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3 years ago

Question #2

Engineering

1 answer:

alexdok [17]3 years ago

5 0

Note, I answered from a general environmental perspective.

Answer:

True

Explanation:

It is quite true that because people are becoming more aware of our environment, environmental issues like global warming and climate change are now hotly debated topics among citizens.

Hence, it has created a need for scientists and engineers to help citizens and companies make valid decisions concerning products and practices that would reduce the effects of climate change.

For example, the following practices have been recommended:

cutting of greenhouse gases emitted by cars and companies.
shifting to eco-friendly building designs.
reinventing the waste recycling processes.

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astraxan [27]

Answer:

C. 420 x 594 millimeters

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3 years ago

What is an ip Number

gladu [14]

Answer:

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Explanation:

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3 years ago

The temperature at the bottom of a reservoir is TL = 280 K and the surface temperature is TH = 295 K. This temperature differenc

Tanzania [10]

a) For the thermal efficiency we have

$\eta_{th} = \frac{Q_{out}}{Q_{in}} = \frac{|W|}{|Q_h|}\\\eta_{th} = \frac{|W|}{|W|+|Q_2|}$

With the previously values we know that

$W=8kW$ and $Q_L = 1440/6kW$ (convert the min to sec)

Replacing the values

$\eta_{th}=\frac{8}{8+1440/6}=\frac{1}{31}\\\eta_{th}\% = 3.225\%$

b) We use the formula of carnot efficiency

$\eta_{th}=1-\frac{T_l}{T_h}\\\eta_{th}\% =(1-\frac{280}{295})*100\\\eta_{th}\%=5.085\%$

**Note that apply the formula of carnot cycle we need to consider that there is no exchange of heat, there is no friction and the reservior are completely insulated

8 0

3 years ago

What is the preferred approach to risk mitigation?

maw [93]

Answer:

The correct option is;

Terminate

Explanation:

Termination of the risk is equivalent to elimination of the risk by avoiding the activity that brings about the risk or by using a different process that does not include the risk observed in the previous process option

When the reward far outweigh the risk, it may be decided to terminate or eliminate the risk and miss the reward and also terminate the likelihood of the losses to be incurred.

7 0

3 years ago

The mechanical properties of a metal may be improved by incorporating fine particles of its oxide. Given that the moduli of elas

andriy [413]

Answer:

Uper Bound = 175.5 GPa, Lower Bound = 85.26 GPa

Explanation:

Rule of mixtures equations:

For a two-phase composite, modulus of elasticity upper-bound expression is,

E(c)(u) = E(m) x V(m) + E(p) x V(p)

Here, E(m) is the modulus of elasticity of matrix, E(p) is the modulus of elasticity of patriciate phase, E(c) is the modulus of elasticity of composite, V(m) is the volume fraction of matrix and V(p) is the volume fraction of composite.

For a two-phase composite, modulus of elasticity lower-bound expression is,

E(c)(l) = E(m) x E(p)/V(m) x E(p)+V(p) x E(m)

Consider the expression of rule of mixtures for upper-bound and calculate the modulus of elasticity upper-bound.

E(c)(u) = E(m) x V(m) + E(p) x V(p), (1)

Calculate the volume fraction of matrix.

V(m) + V(p) = 1

Substitute 0.35 for V(p).

V(m) + 0.35 = 1

V(m) = 0.65

From equation (1);

Substitute 60 GPa for E(m), 390GPa for E(p), 0.65 for V(m) and 0.35 for V(p).

E(c)(u )= E(m) x V(m) + E(p) x V(p)

E(c)(u) = (60 × 0.65) + (390 × 0.35)

E(c)(u) = 175.5 GPa

The modulus of elasticity upper-bound is 175.5GPa.

The modulus of elasticity of upper-bound can be calculated using the rule of mixtures expression. Since the sum of volume fraction of matrix and volume fraction of composite is equal to one V(m) + V(p) = 1. Substitute the value of volume fraction of matrix as 0.69 and obtain the volume fraction of matrix.

Consider the expression of rule of mixtures for lower-bound and calculate the modulus of elasticity upper-bound.

E(c)(l) = (E(m) x E(p))/ (V(m) x E(p) + V(p) x E(m))

Substitute 60 GPa for E(m), 390GPa for E(p), 0.65 for V(m) and 0.35 for V(p).

E(c)(l) = 60 × 390/(0.65 × 390) +(0.35 × 60)

E(c)(l) = 23400/274.5

E(c)(l) = 85.26 GPa

The modulus of elasticity lower-bound is 85.26 GPa.

8 0

4 years ago