# Tag Info

## Hot answers tagged mechanical-engineering

9

The ISO metric bolt has its diameter as the numeral part of the name. So M8 has a diameter of 8mm compared to that of the M4 bolt. So far scaling would make sense. However, the pitch of them is not proportional and would be wrong if you scale them. her is a figure from Wikipedia. Wiki .

6

We cannot obtain negative temperatures in thermodynamics calculations. Only the absolute scales prevent this. The two absolute scales are Kelvin and degrees Rankin. Here are the two calculations to show that both give the same result. I take that $r^{k-1} = 3.45$ based on using your Rankin values. $$T_f = (50 + 459.67)(3.45) = 1763\ ^o\mathrm{R}$$ T_i = ((...

2

That is just clearance between the Cotter and the Socket/Spigot. The Cotter pushes only one one side of the slot that it is fitted into, so there should be clearance on the opposite side to ensure this. "D" = the last two digits of the roll number, as shown at the bottom right. The image below is taken from https://www.youtube.com/watch?v=7sUjb-...

1

Your calculations are probably wrong. Peltier effect coolers are known to be extremely inefficient in converting electrical power into useful refrigeration. This is why they are not commonly used in things like home refrigerators and air conditioning units, where heat pumps are far more effective. The figure of merit for refrigeration efficiency in things ...

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