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Natasha2012 [34]
3 years ago
12

The diffusion coefficients for species A in metal B are given at two temperatures:

Engineering
1 answer:
Kruka [31]3 years ago
5 0

Answer:

a) 149 kJ/mol, b) 6.11*10^-11 m^2/s ,c) 2.76*10^-16 m^2/s

Explanation:

Diffusion is governed by Arrhenius equation

D = D_0e^{\frac{-Q_d}{RT} }

I will be using R in the equation instead of k_b as the problem asks for molar activation energy

I will be using

R = 8.314\ J/mol*K

and

°C + 273 = K

here, adjust your precision as neccessary

Since we got 2 difusion coefficients at 2 temperatures alredy, we can simply turn these into 2 linear equations to solve for a) and b) simply by taking logarithm

So:

ln(6.69*10^{-17})=ln(D_0) -\frac{Q_d}{R*(1030+273)}

and

ln(6.56*10^{-16}) = ln(D_0) -\frac{Q_d}{R*(1290+273)}

You might notice that these equations have the form of  

d=y-ax

You can solve this equation system easily using calculator, and you will eventually get

D_0 =6.11*10^{-11}\ m^2/s\\ Q_d=1.49 *10^3\ J/mol

After you got those 2 parameters, the rest is easy, you can just plug them all   including the given temperature of 1180°C into the Arrhenius equation

6.11*10^{-11}e^{\frac{149\ 000}{8.143*(1180+273)}

And you should get D = 2.76*10^-16 m^/s as an answer for c)

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Define the difference between elastic and plastic deformation in terms of the effect on the crystal lattice structure.
grin007 [14]

Answer:

Elastic Deformation:

  • Elastic deformation is due to the elasticity of the body i.e., the deformation disappears on removal of external forces and the lattice regain its original structure.
  • This type of deformation is temporary  in nature.
  • This type of deformation depends mainly on the chemical bonding of the substance.
  • It occurs due to bending or stretching of chemical bond under applied stress where atoms do not slip pass over each other.
  • It is a reversible process.

Plastic Deformation:

  • Plastic deformation is due to the plasticity of the body i,e., the structure can be easily shaped or molded .
  • This type of deformation is permanent  in nature.
  • This type of deformation occurs mainly due to breakage of chemical bonds(limited in number) between constituent atoms.
  • Atoms may slip pass each other causing dislocation of atoms , resulting in permanent deformation even after stress is removed.
  • It is an irreversible process.
3 0
3 years ago
A single lane highway has a horizontal curve. The curve has a super elevation of 4% and a design speed of 45 mph. The PC station
andreyandreev [35.5K]

Answer: 112 + 19.27

Explanation:

Super elevation is an inward transverse slope provided through out the length of the horizontal curve which ends up serving as a counteract to the centrifugal force and checks tendency of overturning. It changes from infinite radius to radius of a transition curve.

Super curve elevation (e) = 4%

4/100= 0.04

e= V^2/gR

Make R the subject of the formula.

egR= V^2

R= V^2/eg

V= 45mph

=45 × 0.44704m/s

=20.1168m/s

g (force due to gravity) =9.81

Therefore,

R= (20.1168)^2/9.81 × 0.04

= 1031.31m

Tangent Length( T) = PI - PC

Tangent Length= 10875 - 10500

=375m

T= R Tan(I/2)

375= 1031.31 × Tan(I/2)

I= 39.96

Also,

L= πRI/180

= 719.27m

Station PT= Stat PC+ L

10500 + 719.27

=11219.27

=112 + 19.27

6 0
3 years ago
Convert 0.025 in into mm.
malfutka [58]

Answer:  0.025 in = 0.065 mm

Explanation:  To convert the value in inches to mm we have to multiply the inches by the conversion factor 25.4.

So, 0.025 × 25.4 = 0.065 mm (millimeter)

Conversion formula for calculation in (inch) into mm is:

      Value in mm = Value in in × 25.4

  • One inch is equal to the 25.4 mm.
3 0
3 years ago
Read 2 more answers
If you are sampling a 50Hz signal, what is the minimum sampling rate necessary to prevent aliasing?Why?
horsena [70]

Answer:

100Hz

Explanation:

The minimum sampling rate to prevent aliasing is at least double your sample frequency.

50*2 = 100Hz

This is called the Nyquist Sampling Rate if you wanna learn more about it.

6 0
3 years ago
You have designed a treatment system for contaminant Z. The treatment system consists of a pipe that feeds into a CSTR. The pipe
IRISSAK [1]

Answer:

0.667 per day.

Explanation:

Our values here are

Q=10m^3/dV_p=15m^3\\V_{cstr}=60m^3\\c_p=2500mg/L\\c_{cstr}=500mg/L

Degradation constant=k and is unknown.

We calculate the concentration through the formula,

cc_{cstr} =\frac{c_{in}}{1+K(V/Q)} \\cc_{cstr}=\frac{c_p}{1+K*\frac{V_{csrt}}{Q}}

Replacing values we have

1+k(\frac{60}{10})=\frac{2500}{500}\\1+k=5\\K(6)=5-1\\K(6)=4\\K=2/3\\K=0.667/day

That is the degradation constant of Z-contaminant

3 0
3 years ago
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