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3 years ago

Do you understand entropy? Why the concept of entropy is difficult to engineering students?

Engineering

1 answer:

Darya [45]3 years ago

4 0

Answer:

Entropy:

Entropy is the measure of randomness of system.In other words the entropy is the measurement of tendency of system towards the disorder.

The concept of entropy arise from second law of thermodynamics.It is given as follows

$ds=\int \dfrac{dQ}{T}$

Entropy is a extensive property of system .

Entropy of universe = Entropy of system + Entropy of surrounding.

The entropy of the system can be zero,positive and negative.But entropy of the surrounding can not be negative,but it can be zero or positive.

Actually the concept of entropy is difficult to understand because we can not visualize because it is not like beam and like rods.Only we have to realize that there is entropy.

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1. A cylindrical casting is 0.3 m in diameter and 0.5 m in length. Another casting has the same metal is rectangular in cross-se

Lorico [155]

Based on the Chvorinov's rule, the diference in the solidification times of the two castings is 14.092 times the solidification time of the prism casting.

<h3>How to apply the Chvorinov's rule for casting processes</h3>

The Chvorinov's rule is an empirical method to estimate the cooling time of a casting in terms of a reference time. This rule states that cooling time (t) is directly proportional to the square of the volume (V), in cubic meters, divided to the surface area (A), in square meters. Now we proceed to model each casting:

<h3>Cylindrical casting</h3>

t = C · [0.25π · D² · L/(0.5π · D² + π · D · L)]²

t = C · [0.25 · D · L/(0.5 · D + L)]² (1)

<h3>Prism casting</h3>

t' = C · [3 · T² · L/(6 · T · L + 2 · T · L + 6 · T²)]²

t' = C · [3 · T · L/(8 · L + 6 · T)]² (2)

<h3>Relationship between the cross sections of both castings</h3>

3 · T² = 0.25π · D² (3)

Where:

t - Cooling time of the cylindrical casting, in time unit.
t' - Cooling time of the prism casting, in time unit.
C - Cooling factor, in time unit per square meter.
D - Diameter of the cylinder, in meters.
L - Length of the casting, in meters.
T - Width of the cross section of the prism casting, in meters.

If we know that D = 0.3 m, then the thickness of the prism casting is:

$T = \sqrt{\frac{\pi}{12} }\cdot D$

T ≈ 0.153 m

And (1) and (2) simplified into these forms:

<h3>Cylindrical casting</h3>

t = C · {0.25π · (0.3 m) · (0.5 m)/[0.5 · (0.3 m) + 0.5 m]}²

t = 0.0329 · C (1b)

<h3>Prism casting</h3>

t' = C · {3 · (0.153 m) · (0.5 m)/[8 · (0.5 m) + 6 · (0.153 m)]}²

t' = 0.00218 · C (2b)

Lastly we find the percentual difference in the solidification times of the two castings by using the following expression:

r = (1 - t'/t) × 100 %

r = (1 - 0.00218/0.0329) × 100 %

r = 93.374 %

The cooling time of the prism casting is 6.626 % of the solidification time of the cylindrical casting. The diference in the solidification times of the two castings is 14.092 times the solidification time of the prism casting. $\blacksquare$

To learn more on solidification times, we kindly invite to check this verified question: brainly.com/question/13536247

3 0

3 years ago

7.13 An intersection approach has a saturation flow rate of 1500 veh/h, and vehicles arrive at the approach at the rate of 800 v

Naddik [55]

Answer:

23.34 seconds

Explanation:

Flow rate = 1500

Arrival = 800 vehicle per hour

Cycle c = 60 seconds

Dissipation time = 10 seconds

Arrival time = 800/3600 = 0.2222

Rate of departure = 1500/3600 = 0.4167

Traffic density p = 0.2222/0.4167 = 0.5332

Real time = r

r + to + 10 = c

to = c-r-10 ----1

t0 = p*r/1-p ----2

Equate both 1 and 2

C-r-10 = p*r/1-p

60-r-10 = 0.5332r/1-0.5332

50-r = 0.5332r/0.4668

50-r = 1.1422r

50 = 1.1422r + r

50 = 2.1422r

r = 50/2.1422

r = 23.34 seconds

7 0

3 years ago

Roentgens are used to measure the amount of:

lesya692 [45]

Answer: Radiation

Explanation:

5 0

3 years ago

As a manufacturing automation engineer, you are asked to design a control system to automate a bottle-filler machine for bottled

Kipish [7]

Answer:

search up in google

Explanation:

8 0

3 years ago

Which of the following is true Select one: a. HTML stands for Hyper Text Markup Language is a language for describing web pages

Free_Kalibri [48]

Answer:

The answer to the above question is option C (HTML stands for Hyper Text Markup Language is a language for describing web pages and not a programming language).

Explanation:

HTML stands for Hypertext Markup Language.

HTML is a web language that allows users to create and structure sections, paragraphs, headings, links, and block quotes to define the structure of web pages by using various tags.

HTML describes the structure of a web page semantically and HTML elements are the building blocks of HTML pages.

HTML runs natively in every web browser. When working with HTML, simple code structures (tags and attributes) are used to mark up a website page. To identify HTML documents, they are files that end with a .html or .htm extension.

HTML is not a programming language, because it doesn't have the ability to be used as functional purposes, it can only be used for structural purposes. HTML only contains a set of rules for encoding documents in a format that is both human and machine readable.

HTML is also not a sequential programming language (Sequential languages are languages that were designed for writing sequential programs), as one cannot encode logical instructions to a computer processor using HTML.

7 0

3 years ago