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  2. Isotope-ratio mass spectrometry - Wikipedia

    en.wikipedia.org/wiki/Isotope-ratio_mass...

    The two most common types of IRMS instruments are continuous flow [7] and dual inlet. In dual inlet IRMS, purified gas obtained from a sample is alternated rapidly with a standard gas (of known isotopic composition) by means of a system of valves, so that a number of comparison measurements are made of both gases. In continuous flow IRMS ...

  3. Gibbs free energy - Wikipedia

    en.wikipedia.org/wiki/Gibbs_free_energy

    In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol ) is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure–volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure.

  4. Heat equation - Wikipedia

    en.wikipedia.org/wiki/Heat_equation

    In general, the study of heat conduction is based on several principles. Heat flow is a form of energy flow, and as such it is meaningful to speak of the time rate of flow of heat into a region of space. The time rate of heat flow into a region V is given by a time-dependent quantity q t (V).

  5. First law of thermodynamics (fluid mechanics) - Wikipedia

    en.wikipedia.org/wiki/First_law_of...

    is the flow velocity. and is the heat flux vector. Because it expresses conservation of total energy, this is sometimes referred to as the energy balance equation of continuous media. The first law is used to derive the non-conservation form of the Navier–Stokes equations. [3]

  6. Energy minimization - Wikipedia

    en.wikipedia.org/wiki/Energy_minimization

    As described above, some method such as quantum mechanics can be used to calculate the energy, E(r) , the gradient of the PES, that is, the derivative of the energy with respect to the position of the atoms, ∂E/∂r and the second derivative matrix of the system, ∂∂E/∂r i ∂r j, also known as the Hessian matrix, which describes the curvature of the PES at r.

  7. Computational fluid dynamics - Wikipedia

    en.wikipedia.org/wiki/Computational_fluid_dynamics

    The resulting equations for density, momentum and energy can be manipulated into a pressure equation, giving the well-known sound wave equation. Shallow water equations (SW): Consider a flow near a wall where the wall-parallel length-scale of interest is much larger than the wall-normal length-scale of interest. Start with the EE.

  8. Bernoulli's principle - Wikipedia

    en.wikipedia.org/wiki/Bernoulli's_principle

    Bernoulli's principle can be used to calculate the lift force on an airfoil, if the behaviour of the fluid flow in the vicinity of the foil is known. For example, if the air flowing past the top surface of an aircraft wing is moving faster than the air flowing past the bottom surface, then Bernoulli's principle implies that the pressure on the ...

  9. First law of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/First_law_of_thermodynamics

    The rate of dissipation by friction of kinetic energy of localised bulk flow into internal energy, [65] [66] [67] whether in turbulent or in streamlined flow, is an important quantity in non-equilibrium thermodynamics. This is a serious difficulty for attempts to define entropy for time-varying spatially inhomogeneous systems.