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  2. Near-infrared spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Near-infrared_spectroscopy

    NIR absorption bands are typically 10–100 times weaker than the corresponding fundamental mid-IR absorption band.) [4] The lower absorption allows NIR radiation to penetrate much further into a sample than mid infrared radiation. Near-infrared spectroscopy is, therefore, not a particularly sensitive technique, but it can be very useful in ...

  3. Arrhenius equation - Wikipedia

    en.wikipedia.org/wiki/Arrhenius_equation

    In physical chemistry, the Arrhenius equation is a formula for the temperature dependence of reaction rates.The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that the van 't Hoff equation for the temperature dependence of equilibrium constants suggests such a formula for the rates of both forward and ...

  4. File:Temperature-relative humidity chart - PMV method.pdf

    en.wikipedia.org/wiki/File:Temperature-relative...

    The representation is made on a temperature-relative humidity, instead of a standard psychrometric chart. The comfort zone in blue represents the 90% of acceptability, which means the conditions between -0.5 and +0.5 PMV, or PPD < 10%.

  5. Normalized difference vegetation index - Wikipedia

    en.wikipedia.org/wiki/Normalized_difference...

    NDVI is functionally and linearly equivalent to the ratio NIR / (NIR+VIS), which ranges from 0 to 1 and is thus never negative nor limitless in range. [6] But the most important concept in the understanding of the NDVI algebraic formula is that, despite its name, it is a transformation of a spectral ratio (NIR/VIS), and it has no functional ...

  6. Near-infrared window in biological tissue - Wikipedia

    en.wikipedia.org/wiki/Near-infrared_window_in...

    The near-infrared (NIR) window (also known as optical window or therapeutic window) defines the range of wavelengths from 650 to 1350 nanometre (nm) where light has its maximum depth of penetration in tissue. [1] Within the NIR window, scattering is the most dominant light-tissue interaction, and therefore the propagating light becomes diffused ...

  7. Heisler chart - Wikipedia

    en.wikipedia.org/wiki/Heisler_Chart

    These first Heisler–Gröber charts were based upon the first term of the exact Fourier series solution for an infinite plane wall: (,) = = [⁡ + ⁡ ⁡], [1]where T i is the initial uniform temperature of the slab, T ∞ is the constant environmental temperature imposed at the boundary, x is the location in the plane wall, λ is the root of λ * tan λ = Bi, and α is thermal diffusivity.

  8. Diffuse reflectance spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Diffuse_reflectance...

    They developed a scheme, subject to the limitations of a two-flux model, to calculate the "scatter corrected absorbance" for a sample. [27] The decadic absorbance of a scattering sample is defined as −log 10 (R+T) or −log 10 (1−A). For a non scattering sample, R = 0, and the expression becomes −log 10 T or log(⁠ 1 / T ⁠), which is ...

  9. Goff–Gratch equation - Wikipedia

    en.wikipedia.org/wiki/Goff–Gratch_equation

    The Goff–Gratch equation is one (arguably the first reliable in history) amongst many experimental correlation proposed to estimate the saturation water vapor pressure at a given temperature. Another similar equation based on more recent data is the Arden Buck equation .