;
;jeff snider, univeristy of wyoming, march 2006
;
pro scrit, salt_size, insoluble_size, sratio_crit, activation_size
;
common  constants, gascon, rho_h2o, mw_nh42so4, rho_nh42so4, sigma_0,      $
        sigma_t, dsigmadmolality_nh42so4, dsigmadmolality_nacl, mw_h2o,    $
        mw_nacl, rho_nacl, tkmelt, c_nh42so4, a_nh42so4, c_nacl, a_nacl,   $
        cp_air_o, cp_h2o_o, mw_air, gravity, p0, alpha, beta_local,        $
        gascon_h2o, cw_h2o_o, tk_o, lv_o, ew_o, tk_aerosol, salt_type,     $
        epsilon, c_twomey, k_twomey, aerosol_type, right_tail,             $
        gascon_air, tc_base, tk_base, p_base, h_start, hmax,               $
        r0, dt, rmin, rmax, coef, epsilon_aerosol, specific_volume_meas,   $
        nchan, mw_salt, rho_salt, a_salt, c_salt, specific_volume_base,    $
        dsigmadmolality_salt, rho_insoluble, volume_insoluble_to_soluble,  $
        mixrat_tot_1,r_1,geo_sigma_1,mixrat_tot_2,r_2,geo_sigma_2,         $
        tk_start,p_start,sratio_start,mixrat_tot_3,r_3,geo_sigma_3
;
tk = tk_aerosol
;
;reject requests with unrealistic values of salt_size
;
if salt_size lt 0.d then begin
 print,'*scrit*  ',salt_size
 stop
endif
;
if salt_type eq 'nacl' then begin
 wet_size      = (4.d*salt_size^3.d + insoluble_size^3.d)^(1.d/3.d)
endif else if salt_type eq 'nh42so4' then begin
 wet_size      = (2.d*salt_size^3.d + insoluble_size^3.d)^(1.d/3.d)
endif
;
crit_flag = 1
sratio_bdry, crit_flag, wet_size, salt_size, insoluble_size, sratio, loop_count, mw_on_mtot, rho_solution, $
             water_activity, molality, wgtf, sigma, kelvin
sratio_new = sratio
sratio_old = 0.99d * sratio
count = 0
;
;calculate the critical supersaturation
;
while sratio_new gt sratio_old do begin
 count = count + 1
 crit_flag = 1
 wet_size = wet_size*1.01d
 sratio_bdry, crit_flag, wet_size, salt_size, insoluble_size, sratio, loop_count, mw_on_mtot, rho_solution, $
              water_activity, molality, wgtf, sigma, kelvin
 sratio_old = sratio_new
 sratio_new = sratio
endwhile
;
;print, format = '(2i10,x,e12.3,2(x,f9.7),x,e12.3,x,f9.5,x,e12.3,2(x,f9.5))', count, loop_count, salt_size, sratio_old, sratio_new, $
;       2.*(sratio_new-sratio_old)/(sratio_old+sratio_new), water_activity, wet_size, molality, wgtf
;
sratio_crit     = sratio_old
activation_size = wet_size
;
;print, format = '(x,f9.5,x,e12.3,x,f9.5,x,e12.3,2(x,f9.5),x,f9.1)', sratio_old, salt_size, water_activity, wet_size, molality, wgtf, rho_solution
;
return
;
end