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3 years ago

Define coordination number. How does this differ from atomic packing factor?

Engineering

1 answer:

Fynjy0 [20]3 years ago

4 0

Answer:

Coordination number:

Coordination number can be defined as the number of nearest atoms which touch the central atom.In simple word the number of neighbours atoms which touches a an atoms.

Atomic packing factor :

It is also known as packing efficiency.It is the fraction of volume in a Crystal which is filled by constituent particles.It is always less than 1.Generally it is represented in the fraction.

Ex:

Lets take FCC cubic cell

Coordination number = 12 .

Atomic packing factor = 74%

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A semiconductor is a solid substance that has a conductivity between that of an insulator and that of most metals. (True , False

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The answer is : True

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2 years ago

Consider a cubic workpiece of rigid perfect plastic material with side length lo. The cube is deformed plastically to the shape

Taya2010 [7]

Answer: ε₁+ε₂+ε₃ = 0

Explanation: Considering the initial and final volume to be constant which gives rise to the relation:-

l₀l₀l₀=l₁l₂l₃

$\frac{lo*lo*lo}{l1*l2*l3}=1.0$

taking natural log on both sides

$ln(\frac{(lo*lo*lo)}{l1*l2*l3})=ln(1)$

Considering the logarithmic Laws of division and multiplication :

ln(AB) = ln(A)+ln(B)

ln(A/B) = ln(A)-ln(B)

$ln(\frac{(l1)}{lo})*ln(\frac{(l2)}{lo})*ln(\frac{(l3)}{lo}) = 0$

Use the image attached to see the definition of true strain defined as

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8 0

3 years ago

Generally, final design results are rounded to or fixed to three digits because the given data cannot justify a greater display.

creativ13 [48]

Answer:

(a) 1.90 kpsi

(b) 0.40 kpsi

(d) 0.009

(a) 8 MPa

(b) 1.30 cm⁴

(d) 62.2 MPa

Explanation:

(a) σ = M/Z, where M = 1770 lbf·in and Z = 0.943 in³.

1770/0.943 = 1876.988 lbf/in² = 1.90 kpsi

(b) σ = F/A, where F = 9440 lbf and A = 23.8 in².

9440 /23.8 = 396.639 lbf/in² = 0.4 kpsi

F = 270 lbf

l = 31.5 in.

E = 30 Mpsi

I = 0.154 in.⁴

y = 270×31.5³/(3×30×10⁶×0.154) = 0.61 in.

(d) θ = Tl/(GJ), where T = 9740 lbf·in, l = 9.85 in. G = 11.3 Mpsi, and d = 1.00 in.

J = π·d⁴/32 = π/32 in.⁴

∴ θ = 9740 × 9.85 /(11.3 × 10⁶× π/32) = 0.009

(a) σ = F/wt, where F = 1 kN, w = 25 mm, and t = 5 mm

∴ σ = 1000/(0.025 × 0.005) = 8 MPa

(b) I = bh³/12, where b = 10 mm and h = 25 mm.

10×25³/12 = 1.30 cm⁴

I = π × 25.4⁴/64 = 2.04 cm⁴

(d) τ = 16×T/(π×d³), where T = 25 N·m, and d = 12.7 mm.

16×25/(π×0.0127³) = 62.2 MPa.

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3 years ago

Why would the shear stress be considered as the momentum flux.

oksano4ka [1.4K]

Answer:

A fluid flowing along a flat plate will stick to it at the point of contact

Explanation:

and this is known as the no-slip condition. ... This is the precise reason why shear stress in a fluid can also be interpreted as the flux of momentum.

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2 years ago

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Airida [17]

Answer:

As the x-values go to negative infinity, the function’s values go to positive infinity.

Explanation:

if the ans choices are:

As the x-values go to negative infinity, the function’s values go to negative infinity.

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As the x-values go to positive infinity, the function’s values go to negative infinity.

As the x-values go to positive infinity, the function’s values go to zero.

the ans is the 2nd choice

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3 years ago

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