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matrenka [14]
3 years ago
10

A wastewater is to be disinfected using ultraviolet (UV) light. Batch experiments find that the bacterial concentration decays u

nder UV light with first-order kinetics, with a half of the initial bacteria killed after 6.2 minutes of illumination. You need to design a reactor than can kill 99% of bacteria in a stream having a flow rate of 140, 000 gal/d. Assume that regardless of the reactor type it will be possible to have UV illumination conditions identical to those of the batch experiment. a. Based on the batch experiments, what is the first-order rate constant k for bacterial inactivation
Engineering
1 answer:
Ksivusya [100]3 years ago
7 0

Answer:

k = 0.1118 per min

Explanation:

Assume;

Initial number of bacteria = N0

Number of bacteria IN 'T' time = Nt

So,

Nt=N0e^{-kt}\\\\in\ 6.2 min\\\\\\frac{N0}{2}= N0e^{-k(6.2)}\\\\ln\frac{1}{2} = -k[6.2]

k = 0.1118 per min

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The knob at the front of the miter saw about belt height is used to adjust the miter angle true or false
irinina [24]

Answer:

True.

Explanation:

There are two basic saw angles, and the little nob on the front controls the one angle, and the one on the rear controls the other.

4 0
3 years ago
In a particular application involving airflow over a heated surface, the boundary layer temperature distribution may be approxim
diamong [38]

Answer:

Explanation:

In a particular application involving airflow over a heated surface, the boundary layer temperature distribution, T(y), may be approximated as:

[ T(y) - Ts / T∞ - Ts ] = 1 - e^( -Pr (U∞y / v) )

where y is the distance normal to the surface and the Prandtl number, Pr = Cpu/k = 0.7, is a dimensionless fluid property. a.) If T∞ = 380 K, Ts = 320 K, and U∞/v = 3600 m-1, what is the surface heat flux? Is this into or out of the wall? (~-5000 W/m2 , ?). b.) Plot the temperature distribution for y = 0 to y = 0.002 m. Set the axes ranges from 380 to 320 for temperature and from 0 to 0.002 m for y. Be sure to evaluate properties at the film temperature.

3 0
4 years ago
What is the last item on the vehicle starting checklist
larisa86 [58]

The last item on the vehicle starting checklist before a driver begins to travel is for the driver to release the service brake.

<h3>What does it mean to release the brake?</h3>

The Release Parking Brake message implies that your parking brake is said to be currently engaged and as such one needs to  release the parking brake before one can be able to drive the vehicle.

Therefore, The last item on the vehicle starting checklist before a driver begins to travel is for the driver to release the service brake.

See full question below

what is the last item on the vehicle starting checklist before a driver begins to travel?

Learn more about checklist from

brainly.com/question/16041035

#SPJ11

4 0
2 years ago
Which of the following uses pressure and flow to transmit power from one location to another?
lord [1]

Answer:

fluid power

Explanation:

fluids commonly used in fluid power are Oil, Water, Air, CO², and Nitrogen gas, fluid power is commonly confused with hydraulic power, which only uses liquids, fluid power uses either liquids or gases

5 0
2 years ago
Radio Frequency IDentification (RFID) tags and readers are a category of low-end wireless devices that people may not recognize
Fittoniya [83]

Answer:

See explaination.

Explanation:

Radio Frequency Identification (RFID) tags and readers uses the electromagnetic waves to identify and track the attached objects.

A tag is attached to the object which is to be identified or tracked, and reader is used to read the response and send the acknowledgement. Therefore, RFID tags and readers are used in many industries, passports, transportations and pet identification etc.

i.

RFID technology is used in smartcards, implants for pets, passports and library books to identify and track the persons, objects and pets etc.

Hence, we can say that option (i) is true.

ii.

Electronic Product Code (EPC) is a small code stored in the RFID tag. The code stored in the memory is 96 bits which are used to identify the organization which manages the data, unique number to identify the product and a number to identify the particular tag and etc.

EPC is a unique identification number, it can read and be written by the RFID reader. It is used in supply chains instead of a bar code even though expansive.

Hence, option (ii) is true.

iii.

Tags are used to identify and track the objects. It doesn’t belong to base stations and access points as a Wi-Fi networks.

Therefore, option (iii) is false.

iv.

The EPC Generation 2 RFID tag is used to improve the security by enabling the authentication features. It is not the similar way of data transmission in the other wireless situations.

Therefore, option (iv) is false.

Finally, the options (i) and (ii) are TRUE, while (iii) and (iv) are FALSE.

8 0
3 years ago
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