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  2. Johnson's parabolic formula - Wikipedia

    en.wikipedia.org/wiki/Johnson's_parabolic_formula

    Graph of Johnson's parabola (plotted in red) against Euler's formula, with the transition point indicated. The area above the curve indicates failure. The Johnson parabola creates a new region of failure. In structural engineering, Johnson's parabolic formula is an empirically based equation for calculating the critical buckling stress of a column.

  3. Johnson–Nyquist noise - Wikipedia

    en.wikipedia.org/wiki/Johnson–Nyquist_noise

    Johnson–Nyquist noise (thermal noise, Johnson noise, or Nyquist noise) is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens regardless of any applied voltage.

  4. Euler's critical load - Wikipedia

    en.wikipedia.org/wiki/Euler's_critical_load

    This formula was derived in 1744 by the Swiss mathematician Leonhard Euler. [2] The column will remain straight for loads less than the critical load. The critical load is the greatest load that will not cause lateral deflection (buckling). For loads greater than the critical load, the column will deflect laterally.

  5. Why sudden loud booms sometimes occur when it's very ... - AOL

    www.aol.com/weather/why-sudden-loud-booms...

    When the temperature drops rapidly, within approximately 12 to 48 hours, water that has collected below the ground's surface freezes solid and expands quickly. This change cracks the ground ...

  6. ITU-R 468 noise weighting - Wikipedia

    en.wikipedia.org/wiki/ITU-R_468_noise_weighting

    ITU-R 468 (originally defined in CCIR recommendation 468-4, therefore formerly also known as CCIR weighting; sometimes referred to as CCIR-1k) is a standard relating to noise measurement, widely used when measuring noise in audio systems. The standard, [1] now referred to as ITU-R BS.468-4, defines a weighting filter curve, together with a ...

  7. Illusory continuity of tones - Wikipedia

    en.wikipedia.org/wiki/Illusory_continuity_of_tones

    The foreground and background noise must both be fitting to the criteria required for this illusion, and not just one or the other. [ 8 ] Essentially, a sound in the foreground that is interrupted without the gap being filled by some other background noise is perceived is discontinuous, but if another sound is present during this gap, the sound ...

  8. Physics of whistles - Wikipedia

    en.wikipedia.org/wiki/Physics_of_whistles

    The various modes are described by an integer n with an empirical delay constant β (near 0.25). The integer n is closely related to the number of vortices en route to the edge. It is clear from shadowgraphs that the fluctuating force near the downstream edge is the sound source.

  9. Y-factor - Wikipedia

    en.wikipedia.org/wiki/Y-factor

    The noise power at the output of the amplifier (i.e. the noise power coupled to an impedance-matched load that is connected to the amplifier output) is P out = Gk B (T R + T amp)B, where G is the amplifier power gain, and T amp is the amplifier noise temperature. In the Y-factor technique, P out is measured for two different, known values of T R.