def DIPPR9H(ws, ks):
    r'''Calculates thermal conductivity of a liquid mixture according to
    mixing rules in [1]_ and also in [2]_.

    .. math::
        \lambda_m = \left( \sum_i w_i \lambda_i^{-2}\right)^{-1/2}

    Parameters
    ----------
    ws : float
        Mass fractions of components
    ks : float
        Liquid thermal conductivites of all components, [W/m/K]

    Returns
    -------
    kl : float
        Thermal conductivity of liquid mixture, [W/m/K]

    Notes
    -----
    This equation is entirely dimensionless; all dimensions cancel.
    The example is from [2]_; all results agree.
    The original source has not been reviewed.

    DIPPR Procedure 9H: Method for the Thermal Conductivity of Nonaqueous Liquid Mixtures

    Average deviations of 3%. for 118 nonaqueous systems with 817 data points.
    Max deviation 20%. According to DIPPR.

    Examples
    --------
    >>> DIPPR9H([0.258, 0.742], [0.1692, 0.1528])
    0.15657104706719646

    References
    ----------
    .. [1] Reid, Robert C.; Prausnitz, John M.; Poling, Bruce E. The
       Properties of Gases and Liquids. McGraw-Hill Companies, 1987.
    .. [2] Danner, Ronald P, and Design Institute for Physical Property Data.
       Manual for Predicting Chemical Process Design Data. New York, N.Y, 1982.
    '''
    if not none_and_length_check([ks, ws]):  # check same-length inputs
        raise Exception('Function inputs are incorrect format')
    return sum(ws[i]/ks[i]**2 for i in range(len(ws)))**(-0.5)
def DIPPR9H(ws, ks):
    r'''Calculates thermal conductivity of a liquid mixture according to
    mixing rules in [1]_ and also in [2]_.

    .. math::
        \lambda_m = \left( \sum_i w_i \lambda_i^{-2}\right)^{-1/2}

    Parameters
    ----------
    ws : float
        Mass fractions of components
    ks : float
        Liquid thermal conductivites of all components, [W/m/K]

    Returns
    -------
    kl : float
        Thermal conductivity of liquid mixture, [W/m/K]

    Notes
    -----
    This equation is entirely dimensionless; all dimensions cancel.
    The example is from [2]_; all results agree.
    The original source has not been reviewed.

    DIPPR Procedure 9H: Method for the Thermal Conductivity of Nonaqueous Liquid Mixtures

    Average deviations of 3%. for 118 nonaqueous systems with 817 data points.
    Max deviation 20%. According to DIPPR.

    Examples
    --------
    >>> DIPPR9H([0.258, 0.742], [0.1692, 0.1528])
    0.15657104706719646

    References
    ----------
    .. [1] Reid, Robert C.; Prausnitz, John M.; Poling, Bruce E. The
       Properties of Gases and Liquids. McGraw-Hill Companies, 1987.
    .. [2] Danner, Ronald P, and Design Institute for Physical Property Data.
       Manual for Predicting Chemical Process Design Data. New York, N.Y, 1982.
    '''
    if not none_and_length_check([ks, ws]):  # check same-length inputs
        raise Exception('Function inputs are incorrect format')
    return sum(ws[i]/ks[i]**2 for i in range(len(ws)))**(-0.5)
def DIPPR9H ( ws , ks ) : if not none_and_length_check ( [ ks , ws ] ) : # check same-length inputs raise Exception ( 'Function inputs are incorrect format' ) return sum ( ws [ i ] / ks [ i ] ** 2 for i in range ( len ( ws ) ) ) ** ( - 0.5 )
r'''Calculates thermal conductivity of a liquid mixture according to
    mixing rules in [1]_ and also in [2]_.

    .. math::
        \lambda_m = \left( \sum_i w_i \lambda_i^{-2}\right)^{-1/2}

    Parameters
    ----------
    ws : float
        Mass fractions of components
    ks : float
        Liquid thermal conductivites of all components, [W/m/K]

    Returns
    -------
    kl : float
        Thermal conductivity of liquid mixture, [W/m/K]

    Notes
    -----
    This equation is entirely dimensionless; all dimensions cancel.
    The example is from [2]_; all results agree.
    The original source has not been reviewed.

    DIPPR Procedure 9H: Method for the Thermal Conductivity of Nonaqueous Liquid Mixtures

    Average deviations of 3%. for 118 nonaqueous systems with 817 data points.
    Max deviation 20%. According to DIPPR.

    Examples
    --------
    >>> DIPPR9H([0.258, 0.742], [0.1692, 0.1528])
    0.15657104706719646

    References
    ----------
    .. [1] Reid, Robert C.; Prausnitz, John M.; Poling, Bruce E. The
       Properties of Gases and Liquids. McGraw-Hill Companies, 1987.
    .. [2] Danner, Ronald P, and Design Institute for Physical Property Data.
       Manual for Predicting Chemical Process Design Data. New York, N.Y, 1982.
r Calculates thermal conductivity of a liquid mixture according to mixing rules in [ 1 ] _ and also in [ 2 ] _ .