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where t 1 and t 2 are the initial and final times (in seconds) chosen to maximize HIC, and acceleration a is measured in gs (standard gravity acceleration). The time duration, t 2 – t 1, is limited to a maximum value of 36 ms, [1] [2] usually 15 ms. [3] This means that the HIC includes the effects of head acceleration and the duration of the ...
A complicating matter regarding bolt thrust is that a cartridge case expands and deforms under high pressure and starts to "stick" to the chamber. This "friction-effect" can be accounted for with finite elements calculations on a computer, but it is a lot of specialized work and generally not worth the trouble. [2]
[1] [4] That is, if a given munitions design has a CEP of 100 m, when 100 munitions are targeted at the same point, an average of 50 will fall within a circle with a radius of 100 m about that point. There are associated concepts, such as the DRMS (distance root mean square), which is the square root of the average squared distance error, a ...
The piezo measuring device (transducer) is positioned at a distance of 25 millimetres (0.98 in) from the breech face when the length of the cartridge case permits that, including limits. When the length of the cartridge case is too short, pressure measurement will take place at a chambering specific defined shorter distance from the breech face ...
Bullet's Brinell hardness number (BHN) x 9.80665 N/kgf×10 6 mm²/m² = [N/m²] = pressure in pascals Bullet's BHN x 1422 = pressure in pounds per square inch [3]. The conversion factor of 1422 is mathematically derived in order to convert the pressure in kgf/mm 2 (the units used to measure BHN) to lbf/in 2 (the units used to measure cartridge pressure).
In mathematics, the second moment method is a technique used in probability theory and analysis to show that a random variable has positive probability of being positive. More generally, the "moment method" consists of bounding the probability that a random variable fluctuates far from its mean, by using its moments. [1]
Drilling Formula Sheets is a set of Drilling Formulas used commonly by drilling engineers in the onshore and offshore oil drilling industry. They are used as part of a key piece of engineering work called Well Control .
In oil field tubing, buttress thread is a pipe thread form designed to provide a tight hydraulic seal. The thread form is similar to that of Acme thread [10] but there are two distinct threaded portions of differing diameters and profiles, the larger having a wedging profile, with a tapered sealing portion in between the larger and smaller diameters.