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  2. Gibbs–Helmholtz equation - Wikipedia

    en.wikipedia.org/wiki/Gibbs–Helmholtz_equation

    The definition of the Gibbs function is = + where H is the enthalpy defined by: = +. Taking differentials of each definition to find dH and dG, then using the fundamental thermodynamic relation (always true for reversible or irreversible processes): = where S is the entropy, V is volume, (minus sign due to reversibility, in which dU = 0: work other than pressure-volume may be done and is equal ...

  3. Zero-inflated model - Wikipedia

    en.wikipedia.org/wiki/Zero-inflated_model

    Data with such an excess of zero counts are described as Zero-inflated. [4] Example histograms of zero-inflated Poisson distributions with mean of 5 or 10 and proportion of zero inflation of 0.2 or 0.5 are shown below, based on the R program ZeroInflPoiDistPlots.R from Bilder and Laughlin. [1]

  4. Hurdle model - Wikipedia

    en.wikipedia.org/wiki/Hurdle_model

    A hurdle model is a class of statistical models where a random variable is modelled using two parts, the first of which is the probability of attaining the value 0, and the second part models the probability of the non-zero values. The use of hurdle models is often motivated by an excess of zeroes in the data that is not sufficiently accounted ...

  5. Combining rules - Wikipedia

    en.wikipedia.org/wiki/Combining_rules

    The Lennard-Jones Potential is a mathematically simple model for the interaction between a pair of atoms or molecules. [3] [4] One of the most common forms is = [() ()] where ε is the depth of the potential well, σ is the finite distance at which the inter-particle potential is zero, r is the distance between the particles.

  6. Archimedes' principle - Wikipedia

    en.wikipedia.org/wiki/Archimedes'_principle

    The net force on the object must be zero if it is to be a situation of fluid statics such that Archimedes principle is applicable, and is thus the sum of the buoyancy force and the object's weight F net = 0 = m g − ρ f V disp g {\displaystyle F_{\text{net}}=0=mg-\rho _{f}V_{\text{disp}}g\,}

  7. Fugacity - Wikipedia

    en.wikipedia.org/wiki/Fugacity

    The fugacity of a condensed phase (liquid or solid) is defined the same way as for a gas: = ⁡ and = It is difficult to measure fugacity in a condensed phase directly; but if the condensed phase is saturated (in equilibrium with the vapor phase), the chemical potentials of the two phases are equal (μ c = μ g).

  8. Thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_equations

    Only one equation of state will not be sufficient to reconstitute the fundamental equation. All equations of state will be needed to fully characterize the thermodynamic system. Note that what is commonly called "the equation of state" is just the "mechanical" equation of state involving the Helmholtz potential and the volume:

  9. Activation energy - Wikipedia

    en.wikipedia.org/wiki/Activation_energy

    In the equation, k B and h are the Boltzmann and Planck constants, respectively. Although the equations look similar, it is important to note that the Gibbs energy contains an entropic term in addition to the enthalpic one. In the Arrhenius equation, this entropic term is accounted for by the pre-exponential factor A.