • A 1020 Cold-Drawn steel shaft is to transmit 20 hp while rotating at 1750 rpm. Calculate the transmitted torque in lbs. in. Igno
    6·1 answer
  • Given the inherent costs of regulation it is safe to say that there is always a negative economic impact associated with regulat
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!