def Nishino_Yamazaki(x, rhol, rhog):
    r'''Calculates void fraction in two-phase flow according to the model
    presented in [1]_ as shown in [2]_.

    .. math::
        \alpha = 1 - \left(\frac{1-x}{x}\frac{\rho_g}{\rho_l}\right)^{0.5}
        \alpha_h^{0.5}
        
    Parameters
    ----------
    x : float
        Quality at the specific tube interval []
    rhol : float
        Density of the liquid [kg/m^3]
    rhog : float
        Density of the gas [kg/m^3]

    Returns
    -------
    alpha : float
        Void fraction (area of gas / total area of channel), [-]

    Notes
    -----
    [1]_ is in Japanese. 
    
    [3]_ either shows this model as iterative in terms of voidage, or forgot
    to add a H subscript to its second voidage term; the second is believed
    more likely.

    Examples
    --------
    >>> Nishino_Yamazaki(.4, 800, 2.5)
    0.931694583962682

    References
    ----------
    .. [1] Nishino, Haruo, and Yasaburo Yamazaki. "A New Method of Evaluating 
       Steam Volume Fractions in Boiling Systems." Journal of the Atomic Energy
       Society of Japan / Atomic Energy Society of Japan 5, no. 1 (1963): 
       39-46. doi:10.3327/jaesj.5.39.
    .. [2] Xu, Yu, and Xiande Fang. "Correlations of Void Fraction for Two-
       Phase Refrigerant Flow in Pipes." Applied Thermal Engineering 64, no. 
       1-2 (March 2014): 242–51. doi:10.1016/j.applthermaleng.2013.12.032. 
    .. [3] Woldesemayat, Melkamu A., and Afshin J. Ghajar. "Comparison of Void 
       Fraction Correlations for Different Flow Patterns in Horizontal and 
       Upward Inclined Pipes." International Journal of Multiphase Flow 33, 
       no. 4 (April 2007): 347-370. doi:10.1016/j.ijmultiphaseflow.2006.09.004.
    '''
    alpha_h = homogeneous(x, rhol, rhog)
    return 1 - ((1-x)*rhog/x/rhol)**0.5*alpha_h**0.5