uniform circular motion
| alveolar gas equation | The equation defining the steady state relation of the alveolar oxygen pressure to the barometric pressure, inspired gas composition, alveolar carbon dioxide pressure, and respiratory exchange ratio; the equation is used in various forms depending upon which simplifying assumptions are acceptable for different applications. (05 Mar 2000) |
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| arrhenius equation | This equation expresses the logarithmic relationship between the rate constant of a reaction and the reciprocal of the temperature (expressed in K). (09 Oct 1997) |
| Bohr's equation | An equation to calculate the respiratory dead space from the fact that gas expired from the lungs is a mixture of gas from the dead space and gas from the alveoli, i.e., the dead space volume divided by the tidal volume equals the difference between alveolar and mixed expired gas composition, divided by the difference between alveolar and inspired gas composition; gas composition can be expressed in any consistent units of concentration or partial pressure of oxygen or carbon dioxide. (05 Mar 2000) |
| boltzmann equation | <radiobiology> Fundamental equation in kinetic theory which describes the evolution of the distribution function. (See also Vlasov equation.) The actual equation is given in most texts covering plasma kinetic theory. (09 Oct 1997) |
| van't Hoff's equation | Equation for osmotic pressure of dilute solutions. See: van't Hoff's law. For any reaction, d(ln Keq/d(1/T) equals -dH/R where Keq is the equilibrium constant, T the absolute temperature, R is the universal gas constant, and dH is the change in enthalpy; thus, plotting ln Keq vs. 1/T allows the determination of dH. (05 Mar 2000) |
| Gay-Lussac's equation | The overall chemical equation for alcoholic fermentation; C6H12O6 = 2CO2 + 2CH3CH2OH. (05 Mar 2000) |
| rate equation | A mathematical expression for a chemical, radiochemical, or enzyme-catalyzed reaction. (05 Mar 2000) |
| Rayleigh equation | A ratio of red to green required by each observer to match spectral yellow. Synonym: Rayleigh test. (05 Mar 2000) |
| Gibbs-Helmholtz equation | An equation expressing the relationship in a galvanic cell between the chemical energy transformed and the maximal electromotive force obtainable. (05 Mar 2000) |
| Victor-Michaelis-Menten equation | <chemistry> Equation derived from a simple kinetic model for a single-substrate non-cooperative enzyme-catalyzed reaction that successfully accounts for the hyperbolic adsorption isotherm) relationship between substrate concentration and reaction rate. V = Vmax x S/(S + Km), where V is the initial velocity of the reaction, Km is the Michaelis constant, Vmax is the maximum rate approached by very high substrate concentrations and S is the initial substrate concentration. Similar equations can be derived for conditions in which the product is present and for multisubstrate enzymes. Synonym: Victor-Michaelis-Menten equation. (12 Jul 2000) |
| Goldman equation | An equation derived to predict membrane potentials in terms of the membrane's permeability to ions and their concentrations on either side. Synonym: constant field equation, Goldman-Hodgkin-Katz equation, GHK equation. (05 Mar 2000) |
| Goldman-Hodgkin-Katz equation | An equation derived to predict membrane potentials in terms of the membrane's permeability to ions and their concentrations on either side. Synonym: constant field equation, Goldman-Hodgkin-Katz equation, GHK equation. (05 Mar 2000) |
| grad-shafranov equation | <radiobiology> Reduced magnetohydrodynamic-equilibrium equation for an axisymmetric, toroidal plasma. (Similar reduced equations can be derived for the cases of helical symmetry and for the straight cylinder.) Analytic and numerical studies of these equations are important in exploring potential plasma configurations. The lowest order force balance in the plasma is simply that the Lorentz force must be balanced by the pressure force. This balance, combined with Maxwell's equations, determines the equilibrium configuration of the magnetic field. When the toroidal configuration is axisymmetric, and the equilibrium plasma flow is zero, the magnetic field may be written in terms of a stream function \psi that satisfies the Grad-Shafranov equation \Delta\psi = - \mu_0 R^2 p'(\psi) - FF'(\psi). Here p is the plasma pressure and f = R B_\phi. (R is the radial distance from the axis of the machine). In an axisymmetric torus, in the absence of equilibrium plasma fluid flows, the magnetic field may be written in terms of a scalar potential. When the plasma is in equilibrium (forces balance and the plasma is stationary), this scalar potential obeys a non-linear elliptic equation known as the Grad-Shafranov equation. (09 Oct 1997) |
| chemical equation | A representation of a chemical reaction in which chemical symbols represent reactants on the left side and products on the right side. (09 Oct 1997) |
| personal equation | A slight error in judgment, perceptual response, or action peculiar to the individual and so constant that it is usually possible to allow for it in accepting the person's statements or conclusions, thus arriving at approximate exactness; observed in persons whose work involves readings of events in time, such as navigators and air traffic controllers. (05 Mar 2000) |