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Nesterboy [21]
1 year ago
10

By the end of the day, a 45 ft x 25 ft x 8 ft office has a carbon dioxide air level of 1,100 ppm. Determine the time in hours ne

cessary to reduce this concentration to ambient levels (approximately 325 ppm) assuming 20% of the return is "fresh" makeup air and there are two air changes per hour.
Engineering
1 answer:
Julli [10]1 year ago
6 0

The total hours that are necessary to reduce carbon dioxide level to at least 325 ppm are 4 hours.

<h3>How does carbon dioxide concentration change over time?</h3>

First hour:

  • 1,100 - 20 %
  • 1,100 - 220 = 880

  • 880 - 20%
  • 880 - 176 = 704

Second hour:

  • 704 - 20%
  • 704 - 140.8 =663.2

  • 663.2 - 20%
  • 663.2 - 132.64 = 530.56

Third hour:

  • 530.56 - 20%
  • 530.56 - 106.112 = 424.44

  • 424.44 - 20%
  • 424.44 - 84.88 = 339.55

Fourth hour:

  • 339.55 - 20%
  • 339.55 - 67.91 = 271.64

Learn more about carbon dioxide in: brainly.com/question/3049557

#SPJ1

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Water at a pressure of 3 bars enters a short horizontal convergent channel at 3.5 m/s. The upstream and downstream diameters of
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Answer:

The pressure reduces to 2.588 bars.

Explanation:

According to Bernoulli's theorem for ideal flow we have

\frac{P}{\gamma _{w}}+\frac{V^{2}}{2g}+z=constant

Since the losses are neglected thus applying this theorm between upper and lower porion we have

\frac{P_{u}}{\gamma _{w}}+\frac{V-{u}^{2}}{2g}+z_{u}=\frac{P_{L}}{\gamma _{w}}+\frac{V{L}^{2}}{2g}+z_{L}

Now by continuity equation we have

A_{u}v_{u}=A_{L}v_{L}\\\\\therefore v_{L}=\frac{A_{u}}{A_{L}}\times v_{u}\\\\v_{L}=\frac{d^{2}_{u}}{d^{2}_{L}}\times v_{u}\\\\\therefore v_{L}=\frac{2500}{900}\times 3.5\\\\\therefore v_{L}=9.72m/s

Applying the values in the Bernoulli's equation we get

\frac{P_{L}}{\gamma _{w}}=\frac{300000}{\gamma _{w}}+\frac{3.5^{2}}{2g}-\frac{9.72^{2}}{2g}(\because z_{L}=z_{u})\\\\\frac{P_{L}}{\gamma _{w}}=26.38m\\\\\therefore P_{L}=258885.8Pa\\\\\therefore P_{L}=2.588bars

6 0
3 years ago
1. Which of the following will cause a spark knock?
zlopas [31]

Answer:

I couldn't find options for your question online, but I can give you an explanation so you can choose the correct option.

Explanation:

A spark knock is a form of unpredictable behavior that occurs in combustion, that is, in the chemical reaction that occurs between oxygen and an oxidizable material. Such combustion is usually manifested by incandescence or flame.

The spark knock is a detonation that occurs when there is a lot of pressure in the fuel.

<u>Some situations in which this can happen are: </u>

  • Engine overloaded.
  • Maximum pressure in the cylinders.
  • Engine overheated.
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5 0
3 years ago
People with skills and training in areas such as marketing or accounting are an important part of the manufacturing industry.
adelina 88 [10]

Answer:

true

Explanation:

8 0
2 years ago
C#: Arrays - Ask the user how many students names they want to store. You will create two parallel arrays (e.g. 2 arrays with th
zhenek [66]

Answer:

  1. using System;      
  2. public class Program
  3. {
  4. public static void Main()
  5. {
  6.  Console.WriteLine("Enter number of students: ");
  7.  int num = Convert.ToInt32(Console.ReadLine());
  8.  string [] firstName = new string[num];
  9.  string [] lastName = new string[num];
  10.  
  11.  for(int i=0 ; i < num; i++){
  12.   Console.WriteLine("Enter first name: ");
  13.   firstName[i] = Console.ReadLine();
  14.    
  15.   Console.WriteLine("Enter last name: ");
  16.   lastName[i] = Console.ReadLine();
  17.  }
  18.  
  19.  for(int j=0; j < num; j++){
  20.   Console.WriteLine(lastName[j] + "," + firstName[j]);
  21.  }
  22. }
  23. }

Explanation:

Firstly, prompt user to enter number of student to be stored (Line 6- 7). Next, create two array, firstName and lastName with num size (Line 8-9).

Create a for-loop to repeat for num times and prompt user to enter first name and last name and then store them in the firstName and lastName array, respectively (Line 11 - 17).

Create another for loop to traverse through the lastName and firstName array and display the last name and first name by following the format given in the question (Line 19 - 21).

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3 years ago
Which regulations are related to guard rail height and dimensions and uniformity of stairs?
galina1969 [7]

Answer:

C.

structural safety

Explanation:

Guards protecting floor surfaces must be 36 inches in height, while guards for stairs must be 34 inches in height measured vertically from the tread nosing. A guard may also serve as the required handrail (34 to 38 inches high) provided the top rail meets the requirements for grip size.

4 0
3 years ago
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