Answer:
One sheave means that you are using a single drum winder. They are the worst! Double drum winders control easier, brake better and are much more efficient. They save time ( two skips or cages) and can be clutched to perform faster shift transport. A single drum is slow, unbalanced and can be a nightmare if it trips out during hoisting. If the brake system is not perfect it can be a real hairy experience. For a runaway single drum, there is no counterbalance effect. It always runs to destruction. With a double drum, the driver still has a chance to control the winder to a certain extent and he has two sets of brakes to rely on. A single sheave could also mean a shaft with a single compartment. No second means of escape unless there are ladders or stairways. Not a very healthy situation.
Those are just a few points. I am sure much more can be said in favor of a double drum winder and two or more sheaves in the headgear. Most of the shafts I have worked at have multiple winders and up to ten compartments. They all have a small single drum service winder for emergencies and moves of personnel during shift times. They are referred to as the Mary - Annes. Apparently, the name originated in the U.K. where an aristocratic mine owner named the first such winder after his mistress.
Explanation:
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Answer:
The first argument listed after IF
Explanation:
When the two variables are listed next to each other, Excel will find and calculate the correlation between them.
A mail server. --------------------------------------------
Answer:d) Mono-alphabetic substitution rules
Explanation: Poly-alphabetic cipher is the cryptography that is done by using the many alphabets in substitutional way. They are supposed to have a good security because they use cipher text alphabets for the encryption and then decrypts it.
Substitution of the alphabets is done by the rule of the mono-alphabetic substitution rules.Other given options are incorrect because they are not used in the cryptography of the alphabetic cipher. Thus option (d) is the correct answer.
