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3 years ago

When in a flow do the streamlines, streak lines and timelines coincide?

Engineering

1 answer:

Wittaler [7]3 years ago

5 0

Answer:

In steady flow

Explanation:

As we know that flow maybe steady flow or maybe unsteady flow.In steady flow the properties does not change with time but on the other hand in unsteady flow the properties changes with time.Also in unsteady flow streamlines,streak lines and timelines all are different but on the other hand in steady flow flow streamlines,streak lines and timelines all are coincide.

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Which is a common refrigerant for domestic air conditioners?

Reptile [31]

Answer:

Explanation:

The most common HFC used in air conditioners is R-410A. This refrigerant is better than R-22 in terms of “Ozone Depletion” potential and energy efficiency, but it still causes global warming. A few more HFCs that are commonly used are: R-32 in Air Conditioners and R-134A in refrigerators.

4 0

3 years ago

Read 2 more answers

With a very precise volumetric measuring device, the volume of a liquid sample is determined to be 6.321 L (liters). Three stude

zheka24 [161]

Answer:

See explanation

Explanation:

Solution:-

- Three students measure the volume of a liquid sample which is 6.321 L.

- Each student measured the liquid sample 4 times. The data is provided for each measurement taken by each student as follows:

Students

Trial A B C

1 6.35 6.31 6.38

2 6.32 6.31 6.32

3 6.33 6.32 6.36

4 6.36 6.35 6.36

- We will define the two terms stated in the question " precision " and "accuracy"

- Precision refers to how close the values are to the sample mean. The dense cluster of data is termed to be more precise. We will use the knowledge of statistics and determine the sample standard deviation for each student.

- The mean measurement taken by each student would be as follows:

$E ( A ) = \frac{6.35 +6.32+6.33+6.36}{4} \\\\E ( A ) = 6.34\\\\E ( B ) = \frac{6.31 +6.31+6.32+6.35}{4} \\\\E ( B ) = 6.3225\\\\E ( C ) = \frac{6.38 +6.32+6.36+6.36}{4} \\\\E ( C ) = 6.355\\$

- The precision can be quantize in terms of variance or standard deviation of data. Therefore, we will calculate the variance of each data:

$Var ( A ) = \frac{6.35^2+6.32^2+6.33^2+6.36^2}{4} - 6.34^2\\\\Var ( A ) = 0.00025\\\\Var ( B ) = \frac{6.31^2+6.31^2+6.32^2+6.35^2}{4} - 6.3225^2\\\\Var ( B ) = 0.00026875\\\\Var ( C ) = \frac{6.38^2+6.32^2+6.36^2+6.36^2}{4} - 6.355^2\\\\Var ( C ) = 0.000475\\$

- We will rank each student sample data in term sof precision by using the values of variance. The smallest spread or variance corresponds to highest precision. So we have:

Var ( A ) < Var ( B ) < Var ( C )

most precise Least precise

- Accuracy refers to how close the sample mean is to the actual data value. Where the actual volume of the liquid specimen was given to be 6.321 L. We will evaluate the percentage difference of sample values obtained by each student .

$P ( A ) = \frac{6.34-6.321}{6.321}*100= 0.30058\\\\P ( B ) = \frac{6.3225-6.321}{6.321}*100= 0.02373\\\\P ( C ) = \frac{6.355-6.321}{6.321}*100= 0.53788\\$

- Now we will rank the sample means values obtained by each student relative to the actual value of the volume of liquid specimen with the help of percentage difference calculated above. The least percentage difference corresponds to the highest accuracy as follows:

P ( B ) < P ( A ) < P ( C )

most accurate least accurate

7 0

3 years ago

Propane burns at an equivalence ratio (ER) of 0.6, determine actual air-fuel ratio. If excess air is 5%, what will be the actual

dimaraw [331]

Answer:

when 5% excess air is supplied, moles of air supplied/moles of fuel = $23.81\times 1.05 =25$

Explanation:

Equivalence ratio = 0.6

Equivalence ratio = Actual air to fuel ratio (AAFR)/ stoichiometric air to fuel ratio SAFR

combustion reaction of propane is

$C_3H_8+ 5O_2 ----->3CO_2+4H_2O$

From above reaction, 1 mole of propane, from the reaction, 5 moles of oxygen required,

we know that air contains 21% O_2 and 79% N_2,

Therefore, moles of air based on stoichiometry $= \frac{5}{0.21} = 23.81$

Theoretical air to fuel ratio $= \frac{23.81}{1} = 23.81$

Given $\frac{AFR}{SFR} = 0.6$

Actual Air Fuel Ratio $= 23.81\times 0.6 = 14.3$

when 5% excess air is supplied, moles of air supplied/moles of fuel = $23.81\times 1.05 =25$

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3 years ago

How many broadcast or vlan is in this switchs and router ? and why?

Mnenie [13.5K]

Answer:The move from hubs (shared networks) to switched networks was a big improvement. Control over collisions, increased throughput, and the additional features offered by switches all provide ample incentive to upgrade infrastructure. But Layer 2 switched topologies are not without their difficulties. Extensive flat topologies can create congested broadcast domains and can involve compromises with security, redundancy, and load balancing. These issues can be mitigated through the use of virtual local area networks, or VLANs. This chapter provides the structure and operation of VLANs as standardized in IEEE 802.1Q. This discussion will include trunking methods used for interconnecting devices on VLANs.

Problem: Big Broadcast Domains

With any single shared media LAN segment, transmissions propagate through the entire segment. As traffic activity increases, more collisions occur and transmitting nodes must back off and wait before attempting the transmission again. While the collision is cleared, other nodes must also wait, further increasing congestion on the LAN segment.

The left side of Figure 4-1 depicts a small network in which PC 2 and PC 4 attempt transmissions at the same time. The frames propagate away from the computers, eventually colliding with each other somewhere in between the two nodes as shown on the right. The increased voltage and power then propagate away from the scene of the collision. Note that the collision does not continue past the switches on either end. These are the boundaries of the collision domain. This is one of the primary reasons for switches replacing hubs. Hubs (and access points) simply do not scale well as network traffic increases.

7 0

3 years ago

Stewart Parnell, the former CEO of the now-bankrupt Peanut Corporation of America, was charged with falsifying food safety repor

valentina_108 [34]

Answer:

The person responsible for the certifications could also be criminally responsible.

Explanation:

In the text above we can notice the variation of the salmonela results tests in which implies that someone deliberately changed the certificates.

The person who emitted the certificates before the tests even been ready indicates an indirect influence on the decision, either through bribery or internal agreements, this shows that they would work in conjunction with Stewart Parnell to release unsafe products.

8 0

3 years ago