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  2. Power factor - Wikipedia

    en.wikipedia.org/wiki/Power_factor

    Power flow calculated from AC voltage and current entering a load having a zero power factor (ϕ = 90°, cos(ϕ) = 0).The blue line shows the instantaneous power entering the load: all of the energy received during the first (or third) quarter cycle is returned to the grid during the second (or fourth) quarter cycle, resulting in an average power flow (light blue line) of zero.

  3. Taft equation - Wikipedia

    en.wikipedia.org/wiki/Taft_equation

    where ⁡ is the ratio of the rate of the substituted reaction compared to the reference reaction, ρ* is the sensitivity factor for the reaction to polar effects, σ* is the polar substituent constant that describes the field and inductive effects of the substituent, δ is the sensitivity factor for the reaction to steric effects, and E s is ...

  4. Thermoelectric materials - Wikipedia

    en.wikipedia.org/wiki/Thermoelectric_materials

    The efficiency of a thermoelectric device for electricity generation is given by , defined as =.. The maximum efficiency of a thermoelectric device is typically described in terms of its device figure of merit where the maximum device efficiency is approximately given by [7] = + ¯ + ¯ +, where is the fixed temperature at the hot junction, is the fixed temperature at the surface being cooled ...

  5. Inductive effect - Wikipedia

    en.wikipedia.org/wiki/Inductive_effect

    The -I effect is a permanent effect & generally represented by an arrow on the bond. [citation needed] However, some groups, such as the alkyl group, are less electron-withdrawing than hydrogen and are therefore considered as electron-releasing/ electron-donating groups. This is electron-releasing character and is indicated by the +I effect. In ...

  6. Chemical kinetics - Wikipedia

    en.wikipedia.org/wiki/Chemical_kinetics

    Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a reaction occurs but in itself tells nothing about its rate.

  7. Alpha effect - Wikipedia

    en.wikipedia.org/wiki/Alpha_effect

    The alpha effect is also dependent on solvent but not in a predictable way: it can increase or decrease with solvent mix composition or even go through a maximum. [12] At least in some cases, the alpha effect has been observed to vanish if the reaction is conducted in the gas phase, leading some to conclude that it is primarily a solvation ...

  8. Bernoulli's principle - Wikipedia

    en.wikipedia.org/wiki/Bernoulli's_principle

    Bernoulli's principle is a key concept in fluid dynamics that relates pressure, density, speed and height. Bernoulli's principle states that an increase in the speed of a parcel of fluid occurs simultaneously with a decrease in either the pressure or the height above a datum. [1]:

  9. Lead - Wikipedia

    en.wikipedia.org/wiki/Lead

    This is attributable to relativistic effects, specifically the inert pair effect, which manifests itself when there is a large difference in electronegativity between lead and oxide, halide, or nitride anions, leading to a significant partial positive charge on lead. The result is a stronger contraction of the lead 6s orbital than is the case ...