The textile industry has seen steady growth in the United States.<br> O True<br> O False

For a steel alloy it has been determined that a carburizing heat treatment of 15 h duration will raise the carbon concentration

Amiraneli [1.4K]

Answer:

135 hour

Explanation:

It is given that a carburizing heat treatment of 15 hour will raise the carbon concentration by 0.35 wt% at a point of 2 mm from the surface.

We have to find the time necessary to achieve the same concentration at a 6 mm position.

we know that $\frac{x_1^2}{Dt}=constant$ where x is distance and t is time .As the temperature is constant so D will be also constant

So $\frac{x_1^2}{t}=constant$

then $\frac{x_1^2}{t_1}=\frac{x_2^2}{t_2}$ we have given $x_1=2 mm\ ,t_1=15 hour\ ,x_2=6\ mm$ and we have to find $t_2$ putting all these value in equation

$\frac{2^2}{15}=\frac{6^2}{t_2}$

so $t_2=135\ hour$

5 0

3 years ago

The hot and cold inlet temperatures to a concentric tube heat exchanger are Th,i = 200°C, Tc,i = 100°C, respectively. The outlet

alexgriva [62]

Answer:Counter,

0.799,

1.921

Explanation:

Given data

$T_{h_i}=200^{\circ}C$

$T_{h_o}=120^{\circ}C$

$T_{c_i}=100^{\circ}C$

$T_{c_o}=125^{\circ}C$

Since outlet temperature of cold liquid is greater than hot fluid outlet temperature therefore it is counter flow heat exchanger

Equating Heat exchange

$m_hc_{ph}\left [ T_{h_i}-T_{h_o}\right ]=m_cc_{pc}\left [ T_{c_o}-T_{c_i}\right ]$

$\frac{m_hc_{ph}}{m_cc_{pc}}$ = $\frac{125-100}{200-120}=\frac{25}{80}=C\left ( capacity rate ratio\right )$

we can see that heat capacity of hot fluid is minimum

Also from energy balance

$Q=UA\Delta T_m=\left ( mc_p\right )_{h}\left ( T_{h_i}-T_{h_o}\right )$

$NTU=\frac{UA}{\left ( mc_p\right )_{h}}$ = $\frac{\left ( T_{h_i}-T_{h_o}\right )}{T_m}$

$T_m=\frac{\left ( 200-125\right )-\left ( 120-100\right )}{\ln \frac{75}{20}}$

$T_m=41.63^{\circ}C$

NTU=1.921

$And\ effectiveness \epsilon =\frac{1-exp\left ( -NTU\left ( 1-c\right )\right )}{1-c\left ( -NTU\left ( 1-c\right )\right )}$

$\epsilon =\frac{1-exp\left ( -1.921\left ( 1-0.3125\right )\right )}{1-0.3125exp\left ( -1.921\left ( 1-0.3125\right )\right )}$

$\epsilon =\frac{1-exp\left ( -1.32068\right )}{1-0.3125exp\left ( -1.32068\right )}$

$\epsilon =\frac{1-0.2669}{1-0.0834}$

$\epsilon =0.799$

5 0

3 years ago

Which of the following headlines about the French Revolution is not true?

Sever21 [200]

Answer:

d) "Napoleon Declares Himself Holy Roman Emperor"

Explanation:

The French Revolution is defined as a period of the major social upheaval which began in the year 1787 and lasted till year 1799. This revolution completely redefined the the very nature of the political power in France. and also the relationship between the rulers of France and the people they governed.

The 1789 Estates-General was the 1st meeting since year 1614 of the French Estates-General. It is a general assembly which represents the French estates of realm.

During the French revolution was at peak, the National Assembly issued the Declaration of the rights of the man to the public.

Maximilien Robespierre was considered to be one of the most influential figure and most important statesman during the French Revolution.

Thus all the options (a),(b) and (c) are headlines about the French Revolution, except option (d).

3 0

2 years ago

A 3-oz serving of roasted, skinless chicken breast contains 140 Cal, 27 g of protein, 3 g of fat, 13 mg of calcium, and 64 mg of

Art [367]

Answer:

Explanation:

a) Given C [ cal pro fat calc sod]

[140 27 3 13 64]

P = [cal pro fat calc sod]

[180 4 11 24 662]

B = [cal pro fat calc sod]

[50 5 1 82 20]

To find C+2P+3B = [140 27 3 13 64] + 2[180 4 11 24 662] + 3[50 5 1 82 20]

= [650 54 28 307 1448]

The entries represent skinless chicken breast , One-half cup of potato salad and One broccoli spear.

7 0

2 years ago

What is capillary action?

BARSIC [14]

Capillary action occurs When the adhesion to the walls stronger than dirt cohesive forces between a liquid molecules. the head towards Capillery action will take water in a uniform circular is limited by surface tension and, of course, gravity.

4 0

1 year ago

The textile industry has seen steady growth in the United States. O True O False