Small scratches from careless handling can cause failure under the strong forces imposed during a run.
They are molded from a flexible transparent plastic similar to polythene, are semi-conical in shape, with integral, hinged sealing caps.
It is known that the solution exists if and only if both k and n-k can be expressed as a sum of prime factors of n.[3] Small differences in mass of the load can result in a large force imbalance when the rotor is at high speed.
Modern centrifuges generally have features that prevent accidental contact with a moving rotor as the main lid is locked during the run.
Rotor failure, caused by mechanical stress from the high forces imparted by the motor, can occur due to manufacturing defects, routine wear and tear, or improper use and maintenance.
Uncontained rotor failures have shattered laboratory windows and destroyed refrigerators and cabinetry.
To reduce the risk of rotor failures, centrifuge manufacturers specify operating and maintenance procedures to ensure that rotors are regularly inspected and removed from service or derated (only operated at lower speeds) when they are past their expected lifetime.
After the run, the entire rotor assembly, including the lid, is removed from the centrifuge to the hood for further steps, maintaining the samples within a closed system.