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Example showing the difference between D 50 and the De Brouckere Mean on a typical volume-weighted particle size distribution. The De Brouckere mean diameter is the mean of a particle size distribution weighted by the volume (also called volume-weighted mean diameter, volume moment mean diameter. [1] or volume-weighted mean size [2]). It is the ...
Second, Richter arbitrarily defined the zero point of the scale to be where an earthquake at a distance of 100 km makes a maximum horizontal displacement of 0.001 mm (1 μm, or 0.00004 in.) on a seismogram recorded with a Wood-Anderson torsion seismograph. [14]
The Richter scale [1] (/ ˈ r ɪ k t ər /), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, [2] is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and presented in Richter's landmark 1935 paper, where he called it the "magnitude scale". [3]
Thus, a magnitude zero microearthquake has a seismic moment of approximately 1.1 × 10 9 N⋅m, while the Great Chilean earthquake of 1960, with an estimated moment magnitude of 9.4–9.6, had a seismic moment between 1.4 × 10 23 N⋅m and 2.8 × 10 23 N⋅m. Seismic moment magnitude (M wg or Das Magnitude Scale ) and moment magnitude (M w) scales
There is correlation between these scales, but not always absolute agreement since experiences and damage can be affected by many other factors, including the quality of earthquake engineering. Generally speaking, 0.001 g (0.01 m/s 2) – perceptible by people; 0.02 g (0.2 m/s 2) – people lose their balance
Therefore, the total number of subgroups of D n (n ≥ 1), is equal to d(n) + σ(n), where d(n) is the number of positive divisors of n and σ(n) is the sum of the positive divisors of n. See list of small groups for the cases n ≤ 8. The dihedral group of order 8 (D 4) is the smallest example of a group that is not a T-group.
Enjoy a classic game of Hearts and watch out for the Queen of Spades!
The final digit of a triangular number is 0, 1, 3, 5, 6, or 8, and thus such numbers never end in 2, 4, 7, or 9. A final 3 must be preceded by a 0 or 5; a final 8 must be preceded by a 2 or 7. In base 10, the digital root of a nonzero triangular number is always 1, 3, 6, or 9. Hence, every triangular number is either divisible by three or has a ...