Answer:
Please select the correct statements concerning use of a centrifuge. (Select all that apply.)
(a) When placing test tubes in the centrifuge, what are the best practices?
- Wait until all positions on the rotor contain a test tube before activating the centrifuge.
- <u>Place test tubes containing approximately equal volumes in opposite positions on the rotor.</u>
- Carefully stopper the test tubes to ensure the liquids do not spill out.
- <u>Never put stoppers or other items in the centrifuge with your tubes</u>.
(b) When operating the centrifuge, students should do which of the following?
- <u>Make sure that the lid is completely shut and the safety knob is turned to engage the safety switch.</u>
- <u>Centrifuge for approximately 30 minutes</u>.
- Centrifuge for approximately 30 seconds.
- Mid-way through the process, open the lid of the centrifuge and check to be sure it is operating.
(c) When the centrifuge process is complete, students should do which of the following?
- <u>Using the eye-hole on top, monitor the spinning rate and open the lid only after the rotor has slowed significantly</u>.
- Immediately open the lid of the centrifuge to remove the test tubes before they are damaged.
- <u>Wait for the rotor to come to a complete stop before attempting to remove your test tubes</u>.
- Reach out and carefully slow the rotor with your hand so you may finish the lab faster.
Explanation:
I UNDERLINED and BOLD the answers that apply
Answer:
hypoeutectoid
Explanation:
ferrite: pure form of iron
cementite: It is iron carbide with 93.3% iron and 6.67% carbon
hypoeutectoid: Eutectoid steel with carbon fraction less than 0.8%
hypereutectoid: Eutectoid Steel with carbon content more than 0.8%
For the mentioned iron-carbide alloy,
% of carbon in iron-carbide alloy= percentage of cementite × percentage of carbon in cementite
% of carbon in iron-carbide alloy= 0.09× 0.0667
= 0.6%
so the alloy is hypoeutectoid
Answer:
False. Apart from heat loss, there are some other energy loss factors in electric motors.
They are:
(1) Core losses
(2) Windage losses
(3) Eddy Current
(4) Stray Load
Explanation:
STATOR RESISTANCE/HEAT LOSS(Heat loss I^2*R), which is the product of the square of the current multiplied by the resistance of the stator winding. The rotor also experiences I^2*R losses in the squirrel-cage rotor bars, called rotor resistance loss (rotor I^2*R).
CORE LOSSES also occur, originating in the lamination steel. Core losses include hysteresis losses, which result from reorientation of the magnetic field within the motor’s lamination steel, and eddy current losses resulting from electrical currents produced between laminations due to the presence of a changing magnetic field.
These electrical currents occur in both stator and rotor cores, but primarily in the stator, as these losses are proportional to the frequency of the current. The frequency of current in the rotor bars is only a small fraction of the line frequency, as the rotor current frequency is proportional to slip (the difference between operating speed and synchronous speed). Both the stator and rotor laminations have an insulated coating to reduce shorting losses (eddy current) from adjacent laminations.
Friction losses are from the motor bearings and lubrication.
WINDAGE LOSSES combine losses from the rotor spinning in air that creates drag and those from cooling fans used on the motor, along with friction losses in the bearings.
STRAY LOAD losses also are present.
Answer:
Have the power company install insulated sleeves (also known as “eels”) over power lines.
Wearing PPE is the only way to prevent being electrocuted
Explanation:
To prevent electrocution at workplace, employers can ensure that the power company install insulated sleeves (also known as “eels”) over power lines. Additionally, the employees should wear PPEs which are insulators to prevent electrocution.
Answer:
well my bff is trans so yes I guess xd