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  2. Prony brake - Wikipedia

    en.wikipedia.org/wiki/Prony_brake

    Prony brake dynamometers at a tractor contest in 1910 Schematic of a Prony brake Actual Prony Brake built for testing 5HP Steam Engine. The Prony brake is a simple device invented by Gaspard de Prony in 1821 to measure the torque produced by an engine. The term "brake horsepower" is one measurement of power derived from this method of measuring ...

  3. Dynamometer - Wikipedia

    en.wikipedia.org/wiki/Dynamometer

    Torque measurement is somewhat complicated since there are two machines in tandem - an inline torque transducer is the preferred method of torque measurement in this case. An eddy-current or waterbrake dynamometer, with electronic control combined with a variable frequency drive and AC induction motor, is a commonly used configuration of this type.

  4. Single photon absorptiometry - Wikipedia

    en.wikipedia.org/wiki/Single_photon_absorptiometry

    Single photon absorption is the earliest method to measure bone mineral density accurately. Its basic principle is that bone mineral density can be obtained by the law of absorption. In this law, the important parameters to be obtained are bone thickness, bone absorption coefficient and radiation intensity (or counting) after bone absorption.

  5. Specific absorption rate - Wikipedia

    en.wikipedia.org/wiki/Specific_absorption_rate

    Specific energy absorption rate (SAR) averaged over the whole body or over parts of the body, is defined as the rate at which energy is absorbed per unit mass of body tissue and is expressed in watts per kilogram (W/kg). Whole body SAR is a widely accepted measure for relating adverse thermal effects to RF exposure. [9]

  6. Absorption (electromagnetic radiation) - Wikipedia

    en.wikipedia.org/wiki/Absorption_(electromagnetic...

    By recording the attenuation of light for various wavelengths, an absorption spectrum can be obtained. In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy—and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy). [1]

  7. Absorption spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Absorption_spectroscopy

    Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field.

  8. Urbach energy - Wikipedia

    en.wikipedia.org/wiki/Urbach_energy

    The Urbach Energy, or Urbach Edge, is a parameter typically denoted , with dimensions of energy, used to quantify energetic disorder in the band edges of a semiconductor. It is evaluated by fitting the absorption coefficient as a function of energy to an exponential function.

  9. Schwarzschild's equation for radiative transfer - Wikipedia

    en.wikipedia.org/wiki/Schwarzschild's_equation...

    In "line-by-line" methods, the change in spectral intensity (dI λ, W/sr/m 2 /μm) is numerically integrated using a wavelength increment small enough (less than 1 nm) to accurately describe the shape of each absorption line. The HITRAN database contains the parameters needed to describe 7.4 million absorption lines for 47 GHGs and 120 ...