import math


def evap_fract_mishra_kumar(theta_wtt, evaporated_fract, T, eb_T, dist_T):
    """
    Return the evaporated fraction by unit of time [/s]
    source:(Stiver and Mackay, 1984)

    Parameters
    ----------
    theta_wtt : Theta without the time [1/s]
    evaporated_fract : Fraction of oil evaporated []
    T : Temperature [K]
    eb_T : Initial boiling temperature [K]
    dist_T : Gradient of oil distribution curve [K]


    """
    if dist_T < 0:
        print("Distilation temperature negative!")
    return (theta_wtt *
            math.exp(6.3-10.3*((eb_T + dist_T * evaporated_fract) /T)))