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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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In an air standard diesel cycle compression starts at 100kpa and 300k. the compression ratio is 16 to 1. The maximum cycle tempe
KIM [24]

Answer:

\eta=0.60

Explanation:

Given :Take \gamma=1.4 for air

      P_1=100 KPa  ,T_1=300K

  \frac{V_1}{V_2}=r ⇒ r=16

As we know that  

   T_2=T_1(r^{\gamma-1})

So T_2=300\times 16^{\gamma-1}

  T_2=909.42K

Now find the cut off ration \rho

      \rho=\frac{V_3}{V_2}  

         \frac{V_3}{V_2}=\frac{T_3}{T_2}

\rho=\frac{2031}{909.42}

 \rho=2.23

So efficiency of diesel engine

\eta =1-\dfrac{\rho^\gamma-1}{\gamma\times r^{\gamma-1}(\rho-1)}

Now by putting the all values

\eta =1-\dfrac{2.23^{1.4}-1}{1.4\times 16^{1.4-1}(2.23-1)}

So \eta=0.60

So the efficiency of diesel engine=0.60

     

7 0
3 years ago
6.28 A six-lane freeway (three lanes in each direction) in rolling terrain has 10-ft lanes and obstructions 4 ft from the right
dimulka [17.4K]

Answer:

Assume Base free flow speed (BFFS) = 70 mph

Lane width = 10 ft

Reduction in speed corresponding to lane width, fLW = 6.6 mph

Lateral Clearance = 4 ft

Reduction in speed corresponding to lateral clearance, fLC = 0.8 mph

Interchanges/Ramps = 9/ 6 miles = 1.5 /mile

Reduction in speed corresponding to Interchanges/ramps, fID = 5 mph

No. of lanes = 3

Reduction in speed corresponding to number of lanes, fN = 3 mph

Free Flow Speed (FFS) = BFFS – fLW – fLC – fN – fID = 70 – 6.6 – 0.8 – 3 – 5 = 54.6 mph

Peak Flow, V = 2000 veh/hr

Peak 15-min flow = 600 veh

Peak-hour factor = 2000/ (4*600) = 0.83

Trucks and Buses = 12 %

RVs = 6 %

Rolling Terrain

fHV = 1/ (1 + 0.12 (2.5-1) + 0.06 (2.0-1)) = 1/1.24 = 0.806

fP = 1.0

Peak Flow Rate, Vp = V / (PHV*n*fHV*fP) = 2000/ (0.83*3*0.806*1.0) = 996.54 ~ 997 veh/hr/ln

Vp < (3400 – 30 FFS)

S = FFS

S = 54.6 mph

Density = Vp/S = (997) / (54.6) = 18.26 veh/mi/ln

7 0
3 years ago
Explain the Corona discharge?​
rosijanka [135]

Answer:

• Corona discharge means <u> </u><u>neutralization</u><u> </u><u>of</u><u> </u><u>charge</u><u> </u><u>action</u><u> </u><u>at</u><u> </u><u>a</u><u> </u><u>sharp</u><u> </u><u>point</u>

example; a pear shaped conductor, lightening conductor, van de graaf generator.

Explanation:

• In corona discharge, When a sharp conductor is placed somewhere in open space. The charges of opposite chrage attract the opposite ions in the air around that conductor.

• This increases the charge density and electric field intensity at the sharp point, this neutralises the charge at sharp point hence a discharge known as corona discharge occurs.

.

8 0
3 years ago
Hey answr this sajida Yusof
Allisa [31]
What do u need? Rusbaisuwvwbs
5 0
3 years ago
Read 2 more answers
This graph shows the US unemployment rate from<br> August 2010 to November 2011
MrRissso [65]

The graph could help an economist predict that how many people will be out of work in the next year. The correct option is c.

<h3>What is unemployment?</h3>

Unemployment is the condition where people who have knowledge or eligible for doing job, but they are not getting job. Unemployment is the scarcity of jobs.

The options are attached:

a. how the government will address unemployment.

b. why workers might have a harder time finding jobs.

c. how many people will be out of work in the next year.

d. why producers might hire fewer workers in the future.

Thus, the correct option is c. how many people will be out of work in the next year.

Learn more about unemployment

brainly.com/question/14227610

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3 0
1 year ago
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